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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Atmel AC97C
*
* Copyright (C) 2005-2009 Atmel Corporation
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/atmel_pdc.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/io.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/ac97_codec.h>
#include <sound/memalloc.h>
#include "ac97c.h"
/* Serialize access to opened variable */
static DEFINE_MUTEX(opened_mutex);
struct atmel_ac97c {
struct clk *pclk;
struct platform_device *pdev;
struct snd_pcm_substream *playback_substream;
struct snd_pcm_substream *capture_substream;
struct snd_card *card;
struct snd_pcm *pcm;
struct snd_ac97 *ac97;
struct snd_ac97_bus *ac97_bus;
u64 cur_format;
unsigned int cur_rate;
int playback_period, capture_period;
/* Serialize access to opened variable */
spinlock_t lock;
void __iomem *regs;
int irq;
int opened;
struct gpio_desc *reset_pin;
};
#define get_chip(card) ((struct atmel_ac97c *)(card)->private_data)
#define ac97c_writel(chip, reg, val) \
__raw_writel((val), (chip)->regs + AC97C_##reg)
#define ac97c_readl(chip, reg) \
__raw_readl((chip)->regs + AC97C_##reg)
static const struct snd_pcm_hardware atmel_ac97c_hw = {
.info = (SNDRV_PCM_INFO_MMAP
| SNDRV_PCM_INFO_MMAP_VALID
| SNDRV_PCM_INFO_INTERLEAVED
| SNDRV_PCM_INFO_BLOCK_TRANSFER
| SNDRV_PCM_INFO_JOINT_DUPLEX
| SNDRV_PCM_INFO_RESUME
| SNDRV_PCM_INFO_PAUSE),
.formats = (SNDRV_PCM_FMTBIT_S16_BE
| SNDRV_PCM_FMTBIT_S16_LE),
.rates = (SNDRV_PCM_RATE_CONTINUOUS),
.rate_min = 4000,
.rate_max = 48000,
.channels_min = 1,
.channels_max = 2,
.buffer_bytes_max = 2 * 2 * 64 * 2048,
.period_bytes_min = 4096,
.period_bytes_max = 4096,
.periods_min = 6,
.periods_max = 64,
};
static int atmel_ac97c_playback_open(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
mutex_lock(&opened_mutex);
chip->opened++;
runtime->hw = atmel_ac97c_hw;
if (chip->cur_rate) {
runtime->hw.rate_min = chip->cur_rate;
runtime->hw.rate_max = chip->cur_rate;
}
if (chip->cur_format)
runtime->hw.formats = pcm_format_to_bits(chip->cur_format);
mutex_unlock(&opened_mutex);
chip->playback_substream = substream;
return 0;
}
static int atmel_ac97c_capture_open(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
mutex_lock(&opened_mutex);
chip->opened++;
runtime->hw = atmel_ac97c_hw;
if (chip->cur_rate) {
runtime->hw.rate_min = chip->cur_rate;
runtime->hw.rate_max = chip->cur_rate;
}
if (chip->cur_format)
runtime->hw.formats = pcm_format_to_bits(chip->cur_format);
mutex_unlock(&opened_mutex);
chip->capture_substream = substream;
return 0;
}
static int atmel_ac97c_playback_close(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
mutex_lock(&opened_mutex);
chip->opened--;
if (!chip->opened) {
chip->cur_rate = 0;
chip->cur_format = 0;
}
mutex_unlock(&opened_mutex);
chip->playback_substream = NULL;
return 0;
}
static int atmel_ac97c_capture_close(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
mutex_lock(&opened_mutex);
chip->opened--;
if (!chip->opened) {
chip->cur_rate = 0;
chip->cur_format = 0;
}
mutex_unlock(&opened_mutex);
chip->capture_substream = NULL;
return 0;
}
static int atmel_ac97c_playback_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
/* Set restrictions to params. */
mutex_lock(&opened_mutex);
chip->cur_rate = params_rate(hw_params);
chip->cur_format = params_format(hw_params);
mutex_unlock(&opened_mutex);
return 0;
}
static int atmel_ac97c_capture_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *hw_params)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
/* Set restrictions to params. */
mutex_lock(&opened_mutex);
chip->cur_rate = params_rate(hw_params);
chip->cur_format = params_format(hw_params);
mutex_unlock(&opened_mutex);
return 0;
}
static int atmel_ac97c_playback_prepare(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
int block_size = frames_to_bytes(runtime, runtime->period_size);
unsigned long word = ac97c_readl(chip, OCA);
int retval;
chip->playback_period = 0;
word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
/* assign channels to AC97C channel A */
switch (runtime->channels) {
case 1:
word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
break;
case 2:
word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
| AC97C_CH_ASSIGN(PCM_RIGHT, A);
break;
default:
/* TODO: support more than two channels */
return -EINVAL;
}
ac97c_writel(chip, OCA, word);
/* configure sample format and size */
word = ac97c_readl(chip, CAMR);
if (chip->opened <= 1)
word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
else
word |= AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
switch (runtime->format) {
case SNDRV_PCM_FORMAT_S16_LE:
break;
case SNDRV_PCM_FORMAT_S16_BE:
word &= ~(AC97C_CMR_CEM_LITTLE);
break;
default:
word = ac97c_readl(chip, OCA);
word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
ac97c_writel(chip, OCA, word);
return -EINVAL;
}
/* Enable underrun interrupt on channel A */
word |= AC97C_CSR_UNRUN;
ac97c_writel(chip, CAMR, word);
/* Enable channel A event interrupt */
word = ac97c_readl(chip, IMR);
word |= AC97C_SR_CAEVT;
ac97c_writel(chip, IER, word);
/* set variable rate if needed */
if (runtime->rate != 48000) {
word = ac97c_readl(chip, MR);
word |= AC97C_MR_VRA;
ac97c_writel(chip, MR, word);
} else {
word = ac97c_readl(chip, MR);
word &= ~(AC97C_MR_VRA);
ac97c_writel(chip, MR, word);
}
retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_FRONT_DAC_RATE,
runtime->rate);
if (retval)
dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
runtime->rate);
/* Initialize and start the PDC */
writel(runtime->dma_addr, chip->regs + ATMEL_PDC_TPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_TCR);
writel(runtime->dma_addr + block_size, chip->regs + ATMEL_PDC_TNPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_TNCR);
return retval;
}
static int atmel_ac97c_capture_prepare(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
int block_size = frames_to_bytes(runtime, runtime->period_size);
unsigned long word = ac97c_readl(chip, ICA);
int retval;
chip->capture_period = 0;
word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
/* assign channels to AC97C channel A */
switch (runtime->channels) {
case 1:
word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
break;
case 2:
word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
| AC97C_CH_ASSIGN(PCM_RIGHT, A);
break;
default:
/* TODO: support more than two channels */
return -EINVAL;
}
ac97c_writel(chip, ICA, word);
/* configure sample format and size */
word = ac97c_readl(chip, CAMR);
if (chip->opened <= 1)
word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
else
word |= AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
switch (runtime->format) {
case SNDRV_PCM_FORMAT_S16_LE:
break;
case SNDRV_PCM_FORMAT_S16_BE:
word &= ~(AC97C_CMR_CEM_LITTLE);
break;
default:
word = ac97c_readl(chip, ICA);
word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
ac97c_writel(chip, ICA, word);
return -EINVAL;
}
/* Enable overrun interrupt on channel A */
word |= AC97C_CSR_OVRUN;
ac97c_writel(chip, CAMR, word);
/* Enable channel A event interrupt */
word = ac97c_readl(chip, IMR);
word |= AC97C_SR_CAEVT;
ac97c_writel(chip, IER, word);
/* set variable rate if needed */
if (runtime->rate != 48000) {
word = ac97c_readl(chip, MR);
word |= AC97C_MR_VRA;
ac97c_writel(chip, MR, word);
} else {
word = ac97c_readl(chip, MR);
word &= ~(AC97C_MR_VRA);
ac97c_writel(chip, MR, word);
}
retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_LR_ADC_RATE,
runtime->rate);
if (retval)
dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
runtime->rate);
/* Initialize and start the PDC */
writel(runtime->dma_addr, chip->regs + ATMEL_PDC_RPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_RCR);
writel(runtime->dma_addr + block_size, chip->regs + ATMEL_PDC_RNPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_RNCR);
return retval;
}
static int
atmel_ac97c_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
unsigned long camr, ptcr = 0;
camr = ac97c_readl(chip, CAMR);
switch (cmd) {
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_START:
ptcr = ATMEL_PDC_TXTEN;
camr |= AC97C_CMR_CENA | AC97C_CSR_ENDTX;
break;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_STOP:
ptcr |= ATMEL_PDC_TXTDIS;
if (chip->opened <= 1)
camr &= ~AC97C_CMR_CENA;
break;
default:
return -EINVAL;
}
ac97c_writel(chip, CAMR, camr);
writel(ptcr, chip->regs + ATMEL_PDC_PTCR);
return 0;
}
static int
atmel_ac97c_capture_trigger(struct snd_pcm_substream *substream, int cmd)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
unsigned long camr, ptcr = 0;
camr = ac97c_readl(chip, CAMR);
ptcr = readl(chip->regs + ATMEL_PDC_PTSR);
switch (cmd) {
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_START:
ptcr = ATMEL_PDC_RXTEN;
camr |= AC97C_CMR_CENA | AC97C_CSR_ENDRX;
break;
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_STOP:
ptcr |= ATMEL_PDC_RXTDIS;
if (chip->opened <= 1)
camr &= ~AC97C_CMR_CENA;
break;
default:
return -EINVAL;
}
ac97c_writel(chip, CAMR, camr);
writel(ptcr, chip->regs + ATMEL_PDC_PTCR);
return 0;
}
static snd_pcm_uframes_t
atmel_ac97c_playback_pointer(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
snd_pcm_uframes_t frames;
unsigned long bytes;
bytes = readl(chip->regs + ATMEL_PDC_TPR);
bytes -= runtime->dma_addr;
frames = bytes_to_frames(runtime, bytes);
if (frames >= runtime->buffer_size)
frames -= runtime->buffer_size;
return frames;
}
static snd_pcm_uframes_t
atmel_ac97c_capture_pointer(struct snd_pcm_substream *substream)
{
struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
struct snd_pcm_runtime *runtime = substream->runtime;
snd_pcm_uframes_t frames;
unsigned long bytes;
bytes = readl(chip->regs + ATMEL_PDC_RPR);
bytes -= runtime->dma_addr;
frames = bytes_to_frames(runtime, bytes);
if (frames >= runtime->buffer_size)
frames -= runtime->buffer_size;
return frames;
}
static const struct snd_pcm_ops atmel_ac97_playback_ops = {
.open = atmel_ac97c_playback_open,
.close = atmel_ac97c_playback_close,
.hw_params = atmel_ac97c_playback_hw_params,
.prepare = atmel_ac97c_playback_prepare,
.trigger = atmel_ac97c_playback_trigger,
.pointer = atmel_ac97c_playback_pointer,
};
static const struct snd_pcm_ops atmel_ac97_capture_ops = {
.open = atmel_ac97c_capture_open,
.close = atmel_ac97c_capture_close,
.hw_params = atmel_ac97c_capture_hw_params,
.prepare = atmel_ac97c_capture_prepare,
.trigger = atmel_ac97c_capture_trigger,
.pointer = atmel_ac97c_capture_pointer,
};
static irqreturn_t atmel_ac97c_interrupt(int irq, void *dev)
{
struct atmel_ac97c *chip = (struct atmel_ac97c *)dev;
irqreturn_t retval = IRQ_NONE;
u32 sr = ac97c_readl(chip, SR);
u32 casr = ac97c_readl(chip, CASR);
u32 cosr = ac97c_readl(chip, COSR);
u32 camr = ac97c_readl(chip, CAMR);
if (sr & AC97C_SR_CAEVT) {
struct snd_pcm_runtime *runtime;
int offset, next_period, block_size;
dev_dbg(&chip->pdev->dev, "channel A event%s%s%s%s%s%s\n",
(casr & AC97C_CSR_OVRUN) ? " OVRUN" : "",
(casr & AC97C_CSR_RXRDY) ? " RXRDY" : "",
(casr & AC97C_CSR_UNRUN) ? " UNRUN" : "",
(casr & AC97C_CSR_TXEMPTY) ? " TXEMPTY" : "",
(casr & AC97C_CSR_TXRDY) ? " TXRDY" : "",
!casr ? " NONE" : "");
if ((casr & camr) & AC97C_CSR_ENDTX) {
runtime = chip->playback_substream->runtime;
block_size = frames_to_bytes(runtime, runtime->period_size);
chip->playback_period++;
if (chip->playback_period == runtime->periods)
chip->playback_period = 0;
next_period = chip->playback_period + 1;
if (next_period == runtime->periods)
next_period = 0;
offset = block_size * next_period;
writel(runtime->dma_addr + offset, chip->regs + ATMEL_PDC_TNPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_TNCR);
snd_pcm_period_elapsed(chip->playback_substream);
}
if ((casr & camr) & AC97C_CSR_ENDRX) {
runtime = chip->capture_substream->runtime;
block_size = frames_to_bytes(runtime, runtime->period_size);
chip->capture_period++;
if (chip->capture_period == runtime->periods)
chip->capture_period = 0;
next_period = chip->capture_period + 1;
if (next_period == runtime->periods)
next_period = 0;
offset = block_size * next_period;
writel(runtime->dma_addr + offset, chip->regs + ATMEL_PDC_RNPR);
writel(block_size / 2, chip->regs + ATMEL_PDC_RNCR);
snd_pcm_period_elapsed(chip->capture_substream);
}
retval = IRQ_HANDLED;
}
if (sr & AC97C_SR_COEVT) {
dev_info(&chip->pdev->dev, "codec channel event%s%s%s%s%s\n",
(cosr & AC97C_CSR_OVRUN) ? " OVRUN" : "",
(cosr & AC97C_CSR_RXRDY) ? " RXRDY" : "",
(cosr & AC97C_CSR_TXEMPTY) ? " TXEMPTY" : "",
(cosr & AC97C_CSR_TXRDY) ? " TXRDY" : "",
!cosr ? " NONE" : "");
retval = IRQ_HANDLED;
}
if (retval == IRQ_NONE) {
dev_err(&chip->pdev->dev, "spurious interrupt sr 0x%08x "
"casr 0x%08x cosr 0x%08x\n", sr, casr, cosr);
}
return retval;
}
static const struct ac97_pcm at91_ac97_pcm_defs[] = {
/* Playback */
{
.exclusive = 1,
.r = { {
.slots = ((1 << AC97_SLOT_PCM_LEFT)
| (1 << AC97_SLOT_PCM_RIGHT)),
} },
},
/* PCM in */
{
.stream = 1,
.exclusive = 1,
.r = { {
.slots = ((1 << AC97_SLOT_PCM_LEFT)
| (1 << AC97_SLOT_PCM_RIGHT)),
} }
},
/* Mic in */
{
.stream = 1,
.exclusive = 1,
.r = { {
.slots = (1<<AC97_SLOT_MIC),
} }
},
};
static int atmel_ac97c_pcm_new(struct atmel_ac97c *chip)
{
struct snd_pcm *pcm;
struct snd_pcm_hardware hw = atmel_ac97c_hw;
int retval;
retval = snd_ac97_pcm_assign(chip->ac97_bus,
ARRAY_SIZE(at91_ac97_pcm_defs),
at91_ac97_pcm_defs);
if (retval)
return retval;
retval = snd_pcm_new(chip->card, chip->card->shortname, 0, 1, 1, &pcm);
if (retval)
return retval;
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &atmel_ac97_capture_ops);
snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &atmel_ac97_playback_ops);
snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
&chip->pdev->dev, hw.periods_min * hw.period_bytes_min,
hw.buffer_bytes_max);
pcm->private_data = chip;
pcm->info_flags = 0;
strcpy(pcm->name, chip->card->shortname);
chip->pcm = pcm;
return 0;
}
static int atmel_ac97c_mixer_new(struct atmel_ac97c *chip)
{
struct snd_ac97_template template;
memset(&template, 0, sizeof(template));
template.private_data = chip;
return snd_ac97_mixer(chip->ac97_bus, &template, &chip->ac97);
}
static void atmel_ac97c_write(struct snd_ac97 *ac97, unsigned short reg,
unsigned short val)
{
struct atmel_ac97c *chip = get_chip(ac97);
unsigned long word;
int timeout = 40;
word = (reg & 0x7f) << 16 | val;
do {
if (ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) {
ac97c_writel(chip, COTHR, word);
return;
}
udelay(1);
} while (--timeout);
dev_dbg(&chip->pdev->dev, "codec write timeout\n");
}
static unsigned short atmel_ac97c_read(struct snd_ac97 *ac97,
unsigned short reg)
{
struct atmel_ac97c *chip = get_chip(ac97);
unsigned long word;
int timeout = 40;
int write = 10;
word = (0x80 | (reg & 0x7f)) << 16;
if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0)
ac97c_readl(chip, CORHR);
retry_write:
timeout = 40;
do {
if ((ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) != 0) {
ac97c_writel(chip, COTHR, word);
goto read_reg;
}
udelay(10);
} while (--timeout);
if (!--write)
goto timed_out;
goto retry_write;
read_reg:
do {
if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0) {
unsigned short val = ac97c_readl(chip, CORHR);
return val;
}
udelay(10);
} while (--timeout);
if (!--write)
goto timed_out;
goto retry_write;
timed_out:
dev_dbg(&chip->pdev->dev, "codec read timeout\n");
return 0xffff;
}
static void atmel_ac97c_reset(struct atmel_ac97c *chip)
{
ac97c_writel(chip, MR, 0);
ac97c_writel(chip, MR, AC97C_MR_ENA);
ac97c_writel(chip, CAMR, 0);
ac97c_writel(chip, COMR, 0);
if (!IS_ERR(chip->reset_pin)) {
gpiod_set_value(chip->reset_pin, 0);
/* AC97 v2.2 specifications says minimum 1 us. */
udelay(2);
gpiod_set_value(chip->reset_pin, 1);
} else {
ac97c_writel(chip, MR, AC97C_MR_WRST | AC97C_MR_ENA);
udelay(2);
ac97c_writel(chip, MR, AC97C_MR_ENA);
}
}
static const struct of_device_id atmel_ac97c_dt_ids[] = {
{ .compatible = "atmel,at91sam9263-ac97c", },
{ }
};
MODULE_DEVICE_TABLE(of, atmel_ac97c_dt_ids);
static int atmel_ac97c_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct snd_card *card;
struct atmel_ac97c *chip;
struct resource *regs;
struct clk *pclk;
static const struct snd_ac97_bus_ops ops = {
.write = atmel_ac97c_write,
.read = atmel_ac97c_read,
};
int retval;
int irq;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_dbg(&pdev->dev, "no memory resource\n");
return -ENXIO;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_dbg(&pdev->dev, "could not get irq: %d\n", irq);
return irq;
}
pclk = clk_get(&pdev->dev, "ac97_clk");
if (IS_ERR(pclk)) {
dev_dbg(&pdev->dev, "no peripheral clock\n");
return PTR_ERR(pclk);
}
retval = clk_prepare_enable(pclk);
if (retval)
goto err_prepare_enable;
retval = snd_card_new(&pdev->dev, SNDRV_DEFAULT_IDX1,
SNDRV_DEFAULT_STR1, THIS_MODULE,
sizeof(struct atmel_ac97c), &card);
if (retval) {
dev_dbg(&pdev->dev, "could not create sound card device\n");
goto err_snd_card_new;
}
chip = get_chip(card);
retval = request_irq(irq, atmel_ac97c_interrupt, 0, "AC97C", chip);
if (retval) {
dev_dbg(&pdev->dev, "unable to request irq %d\n", irq);
goto err_request_irq;
}
chip->irq = irq;
spin_lock_init(&chip->lock);
strcpy(card->driver, "Atmel AC97C");
strcpy(card->shortname, "Atmel AC97C");
sprintf(card->longname, "Atmel AC97 controller");
chip->card = card;
chip->pclk = pclk;
chip->pdev = pdev;
chip->regs = ioremap(regs->start, resource_size(regs));
if (!chip->regs) {
dev_dbg(&pdev->dev, "could not remap register memory\n");
retval = -ENOMEM;
goto err_ioremap;
}
chip->reset_pin = devm_gpiod_get_index(dev, "ac97", 2, GPIOD_OUT_HIGH);
if (IS_ERR(chip->reset_pin))
dev_dbg(dev, "reset pin not available\n");
atmel_ac97c_reset(chip);
/* Enable overrun interrupt from codec channel */
ac97c_writel(chip, COMR, AC97C_CSR_OVRUN);
ac97c_writel(chip, IER, ac97c_readl(chip, IMR) | AC97C_SR_COEVT);
retval = snd_ac97_bus(card, 0, &ops, chip, &chip->ac97_bus);
if (retval) {
dev_dbg(&pdev->dev, "could not register on ac97 bus\n");
goto err_ac97_bus;
}
retval = atmel_ac97c_mixer_new(chip);
if (retval) {
dev_dbg(&pdev->dev, "could not register ac97 mixer\n");
goto err_ac97_bus;
}
retval = atmel_ac97c_pcm_new(chip);
if (retval) {
dev_dbg(&pdev->dev, "could not register ac97 pcm device\n");
goto err_ac97_bus;
}
retval = snd_card_register(card);
if (retval) {
dev_dbg(&pdev->dev, "could not register sound card\n");
goto err_ac97_bus;
}
platform_set_drvdata(pdev, card);
dev_info(&pdev->dev, "Atmel AC97 controller at 0x%p, irq = %d\n",
chip->regs, irq);
return 0;
err_ac97_bus:
iounmap(chip->regs);
err_ioremap:
free_irq(irq, chip);
err_request_irq:
snd_card_free(card);
err_snd_card_new:
clk_disable_unprepare(pclk);
err_prepare_enable:
clk_put(pclk);
return retval;
}
#ifdef CONFIG_PM_SLEEP
static int atmel_ac97c_suspend(struct device *pdev)
{
struct snd_card *card = dev_get_drvdata(pdev);
struct atmel_ac97c *chip = card->private_data;
clk_disable_unprepare(chip->pclk);
return 0;
}
static int atmel_ac97c_resume(struct device *pdev)
{
struct snd_card *card = dev_get_drvdata(pdev);
struct atmel_ac97c *chip = card->private_data;
int ret = clk_prepare_enable(chip->pclk);
return ret;
}
static SIMPLE_DEV_PM_OPS(atmel_ac97c_pm, atmel_ac97c_suspend, atmel_ac97c_resume);
#define ATMEL_AC97C_PM_OPS &atmel_ac97c_pm
#else
#define ATMEL_AC97C_PM_OPS NULL
#endif
static void atmel_ac97c_remove(struct platform_device *pdev)
{
struct snd_card *card = platform_get_drvdata(pdev);
struct atmel_ac97c *chip = get_chip(card);
ac97c_writel(chip, CAMR, 0);
ac97c_writel(chip, COMR, 0);
ac97c_writel(chip, MR, 0);
clk_disable_unprepare(chip->pclk);
clk_put(chip->pclk);
iounmap(chip->regs);
free_irq(chip->irq, chip);
snd_card_free(card);
}
static struct platform_driver atmel_ac97c_driver = {
.probe = atmel_ac97c_probe,
.remove_new = atmel_ac97c_remove,
.driver = {
.name = "atmel_ac97c",
.pm = ATMEL_AC97C_PM_OPS,
.of_match_table = atmel_ac97c_dt_ids,
},
};
module_platform_driver(atmel_ac97c_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for Atmel AC97 controller");
MODULE_AUTHOR("Hans-Christian Egtvedt <[email protected]>");
| linux-master | sound/atmel/ac97c.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* tsacct.c - System accounting over taskstats interface
*
* Copyright (C) Jay Lan, <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/sched/cputime.h>
#include <linux/tsacct_kern.h>
#include <linux/acct.h>
#include <linux/jiffies.h>
#include <linux/mm.h>
/*
* fill in basic accounting fields
*/
void bacct_add_tsk(struct user_namespace *user_ns,
struct pid_namespace *pid_ns,
struct taskstats *stats, struct task_struct *tsk)
{
const struct cred *tcred;
u64 utime, stime, utimescaled, stimescaled;
u64 now_ns, delta;
time64_t btime;
BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
/* calculate task elapsed time in nsec */
now_ns = ktime_get_ns();
/* store whole group time first */
delta = now_ns - tsk->group_leader->start_time;
/* Convert to micro seconds */
do_div(delta, NSEC_PER_USEC);
stats->ac_tgetime = delta;
delta = now_ns - tsk->start_time;
do_div(delta, NSEC_PER_USEC);
stats->ac_etime = delta;
/* Convert to seconds for btime (note y2106 limit) */
btime = ktime_get_real_seconds() - div_u64(delta, USEC_PER_SEC);
stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
stats->ac_btime64 = btime;
if (tsk->flags & PF_EXITING)
stats->ac_exitcode = tsk->exit_code;
if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC))
stats->ac_flag |= AFORK;
if (tsk->flags & PF_SUPERPRIV)
stats->ac_flag |= ASU;
if (tsk->flags & PF_DUMPCORE)
stats->ac_flag |= ACORE;
if (tsk->flags & PF_SIGNALED)
stats->ac_flag |= AXSIG;
stats->ac_nice = task_nice(tsk);
stats->ac_sched = tsk->policy;
stats->ac_pid = task_pid_nr_ns(tsk, pid_ns);
stats->ac_tgid = task_tgid_nr_ns(tsk, pid_ns);
rcu_read_lock();
tcred = __task_cred(tsk);
stats->ac_uid = from_kuid_munged(user_ns, tcred->uid);
stats->ac_gid = from_kgid_munged(user_ns, tcred->gid);
stats->ac_ppid = pid_alive(tsk) ?
task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
rcu_read_unlock();
task_cputime(tsk, &utime, &stime);
stats->ac_utime = div_u64(utime, NSEC_PER_USEC);
stats->ac_stime = div_u64(stime, NSEC_PER_USEC);
task_cputime_scaled(tsk, &utimescaled, &stimescaled);
stats->ac_utimescaled = div_u64(utimescaled, NSEC_PER_USEC);
stats->ac_stimescaled = div_u64(stimescaled, NSEC_PER_USEC);
stats->ac_minflt = tsk->min_flt;
stats->ac_majflt = tsk->maj_flt;
strncpy(stats->ac_comm, tsk->comm, sizeof(stats->ac_comm));
}
#ifdef CONFIG_TASK_XACCT
#define KB 1024
#define MB (1024*KB)
#define KB_MASK (~(KB-1))
/*
* fill in extended accounting fields
*/
void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
{
struct mm_struct *mm;
/* convert pages-nsec/1024 to Mbyte-usec, see __acct_update_integrals */
stats->coremem = p->acct_rss_mem1 * PAGE_SIZE;
do_div(stats->coremem, 1000 * KB);
stats->virtmem = p->acct_vm_mem1 * PAGE_SIZE;
do_div(stats->virtmem, 1000 * KB);
mm = get_task_mm(p);
if (mm) {
/* adjust to KB unit */
stats->hiwater_rss = get_mm_hiwater_rss(mm) * PAGE_SIZE / KB;
stats->hiwater_vm = get_mm_hiwater_vm(mm) * PAGE_SIZE / KB;
mmput(mm);
}
stats->read_char = p->ioac.rchar & KB_MASK;
stats->write_char = p->ioac.wchar & KB_MASK;
stats->read_syscalls = p->ioac.syscr & KB_MASK;
stats->write_syscalls = p->ioac.syscw & KB_MASK;
#ifdef CONFIG_TASK_IO_ACCOUNTING
stats->read_bytes = p->ioac.read_bytes & KB_MASK;
stats->write_bytes = p->ioac.write_bytes & KB_MASK;
stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes & KB_MASK;
#else
stats->read_bytes = 0;
stats->write_bytes = 0;
stats->cancelled_write_bytes = 0;
#endif
}
#undef KB
#undef MB
static void __acct_update_integrals(struct task_struct *tsk,
u64 utime, u64 stime)
{
u64 time, delta;
if (!likely(tsk->mm))
return;
time = stime + utime;
delta = time - tsk->acct_timexpd;
if (delta < TICK_NSEC)
return;
tsk->acct_timexpd = time;
/*
* Divide by 1024 to avoid overflow, and to avoid division.
* The final unit reported to userspace is Mbyte-usecs,
* the rest of the math is done in xacct_add_tsk.
*/
tsk->acct_rss_mem1 += delta * get_mm_rss(tsk->mm) >> 10;
tsk->acct_vm_mem1 += delta * READ_ONCE(tsk->mm->total_vm) >> 10;
}
/**
* acct_update_integrals - update mm integral fields in task_struct
* @tsk: task_struct for accounting
*/
void acct_update_integrals(struct task_struct *tsk)
{
u64 utime, stime;
unsigned long flags;
local_irq_save(flags);
task_cputime(tsk, &utime, &stime);
__acct_update_integrals(tsk, utime, stime);
local_irq_restore(flags);
}
/**
* acct_account_cputime - update mm integral after cputime update
* @tsk: task_struct for accounting
*/
void acct_account_cputime(struct task_struct *tsk)
{
__acct_update_integrals(tsk, tsk->utime, tsk->stime);
}
/**
* acct_clear_integrals - clear the mm integral fields in task_struct
* @tsk: task_struct whose accounting fields are cleared
*/
void acct_clear_integrals(struct task_struct *tsk)
{
tsk->acct_timexpd = 0;
tsk->acct_rss_mem1 = 0;
tsk->acct_vm_mem1 = 0;
}
#endif
| linux-master | kernel/tsacct.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* latencytop.c: Latency display infrastructure
*
* (C) Copyright 2008 Intel Corporation
* Author: Arjan van de Ven <[email protected]>
*/
/*
* CONFIG_LATENCYTOP enables a kernel latency tracking infrastructure that is
* used by the "latencytop" userspace tool. The latency that is tracked is not
* the 'traditional' interrupt latency (which is primarily caused by something
* else consuming CPU), but instead, it is the latency an application encounters
* because the kernel sleeps on its behalf for various reasons.
*
* This code tracks 2 levels of statistics:
* 1) System level latency
* 2) Per process latency
*
* The latency is stored in fixed sized data structures in an accumulated form;
* if the "same" latency cause is hit twice, this will be tracked as one entry
* in the data structure. Both the count, total accumulated latency and maximum
* latency are tracked in this data structure. When the fixed size structure is
* full, no new causes are tracked until the buffer is flushed by writing to
* the /proc file; the userspace tool does this on a regular basis.
*
* A latency cause is identified by a stringified backtrace at the point that
* the scheduler gets invoked. The userland tool will use this string to
* identify the cause of the latency in human readable form.
*
* The information is exported via /proc/latency_stats and /proc/<pid>/latency.
* These files look like this:
*
* Latency Top version : v0.1
* 70 59433 4897 i915_irq_wait drm_ioctl vfs_ioctl do_vfs_ioctl sys_ioctl
* | | | |
* | | | +----> the stringified backtrace
* | | +---------> The maximum latency for this entry in microseconds
* | +--------------> The accumulated latency for this entry (microseconds)
* +-------------------> The number of times this entry is hit
*
* (note: the average latency is the accumulated latency divided by the number
* of times)
*/
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/latencytop.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/stat.h>
#include <linux/list.h>
#include <linux/stacktrace.h>
#include <linux/sysctl.h>
static DEFINE_RAW_SPINLOCK(latency_lock);
#define MAXLR 128
static struct latency_record latency_record[MAXLR];
int latencytop_enabled;
#ifdef CONFIG_SYSCTL
static int sysctl_latencytop(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
int err;
err = proc_dointvec(table, write, buffer, lenp, ppos);
if (latencytop_enabled)
force_schedstat_enabled();
return err;
}
static struct ctl_table latencytop_sysctl[] = {
{
.procname = "latencytop",
.data = &latencytop_enabled,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = sysctl_latencytop,
},
{}
};
#endif
void clear_tsk_latency_tracing(struct task_struct *p)
{
unsigned long flags;
raw_spin_lock_irqsave(&latency_lock, flags);
memset(&p->latency_record, 0, sizeof(p->latency_record));
p->latency_record_count = 0;
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static void clear_global_latency_tracing(void)
{
unsigned long flags;
raw_spin_lock_irqsave(&latency_lock, flags);
memset(&latency_record, 0, sizeof(latency_record));
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static void __sched
account_global_scheduler_latency(struct task_struct *tsk,
struct latency_record *lat)
{
int firstnonnull = MAXLR;
int i;
/* skip kernel threads for now */
if (!tsk->mm)
return;
for (i = 0; i < MAXLR; i++) {
int q, same = 1;
/* Nothing stored: */
if (!latency_record[i].backtrace[0]) {
if (firstnonnull > i)
firstnonnull = i;
continue;
}
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat->backtrace[q];
if (latency_record[i].backtrace[q] != record) {
same = 0;
break;
}
/* 0 entry marks end of backtrace: */
if (!record)
break;
}
if (same) {
latency_record[i].count++;
latency_record[i].time += lat->time;
if (lat->time > latency_record[i].max)
latency_record[i].max = lat->time;
return;
}
}
i = firstnonnull;
if (i >= MAXLR)
return;
/* Allocted a new one: */
memcpy(&latency_record[i], lat, sizeof(struct latency_record));
}
/**
* __account_scheduler_latency - record an occurred latency
* @tsk - the task struct of the task hitting the latency
* @usecs - the duration of the latency in microseconds
* @inter - 1 if the sleep was interruptible, 0 if uninterruptible
*
* This function is the main entry point for recording latency entries
* as called by the scheduler.
*
* This function has a few special cases to deal with normal 'non-latency'
* sleeps: specifically, interruptible sleep longer than 5 msec is skipped
* since this usually is caused by waiting for events via select() and co.
*
* Negative latencies (caused by time going backwards) are also explicitly
* skipped.
*/
void __sched
__account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
{
unsigned long flags;
int i, q;
struct latency_record lat;
/* Long interruptible waits are generally user requested... */
if (inter && usecs > 5000)
return;
/* Negative sleeps are time going backwards */
/* Zero-time sleeps are non-interesting */
if (usecs <= 0)
return;
memset(&lat, 0, sizeof(lat));
lat.count = 1;
lat.time = usecs;
lat.max = usecs;
stack_trace_save_tsk(tsk, lat.backtrace, LT_BACKTRACEDEPTH, 0);
raw_spin_lock_irqsave(&latency_lock, flags);
account_global_scheduler_latency(tsk, &lat);
for (i = 0; i < tsk->latency_record_count; i++) {
struct latency_record *mylat;
int same = 1;
mylat = &tsk->latency_record[i];
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long record = lat.backtrace[q];
if (mylat->backtrace[q] != record) {
same = 0;
break;
}
/* 0 entry is end of backtrace */
if (!record)
break;
}
if (same) {
mylat->count++;
mylat->time += lat.time;
if (lat.time > mylat->max)
mylat->max = lat.time;
goto out_unlock;
}
}
/*
* short term hack; if we're > 32 we stop; future we recycle:
*/
if (tsk->latency_record_count >= LT_SAVECOUNT)
goto out_unlock;
/* Allocated a new one: */
i = tsk->latency_record_count++;
memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));
out_unlock:
raw_spin_unlock_irqrestore(&latency_lock, flags);
}
static int lstats_show(struct seq_file *m, void *v)
{
int i;
seq_puts(m, "Latency Top version : v0.1\n");
for (i = 0; i < MAXLR; i++) {
struct latency_record *lr = &latency_record[i];
if (lr->backtrace[0]) {
int q;
seq_printf(m, "%i %lu %lu",
lr->count, lr->time, lr->max);
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
unsigned long bt = lr->backtrace[q];
if (!bt)
break;
seq_printf(m, " %ps", (void *)bt);
}
seq_puts(m, "\n");
}
}
return 0;
}
static ssize_t
lstats_write(struct file *file, const char __user *buf, size_t count,
loff_t *offs)
{
clear_global_latency_tracing();
return count;
}
static int lstats_open(struct inode *inode, struct file *filp)
{
return single_open(filp, lstats_show, NULL);
}
static const struct proc_ops lstats_proc_ops = {
.proc_open = lstats_open,
.proc_read = seq_read,
.proc_write = lstats_write,
.proc_lseek = seq_lseek,
.proc_release = single_release,
};
static int __init init_lstats_procfs(void)
{
proc_create("latency_stats", 0644, NULL, &lstats_proc_ops);
#ifdef CONFIG_SYSCTL
register_sysctl_init("kernel", latencytop_sysctl);
#endif
return 0;
}
device_initcall(init_lstats_procfs);
| linux-master | kernel/latencytop.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/static_call.h>
#include <linux/bug.h>
#include <linux/smp.h>
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/processor.h>
#include <asm/sections.h>
extern struct static_call_site __start_static_call_sites[],
__stop_static_call_sites[];
extern struct static_call_tramp_key __start_static_call_tramp_key[],
__stop_static_call_tramp_key[];
static int static_call_initialized;
/*
* Must be called before early_initcall() to be effective.
*/
void static_call_force_reinit(void)
{
if (WARN_ON_ONCE(!static_call_initialized))
return;
static_call_initialized++;
}
/* mutex to protect key modules/sites */
static DEFINE_MUTEX(static_call_mutex);
static void static_call_lock(void)
{
mutex_lock(&static_call_mutex);
}
static void static_call_unlock(void)
{
mutex_unlock(&static_call_mutex);
}
static inline void *static_call_addr(struct static_call_site *site)
{
return (void *)((long)site->addr + (long)&site->addr);
}
static inline unsigned long __static_call_key(const struct static_call_site *site)
{
return (long)site->key + (long)&site->key;
}
static inline struct static_call_key *static_call_key(const struct static_call_site *site)
{
return (void *)(__static_call_key(site) & ~STATIC_CALL_SITE_FLAGS);
}
/* These assume the key is word-aligned. */
static inline bool static_call_is_init(struct static_call_site *site)
{
return __static_call_key(site) & STATIC_CALL_SITE_INIT;
}
static inline bool static_call_is_tail(struct static_call_site *site)
{
return __static_call_key(site) & STATIC_CALL_SITE_TAIL;
}
static inline void static_call_set_init(struct static_call_site *site)
{
site->key = (__static_call_key(site) | STATIC_CALL_SITE_INIT) -
(long)&site->key;
}
static int static_call_site_cmp(const void *_a, const void *_b)
{
const struct static_call_site *a = _a;
const struct static_call_site *b = _b;
const struct static_call_key *key_a = static_call_key(a);
const struct static_call_key *key_b = static_call_key(b);
if (key_a < key_b)
return -1;
if (key_a > key_b)
return 1;
return 0;
}
static void static_call_site_swap(void *_a, void *_b, int size)
{
long delta = (unsigned long)_a - (unsigned long)_b;
struct static_call_site *a = _a;
struct static_call_site *b = _b;
struct static_call_site tmp = *a;
a->addr = b->addr - delta;
a->key = b->key - delta;
b->addr = tmp.addr + delta;
b->key = tmp.key + delta;
}
static inline void static_call_sort_entries(struct static_call_site *start,
struct static_call_site *stop)
{
sort(start, stop - start, sizeof(struct static_call_site),
static_call_site_cmp, static_call_site_swap);
}
static inline bool static_call_key_has_mods(struct static_call_key *key)
{
return !(key->type & 1);
}
static inline struct static_call_mod *static_call_key_next(struct static_call_key *key)
{
if (!static_call_key_has_mods(key))
return NULL;
return key->mods;
}
static inline struct static_call_site *static_call_key_sites(struct static_call_key *key)
{
if (static_call_key_has_mods(key))
return NULL;
return (struct static_call_site *)(key->type & ~1);
}
void __static_call_update(struct static_call_key *key, void *tramp, void *func)
{
struct static_call_site *site, *stop;
struct static_call_mod *site_mod, first;
cpus_read_lock();
static_call_lock();
if (key->func == func)
goto done;
key->func = func;
arch_static_call_transform(NULL, tramp, func, false);
/*
* If uninitialized, we'll not update the callsites, but they still
* point to the trampoline and we just patched that.
*/
if (WARN_ON_ONCE(!static_call_initialized))
goto done;
first = (struct static_call_mod){
.next = static_call_key_next(key),
.mod = NULL,
.sites = static_call_key_sites(key),
};
for (site_mod = &first; site_mod; site_mod = site_mod->next) {
bool init = system_state < SYSTEM_RUNNING;
struct module *mod = site_mod->mod;
if (!site_mod->sites) {
/*
* This can happen if the static call key is defined in
* a module which doesn't use it.
*
* It also happens in the has_mods case, where the
* 'first' entry has no sites associated with it.
*/
continue;
}
stop = __stop_static_call_sites;
if (mod) {
#ifdef CONFIG_MODULES
stop = mod->static_call_sites +
mod->num_static_call_sites;
init = mod->state == MODULE_STATE_COMING;
#endif
}
for (site = site_mod->sites;
site < stop && static_call_key(site) == key; site++) {
void *site_addr = static_call_addr(site);
if (!init && static_call_is_init(site))
continue;
if (!kernel_text_address((unsigned long)site_addr)) {
/*
* This skips patching built-in __exit, which
* is part of init_section_contains() but is
* not part of kernel_text_address().
*
* Skipping built-in __exit is fine since it
* will never be executed.
*/
WARN_ONCE(!static_call_is_init(site),
"can't patch static call site at %pS",
site_addr);
continue;
}
arch_static_call_transform(site_addr, NULL, func,
static_call_is_tail(site));
}
}
done:
static_call_unlock();
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(__static_call_update);
static int __static_call_init(struct module *mod,
struct static_call_site *start,
struct static_call_site *stop)
{
struct static_call_site *site;
struct static_call_key *key, *prev_key = NULL;
struct static_call_mod *site_mod;
if (start == stop)
return 0;
static_call_sort_entries(start, stop);
for (site = start; site < stop; site++) {
void *site_addr = static_call_addr(site);
if ((mod && within_module_init((unsigned long)site_addr, mod)) ||
(!mod && init_section_contains(site_addr, 1)))
static_call_set_init(site);
key = static_call_key(site);
if (key != prev_key) {
prev_key = key;
/*
* For vmlinux (!mod) avoid the allocation by storing
* the sites pointer in the key itself. Also see
* __static_call_update()'s @first.
*
* This allows architectures (eg. x86) to call
* static_call_init() before memory allocation works.
*/
if (!mod) {
key->sites = site;
key->type |= 1;
goto do_transform;
}
site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
if (!site_mod)
return -ENOMEM;
/*
* When the key has a direct sites pointer, extract
* that into an explicit struct static_call_mod, so we
* can have a list of modules.
*/
if (static_call_key_sites(key)) {
site_mod->mod = NULL;
site_mod->next = NULL;
site_mod->sites = static_call_key_sites(key);
key->mods = site_mod;
site_mod = kzalloc(sizeof(*site_mod), GFP_KERNEL);
if (!site_mod)
return -ENOMEM;
}
site_mod->mod = mod;
site_mod->sites = site;
site_mod->next = static_call_key_next(key);
key->mods = site_mod;
}
do_transform:
arch_static_call_transform(site_addr, NULL, key->func,
static_call_is_tail(site));
}
return 0;
}
static int addr_conflict(struct static_call_site *site, void *start, void *end)
{
unsigned long addr = (unsigned long)static_call_addr(site);
if (addr <= (unsigned long)end &&
addr + CALL_INSN_SIZE > (unsigned long)start)
return 1;
return 0;
}
static int __static_call_text_reserved(struct static_call_site *iter_start,
struct static_call_site *iter_stop,
void *start, void *end, bool init)
{
struct static_call_site *iter = iter_start;
while (iter < iter_stop) {
if (init || !static_call_is_init(iter)) {
if (addr_conflict(iter, start, end))
return 1;
}
iter++;
}
return 0;
}
#ifdef CONFIG_MODULES
static int __static_call_mod_text_reserved(void *start, void *end)
{
struct module *mod;
int ret;
preempt_disable();
mod = __module_text_address((unsigned long)start);
WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
if (!try_module_get(mod))
mod = NULL;
preempt_enable();
if (!mod)
return 0;
ret = __static_call_text_reserved(mod->static_call_sites,
mod->static_call_sites + mod->num_static_call_sites,
start, end, mod->state == MODULE_STATE_COMING);
module_put(mod);
return ret;
}
static unsigned long tramp_key_lookup(unsigned long addr)
{
struct static_call_tramp_key *start = __start_static_call_tramp_key;
struct static_call_tramp_key *stop = __stop_static_call_tramp_key;
struct static_call_tramp_key *tramp_key;
for (tramp_key = start; tramp_key != stop; tramp_key++) {
unsigned long tramp;
tramp = (long)tramp_key->tramp + (long)&tramp_key->tramp;
if (tramp == addr)
return (long)tramp_key->key + (long)&tramp_key->key;
}
return 0;
}
static int static_call_add_module(struct module *mod)
{
struct static_call_site *start = mod->static_call_sites;
struct static_call_site *stop = start + mod->num_static_call_sites;
struct static_call_site *site;
for (site = start; site != stop; site++) {
unsigned long s_key = __static_call_key(site);
unsigned long addr = s_key & ~STATIC_CALL_SITE_FLAGS;
unsigned long key;
/*
* Is the key is exported, 'addr' points to the key, which
* means modules are allowed to call static_call_update() on
* it.
*
* Otherwise, the key isn't exported, and 'addr' points to the
* trampoline so we need to lookup the key.
*
* We go through this dance to prevent crazy modules from
* abusing sensitive static calls.
*/
if (!kernel_text_address(addr))
continue;
key = tramp_key_lookup(addr);
if (!key) {
pr_warn("Failed to fixup __raw_static_call() usage at: %ps\n",
static_call_addr(site));
return -EINVAL;
}
key |= s_key & STATIC_CALL_SITE_FLAGS;
site->key = key - (long)&site->key;
}
return __static_call_init(mod, start, stop);
}
static void static_call_del_module(struct module *mod)
{
struct static_call_site *start = mod->static_call_sites;
struct static_call_site *stop = mod->static_call_sites +
mod->num_static_call_sites;
struct static_call_key *key, *prev_key = NULL;
struct static_call_mod *site_mod, **prev;
struct static_call_site *site;
for (site = start; site < stop; site++) {
key = static_call_key(site);
if (key == prev_key)
continue;
prev_key = key;
for (prev = &key->mods, site_mod = key->mods;
site_mod && site_mod->mod != mod;
prev = &site_mod->next, site_mod = site_mod->next)
;
if (!site_mod)
continue;
*prev = site_mod->next;
kfree(site_mod);
}
}
static int static_call_module_notify(struct notifier_block *nb,
unsigned long val, void *data)
{
struct module *mod = data;
int ret = 0;
cpus_read_lock();
static_call_lock();
switch (val) {
case MODULE_STATE_COMING:
ret = static_call_add_module(mod);
if (ret) {
WARN(1, "Failed to allocate memory for static calls");
static_call_del_module(mod);
}
break;
case MODULE_STATE_GOING:
static_call_del_module(mod);
break;
}
static_call_unlock();
cpus_read_unlock();
return notifier_from_errno(ret);
}
static struct notifier_block static_call_module_nb = {
.notifier_call = static_call_module_notify,
};
#else
static inline int __static_call_mod_text_reserved(void *start, void *end)
{
return 0;
}
#endif /* CONFIG_MODULES */
int static_call_text_reserved(void *start, void *end)
{
bool init = system_state < SYSTEM_RUNNING;
int ret = __static_call_text_reserved(__start_static_call_sites,
__stop_static_call_sites, start, end, init);
if (ret)
return ret;
return __static_call_mod_text_reserved(start, end);
}
int __init static_call_init(void)
{
int ret;
/* See static_call_force_reinit(). */
if (static_call_initialized == 1)
return 0;
cpus_read_lock();
static_call_lock();
ret = __static_call_init(NULL, __start_static_call_sites,
__stop_static_call_sites);
static_call_unlock();
cpus_read_unlock();
if (ret) {
pr_err("Failed to allocate memory for static_call!\n");
BUG();
}
#ifdef CONFIG_MODULES
if (!static_call_initialized)
register_module_notifier(&static_call_module_nb);
#endif
static_call_initialized = 1;
return 0;
}
early_initcall(static_call_init);
#ifdef CONFIG_STATIC_CALL_SELFTEST
static int func_a(int x)
{
return x+1;
}
static int func_b(int x)
{
return x+2;
}
DEFINE_STATIC_CALL(sc_selftest, func_a);
static struct static_call_data {
int (*func)(int);
int val;
int expect;
} static_call_data [] __initdata = {
{ NULL, 2, 3 },
{ func_b, 2, 4 },
{ func_a, 2, 3 }
};
static int __init test_static_call_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(static_call_data); i++ ) {
struct static_call_data *scd = &static_call_data[i];
if (scd->func)
static_call_update(sc_selftest, scd->func);
WARN_ON(static_call(sc_selftest)(scd->val) != scd->expect);
}
return 0;
}
early_initcall(test_static_call_init);
#endif /* CONFIG_STATIC_CALL_SELFTEST */
| linux-master | kernel/static_call_inline.c |
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/device.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/ioremap.h>
#ifndef arch_memremap_wb
static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
{
#ifdef ioremap_cache
return (__force void *)ioremap_cache(offset, size);
#else
return (__force void *)ioremap(offset, size);
#endif
}
#endif
#ifndef arch_memremap_can_ram_remap
static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
unsigned long flags)
{
return true;
}
#endif
static void *try_ram_remap(resource_size_t offset, size_t size,
unsigned long flags)
{
unsigned long pfn = PHYS_PFN(offset);
/* In the simple case just return the existing linear address */
if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
arch_memremap_can_ram_remap(offset, size, flags))
return __va(offset);
return NULL; /* fallback to arch_memremap_wb */
}
/**
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
* @size: size of remap
* @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
* MEMREMAP_ENC, MEMREMAP_DEC
*
* memremap() is "ioremap" for cases where it is known that the resource
* being mapped does not have i/o side effects and the __iomem
* annotation is not applicable. In the case of multiple flags, the different
* mapping types will be attempted in the order listed below until one of
* them succeeds.
*
* MEMREMAP_WB - matches the default mapping for System RAM on
* the architecture. This is usually a read-allocate write-back cache.
* Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM
* memremap() will bypass establishing a new mapping and instead return
* a pointer into the direct map.
*
* MEMREMAP_WT - establish a mapping whereby writes either bypass the
* cache or are written through to memory and never exist in a
* cache-dirty state with respect to program visibility. Attempts to
* map System RAM with this mapping type will fail.
*
* MEMREMAP_WC - establish a writecombine mapping, whereby writes may
* be coalesced together (e.g. in the CPU's write buffers), but is otherwise
* uncached. Attempts to map System RAM with this mapping type will fail.
*/
void *memremap(resource_size_t offset, size_t size, unsigned long flags)
{
int is_ram = region_intersects(offset, size,
IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
void *addr = NULL;
if (!flags)
return NULL;
if (is_ram == REGION_MIXED) {
WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
&offset, (unsigned long) size);
return NULL;
}
/* Try all mapping types requested until one returns non-NULL */
if (flags & MEMREMAP_WB) {
/*
* MEMREMAP_WB is special in that it can be satisfied
* from the direct map. Some archs depend on the
* capability of memremap() to autodetect cases where
* the requested range is potentially in System RAM.
*/
if (is_ram == REGION_INTERSECTS)
addr = try_ram_remap(offset, size, flags);
if (!addr)
addr = arch_memremap_wb(offset, size);
}
/*
* If we don't have a mapping yet and other request flags are
* present then we will be attempting to establish a new virtual
* address mapping. Enforce that this mapping is not aliasing
* System RAM.
*/
if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
&offset, (unsigned long) size);
return NULL;
}
if (!addr && (flags & MEMREMAP_WT))
addr = ioremap_wt(offset, size);
if (!addr && (flags & MEMREMAP_WC))
addr = ioremap_wc(offset, size);
return addr;
}
EXPORT_SYMBOL(memremap);
void memunmap(void *addr)
{
if (is_ioremap_addr(addr))
iounmap((void __iomem *) addr);
}
EXPORT_SYMBOL(memunmap);
static void devm_memremap_release(struct device *dev, void *res)
{
memunmap(*(void **)res);
}
static int devm_memremap_match(struct device *dev, void *res, void *match_data)
{
return *(void **)res == match_data;
}
void *devm_memremap(struct device *dev, resource_size_t offset,
size_t size, unsigned long flags)
{
void **ptr, *addr;
ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
dev_to_node(dev));
if (!ptr)
return ERR_PTR(-ENOMEM);
addr = memremap(offset, size, flags);
if (addr) {
*ptr = addr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
return ERR_PTR(-ENXIO);
}
return addr;
}
EXPORT_SYMBOL(devm_memremap);
void devm_memunmap(struct device *dev, void *addr)
{
WARN_ON(devres_release(dev, devm_memremap_release,
devm_memremap_match, addr));
}
EXPORT_SYMBOL(devm_memunmap);
| linux-master | kernel/iomem.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kexec.c - kexec system call core code.
* Copyright (C) 2002-2004 Eric Biederman <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/btf.h>
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <linux/reboot.h>
#include <linux/ioport.h>
#include <linux/hardirq.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/utsname.h>
#include <linux/numa.h>
#include <linux/suspend.h>
#include <linux/device.h>
#include <linux/freezer.h>
#include <linux/panic_notifier.h>
#include <linux/pm.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
#include <linux/hugetlb.h>
#include <linux/objtool.h>
#include <linux/kmsg_dump.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <crypto/hash.h>
#include "kexec_internal.h"
atomic_t __kexec_lock = ATOMIC_INIT(0);
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
int kexec_should_crash(struct task_struct *p)
{
/*
* If crash_kexec_post_notifiers is enabled, don't run
* crash_kexec() here yet, which must be run after panic
* notifiers in panic().
*/
if (crash_kexec_post_notifiers)
return 0;
/*
* There are 4 panic() calls in make_task_dead() path, each of which
* corresponds to each of these 4 conditions.
*/
if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops)
return 1;
return 0;
}
int kexec_crash_loaded(void)
{
return !!kexec_crash_image;
}
EXPORT_SYMBOL_GPL(kexec_crash_loaded);
/*
* When kexec transitions to the new kernel there is a one-to-one
* mapping between physical and virtual addresses. On processors
* where you can disable the MMU this is trivial, and easy. For
* others it is still a simple predictable page table to setup.
*
* In that environment kexec copies the new kernel to its final
* resting place. This means I can only support memory whose
* physical address can fit in an unsigned long. In particular
* addresses where (pfn << PAGE_SHIFT) > ULONG_MAX cannot be handled.
* If the assembly stub has more restrictive requirements
* KEXEC_SOURCE_MEMORY_LIMIT and KEXEC_DEST_MEMORY_LIMIT can be
* defined more restrictively in <asm/kexec.h>.
*
* The code for the transition from the current kernel to the
* new kernel is placed in the control_code_buffer, whose size
* is given by KEXEC_CONTROL_PAGE_SIZE. In the best case only a single
* page of memory is necessary, but some architectures require more.
* Because this memory must be identity mapped in the transition from
* virtual to physical addresses it must live in the range
* 0 - TASK_SIZE, as only the user space mappings are arbitrarily
* modifiable.
*
* The assembly stub in the control code buffer is passed a linked list
* of descriptor pages detailing the source pages of the new kernel,
* and the destination addresses of those source pages. As this data
* structure is not used in the context of the current OS, it must
* be self-contained.
*
* The code has been made to work with highmem pages and will use a
* destination page in its final resting place (if it happens
* to allocate it). The end product of this is that most of the
* physical address space, and most of RAM can be used.
*
* Future directions include:
* - allocating a page table with the control code buffer identity
* mapped, to simplify machine_kexec and make kexec_on_panic more
* reliable.
*/
/*
* KIMAGE_NO_DEST is an impossible destination address..., for
* allocating pages whose destination address we do not care about.
*/
#define KIMAGE_NO_DEST (-1UL)
#define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long dest);
int sanity_check_segment_list(struct kimage *image)
{
int i;
unsigned long nr_segments = image->nr_segments;
unsigned long total_pages = 0;
unsigned long nr_pages = totalram_pages();
/*
* Verify we have good destination addresses. The caller is
* responsible for making certain we don't attempt to load
* the new image into invalid or reserved areas of RAM. This
* just verifies it is an address we can use.
*
* Since the kernel does everything in page size chunks ensure
* the destination addresses are page aligned. Too many
* special cases crop of when we don't do this. The most
* insidious is getting overlapping destination addresses
* simply because addresses are changed to page size
* granularity.
*/
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
if (mstart > mend)
return -EADDRNOTAVAIL;
if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
return -EADDRNOTAVAIL;
if (mend >= KEXEC_DESTINATION_MEMORY_LIMIT)
return -EADDRNOTAVAIL;
}
/* Verify our destination addresses do not overlap.
* If we alloed overlapping destination addresses
* through very weird things can happen with no
* easy explanation as one segment stops on another.
*/
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
unsigned long j;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
for (j = 0; j < i; j++) {
unsigned long pstart, pend;
pstart = image->segment[j].mem;
pend = pstart + image->segment[j].memsz;
/* Do the segments overlap ? */
if ((mend > pstart) && (mstart < pend))
return -EINVAL;
}
}
/* Ensure our buffer sizes are strictly less than
* our memory sizes. This should always be the case,
* and it is easier to check up front than to be surprised
* later on.
*/
for (i = 0; i < nr_segments; i++) {
if (image->segment[i].bufsz > image->segment[i].memsz)
return -EINVAL;
}
/*
* Verify that no more than half of memory will be consumed. If the
* request from userspace is too large, a large amount of time will be
* wasted allocating pages, which can cause a soft lockup.
*/
for (i = 0; i < nr_segments; i++) {
if (PAGE_COUNT(image->segment[i].memsz) > nr_pages / 2)
return -EINVAL;
total_pages += PAGE_COUNT(image->segment[i].memsz);
}
if (total_pages > nr_pages / 2)
return -EINVAL;
/*
* Verify we have good destination addresses. Normally
* the caller is responsible for making certain we don't
* attempt to load the new image into invalid or reserved
* areas of RAM. But crash kernels are preloaded into a
* reserved area of ram. We must ensure the addresses
* are in the reserved area otherwise preloading the
* kernel could corrupt things.
*/
if (image->type == KEXEC_TYPE_CRASH) {
for (i = 0; i < nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz - 1;
/* Ensure we are within the crash kernel limits */
if ((mstart < phys_to_boot_phys(crashk_res.start)) ||
(mend > phys_to_boot_phys(crashk_res.end)))
return -EADDRNOTAVAIL;
}
}
return 0;
}
struct kimage *do_kimage_alloc_init(void)
{
struct kimage *image;
/* Allocate a controlling structure */
image = kzalloc(sizeof(*image), GFP_KERNEL);
if (!image)
return NULL;
image->head = 0;
image->entry = &image->head;
image->last_entry = &image->head;
image->control_page = ~0; /* By default this does not apply */
image->type = KEXEC_TYPE_DEFAULT;
/* Initialize the list of control pages */
INIT_LIST_HEAD(&image->control_pages);
/* Initialize the list of destination pages */
INIT_LIST_HEAD(&image->dest_pages);
/* Initialize the list of unusable pages */
INIT_LIST_HEAD(&image->unusable_pages);
#ifdef CONFIG_CRASH_HOTPLUG
image->hp_action = KEXEC_CRASH_HP_NONE;
image->elfcorehdr_index = -1;
image->elfcorehdr_updated = false;
#endif
return image;
}
int kimage_is_destination_range(struct kimage *image,
unsigned long start,
unsigned long end)
{
unsigned long i;
for (i = 0; i < image->nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz;
if ((end > mstart) && (start < mend))
return 1;
}
return 0;
}
static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order)
{
struct page *pages;
if (fatal_signal_pending(current))
return NULL;
pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order);
if (pages) {
unsigned int count, i;
pages->mapping = NULL;
set_page_private(pages, order);
count = 1 << order;
for (i = 0; i < count; i++)
SetPageReserved(pages + i);
arch_kexec_post_alloc_pages(page_address(pages), count,
gfp_mask);
if (gfp_mask & __GFP_ZERO)
for (i = 0; i < count; i++)
clear_highpage(pages + i);
}
return pages;
}
static void kimage_free_pages(struct page *page)
{
unsigned int order, count, i;
order = page_private(page);
count = 1 << order;
arch_kexec_pre_free_pages(page_address(page), count);
for (i = 0; i < count; i++)
ClearPageReserved(page + i);
__free_pages(page, order);
}
void kimage_free_page_list(struct list_head *list)
{
struct page *page, *next;
list_for_each_entry_safe(page, next, list, lru) {
list_del(&page->lru);
kimage_free_pages(page);
}
}
static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
unsigned int order)
{
/* Control pages are special, they are the intermediaries
* that are needed while we copy the rest of the pages
* to their final resting place. As such they must
* not conflict with either the destination addresses
* or memory the kernel is already using.
*
* The only case where we really need more than one of
* these are for architectures where we cannot disable
* the MMU and must instead generate an identity mapped
* page table for all of the memory.
*
* At worst this runs in O(N) of the image size.
*/
struct list_head extra_pages;
struct page *pages;
unsigned int count;
count = 1 << order;
INIT_LIST_HEAD(&extra_pages);
/* Loop while I can allocate a page and the page allocated
* is a destination page.
*/
do {
unsigned long pfn, epfn, addr, eaddr;
pages = kimage_alloc_pages(KEXEC_CONTROL_MEMORY_GFP, order);
if (!pages)
break;
pfn = page_to_boot_pfn(pages);
epfn = pfn + count;
addr = pfn << PAGE_SHIFT;
eaddr = epfn << PAGE_SHIFT;
if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
kimage_is_destination_range(image, addr, eaddr)) {
list_add(&pages->lru, &extra_pages);
pages = NULL;
}
} while (!pages);
if (pages) {
/* Remember the allocated page... */
list_add(&pages->lru, &image->control_pages);
/* Because the page is already in it's destination
* location we will never allocate another page at
* that address. Therefore kimage_alloc_pages
* will not return it (again) and we don't need
* to give it an entry in image->segment[].
*/
}
/* Deal with the destination pages I have inadvertently allocated.
*
* Ideally I would convert multi-page allocations into single
* page allocations, and add everything to image->dest_pages.
*
* For now it is simpler to just free the pages.
*/
kimage_free_page_list(&extra_pages);
return pages;
}
static struct page *kimage_alloc_crash_control_pages(struct kimage *image,
unsigned int order)
{
/* Control pages are special, they are the intermediaries
* that are needed while we copy the rest of the pages
* to their final resting place. As such they must
* not conflict with either the destination addresses
* or memory the kernel is already using.
*
* Control pages are also the only pags we must allocate
* when loading a crash kernel. All of the other pages
* are specified by the segments and we just memcpy
* into them directly.
*
* The only case where we really need more than one of
* these are for architectures where we cannot disable
* the MMU and must instead generate an identity mapped
* page table for all of the memory.
*
* Given the low demand this implements a very simple
* allocator that finds the first hole of the appropriate
* size in the reserved memory region, and allocates all
* of the memory up to and including the hole.
*/
unsigned long hole_start, hole_end, size;
struct page *pages;
pages = NULL;
size = (1 << order) << PAGE_SHIFT;
hole_start = (image->control_page + (size - 1)) & ~(size - 1);
hole_end = hole_start + size - 1;
while (hole_end <= crashk_res.end) {
unsigned long i;
cond_resched();
if (hole_end > KEXEC_CRASH_CONTROL_MEMORY_LIMIT)
break;
/* See if I overlap any of the segments */
for (i = 0; i < image->nr_segments; i++) {
unsigned long mstart, mend;
mstart = image->segment[i].mem;
mend = mstart + image->segment[i].memsz - 1;
if ((hole_end >= mstart) && (hole_start <= mend)) {
/* Advance the hole to the end of the segment */
hole_start = (mend + (size - 1)) & ~(size - 1);
hole_end = hole_start + size - 1;
break;
}
}
/* If I don't overlap any segments I have found my hole! */
if (i == image->nr_segments) {
pages = pfn_to_page(hole_start >> PAGE_SHIFT);
image->control_page = hole_end;
break;
}
}
/* Ensure that these pages are decrypted if SME is enabled. */
if (pages)
arch_kexec_post_alloc_pages(page_address(pages), 1 << order, 0);
return pages;
}
struct page *kimage_alloc_control_pages(struct kimage *image,
unsigned int order)
{
struct page *pages = NULL;
switch (image->type) {
case KEXEC_TYPE_DEFAULT:
pages = kimage_alloc_normal_control_pages(image, order);
break;
case KEXEC_TYPE_CRASH:
pages = kimage_alloc_crash_control_pages(image, order);
break;
}
return pages;
}
int kimage_crash_copy_vmcoreinfo(struct kimage *image)
{
struct page *vmcoreinfo_page;
void *safecopy;
if (image->type != KEXEC_TYPE_CRASH)
return 0;
/*
* For kdump, allocate one vmcoreinfo safe copy from the
* crash memory. as we have arch_kexec_protect_crashkres()
* after kexec syscall, we naturally protect it from write
* (even read) access under kernel direct mapping. But on
* the other hand, we still need to operate it when crash
* happens to generate vmcoreinfo note, hereby we rely on
* vmap for this purpose.
*/
vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
if (!vmcoreinfo_page) {
pr_warn("Could not allocate vmcoreinfo buffer\n");
return -ENOMEM;
}
safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
if (!safecopy) {
pr_warn("Could not vmap vmcoreinfo buffer\n");
return -ENOMEM;
}
image->vmcoreinfo_data_copy = safecopy;
crash_update_vmcoreinfo_safecopy(safecopy);
return 0;
}
static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
{
if (*image->entry != 0)
image->entry++;
if (image->entry == image->last_entry) {
kimage_entry_t *ind_page;
struct page *page;
page = kimage_alloc_page(image, GFP_KERNEL, KIMAGE_NO_DEST);
if (!page)
return -ENOMEM;
ind_page = page_address(page);
*image->entry = virt_to_boot_phys(ind_page) | IND_INDIRECTION;
image->entry = ind_page;
image->last_entry = ind_page +
((PAGE_SIZE/sizeof(kimage_entry_t)) - 1);
}
*image->entry = entry;
image->entry++;
*image->entry = 0;
return 0;
}
static int kimage_set_destination(struct kimage *image,
unsigned long destination)
{
destination &= PAGE_MASK;
return kimage_add_entry(image, destination | IND_DESTINATION);
}
static int kimage_add_page(struct kimage *image, unsigned long page)
{
page &= PAGE_MASK;
return kimage_add_entry(image, page | IND_SOURCE);
}
static void kimage_free_extra_pages(struct kimage *image)
{
/* Walk through and free any extra destination pages I may have */
kimage_free_page_list(&image->dest_pages);
/* Walk through and free any unusable pages I have cached */
kimage_free_page_list(&image->unusable_pages);
}
void kimage_terminate(struct kimage *image)
{
if (*image->entry != 0)
image->entry++;
*image->entry = IND_DONE;
}
#define for_each_kimage_entry(image, ptr, entry) \
for (ptr = &image->head; (entry = *ptr) && !(entry & IND_DONE); \
ptr = (entry & IND_INDIRECTION) ? \
boot_phys_to_virt((entry & PAGE_MASK)) : ptr + 1)
static void kimage_free_entry(kimage_entry_t entry)
{
struct page *page;
page = boot_pfn_to_page(entry >> PAGE_SHIFT);
kimage_free_pages(page);
}
void kimage_free(struct kimage *image)
{
kimage_entry_t *ptr, entry;
kimage_entry_t ind = 0;
if (!image)
return;
if (image->vmcoreinfo_data_copy) {
crash_update_vmcoreinfo_safecopy(NULL);
vunmap(image->vmcoreinfo_data_copy);
}
kimage_free_extra_pages(image);
for_each_kimage_entry(image, ptr, entry) {
if (entry & IND_INDIRECTION) {
/* Free the previous indirection page */
if (ind & IND_INDIRECTION)
kimage_free_entry(ind);
/* Save this indirection page until we are
* done with it.
*/
ind = entry;
} else if (entry & IND_SOURCE)
kimage_free_entry(entry);
}
/* Free the final indirection page */
if (ind & IND_INDIRECTION)
kimage_free_entry(ind);
/* Handle any machine specific cleanup */
machine_kexec_cleanup(image);
/* Free the kexec control pages... */
kimage_free_page_list(&image->control_pages);
/*
* Free up any temporary buffers allocated. This might hit if
* error occurred much later after buffer allocation.
*/
if (image->file_mode)
kimage_file_post_load_cleanup(image);
kfree(image);
}
static kimage_entry_t *kimage_dst_used(struct kimage *image,
unsigned long page)
{
kimage_entry_t *ptr, entry;
unsigned long destination = 0;
for_each_kimage_entry(image, ptr, entry) {
if (entry & IND_DESTINATION)
destination = entry & PAGE_MASK;
else if (entry & IND_SOURCE) {
if (page == destination)
return ptr;
destination += PAGE_SIZE;
}
}
return NULL;
}
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long destination)
{
/*
* Here we implement safeguards to ensure that a source page
* is not copied to its destination page before the data on
* the destination page is no longer useful.
*
* To do this we maintain the invariant that a source page is
* either its own destination page, or it is not a
* destination page at all.
*
* That is slightly stronger than required, but the proof
* that no problems will not occur is trivial, and the
* implementation is simply to verify.
*
* When allocating all pages normally this algorithm will run
* in O(N) time, but in the worst case it will run in O(N^2)
* time. If the runtime is a problem the data structures can
* be fixed.
*/
struct page *page;
unsigned long addr;
/*
* Walk through the list of destination pages, and see if I
* have a match.
*/
list_for_each_entry(page, &image->dest_pages, lru) {
addr = page_to_boot_pfn(page) << PAGE_SHIFT;
if (addr == destination) {
list_del(&page->lru);
return page;
}
}
page = NULL;
while (1) {
kimage_entry_t *old;
/* Allocate a page, if we run out of memory give up */
page = kimage_alloc_pages(gfp_mask, 0);
if (!page)
return NULL;
/* If the page cannot be used file it away */
if (page_to_boot_pfn(page) >
(KEXEC_SOURCE_MEMORY_LIMIT >> PAGE_SHIFT)) {
list_add(&page->lru, &image->unusable_pages);
continue;
}
addr = page_to_boot_pfn(page) << PAGE_SHIFT;
/* If it is the destination page we want use it */
if (addr == destination)
break;
/* If the page is not a destination page use it */
if (!kimage_is_destination_range(image, addr,
addr + PAGE_SIZE))
break;
/*
* I know that the page is someones destination page.
* See if there is already a source page for this
* destination page. And if so swap the source pages.
*/
old = kimage_dst_used(image, addr);
if (old) {
/* If so move it */
unsigned long old_addr;
struct page *old_page;
old_addr = *old & PAGE_MASK;
old_page = boot_pfn_to_page(old_addr >> PAGE_SHIFT);
copy_highpage(page, old_page);
*old = addr | (*old & ~PAGE_MASK);
/* The old page I have found cannot be a
* destination page, so return it if it's
* gfp_flags honor the ones passed in.
*/
if (!(gfp_mask & __GFP_HIGHMEM) &&
PageHighMem(old_page)) {
kimage_free_pages(old_page);
continue;
}
page = old_page;
break;
}
/* Place the page on the destination list, to be used later */
list_add(&page->lru, &image->dest_pages);
}
return page;
}
static int kimage_load_normal_segment(struct kimage *image,
struct kexec_segment *segment)
{
unsigned long maddr;
size_t ubytes, mbytes;
int result;
unsigned char __user *buf = NULL;
unsigned char *kbuf = NULL;
if (image->file_mode)
kbuf = segment->kbuf;
else
buf = segment->buf;
ubytes = segment->bufsz;
mbytes = segment->memsz;
maddr = segment->mem;
result = kimage_set_destination(image, maddr);
if (result < 0)
goto out;
while (mbytes) {
struct page *page;
char *ptr;
size_t uchunk, mchunk;
page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
if (!page) {
result = -ENOMEM;
goto out;
}
result = kimage_add_page(image, page_to_boot_pfn(page)
<< PAGE_SHIFT);
if (result < 0)
goto out;
ptr = kmap_local_page(page);
/* Start with a clear page */
clear_page(ptr);
ptr += maddr & ~PAGE_MASK;
mchunk = min_t(size_t, mbytes,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
/* For file based kexec, source pages are in kernel memory */
if (image->file_mode)
memcpy(ptr, kbuf, uchunk);
else
result = copy_from_user(ptr, buf, uchunk);
kunmap_local(ptr);
if (result) {
result = -EFAULT;
goto out;
}
ubytes -= uchunk;
maddr += mchunk;
if (image->file_mode)
kbuf += mchunk;
else
buf += mchunk;
mbytes -= mchunk;
cond_resched();
}
out:
return result;
}
static int kimage_load_crash_segment(struct kimage *image,
struct kexec_segment *segment)
{
/* For crash dumps kernels we simply copy the data from
* user space to it's destination.
* We do things a page at a time for the sake of kmap.
*/
unsigned long maddr;
size_t ubytes, mbytes;
int result;
unsigned char __user *buf = NULL;
unsigned char *kbuf = NULL;
result = 0;
if (image->file_mode)
kbuf = segment->kbuf;
else
buf = segment->buf;
ubytes = segment->bufsz;
mbytes = segment->memsz;
maddr = segment->mem;
while (mbytes) {
struct page *page;
char *ptr;
size_t uchunk, mchunk;
page = boot_pfn_to_page(maddr >> PAGE_SHIFT);
if (!page) {
result = -ENOMEM;
goto out;
}
arch_kexec_post_alloc_pages(page_address(page), 1, 0);
ptr = kmap_local_page(page);
ptr += maddr & ~PAGE_MASK;
mchunk = min_t(size_t, mbytes,
PAGE_SIZE - (maddr & ~PAGE_MASK));
uchunk = min(ubytes, mchunk);
if (mchunk > uchunk) {
/* Zero the trailing part of the page */
memset(ptr + uchunk, 0, mchunk - uchunk);
}
/* For file based kexec, source pages are in kernel memory */
if (image->file_mode)
memcpy(ptr, kbuf, uchunk);
else
result = copy_from_user(ptr, buf, uchunk);
kexec_flush_icache_page(page);
kunmap_local(ptr);
arch_kexec_pre_free_pages(page_address(page), 1);
if (result) {
result = -EFAULT;
goto out;
}
ubytes -= uchunk;
maddr += mchunk;
if (image->file_mode)
kbuf += mchunk;
else
buf += mchunk;
mbytes -= mchunk;
cond_resched();
}
out:
return result;
}
int kimage_load_segment(struct kimage *image,
struct kexec_segment *segment)
{
int result = -ENOMEM;
switch (image->type) {
case KEXEC_TYPE_DEFAULT:
result = kimage_load_normal_segment(image, segment);
break;
case KEXEC_TYPE_CRASH:
result = kimage_load_crash_segment(image, segment);
break;
}
return result;
}
struct kexec_load_limit {
/* Mutex protects the limit count. */
struct mutex mutex;
int limit;
};
static struct kexec_load_limit load_limit_reboot = {
.mutex = __MUTEX_INITIALIZER(load_limit_reboot.mutex),
.limit = -1,
};
static struct kexec_load_limit load_limit_panic = {
.mutex = __MUTEX_INITIALIZER(load_limit_panic.mutex),
.limit = -1,
};
struct kimage *kexec_image;
struct kimage *kexec_crash_image;
static int kexec_load_disabled;
#ifdef CONFIG_SYSCTL
static int kexec_limit_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct kexec_load_limit *limit = table->data;
int val;
struct ctl_table tmp = {
.data = &val,
.maxlen = sizeof(val),
.mode = table->mode,
};
int ret;
if (write) {
ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
if (ret)
return ret;
if (val < 0)
return -EINVAL;
mutex_lock(&limit->mutex);
if (limit->limit != -1 && val >= limit->limit)
ret = -EINVAL;
else
limit->limit = val;
mutex_unlock(&limit->mutex);
return ret;
}
mutex_lock(&limit->mutex);
val = limit->limit;
mutex_unlock(&limit->mutex);
return proc_dointvec(&tmp, write, buffer, lenp, ppos);
}
static struct ctl_table kexec_core_sysctls[] = {
{
.procname = "kexec_load_disabled",
.data = &kexec_load_disabled,
.maxlen = sizeof(int),
.mode = 0644,
/* only handle a transition from default "0" to "1" */
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_ONE,
},
{
.procname = "kexec_load_limit_panic",
.data = &load_limit_panic,
.mode = 0644,
.proc_handler = kexec_limit_handler,
},
{
.procname = "kexec_load_limit_reboot",
.data = &load_limit_reboot,
.mode = 0644,
.proc_handler = kexec_limit_handler,
},
{ }
};
static int __init kexec_core_sysctl_init(void)
{
register_sysctl_init("kernel", kexec_core_sysctls);
return 0;
}
late_initcall(kexec_core_sysctl_init);
#endif
bool kexec_load_permitted(int kexec_image_type)
{
struct kexec_load_limit *limit;
/*
* Only the superuser can use the kexec syscall and if it has not
* been disabled.
*/
if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
return false;
/* Check limit counter and decrease it.*/
limit = (kexec_image_type == KEXEC_TYPE_CRASH) ?
&load_limit_panic : &load_limit_reboot;
mutex_lock(&limit->mutex);
if (!limit->limit) {
mutex_unlock(&limit->mutex);
return false;
}
if (limit->limit != -1)
limit->limit--;
mutex_unlock(&limit->mutex);
return true;
}
/*
* No panic_cpu check version of crash_kexec(). This function is called
* only when panic_cpu holds the current CPU number; this is the only CPU
* which processes crash_kexec routines.
*/
void __noclone __crash_kexec(struct pt_regs *regs)
{
/* Take the kexec_lock here to prevent sys_kexec_load
* running on one cpu from replacing the crash kernel
* we are using after a panic on a different cpu.
*
* If the crash kernel was not located in a fixed area
* of memory the xchg(&kexec_crash_image) would be
* sufficient. But since I reuse the memory...
*/
if (kexec_trylock()) {
if (kexec_crash_image) {
struct pt_regs fixed_regs;
crash_setup_regs(&fixed_regs, regs);
crash_save_vmcoreinfo();
machine_crash_shutdown(&fixed_regs);
machine_kexec(kexec_crash_image);
}
kexec_unlock();
}
}
STACK_FRAME_NON_STANDARD(__crash_kexec);
__bpf_kfunc void crash_kexec(struct pt_regs *regs)
{
int old_cpu, this_cpu;
/*
* Only one CPU is allowed to execute the crash_kexec() code as with
* panic(). Otherwise parallel calls of panic() and crash_kexec()
* may stop each other. To exclude them, we use panic_cpu here too.
*/
this_cpu = raw_smp_processor_id();
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
if (old_cpu == PANIC_CPU_INVALID) {
/* This is the 1st CPU which comes here, so go ahead. */
__crash_kexec(regs);
/*
* Reset panic_cpu to allow another panic()/crash_kexec()
* call.
*/
atomic_set(&panic_cpu, PANIC_CPU_INVALID);
}
}
static inline resource_size_t crash_resource_size(const struct resource *res)
{
return !res->end ? 0 : resource_size(res);
}
ssize_t crash_get_memory_size(void)
{
ssize_t size = 0;
if (!kexec_trylock())
return -EBUSY;
size += crash_resource_size(&crashk_res);
size += crash_resource_size(&crashk_low_res);
kexec_unlock();
return size;
}
static int __crash_shrink_memory(struct resource *old_res,
unsigned long new_size)
{
struct resource *ram_res;
ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
if (!ram_res)
return -ENOMEM;
ram_res->start = old_res->start + new_size;
ram_res->end = old_res->end;
ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
ram_res->name = "System RAM";
if (!new_size) {
release_resource(old_res);
old_res->start = 0;
old_res->end = 0;
} else {
crashk_res.end = ram_res->start - 1;
}
crash_free_reserved_phys_range(ram_res->start, ram_res->end);
insert_resource(&iomem_resource, ram_res);
return 0;
}
int crash_shrink_memory(unsigned long new_size)
{
int ret = 0;
unsigned long old_size, low_size;
if (!kexec_trylock())
return -EBUSY;
if (kexec_crash_image) {
ret = -ENOENT;
goto unlock;
}
low_size = crash_resource_size(&crashk_low_res);
old_size = crash_resource_size(&crashk_res) + low_size;
new_size = roundup(new_size, KEXEC_CRASH_MEM_ALIGN);
if (new_size >= old_size) {
ret = (new_size == old_size) ? 0 : -EINVAL;
goto unlock;
}
/*
* (low_size > new_size) implies that low_size is greater than zero.
* This also means that if low_size is zero, the else branch is taken.
*
* If low_size is greater than 0, (low_size > new_size) indicates that
* crashk_low_res also needs to be shrunken. Otherwise, only crashk_res
* needs to be shrunken.
*/
if (low_size > new_size) {
ret = __crash_shrink_memory(&crashk_res, 0);
if (ret)
goto unlock;
ret = __crash_shrink_memory(&crashk_low_res, new_size);
} else {
ret = __crash_shrink_memory(&crashk_res, new_size - low_size);
}
/* Swap crashk_res and crashk_low_res if needed */
if (!crashk_res.end && crashk_low_res.end) {
crashk_res.start = crashk_low_res.start;
crashk_res.end = crashk_low_res.end;
release_resource(&crashk_low_res);
crashk_low_res.start = 0;
crashk_low_res.end = 0;
insert_resource(&iomem_resource, &crashk_res);
}
unlock:
kexec_unlock();
return ret;
}
void crash_save_cpu(struct pt_regs *regs, int cpu)
{
struct elf_prstatus prstatus;
u32 *buf;
if ((cpu < 0) || (cpu >= nr_cpu_ids))
return;
/* Using ELF notes here is opportunistic.
* I need a well defined structure format
* for the data I pass, and I need tags
* on the data to indicate what information I have
* squirrelled away. ELF notes happen to provide
* all of that, so there is no need to invent something new.
*/
buf = (u32 *)per_cpu_ptr(crash_notes, cpu);
if (!buf)
return;
memset(&prstatus, 0, sizeof(prstatus));
prstatus.common.pr_pid = current->pid;
elf_core_copy_regs(&prstatus.pr_reg, regs);
buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
final_note(buf);
}
/*
* Move into place and start executing a preloaded standalone
* executable. If nothing was preloaded return an error.
*/
int kernel_kexec(void)
{
int error = 0;
if (!kexec_trylock())
return -EBUSY;
if (!kexec_image) {
error = -EINVAL;
goto Unlock;
}
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
pm_prepare_console();
error = freeze_processes();
if (error) {
error = -EBUSY;
goto Restore_console;
}
suspend_console();
error = dpm_suspend_start(PMSG_FREEZE);
if (error)
goto Resume_console;
/* At this point, dpm_suspend_start() has been called,
* but *not* dpm_suspend_end(). We *must* call
* dpm_suspend_end() now. Otherwise, drivers for
* some devices (e.g. interrupt controllers) become
* desynchronized with the actual state of the
* hardware at resume time, and evil weirdness ensues.
*/
error = dpm_suspend_end(PMSG_FREEZE);
if (error)
goto Resume_devices;
error = suspend_disable_secondary_cpus();
if (error)
goto Enable_cpus;
local_irq_disable();
error = syscore_suspend();
if (error)
goto Enable_irqs;
} else
#endif
{
kexec_in_progress = true;
kernel_restart_prepare("kexec reboot");
migrate_to_reboot_cpu();
/*
* migrate_to_reboot_cpu() disables CPU hotplug assuming that
* no further code needs to use CPU hotplug (which is true in
* the reboot case). However, the kexec path depends on using
* CPU hotplug again; so re-enable it here.
*/
cpu_hotplug_enable();
pr_notice("Starting new kernel\n");
machine_shutdown();
}
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_kexec(kexec_image);
#ifdef CONFIG_KEXEC_JUMP
if (kexec_image->preserve_context) {
syscore_resume();
Enable_irqs:
local_irq_enable();
Enable_cpus:
suspend_enable_secondary_cpus();
dpm_resume_start(PMSG_RESTORE);
Resume_devices:
dpm_resume_end(PMSG_RESTORE);
Resume_console:
resume_console();
thaw_processes();
Restore_console:
pm_restore_console();
}
#endif
Unlock:
kexec_unlock();
return error;
}
| linux-master | kernel/kexec_core.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* async.c: Asynchronous function calls for boot performance
*
* (C) Copyright 2009 Intel Corporation
* Author: Arjan van de Ven <[email protected]>
*/
/*
Goals and Theory of Operation
The primary goal of this feature is to reduce the kernel boot time,
by doing various independent hardware delays and discovery operations
decoupled and not strictly serialized.
More specifically, the asynchronous function call concept allows
certain operations (primarily during system boot) to happen
asynchronously, out of order, while these operations still
have their externally visible parts happen sequentially and in-order.
(not unlike how out-of-order CPUs retire their instructions in order)
Key to the asynchronous function call implementation is the concept of
a "sequence cookie" (which, although it has an abstracted type, can be
thought of as a monotonically incrementing number).
The async core will assign each scheduled event such a sequence cookie and
pass this to the called functions.
The asynchronously called function should before doing a globally visible
operation, such as registering device numbers, call the
async_synchronize_cookie() function and pass in its own cookie. The
async_synchronize_cookie() function will make sure that all asynchronous
operations that were scheduled prior to the operation corresponding with the
cookie have completed.
Subsystem/driver initialization code that scheduled asynchronous probe
functions, but which shares global resources with other drivers/subsystems
that do not use the asynchronous call feature, need to do a full
synchronization with the async_synchronize_full() function, before returning
from their init function. This is to maintain strict ordering between the
asynchronous and synchronous parts of the kernel.
*/
#include <linux/async.h>
#include <linux/atomic.h>
#include <linux/ktime.h>
#include <linux/export.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include "workqueue_internal.h"
static async_cookie_t next_cookie = 1;
#define MAX_WORK 32768
#define ASYNC_COOKIE_MAX ULLONG_MAX /* infinity cookie */
static LIST_HEAD(async_global_pending); /* pending from all registered doms */
static ASYNC_DOMAIN(async_dfl_domain);
static DEFINE_SPINLOCK(async_lock);
struct async_entry {
struct list_head domain_list;
struct list_head global_list;
struct work_struct work;
async_cookie_t cookie;
async_func_t func;
void *data;
struct async_domain *domain;
};
static DECLARE_WAIT_QUEUE_HEAD(async_done);
static atomic_t entry_count;
static long long microseconds_since(ktime_t start)
{
ktime_t now = ktime_get();
return ktime_to_ns(ktime_sub(now, start)) >> 10;
}
static async_cookie_t lowest_in_progress(struct async_domain *domain)
{
struct async_entry *first = NULL;
async_cookie_t ret = ASYNC_COOKIE_MAX;
unsigned long flags;
spin_lock_irqsave(&async_lock, flags);
if (domain) {
if (!list_empty(&domain->pending))
first = list_first_entry(&domain->pending,
struct async_entry, domain_list);
} else {
if (!list_empty(&async_global_pending))
first = list_first_entry(&async_global_pending,
struct async_entry, global_list);
}
if (first)
ret = first->cookie;
spin_unlock_irqrestore(&async_lock, flags);
return ret;
}
/*
* pick the first pending entry and run it
*/
static void async_run_entry_fn(struct work_struct *work)
{
struct async_entry *entry =
container_of(work, struct async_entry, work);
unsigned long flags;
ktime_t calltime;
/* 1) run (and print duration) */
pr_debug("calling %lli_%pS @ %i\n", (long long)entry->cookie,
entry->func, task_pid_nr(current));
calltime = ktime_get();
entry->func(entry->data, entry->cookie);
pr_debug("initcall %lli_%pS returned after %lld usecs\n",
(long long)entry->cookie, entry->func,
microseconds_since(calltime));
/* 2) remove self from the pending queues */
spin_lock_irqsave(&async_lock, flags);
list_del_init(&entry->domain_list);
list_del_init(&entry->global_list);
/* 3) free the entry */
kfree(entry);
atomic_dec(&entry_count);
spin_unlock_irqrestore(&async_lock, flags);
/* 4) wake up any waiters */
wake_up(&async_done);
}
/**
* async_schedule_node_domain - NUMA specific version of async_schedule_domain
* @func: function to execute asynchronously
* @data: data pointer to pass to the function
* @node: NUMA node that we want to schedule this on or close to
* @domain: the domain
*
* Returns an async_cookie_t that may be used for checkpointing later.
* @domain may be used in the async_synchronize_*_domain() functions to
* wait within a certain synchronization domain rather than globally.
*
* Note: This function may be called from atomic or non-atomic contexts.
*
* The node requested will be honored on a best effort basis. If the node
* has no CPUs associated with it then the work is distributed among all
* available CPUs.
*/
async_cookie_t async_schedule_node_domain(async_func_t func, void *data,
int node, struct async_domain *domain)
{
struct async_entry *entry;
unsigned long flags;
async_cookie_t newcookie;
/* allow irq-off callers */
entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
/*
* If we're out of memory or if there's too much work
* pending already, we execute synchronously.
*/
if (!entry || atomic_read(&entry_count) > MAX_WORK) {
kfree(entry);
spin_lock_irqsave(&async_lock, flags);
newcookie = next_cookie++;
spin_unlock_irqrestore(&async_lock, flags);
/* low on memory.. run synchronously */
func(data, newcookie);
return newcookie;
}
INIT_LIST_HEAD(&entry->domain_list);
INIT_LIST_HEAD(&entry->global_list);
INIT_WORK(&entry->work, async_run_entry_fn);
entry->func = func;
entry->data = data;
entry->domain = domain;
spin_lock_irqsave(&async_lock, flags);
/* allocate cookie and queue */
newcookie = entry->cookie = next_cookie++;
list_add_tail(&entry->domain_list, &domain->pending);
if (domain->registered)
list_add_tail(&entry->global_list, &async_global_pending);
atomic_inc(&entry_count);
spin_unlock_irqrestore(&async_lock, flags);
/* schedule for execution */
queue_work_node(node, system_unbound_wq, &entry->work);
return newcookie;
}
EXPORT_SYMBOL_GPL(async_schedule_node_domain);
/**
* async_schedule_node - NUMA specific version of async_schedule
* @func: function to execute asynchronously
* @data: data pointer to pass to the function
* @node: NUMA node that we want to schedule this on or close to
*
* Returns an async_cookie_t that may be used for checkpointing later.
* Note: This function may be called from atomic or non-atomic contexts.
*
* The node requested will be honored on a best effort basis. If the node
* has no CPUs associated with it then the work is distributed among all
* available CPUs.
*/
async_cookie_t async_schedule_node(async_func_t func, void *data, int node)
{
return async_schedule_node_domain(func, data, node, &async_dfl_domain);
}
EXPORT_SYMBOL_GPL(async_schedule_node);
/**
* async_synchronize_full - synchronize all asynchronous function calls
*
* This function waits until all asynchronous function calls have been done.
*/
void async_synchronize_full(void)
{
async_synchronize_full_domain(NULL);
}
EXPORT_SYMBOL_GPL(async_synchronize_full);
/**
* async_synchronize_full_domain - synchronize all asynchronous function within a certain domain
* @domain: the domain to synchronize
*
* This function waits until all asynchronous function calls for the
* synchronization domain specified by @domain have been done.
*/
void async_synchronize_full_domain(struct async_domain *domain)
{
async_synchronize_cookie_domain(ASYNC_COOKIE_MAX, domain);
}
EXPORT_SYMBOL_GPL(async_synchronize_full_domain);
/**
* async_synchronize_cookie_domain - synchronize asynchronous function calls within a certain domain with cookie checkpointing
* @cookie: async_cookie_t to use as checkpoint
* @domain: the domain to synchronize (%NULL for all registered domains)
*
* This function waits until all asynchronous function calls for the
* synchronization domain specified by @domain submitted prior to @cookie
* have been done.
*/
void async_synchronize_cookie_domain(async_cookie_t cookie, struct async_domain *domain)
{
ktime_t starttime;
pr_debug("async_waiting @ %i\n", task_pid_nr(current));
starttime = ktime_get();
wait_event(async_done, lowest_in_progress(domain) >= cookie);
pr_debug("async_continuing @ %i after %lli usec\n", task_pid_nr(current),
microseconds_since(starttime));
}
EXPORT_SYMBOL_GPL(async_synchronize_cookie_domain);
/**
* async_synchronize_cookie - synchronize asynchronous function calls with cookie checkpointing
* @cookie: async_cookie_t to use as checkpoint
*
* This function waits until all asynchronous function calls prior to @cookie
* have been done.
*/
void async_synchronize_cookie(async_cookie_t cookie)
{
async_synchronize_cookie_domain(cookie, &async_dfl_domain);
}
EXPORT_SYMBOL_GPL(async_synchronize_cookie);
/**
* current_is_async - is %current an async worker task?
*
* Returns %true if %current is an async worker task.
*/
bool current_is_async(void)
{
struct worker *worker = current_wq_worker();
return worker && worker->current_func == async_run_entry_fn;
}
EXPORT_SYMBOL_GPL(current_is_async);
| linux-master | kernel/async.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004 IBM Corporation
*
* Author: Serge Hallyn <[email protected]>
*/
#include <linux/export.h>
#include <linux/uts.h>
#include <linux/utsname.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>
static struct kmem_cache *uts_ns_cache __ro_after_init;
static struct ucounts *inc_uts_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);
}
static void dec_uts_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_UTS_NAMESPACES);
}
static struct uts_namespace *create_uts_ns(void)
{
struct uts_namespace *uts_ns;
uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
if (uts_ns)
refcount_set(&uts_ns->ns.count, 1);
return uts_ns;
}
/*
* Clone a new ns copying an original utsname, setting refcount to 1
* @old_ns: namespace to clone
* Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise
*/
static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
struct uts_namespace *old_ns)
{
struct uts_namespace *ns;
struct ucounts *ucounts;
int err;
err = -ENOSPC;
ucounts = inc_uts_namespaces(user_ns);
if (!ucounts)
goto fail;
err = -ENOMEM;
ns = create_uts_ns();
if (!ns)
goto fail_dec;
err = ns_alloc_inum(&ns->ns);
if (err)
goto fail_free;
ns->ucounts = ucounts;
ns->ns.ops = &utsns_operations;
down_read(&uts_sem);
memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
ns->user_ns = get_user_ns(user_ns);
up_read(&uts_sem);
return ns;
fail_free:
kmem_cache_free(uts_ns_cache, ns);
fail_dec:
dec_uts_namespaces(ucounts);
fail:
return ERR_PTR(err);
}
/*
* Copy task tsk's utsname namespace, or clone it if flags
* specifies CLONE_NEWUTS. In latter case, changes to the
* utsname of this process won't be seen by parent, and vice
* versa.
*/
struct uts_namespace *copy_utsname(unsigned long flags,
struct user_namespace *user_ns, struct uts_namespace *old_ns)
{
struct uts_namespace *new_ns;
BUG_ON(!old_ns);
get_uts_ns(old_ns);
if (!(flags & CLONE_NEWUTS))
return old_ns;
new_ns = clone_uts_ns(user_ns, old_ns);
put_uts_ns(old_ns);
return new_ns;
}
void free_uts_ns(struct uts_namespace *ns)
{
dec_uts_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
kmem_cache_free(uts_ns_cache, ns);
}
static inline struct uts_namespace *to_uts_ns(struct ns_common *ns)
{
return container_of(ns, struct uts_namespace, ns);
}
static struct ns_common *utsns_get(struct task_struct *task)
{
struct uts_namespace *ns = NULL;
struct nsproxy *nsproxy;
task_lock(task);
nsproxy = task->nsproxy;
if (nsproxy) {
ns = nsproxy->uts_ns;
get_uts_ns(ns);
}
task_unlock(task);
return ns ? &ns->ns : NULL;
}
static void utsns_put(struct ns_common *ns)
{
put_uts_ns(to_uts_ns(ns));
}
static int utsns_install(struct nsset *nsset, struct ns_common *new)
{
struct nsproxy *nsproxy = nsset->nsproxy;
struct uts_namespace *ns = to_uts_ns(new);
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
get_uts_ns(ns);
put_uts_ns(nsproxy->uts_ns);
nsproxy->uts_ns = ns;
return 0;
}
static struct user_namespace *utsns_owner(struct ns_common *ns)
{
return to_uts_ns(ns)->user_ns;
}
const struct proc_ns_operations utsns_operations = {
.name = "uts",
.type = CLONE_NEWUTS,
.get = utsns_get,
.put = utsns_put,
.install = utsns_install,
.owner = utsns_owner,
};
void __init uts_ns_init(void)
{
uts_ns_cache = kmem_cache_create_usercopy(
"uts_namespace", sizeof(struct uts_namespace), 0,
SLAB_PANIC|SLAB_ACCOUNT,
offsetof(struct uts_namespace, name),
sizeof_field(struct uts_namespace, name),
NULL);
}
| linux-master | kernel/utsname.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Restartable sequences system call
*
* Copyright (C) 2015, Google, Inc.,
* Paul Turner <[email protected]> and Andrew Hunter <[email protected]>
* Copyright (C) 2015-2018, EfficiOS Inc.,
* Mathieu Desnoyers <[email protected]>
*/
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/rseq.h>
#include <linux/types.h>
#include <asm/ptrace.h>
#define CREATE_TRACE_POINTS
#include <trace/events/rseq.h>
/* The original rseq structure size (including padding) is 32 bytes. */
#define ORIG_RSEQ_SIZE 32
#define RSEQ_CS_NO_RESTART_FLAGS (RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT | \
RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL | \
RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE)
/*
*
* Restartable sequences are a lightweight interface that allows
* user-level code to be executed atomically relative to scheduler
* preemption and signal delivery. Typically used for implementing
* per-cpu operations.
*
* It allows user-space to perform update operations on per-cpu data
* without requiring heavy-weight atomic operations.
*
* Detailed algorithm of rseq user-space assembly sequences:
*
* init(rseq_cs)
* cpu = TLS->rseq::cpu_id_start
* [1] TLS->rseq::rseq_cs = rseq_cs
* [start_ip] ----------------------------
* [2] if (cpu != TLS->rseq::cpu_id)
* goto abort_ip;
* [3] <last_instruction_in_cs>
* [post_commit_ip] ----------------------------
*
* The address of jump target abort_ip must be outside the critical
* region, i.e.:
*
* [abort_ip] < [start_ip] || [abort_ip] >= [post_commit_ip]
*
* Steps [2]-[3] (inclusive) need to be a sequence of instructions in
* userspace that can handle being interrupted between any of those
* instructions, and then resumed to the abort_ip.
*
* 1. Userspace stores the address of the struct rseq_cs assembly
* block descriptor into the rseq_cs field of the registered
* struct rseq TLS area. This update is performed through a single
* store within the inline assembly instruction sequence.
* [start_ip]
*
* 2. Userspace tests to check whether the current cpu_id field match
* the cpu number loaded before start_ip, branching to abort_ip
* in case of a mismatch.
*
* If the sequence is preempted or interrupted by a signal
* at or after start_ip and before post_commit_ip, then the kernel
* clears TLS->__rseq_abi::rseq_cs, and sets the user-space return
* ip to abort_ip before returning to user-space, so the preempted
* execution resumes at abort_ip.
*
* 3. Userspace critical section final instruction before
* post_commit_ip is the commit. The critical section is
* self-terminating.
* [post_commit_ip]
*
* 4. <success>
*
* On failure at [2], or if interrupted by preempt or signal delivery
* between [1] and [3]:
*
* [abort_ip]
* F1. <failure>
*/
static int rseq_update_cpu_node_id(struct task_struct *t)
{
struct rseq __user *rseq = t->rseq;
u32 cpu_id = raw_smp_processor_id();
u32 node_id = cpu_to_node(cpu_id);
u32 mm_cid = task_mm_cid(t);
WARN_ON_ONCE((int) mm_cid < 0);
if (!user_write_access_begin(rseq, t->rseq_len))
goto efault;
unsafe_put_user(cpu_id, &rseq->cpu_id_start, efault_end);
unsafe_put_user(cpu_id, &rseq->cpu_id, efault_end);
unsafe_put_user(node_id, &rseq->node_id, efault_end);
unsafe_put_user(mm_cid, &rseq->mm_cid, efault_end);
/*
* Additional feature fields added after ORIG_RSEQ_SIZE
* need to be conditionally updated only if
* t->rseq_len != ORIG_RSEQ_SIZE.
*/
user_write_access_end();
trace_rseq_update(t);
return 0;
efault_end:
user_write_access_end();
efault:
return -EFAULT;
}
static int rseq_reset_rseq_cpu_node_id(struct task_struct *t)
{
u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED, node_id = 0,
mm_cid = 0;
/*
* Reset cpu_id_start to its initial state (0).
*/
if (put_user(cpu_id_start, &t->rseq->cpu_id_start))
return -EFAULT;
/*
* Reset cpu_id to RSEQ_CPU_ID_UNINITIALIZED, so any user coming
* in after unregistration can figure out that rseq needs to be
* registered again.
*/
if (put_user(cpu_id, &t->rseq->cpu_id))
return -EFAULT;
/*
* Reset node_id to its initial state (0).
*/
if (put_user(node_id, &t->rseq->node_id))
return -EFAULT;
/*
* Reset mm_cid to its initial state (0).
*/
if (put_user(mm_cid, &t->rseq->mm_cid))
return -EFAULT;
/*
* Additional feature fields added after ORIG_RSEQ_SIZE
* need to be conditionally reset only if
* t->rseq_len != ORIG_RSEQ_SIZE.
*/
return 0;
}
static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
{
struct rseq_cs __user *urseq_cs;
u64 ptr;
u32 __user *usig;
u32 sig;
int ret;
#ifdef CONFIG_64BIT
if (get_user(ptr, &t->rseq->rseq_cs))
return -EFAULT;
#else
if (copy_from_user(&ptr, &t->rseq->rseq_cs, sizeof(ptr)))
return -EFAULT;
#endif
if (!ptr) {
memset(rseq_cs, 0, sizeof(*rseq_cs));
return 0;
}
if (ptr >= TASK_SIZE)
return -EINVAL;
urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
return -EFAULT;
if (rseq_cs->start_ip >= TASK_SIZE ||
rseq_cs->start_ip + rseq_cs->post_commit_offset >= TASK_SIZE ||
rseq_cs->abort_ip >= TASK_SIZE ||
rseq_cs->version > 0)
return -EINVAL;
/* Check for overflow. */
if (rseq_cs->start_ip + rseq_cs->post_commit_offset < rseq_cs->start_ip)
return -EINVAL;
/* Ensure that abort_ip is not in the critical section. */
if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
return -EINVAL;
usig = (u32 __user *)(unsigned long)(rseq_cs->abort_ip - sizeof(u32));
ret = get_user(sig, usig);
if (ret)
return ret;
if (current->rseq_sig != sig) {
printk_ratelimited(KERN_WARNING
"Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
sig, current->rseq_sig, current->pid, usig);
return -EINVAL;
}
return 0;
}
static bool rseq_warn_flags(const char *str, u32 flags)
{
u32 test_flags;
if (!flags)
return false;
test_flags = flags & RSEQ_CS_NO_RESTART_FLAGS;
if (test_flags)
pr_warn_once("Deprecated flags (%u) in %s ABI structure", test_flags, str);
test_flags = flags & ~RSEQ_CS_NO_RESTART_FLAGS;
if (test_flags)
pr_warn_once("Unknown flags (%u) in %s ABI structure", test_flags, str);
return true;
}
static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
{
u32 flags, event_mask;
int ret;
if (rseq_warn_flags("rseq_cs", cs_flags))
return -EINVAL;
/* Get thread flags. */
ret = get_user(flags, &t->rseq->flags);
if (ret)
return ret;
if (rseq_warn_flags("rseq", flags))
return -EINVAL;
/*
* Load and clear event mask atomically with respect to
* scheduler preemption.
*/
preempt_disable();
event_mask = t->rseq_event_mask;
t->rseq_event_mask = 0;
preempt_enable();
return !!event_mask;
}
static int clear_rseq_cs(struct task_struct *t)
{
/*
* The rseq_cs field is set to NULL on preemption or signal
* delivery on top of rseq assembly block, as well as on top
* of code outside of the rseq assembly block. This performs
* a lazy clear of the rseq_cs field.
*
* Set rseq_cs to NULL.
*/
#ifdef CONFIG_64BIT
return put_user(0UL, &t->rseq->rseq_cs);
#else
if (clear_user(&t->rseq->rseq_cs, sizeof(t->rseq->rseq_cs)))
return -EFAULT;
return 0;
#endif
}
/*
* Unsigned comparison will be true when ip >= start_ip, and when
* ip < start_ip + post_commit_offset.
*/
static bool in_rseq_cs(unsigned long ip, struct rseq_cs *rseq_cs)
{
return ip - rseq_cs->start_ip < rseq_cs->post_commit_offset;
}
static int rseq_ip_fixup(struct pt_regs *regs)
{
unsigned long ip = instruction_pointer(regs);
struct task_struct *t = current;
struct rseq_cs rseq_cs;
int ret;
ret = rseq_get_rseq_cs(t, &rseq_cs);
if (ret)
return ret;
/*
* Handle potentially not being within a critical section.
* If not nested over a rseq critical section, restart is useless.
* Clear the rseq_cs pointer and return.
*/
if (!in_rseq_cs(ip, &rseq_cs))
return clear_rseq_cs(t);
ret = rseq_need_restart(t, rseq_cs.flags);
if (ret <= 0)
return ret;
ret = clear_rseq_cs(t);
if (ret)
return ret;
trace_rseq_ip_fixup(ip, rseq_cs.start_ip, rseq_cs.post_commit_offset,
rseq_cs.abort_ip);
instruction_pointer_set(regs, (unsigned long)rseq_cs.abort_ip);
return 0;
}
/*
* This resume handler must always be executed between any of:
* - preemption,
* - signal delivery,
* and return to user-space.
*
* This is how we can ensure that the entire rseq critical section
* will issue the commit instruction only if executed atomically with
* respect to other threads scheduled on the same CPU, and with respect
* to signal handlers.
*/
void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs)
{
struct task_struct *t = current;
int ret, sig;
if (unlikely(t->flags & PF_EXITING))
return;
/*
* regs is NULL if and only if the caller is in a syscall path. Skip
* fixup and leave rseq_cs as is so that rseq_sycall() will detect and
* kill a misbehaving userspace on debug kernels.
*/
if (regs) {
ret = rseq_ip_fixup(regs);
if (unlikely(ret < 0))
goto error;
}
if (unlikely(rseq_update_cpu_node_id(t)))
goto error;
return;
error:
sig = ksig ? ksig->sig : 0;
force_sigsegv(sig);
}
#ifdef CONFIG_DEBUG_RSEQ
/*
* Terminate the process if a syscall is issued within a restartable
* sequence.
*/
void rseq_syscall(struct pt_regs *regs)
{
unsigned long ip = instruction_pointer(regs);
struct task_struct *t = current;
struct rseq_cs rseq_cs;
if (!t->rseq)
return;
if (rseq_get_rseq_cs(t, &rseq_cs) || in_rseq_cs(ip, &rseq_cs))
force_sig(SIGSEGV);
}
#endif
/*
* sys_rseq - setup restartable sequences for caller thread.
*/
SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len,
int, flags, u32, sig)
{
int ret;
if (flags & RSEQ_FLAG_UNREGISTER) {
if (flags & ~RSEQ_FLAG_UNREGISTER)
return -EINVAL;
/* Unregister rseq for current thread. */
if (current->rseq != rseq || !current->rseq)
return -EINVAL;
if (rseq_len != current->rseq_len)
return -EINVAL;
if (current->rseq_sig != sig)
return -EPERM;
ret = rseq_reset_rseq_cpu_node_id(current);
if (ret)
return ret;
current->rseq = NULL;
current->rseq_sig = 0;
current->rseq_len = 0;
return 0;
}
if (unlikely(flags))
return -EINVAL;
if (current->rseq) {
/*
* If rseq is already registered, check whether
* the provided address differs from the prior
* one.
*/
if (current->rseq != rseq || rseq_len != current->rseq_len)
return -EINVAL;
if (current->rseq_sig != sig)
return -EPERM;
/* Already registered. */
return -EBUSY;
}
/*
* If there was no rseq previously registered, ensure the provided rseq
* is properly aligned, as communcated to user-space through the ELF
* auxiliary vector AT_RSEQ_ALIGN. If rseq_len is the original rseq
* size, the required alignment is the original struct rseq alignment.
*
* In order to be valid, rseq_len is either the original rseq size, or
* large enough to contain all supported fields, as communicated to
* user-space through the ELF auxiliary vector AT_RSEQ_FEATURE_SIZE.
*/
if (rseq_len < ORIG_RSEQ_SIZE ||
(rseq_len == ORIG_RSEQ_SIZE && !IS_ALIGNED((unsigned long)rseq, ORIG_RSEQ_SIZE)) ||
(rseq_len != ORIG_RSEQ_SIZE && (!IS_ALIGNED((unsigned long)rseq, __alignof__(*rseq)) ||
rseq_len < offsetof(struct rseq, end))))
return -EINVAL;
if (!access_ok(rseq, rseq_len))
return -EFAULT;
current->rseq = rseq;
current->rseq_len = rseq_len;
current->rseq_sig = sig;
/*
* If rseq was previously inactive, and has just been
* registered, ensure the cpu_id_start and cpu_id fields
* are updated before returning to user-space.
*/
rseq_set_notify_resume(current);
return 0;
}
| linux-master | kernel/rseq.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Handling of different ABIs (personalities).
*
* We group personalities into execution domains which have their
* own handlers for kernel entry points, signal mapping, etc...
*
* 2001-05-06 Complete rewrite, Christoph Hellwig ([email protected])
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/personality.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/sysctl.h>
#include <linux/types.h>
#ifdef CONFIG_PROC_FS
static int execdomains_proc_show(struct seq_file *m, void *v)
{
seq_puts(m, "0-0\tLinux \t[kernel]\n");
return 0;
}
static int __init proc_execdomains_init(void)
{
proc_create_single("execdomains", 0, NULL, execdomains_proc_show);
return 0;
}
module_init(proc_execdomains_init);
#endif
SYSCALL_DEFINE1(personality, unsigned int, personality)
{
unsigned int old = current->personality;
if (personality != 0xffffffff)
set_personality(personality);
return old;
}
| linux-master | kernel/exec_domain.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Common SMP CPU bringup/teardown functions
*/
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/kthread.h>
#include <linux/smpboot.h>
#include "smpboot.h"
#ifdef CONFIG_SMP
#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
/*
* For the hotplug case we keep the task structs around and reuse
* them.
*/
static DEFINE_PER_CPU(struct task_struct *, idle_threads);
struct task_struct *idle_thread_get(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
if (!tsk)
return ERR_PTR(-ENOMEM);
return tsk;
}
void __init idle_thread_set_boot_cpu(void)
{
per_cpu(idle_threads, smp_processor_id()) = current;
}
/**
* idle_init - Initialize the idle thread for a cpu
* @cpu: The cpu for which the idle thread should be initialized
*
* Creates the thread if it does not exist.
*/
static __always_inline void idle_init(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
if (!tsk) {
tsk = fork_idle(cpu);
if (IS_ERR(tsk))
pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
else
per_cpu(idle_threads, cpu) = tsk;
}
}
/**
* idle_threads_init - Initialize idle threads for all cpus
*/
void __init idle_threads_init(void)
{
unsigned int cpu, boot_cpu;
boot_cpu = smp_processor_id();
for_each_possible_cpu(cpu) {
if (cpu != boot_cpu)
idle_init(cpu);
}
}
#endif
#endif /* #ifdef CONFIG_SMP */
static LIST_HEAD(hotplug_threads);
static DEFINE_MUTEX(smpboot_threads_lock);
struct smpboot_thread_data {
unsigned int cpu;
unsigned int status;
struct smp_hotplug_thread *ht;
};
enum {
HP_THREAD_NONE = 0,
HP_THREAD_ACTIVE,
HP_THREAD_PARKED,
};
/**
* smpboot_thread_fn - percpu hotplug thread loop function
* @data: thread data pointer
*
* Checks for thread stop and park conditions. Calls the necessary
* setup, cleanup, park and unpark functions for the registered
* thread.
*
* Returns 1 when the thread should exit, 0 otherwise.
*/
static int smpboot_thread_fn(void *data)
{
struct smpboot_thread_data *td = data;
struct smp_hotplug_thread *ht = td->ht;
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
preempt_disable();
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
preempt_enable();
/* cleanup must mirror setup */
if (ht->cleanup && td->status != HP_THREAD_NONE)
ht->cleanup(td->cpu, cpu_online(td->cpu));
kfree(td);
return 0;
}
if (kthread_should_park()) {
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->park && td->status == HP_THREAD_ACTIVE) {
BUG_ON(td->cpu != smp_processor_id());
ht->park(td->cpu);
td->status = HP_THREAD_PARKED;
}
kthread_parkme();
/* We might have been woken for stop */
continue;
}
BUG_ON(td->cpu != smp_processor_id());
/* Check for state change setup */
switch (td->status) {
case HP_THREAD_NONE:
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->setup)
ht->setup(td->cpu);
td->status = HP_THREAD_ACTIVE;
continue;
case HP_THREAD_PARKED:
__set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->unpark)
ht->unpark(td->cpu);
td->status = HP_THREAD_ACTIVE;
continue;
}
if (!ht->thread_should_run(td->cpu)) {
preempt_enable_no_resched();
schedule();
} else {
__set_current_state(TASK_RUNNING);
preempt_enable();
ht->thread_fn(td->cpu);
}
}
}
static int
__smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
struct smpboot_thread_data *td;
if (tsk)
return 0;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, cpu_to_node(cpu));
if (!td)
return -ENOMEM;
td->cpu = cpu;
td->ht = ht;
tsk = kthread_create_on_cpu(smpboot_thread_fn, td, cpu,
ht->thread_comm);
if (IS_ERR(tsk)) {
kfree(td);
return PTR_ERR(tsk);
}
kthread_set_per_cpu(tsk, cpu);
/*
* Park the thread so that it could start right on the CPU
* when it is available.
*/
kthread_park(tsk);
get_task_struct(tsk);
*per_cpu_ptr(ht->store, cpu) = tsk;
if (ht->create) {
/*
* Make sure that the task has actually scheduled out
* into park position, before calling the create
* callback. At least the migration thread callback
* requires that the task is off the runqueue.
*/
if (!wait_task_inactive(tsk, TASK_PARKED))
WARN_ON(1);
else
ht->create(cpu);
}
return 0;
}
int smpboot_create_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
int ret = 0;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry(cur, &hotplug_threads, list) {
ret = __smpboot_create_thread(cur, cpu);
if (ret)
break;
}
mutex_unlock(&smpboot_threads_lock);
return ret;
}
static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (!ht->selfparking)
kthread_unpark(tsk);
}
int smpboot_unpark_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry(cur, &hotplug_threads, list)
smpboot_unpark_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
return 0;
}
static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (tsk && !ht->selfparking)
kthread_park(tsk);
}
int smpboot_park_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
mutex_lock(&smpboot_threads_lock);
list_for_each_entry_reverse(cur, &hotplug_threads, list)
smpboot_park_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
return 0;
}
static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
{
unsigned int cpu;
/* We need to destroy also the parked threads of offline cpus */
for_each_possible_cpu(cpu) {
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (tsk) {
kthread_stop(tsk);
put_task_struct(tsk);
*per_cpu_ptr(ht->store, cpu) = NULL;
}
}
}
/**
* smpboot_register_percpu_thread - Register a per_cpu thread related
* to hotplug
* @plug_thread: Hotplug thread descriptor
*
* Creates and starts the threads on all online cpus.
*/
int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
{
unsigned int cpu;
int ret = 0;
cpus_read_lock();
mutex_lock(&smpboot_threads_lock);
for_each_online_cpu(cpu) {
ret = __smpboot_create_thread(plug_thread, cpu);
if (ret) {
smpboot_destroy_threads(plug_thread);
goto out;
}
smpboot_unpark_thread(plug_thread, cpu);
}
list_add(&plug_thread->list, &hotplug_threads);
out:
mutex_unlock(&smpboot_threads_lock);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
/**
* smpboot_unregister_percpu_thread - Unregister a per_cpu thread related to hotplug
* @plug_thread: Hotplug thread descriptor
*
* Stops all threads on all possible cpus.
*/
void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
{
cpus_read_lock();
mutex_lock(&smpboot_threads_lock);
list_del(&plug_thread->list);
smpboot_destroy_threads(plug_thread);
mutex_unlock(&smpboot_threads_lock);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
| linux-master | kernel/smpboot.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Generate definitions needed by the preprocessor.
* This code generates raw asm output which is post-processed
* to extract and format the required data.
*/
#define __GENERATING_BOUNDS_H
/* Include headers that define the enum constants of interest */
#include <linux/page-flags.h>
#include <linux/mmzone.h>
#include <linux/kbuild.h>
#include <linux/log2.h>
#include <linux/spinlock_types.h>
int main(void)
{
/* The enum constants to put into include/generated/bounds.h */
DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS);
DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES);
#ifdef CONFIG_SMP
DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS));
#endif
DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
#ifdef CONFIG_LRU_GEN
DEFINE(LRU_GEN_WIDTH, order_base_2(MAX_NR_GENS + 1));
DEFINE(__LRU_REFS_WIDTH, MAX_NR_TIERS - 2);
#else
DEFINE(LRU_GEN_WIDTH, 0);
DEFINE(__LRU_REFS_WIDTH, 0);
#endif
/* End of constants */
return 0;
}
| linux-master | kernel/bounds.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/sys.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/mm_inline.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/kmod.h>
#include <linux/ksm.h>
#include <linux/perf_event.h>
#include <linux/resource.h>
#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/posix-timers.h>
#include <linux/security.h>
#include <linux/random.h>
#include <linux/suspend.h>
#include <linux/tty.h>
#include <linux/signal.h>
#include <linux/cn_proc.h>
#include <linux/getcpu.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/seccomp.h>
#include <linux/cpu.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/fs_struct.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/gfp.h>
#include <linux/syscore_ops.h>
#include <linux/version.h>
#include <linux/ctype.h>
#include <linux/syscall_user_dispatch.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <linux/kprobes.h>
#include <linux/user_namespace.h>
#include <linux/time_namespace.h>
#include <linux/binfmts.h>
#include <linux/sched.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/loadavg.h>
#include <linux/sched/stat.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task.h>
#include <linux/sched/cputime.h>
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
#include <linux/nospec.h>
#include <linux/kmsg_dump.h>
/* Move somewhere else to avoid recompiling? */
#include <generated/utsrelease.h>
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/unistd.h>
#include "uid16.h"
#ifndef SET_UNALIGN_CTL
# define SET_UNALIGN_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_UNALIGN_CTL
# define GET_UNALIGN_CTL(a, b) (-EINVAL)
#endif
#ifndef SET_FPEMU_CTL
# define SET_FPEMU_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_FPEMU_CTL
# define GET_FPEMU_CTL(a, b) (-EINVAL)
#endif
#ifndef SET_FPEXC_CTL
# define SET_FPEXC_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_FPEXC_CTL
# define GET_FPEXC_CTL(a, b) (-EINVAL)
#endif
#ifndef GET_ENDIAN
# define GET_ENDIAN(a, b) (-EINVAL)
#endif
#ifndef SET_ENDIAN
# define SET_ENDIAN(a, b) (-EINVAL)
#endif
#ifndef GET_TSC_CTL
# define GET_TSC_CTL(a) (-EINVAL)
#endif
#ifndef SET_TSC_CTL
# define SET_TSC_CTL(a) (-EINVAL)
#endif
#ifndef GET_FP_MODE
# define GET_FP_MODE(a) (-EINVAL)
#endif
#ifndef SET_FP_MODE
# define SET_FP_MODE(a,b) (-EINVAL)
#endif
#ifndef SVE_SET_VL
# define SVE_SET_VL(a) (-EINVAL)
#endif
#ifndef SVE_GET_VL
# define SVE_GET_VL() (-EINVAL)
#endif
#ifndef SME_SET_VL
# define SME_SET_VL(a) (-EINVAL)
#endif
#ifndef SME_GET_VL
# define SME_GET_VL() (-EINVAL)
#endif
#ifndef PAC_RESET_KEYS
# define PAC_RESET_KEYS(a, b) (-EINVAL)
#endif
#ifndef PAC_SET_ENABLED_KEYS
# define PAC_SET_ENABLED_KEYS(a, b, c) (-EINVAL)
#endif
#ifndef PAC_GET_ENABLED_KEYS
# define PAC_GET_ENABLED_KEYS(a) (-EINVAL)
#endif
#ifndef SET_TAGGED_ADDR_CTRL
# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL)
#endif
#ifndef GET_TAGGED_ADDR_CTRL
# define GET_TAGGED_ADDR_CTRL() (-EINVAL)
#endif
#ifndef RISCV_V_SET_CONTROL
# define RISCV_V_SET_CONTROL(a) (-EINVAL)
#endif
#ifndef RISCV_V_GET_CONTROL
# define RISCV_V_GET_CONTROL() (-EINVAL)
#endif
/*
* this is where the system-wide overflow UID and GID are defined, for
* architectures that now have 32-bit UID/GID but didn't in the past
*/
int overflowuid = DEFAULT_OVERFLOWUID;
int overflowgid = DEFAULT_OVERFLOWGID;
EXPORT_SYMBOL(overflowuid);
EXPORT_SYMBOL(overflowgid);
/*
* the same as above, but for filesystems which can only store a 16-bit
* UID and GID. as such, this is needed on all architectures
*/
int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
EXPORT_SYMBOL(fs_overflowuid);
EXPORT_SYMBOL(fs_overflowgid);
/*
* Returns true if current's euid is same as p's uid or euid,
* or has CAP_SYS_NICE to p's user_ns.
*
* Called with rcu_read_lock, creds are safe
*/
static bool set_one_prio_perm(struct task_struct *p)
{
const struct cred *cred = current_cred(), *pcred = __task_cred(p);
if (uid_eq(pcred->uid, cred->euid) ||
uid_eq(pcred->euid, cred->euid))
return true;
if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
return true;
return false;
}
/*
* set the priority of a task
* - the caller must hold the RCU read lock
*/
static int set_one_prio(struct task_struct *p, int niceval, int error)
{
int no_nice;
if (!set_one_prio_perm(p)) {
error = -EPERM;
goto out;
}
if (niceval < task_nice(p) && !can_nice(p, niceval)) {
error = -EACCES;
goto out;
}
no_nice = security_task_setnice(p, niceval);
if (no_nice) {
error = no_nice;
goto out;
}
if (error == -ESRCH)
error = 0;
set_user_nice(p, niceval);
out:
return error;
}
SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
{
struct task_struct *g, *p;
struct user_struct *user;
const struct cred *cred = current_cred();
int error = -EINVAL;
struct pid *pgrp;
kuid_t uid;
if (which > PRIO_USER || which < PRIO_PROCESS)
goto out;
/* normalize: avoid signed division (rounding problems) */
error = -ESRCH;
if (niceval < MIN_NICE)
niceval = MIN_NICE;
if (niceval > MAX_NICE)
niceval = MAX_NICE;
rcu_read_lock();
switch (which) {
case PRIO_PROCESS:
if (who)
p = find_task_by_vpid(who);
else
p = current;
if (p)
error = set_one_prio(p, niceval, error);
break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
read_lock(&tasklist_lock);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
error = set_one_prio(p, niceval, error);
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
read_unlock(&tasklist_lock);
break;
case PRIO_USER:
uid = make_kuid(cred->user_ns, who);
user = cred->user;
if (!who)
uid = cred->uid;
else if (!uid_eq(uid, cred->uid)) {
user = find_user(uid);
if (!user)
goto out_unlock; /* No processes for this user */
}
for_each_process_thread(g, p) {
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
error = set_one_prio(p, niceval, error);
}
if (!uid_eq(uid, cred->uid))
free_uid(user); /* For find_user() */
break;
}
out_unlock:
rcu_read_unlock();
out:
return error;
}
/*
* Ugh. To avoid negative return values, "getpriority()" will
* not return the normal nice-value, but a negated value that
* has been offset by 20 (ie it returns 40..1 instead of -20..19)
* to stay compatible.
*/
SYSCALL_DEFINE2(getpriority, int, which, int, who)
{
struct task_struct *g, *p;
struct user_struct *user;
const struct cred *cred = current_cred();
long niceval, retval = -ESRCH;
struct pid *pgrp;
kuid_t uid;
if (which > PRIO_USER || which < PRIO_PROCESS)
return -EINVAL;
rcu_read_lock();
switch (which) {
case PRIO_PROCESS:
if (who)
p = find_task_by_vpid(who);
else
p = current;
if (p) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
}
break;
case PRIO_PGRP:
if (who)
pgrp = find_vpid(who);
else
pgrp = task_pgrp(current);
read_lock(&tasklist_lock);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
read_unlock(&tasklist_lock);
break;
case PRIO_USER:
uid = make_kuid(cred->user_ns, who);
user = cred->user;
if (!who)
uid = cred->uid;
else if (!uid_eq(uid, cred->uid)) {
user = find_user(uid);
if (!user)
goto out_unlock; /* No processes for this user */
}
for_each_process_thread(g, p) {
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
}
}
if (!uid_eq(uid, cred->uid))
free_uid(user); /* for find_user() */
break;
}
out_unlock:
rcu_read_unlock();
return retval;
}
/*
* Unprivileged users may change the real gid to the effective gid
* or vice versa. (BSD-style)
*
* If you set the real gid at all, or set the effective gid to a value not
* equal to the real gid, then the saved gid is set to the new effective gid.
*
* This makes it possible for a setgid program to completely drop its
* privileges, which is often a useful assertion to make when you are doing
* a security audit over a program.
*
* The general idea is that a program which uses just setregid() will be
* 100% compatible with BSD. A program which uses just setgid() will be
* 100% compatible with POSIX with saved IDs.
*
* SMP: There are not races, the GIDs are checked only by filesystem
* operations (as far as semantic preservation is concerned).
*/
#ifdef CONFIG_MULTIUSER
long __sys_setregid(gid_t rgid, gid_t egid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t krgid, kegid;
krgid = make_kgid(ns, rgid);
kegid = make_kgid(ns, egid);
if ((rgid != (gid_t) -1) && !gid_valid(krgid))
return -EINVAL;
if ((egid != (gid_t) -1) && !gid_valid(kegid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (rgid != (gid_t) -1) {
if (gid_eq(old->gid, krgid) ||
gid_eq(old->egid, krgid) ||
ns_capable_setid(old->user_ns, CAP_SETGID))
new->gid = krgid;
else
goto error;
}
if (egid != (gid_t) -1) {
if (gid_eq(old->gid, kegid) ||
gid_eq(old->egid, kegid) ||
gid_eq(old->sgid, kegid) ||
ns_capable_setid(old->user_ns, CAP_SETGID))
new->egid = kegid;
else
goto error;
}
if (rgid != (gid_t) -1 ||
(egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
new->sgid = new->egid;
new->fsgid = new->egid;
retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
{
return __sys_setregid(rgid, egid);
}
/*
* setgid() is implemented like SysV w/ SAVED_IDS
*
* SMP: Same implicit races as above.
*/
long __sys_setgid(gid_t gid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t kgid;
kgid = make_kgid(ns, gid);
if (!gid_valid(kgid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ns_capable_setid(old->user_ns, CAP_SETGID))
new->gid = new->egid = new->sgid = new->fsgid = kgid;
else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
new->egid = new->fsgid = kgid;
else
goto error;
retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE1(setgid, gid_t, gid)
{
return __sys_setgid(gid);
}
/*
* change the user struct in a credentials set to match the new UID
*/
static int set_user(struct cred *new)
{
struct user_struct *new_user;
new_user = alloc_uid(new->uid);
if (!new_user)
return -EAGAIN;
free_uid(new->user);
new->user = new_user;
return 0;
}
static void flag_nproc_exceeded(struct cred *new)
{
if (new->ucounts == current_ucounts())
return;
/*
* We don't fail in case of NPROC limit excess here because too many
* poorly written programs don't check set*uid() return code, assuming
* it never fails if called by root. We may still enforce NPROC limit
* for programs doing set*uid()+execve() by harmlessly deferring the
* failure to the execve() stage.
*/
if (is_rlimit_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) &&
new->user != INIT_USER)
current->flags |= PF_NPROC_EXCEEDED;
else
current->flags &= ~PF_NPROC_EXCEEDED;
}
/*
* Unprivileged users may change the real uid to the effective uid
* or vice versa. (BSD-style)
*
* If you set the real uid at all, or set the effective uid to a value not
* equal to the real uid, then the saved uid is set to the new effective uid.
*
* This makes it possible for a setuid program to completely drop its
* privileges, which is often a useful assertion to make when you are doing
* a security audit over a program.
*
* The general idea is that a program which uses just setreuid() will be
* 100% compatible with BSD. A program which uses just setuid() will be
* 100% compatible with POSIX with saved IDs.
*/
long __sys_setreuid(uid_t ruid, uid_t euid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kruid, keuid;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
if ((ruid != (uid_t) -1) && !uid_valid(kruid))
return -EINVAL;
if ((euid != (uid_t) -1) && !uid_valid(keuid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ruid != (uid_t) -1) {
new->uid = kruid;
if (!uid_eq(old->uid, kruid) &&
!uid_eq(old->euid, kruid) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
goto error;
}
if (euid != (uid_t) -1) {
new->euid = keuid;
if (!uid_eq(old->uid, keuid) &&
!uid_eq(old->euid, keuid) &&
!uid_eq(old->suid, keuid) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
goto error;
}
if (!uid_eq(new->uid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
new->suid = new->euid;
new->fsuid = new->euid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
flag_nproc_exceeded(new);
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
{
return __sys_setreuid(ruid, euid);
}
/*
* setuid() is implemented like SysV with SAVED_IDS
*
* Note that SAVED_ID's is deficient in that a setuid root program
* like sendmail, for example, cannot set its uid to be a normal
* user and then switch back, because if you're root, setuid() sets
* the saved uid too. If you don't like this, blame the bright people
* in the POSIX committee and/or USG. Note that the BSD-style setreuid()
* will allow a root program to temporarily drop privileges and be able to
* regain them by swapping the real and effective uid.
*/
long __sys_setuid(uid_t uid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kuid;
kuid = make_kuid(ns, uid);
if (!uid_valid(kuid))
return -EINVAL;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
retval = -EPERM;
if (ns_capable_setid(old->user_ns, CAP_SETUID)) {
new->suid = new->uid = kuid;
if (!uid_eq(kuid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
} else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
goto error;
}
new->fsuid = new->euid = kuid;
retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
flag_nproc_exceeded(new);
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE1(setuid, uid_t, uid)
{
return __sys_setuid(uid);
}
/*
* This function implements a generic ability to update ruid, euid,
* and suid. This allows you to implement the 4.4 compatible seteuid().
*/
long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kuid_t kruid, keuid, ksuid;
bool ruid_new, euid_new, suid_new;
kruid = make_kuid(ns, ruid);
keuid = make_kuid(ns, euid);
ksuid = make_kuid(ns, suid);
if ((ruid != (uid_t) -1) && !uid_valid(kruid))
return -EINVAL;
if ((euid != (uid_t) -1) && !uid_valid(keuid))
return -EINVAL;
if ((suid != (uid_t) -1) && !uid_valid(ksuid))
return -EINVAL;
old = current_cred();
/* check for no-op */
if ((ruid == (uid_t) -1 || uid_eq(kruid, old->uid)) &&
(euid == (uid_t) -1 || (uid_eq(keuid, old->euid) &&
uid_eq(keuid, old->fsuid))) &&
(suid == (uid_t) -1 || uid_eq(ksuid, old->suid)))
return 0;
ruid_new = ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
!uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid);
euid_new = euid != (uid_t) -1 && !uid_eq(keuid, old->uid) &&
!uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid);
suid_new = suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) &&
!uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid);
if ((ruid_new || euid_new || suid_new) &&
!ns_capable_setid(old->user_ns, CAP_SETUID))
return -EPERM;
new = prepare_creds();
if (!new)
return -ENOMEM;
if (ruid != (uid_t) -1) {
new->uid = kruid;
if (!uid_eq(kruid, old->uid)) {
retval = set_user(new);
if (retval < 0)
goto error;
}
}
if (euid != (uid_t) -1)
new->euid = keuid;
if (suid != (uid_t) -1)
new->suid = ksuid;
new->fsuid = new->euid;
retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
flag_nproc_exceeded(new);
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
{
return __sys_setresuid(ruid, euid, suid);
}
SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
{
const struct cred *cred = current_cred();
int retval;
uid_t ruid, euid, suid;
ruid = from_kuid_munged(cred->user_ns, cred->uid);
euid = from_kuid_munged(cred->user_ns, cred->euid);
suid = from_kuid_munged(cred->user_ns, cred->suid);
retval = put_user(ruid, ruidp);
if (!retval) {
retval = put_user(euid, euidp);
if (!retval)
return put_user(suid, suidp);
}
return retval;
}
/*
* Same as above, but for rgid, egid, sgid.
*/
long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
{
struct user_namespace *ns = current_user_ns();
const struct cred *old;
struct cred *new;
int retval;
kgid_t krgid, kegid, ksgid;
bool rgid_new, egid_new, sgid_new;
krgid = make_kgid(ns, rgid);
kegid = make_kgid(ns, egid);
ksgid = make_kgid(ns, sgid);
if ((rgid != (gid_t) -1) && !gid_valid(krgid))
return -EINVAL;
if ((egid != (gid_t) -1) && !gid_valid(kegid))
return -EINVAL;
if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
return -EINVAL;
old = current_cred();
/* check for no-op */
if ((rgid == (gid_t) -1 || gid_eq(krgid, old->gid)) &&
(egid == (gid_t) -1 || (gid_eq(kegid, old->egid) &&
gid_eq(kegid, old->fsgid))) &&
(sgid == (gid_t) -1 || gid_eq(ksgid, old->sgid)))
return 0;
rgid_new = rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
!gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid);
egid_new = egid != (gid_t) -1 && !gid_eq(kegid, old->gid) &&
!gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid);
sgid_new = sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) &&
!gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid);
if ((rgid_new || egid_new || sgid_new) &&
!ns_capable_setid(old->user_ns, CAP_SETGID))
return -EPERM;
new = prepare_creds();
if (!new)
return -ENOMEM;
if (rgid != (gid_t) -1)
new->gid = krgid;
if (egid != (gid_t) -1)
new->egid = kegid;
if (sgid != (gid_t) -1)
new->sgid = ksgid;
new->fsgid = new->egid;
retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
{
return __sys_setresgid(rgid, egid, sgid);
}
SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
{
const struct cred *cred = current_cred();
int retval;
gid_t rgid, egid, sgid;
rgid = from_kgid_munged(cred->user_ns, cred->gid);
egid = from_kgid_munged(cred->user_ns, cred->egid);
sgid = from_kgid_munged(cred->user_ns, cred->sgid);
retval = put_user(rgid, rgidp);
if (!retval) {
retval = put_user(egid, egidp);
if (!retval)
retval = put_user(sgid, sgidp);
}
return retval;
}
/*
* "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
* is used for "access()" and for the NFS daemon (letting nfsd stay at
* whatever uid it wants to). It normally shadows "euid", except when
* explicitly set by setfsuid() or for access..
*/
long __sys_setfsuid(uid_t uid)
{
const struct cred *old;
struct cred *new;
uid_t old_fsuid;
kuid_t kuid;
old = current_cred();
old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
kuid = make_kuid(old->user_ns, uid);
if (!uid_valid(kuid))
return old_fsuid;
new = prepare_creds();
if (!new)
return old_fsuid;
if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) ||
uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
ns_capable_setid(old->user_ns, CAP_SETUID)) {
if (!uid_eq(kuid, old->fsuid)) {
new->fsuid = kuid;
if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
goto change_okay;
}
}
abort_creds(new);
return old_fsuid;
change_okay:
commit_creds(new);
return old_fsuid;
}
SYSCALL_DEFINE1(setfsuid, uid_t, uid)
{
return __sys_setfsuid(uid);
}
/*
* Samma på svenska..
*/
long __sys_setfsgid(gid_t gid)
{
const struct cred *old;
struct cred *new;
gid_t old_fsgid;
kgid_t kgid;
old = current_cred();
old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
kgid = make_kgid(old->user_ns, gid);
if (!gid_valid(kgid))
return old_fsgid;
new = prepare_creds();
if (!new)
return old_fsgid;
if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
ns_capable_setid(old->user_ns, CAP_SETGID)) {
if (!gid_eq(kgid, old->fsgid)) {
new->fsgid = kgid;
if (security_task_fix_setgid(new,old,LSM_SETID_FS) == 0)
goto change_okay;
}
}
abort_creds(new);
return old_fsgid;
change_okay:
commit_creds(new);
return old_fsgid;
}
SYSCALL_DEFINE1(setfsgid, gid_t, gid)
{
return __sys_setfsgid(gid);
}
#endif /* CONFIG_MULTIUSER */
/**
* sys_getpid - return the thread group id of the current process
*
* Note, despite the name, this returns the tgid not the pid. The tgid and
* the pid are identical unless CLONE_THREAD was specified on clone() in
* which case the tgid is the same in all threads of the same group.
*
* This is SMP safe as current->tgid does not change.
*/
SYSCALL_DEFINE0(getpid)
{
return task_tgid_vnr(current);
}
/* Thread ID - the internal kernel "pid" */
SYSCALL_DEFINE0(gettid)
{
return task_pid_vnr(current);
}
/*
* Accessing ->real_parent is not SMP-safe, it could
* change from under us. However, we can use a stale
* value of ->real_parent under rcu_read_lock(), see
* release_task()->call_rcu(delayed_put_task_struct).
*/
SYSCALL_DEFINE0(getppid)
{
int pid;
rcu_read_lock();
pid = task_tgid_vnr(rcu_dereference(current->real_parent));
rcu_read_unlock();
return pid;
}
SYSCALL_DEFINE0(getuid)
{
/* Only we change this so SMP safe */
return from_kuid_munged(current_user_ns(), current_uid());
}
SYSCALL_DEFINE0(geteuid)
{
/* Only we change this so SMP safe */
return from_kuid_munged(current_user_ns(), current_euid());
}
SYSCALL_DEFINE0(getgid)
{
/* Only we change this so SMP safe */
return from_kgid_munged(current_user_ns(), current_gid());
}
SYSCALL_DEFINE0(getegid)
{
/* Only we change this so SMP safe */
return from_kgid_munged(current_user_ns(), current_egid());
}
static void do_sys_times(struct tms *tms)
{
u64 tgutime, tgstime, cutime, cstime;
thread_group_cputime_adjusted(current, &tgutime, &tgstime);
cutime = current->signal->cutime;
cstime = current->signal->cstime;
tms->tms_utime = nsec_to_clock_t(tgutime);
tms->tms_stime = nsec_to_clock_t(tgstime);
tms->tms_cutime = nsec_to_clock_t(cutime);
tms->tms_cstime = nsec_to_clock_t(cstime);
}
SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
{
if (tbuf) {
struct tms tmp;
do_sys_times(&tmp);
if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
return -EFAULT;
}
force_successful_syscall_return();
return (long) jiffies_64_to_clock_t(get_jiffies_64());
}
#ifdef CONFIG_COMPAT
static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
{
return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
}
COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
{
if (tbuf) {
struct tms tms;
struct compat_tms tmp;
do_sys_times(&tms);
/* Convert our struct tms to the compat version. */
tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
return -EFAULT;
}
force_successful_syscall_return();
return compat_jiffies_to_clock_t(jiffies);
}
#endif
/*
* This needs some heavy checking ...
* I just haven't the stomach for it. I also don't fully
* understand sessions/pgrp etc. Let somebody who does explain it.
*
* OK, I think I have the protection semantics right.... this is really
* only important on a multi-user system anyway, to make sure one user
* can't send a signal to a process owned by another. -TYT, 12/12/91
*
* !PF_FORKNOEXEC check to conform completely to POSIX.
*/
SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
{
struct task_struct *p;
struct task_struct *group_leader = current->group_leader;
struct pid *pgrp;
int err;
if (!pid)
pid = task_pid_vnr(group_leader);
if (!pgid)
pgid = pid;
if (pgid < 0)
return -EINVAL;
rcu_read_lock();
/* From this point forward we keep holding onto the tasklist lock
* so that our parent does not change from under us. -DaveM
*/
write_lock_irq(&tasklist_lock);
err = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
err = -EINVAL;
if (!thread_group_leader(p))
goto out;
if (same_thread_group(p->real_parent, group_leader)) {
err = -EPERM;
if (task_session(p) != task_session(group_leader))
goto out;
err = -EACCES;
if (!(p->flags & PF_FORKNOEXEC))
goto out;
} else {
err = -ESRCH;
if (p != group_leader)
goto out;
}
err = -EPERM;
if (p->signal->leader)
goto out;
pgrp = task_pid(p);
if (pgid != pid) {
struct task_struct *g;
pgrp = find_vpid(pgid);
g = pid_task(pgrp, PIDTYPE_PGID);
if (!g || task_session(g) != task_session(group_leader))
goto out;
}
err = security_task_setpgid(p, pgid);
if (err)
goto out;
if (task_pgrp(p) != pgrp)
change_pid(p, PIDTYPE_PGID, pgrp);
err = 0;
out:
/* All paths lead to here, thus we are safe. -DaveM */
write_unlock_irq(&tasklist_lock);
rcu_read_unlock();
return err;
}
static int do_getpgid(pid_t pid)
{
struct task_struct *p;
struct pid *grp;
int retval;
rcu_read_lock();
if (!pid)
grp = task_pgrp(current);
else {
retval = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
grp = task_pgrp(p);
if (!grp)
goto out;
retval = security_task_getpgid(p);
if (retval)
goto out;
}
retval = pid_vnr(grp);
out:
rcu_read_unlock();
return retval;
}
SYSCALL_DEFINE1(getpgid, pid_t, pid)
{
return do_getpgid(pid);
}
#ifdef __ARCH_WANT_SYS_GETPGRP
SYSCALL_DEFINE0(getpgrp)
{
return do_getpgid(0);
}
#endif
SYSCALL_DEFINE1(getsid, pid_t, pid)
{
struct task_struct *p;
struct pid *sid;
int retval;
rcu_read_lock();
if (!pid)
sid = task_session(current);
else {
retval = -ESRCH;
p = find_task_by_vpid(pid);
if (!p)
goto out;
sid = task_session(p);
if (!sid)
goto out;
retval = security_task_getsid(p);
if (retval)
goto out;
}
retval = pid_vnr(sid);
out:
rcu_read_unlock();
return retval;
}
static void set_special_pids(struct pid *pid)
{
struct task_struct *curr = current->group_leader;
if (task_session(curr) != pid)
change_pid(curr, PIDTYPE_SID, pid);
if (task_pgrp(curr) != pid)
change_pid(curr, PIDTYPE_PGID, pid);
}
int ksys_setsid(void)
{
struct task_struct *group_leader = current->group_leader;
struct pid *sid = task_pid(group_leader);
pid_t session = pid_vnr(sid);
int err = -EPERM;
write_lock_irq(&tasklist_lock);
/* Fail if I am already a session leader */
if (group_leader->signal->leader)
goto out;
/* Fail if a process group id already exists that equals the
* proposed session id.
*/
if (pid_task(sid, PIDTYPE_PGID))
goto out;
group_leader->signal->leader = 1;
set_special_pids(sid);
proc_clear_tty(group_leader);
err = session;
out:
write_unlock_irq(&tasklist_lock);
if (err > 0) {
proc_sid_connector(group_leader);
sched_autogroup_create_attach(group_leader);
}
return err;
}
SYSCALL_DEFINE0(setsid)
{
return ksys_setsid();
}
DECLARE_RWSEM(uts_sem);
#ifdef COMPAT_UTS_MACHINE
#define override_architecture(name) \
(personality(current->personality) == PER_LINUX32 && \
copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
sizeof(COMPAT_UTS_MACHINE)))
#else
#define override_architecture(name) 0
#endif
/*
* Work around broken programs that cannot handle "Linux 3.0".
* Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
* And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be
* 2.6.60.
*/
static int override_release(char __user *release, size_t len)
{
int ret = 0;
if (current->personality & UNAME26) {
const char *rest = UTS_RELEASE;
char buf[65] = { 0 };
int ndots = 0;
unsigned v;
size_t copy;
while (*rest) {
if (*rest == '.' && ++ndots >= 3)
break;
if (!isdigit(*rest) && *rest != '.')
break;
rest++;
}
v = LINUX_VERSION_PATCHLEVEL + 60;
copy = clamp_t(size_t, len, 1, sizeof(buf));
copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
ret = copy_to_user(release, buf, copy + 1);
}
return ret;
}
SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
{
struct new_utsname tmp;
down_read(&uts_sem);
memcpy(&tmp, utsname(), sizeof(tmp));
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
return 0;
}
#ifdef __ARCH_WANT_SYS_OLD_UNAME
/*
* Old cruft
*/
SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
{
struct old_utsname tmp;
if (!name)
return -EFAULT;
down_read(&uts_sem);
memcpy(&tmp, utsname(), sizeof(tmp));
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
return 0;
}
SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
{
struct oldold_utsname tmp;
if (!name)
return -EFAULT;
memset(&tmp, 0, sizeof(tmp));
down_read(&uts_sem);
memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
up_read(&uts_sem);
if (copy_to_user(name, &tmp, sizeof(tmp)))
return -EFAULT;
if (override_architecture(name))
return -EFAULT;
if (override_release(name->release, sizeof(name->release)))
return -EFAULT;
return 0;
}
#endif
SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
{
int errno;
char tmp[__NEW_UTS_LEN];
if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *u;
add_device_randomness(tmp, len);
down_write(&uts_sem);
u = utsname();
memcpy(u->nodename, tmp, len);
memset(u->nodename + len, 0, sizeof(u->nodename) - len);
errno = 0;
uts_proc_notify(UTS_PROC_HOSTNAME);
up_write(&uts_sem);
}
return errno;
}
#ifdef __ARCH_WANT_SYS_GETHOSTNAME
SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
{
int i;
struct new_utsname *u;
char tmp[__NEW_UTS_LEN + 1];
if (len < 0)
return -EINVAL;
down_read(&uts_sem);
u = utsname();
i = 1 + strlen(u->nodename);
if (i > len)
i = len;
memcpy(tmp, u->nodename, i);
up_read(&uts_sem);
if (copy_to_user(name, tmp, i))
return -EFAULT;
return 0;
}
#endif
/*
* Only setdomainname; getdomainname can be implemented by calling
* uname()
*/
SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
{
int errno;
char tmp[__NEW_UTS_LEN];
if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
errno = -EFAULT;
if (!copy_from_user(tmp, name, len)) {
struct new_utsname *u;
add_device_randomness(tmp, len);
down_write(&uts_sem);
u = utsname();
memcpy(u->domainname, tmp, len);
memset(u->domainname + len, 0, sizeof(u->domainname) - len);
errno = 0;
uts_proc_notify(UTS_PROC_DOMAINNAME);
up_write(&uts_sem);
}
return errno;
}
/* make sure you are allowed to change @tsk limits before calling this */
static int do_prlimit(struct task_struct *tsk, unsigned int resource,
struct rlimit *new_rlim, struct rlimit *old_rlim)
{
struct rlimit *rlim;
int retval = 0;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
if (new_rlim) {
if (new_rlim->rlim_cur > new_rlim->rlim_max)
return -EINVAL;
if (resource == RLIMIT_NOFILE &&
new_rlim->rlim_max > sysctl_nr_open)
return -EPERM;
}
/* Holding a refcount on tsk protects tsk->signal from disappearing. */
rlim = tsk->signal->rlim + resource;
task_lock(tsk->group_leader);
if (new_rlim) {
/*
* Keep the capable check against init_user_ns until cgroups can
* contain all limits.
*/
if (new_rlim->rlim_max > rlim->rlim_max &&
!capable(CAP_SYS_RESOURCE))
retval = -EPERM;
if (!retval)
retval = security_task_setrlimit(tsk, resource, new_rlim);
}
if (!retval) {
if (old_rlim)
*old_rlim = *rlim;
if (new_rlim)
*rlim = *new_rlim;
}
task_unlock(tsk->group_leader);
/*
* RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
* infinite. In case of RLIM_INFINITY the posix CPU timer code
* ignores the rlimit.
*/
if (!retval && new_rlim && resource == RLIMIT_CPU &&
new_rlim->rlim_cur != RLIM_INFINITY &&
IS_ENABLED(CONFIG_POSIX_TIMERS)) {
/*
* update_rlimit_cpu can fail if the task is exiting, but there
* may be other tasks in the thread group that are not exiting,
* and they need their cpu timers adjusted.
*
* The group_leader is the last task to be released, so if we
* cannot update_rlimit_cpu on it, then the entire process is
* exiting and we do not need to update at all.
*/
update_rlimit_cpu(tsk->group_leader, new_rlim->rlim_cur);
}
return retval;
}
SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
{
struct rlimit value;
int ret;
ret = do_prlimit(current, resource, NULL, &value);
if (!ret)
ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
return ret;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
struct compat_rlimit r32;
if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit)))
return -EFAULT;
if (r32.rlim_cur == COMPAT_RLIM_INFINITY)
r.rlim_cur = RLIM_INFINITY;
else
r.rlim_cur = r32.rlim_cur;
if (r32.rlim_max == COMPAT_RLIM_INFINITY)
r.rlim_max = RLIM_INFINITY;
else
r.rlim_max = r32.rlim_max;
return do_prlimit(current, resource, &r, NULL);
}
COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
int ret;
ret = do_prlimit(current, resource, NULL, &r);
if (!ret) {
struct compat_rlimit r32;
if (r.rlim_cur > COMPAT_RLIM_INFINITY)
r32.rlim_cur = COMPAT_RLIM_INFINITY;
else
r32.rlim_cur = r.rlim_cur;
if (r.rlim_max > COMPAT_RLIM_INFINITY)
r32.rlim_max = COMPAT_RLIM_INFINITY;
else
r32.rlim_max = r.rlim_max;
if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit)))
return -EFAULT;
}
return ret;
}
#endif
#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
/*
* Back compatibility for getrlimit. Needed for some apps.
*/
SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
struct rlimit __user *, rlim)
{
struct rlimit x;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
task_lock(current->group_leader);
x = current->signal->rlim[resource];
task_unlock(current->group_leader);
if (x.rlim_cur > 0x7FFFFFFF)
x.rlim_cur = 0x7FFFFFFF;
if (x.rlim_max > 0x7FFFFFFF)
x.rlim_max = 0x7FFFFFFF;
return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
struct compat_rlimit __user *, rlim)
{
struct rlimit r;
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
task_lock(current->group_leader);
r = current->signal->rlim[resource];
task_unlock(current->group_leader);
if (r.rlim_cur > 0x7FFFFFFF)
r.rlim_cur = 0x7FFFFFFF;
if (r.rlim_max > 0x7FFFFFFF)
r.rlim_max = 0x7FFFFFFF;
if (put_user(r.rlim_cur, &rlim->rlim_cur) ||
put_user(r.rlim_max, &rlim->rlim_max))
return -EFAULT;
return 0;
}
#endif
#endif
static inline bool rlim64_is_infinity(__u64 rlim64)
{
#if BITS_PER_LONG < 64
return rlim64 >= ULONG_MAX;
#else
return rlim64 == RLIM64_INFINITY;
#endif
}
static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
{
if (rlim->rlim_cur == RLIM_INFINITY)
rlim64->rlim_cur = RLIM64_INFINITY;
else
rlim64->rlim_cur = rlim->rlim_cur;
if (rlim->rlim_max == RLIM_INFINITY)
rlim64->rlim_max = RLIM64_INFINITY;
else
rlim64->rlim_max = rlim->rlim_max;
}
static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
{
if (rlim64_is_infinity(rlim64->rlim_cur))
rlim->rlim_cur = RLIM_INFINITY;
else
rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
if (rlim64_is_infinity(rlim64->rlim_max))
rlim->rlim_max = RLIM_INFINITY;
else
rlim->rlim_max = (unsigned long)rlim64->rlim_max;
}
/* rcu lock must be held */
static int check_prlimit_permission(struct task_struct *task,
unsigned int flags)
{
const struct cred *cred = current_cred(), *tcred;
bool id_match;
if (current == task)
return 0;
tcred = __task_cred(task);
id_match = (uid_eq(cred->uid, tcred->euid) &&
uid_eq(cred->uid, tcred->suid) &&
uid_eq(cred->uid, tcred->uid) &&
gid_eq(cred->gid, tcred->egid) &&
gid_eq(cred->gid, tcred->sgid) &&
gid_eq(cred->gid, tcred->gid));
if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
return -EPERM;
return security_task_prlimit(cred, tcred, flags);
}
SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
const struct rlimit64 __user *, new_rlim,
struct rlimit64 __user *, old_rlim)
{
struct rlimit64 old64, new64;
struct rlimit old, new;
struct task_struct *tsk;
unsigned int checkflags = 0;
int ret;
if (old_rlim)
checkflags |= LSM_PRLIMIT_READ;
if (new_rlim) {
if (copy_from_user(&new64, new_rlim, sizeof(new64)))
return -EFAULT;
rlim64_to_rlim(&new64, &new);
checkflags |= LSM_PRLIMIT_WRITE;
}
rcu_read_lock();
tsk = pid ? find_task_by_vpid(pid) : current;
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
ret = check_prlimit_permission(tsk, checkflags);
if (ret) {
rcu_read_unlock();
return ret;
}
get_task_struct(tsk);
rcu_read_unlock();
ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
old_rlim ? &old : NULL);
if (!ret && old_rlim) {
rlim_to_rlim64(&old, &old64);
if (copy_to_user(old_rlim, &old64, sizeof(old64)))
ret = -EFAULT;
}
put_task_struct(tsk);
return ret;
}
SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
{
struct rlimit new_rlim;
if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
return -EFAULT;
return do_prlimit(current, resource, &new_rlim, NULL);
}
/*
* It would make sense to put struct rusage in the task_struct,
* except that would make the task_struct be *really big*. After
* task_struct gets moved into malloc'ed memory, it would
* make sense to do this. It will make moving the rest of the information
* a lot simpler! (Which we're not doing right now because we're not
* measuring them yet).
*
* When sampling multiple threads for RUSAGE_SELF, under SMP we might have
* races with threads incrementing their own counters. But since word
* reads are atomic, we either get new values or old values and we don't
* care which for the sums. We always take the siglock to protect reading
* the c* fields from p->signal from races with exit.c updating those
* fields when reaping, so a sample either gets all the additions of a
* given child after it's reaped, or none so this sample is before reaping.
*
* Locking:
* We need to take the siglock for CHILDEREN, SELF and BOTH
* for the cases current multithreaded, non-current single threaded
* non-current multithreaded. Thread traversal is now safe with
* the siglock held.
* Strictly speaking, we donot need to take the siglock if we are current and
* single threaded, as no one else can take our signal_struct away, no one
* else can reap the children to update signal->c* counters, and no one else
* can race with the signal-> fields. If we do not take any lock, the
* signal-> fields could be read out of order while another thread was just
* exiting. So we should place a read memory barrier when we avoid the lock.
* On the writer side, write memory barrier is implied in __exit_signal
* as __exit_signal releases the siglock spinlock after updating the signal->
* fields. But we don't do this yet to keep things simple.
*
*/
static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
{
r->ru_nvcsw += t->nvcsw;
r->ru_nivcsw += t->nivcsw;
r->ru_minflt += t->min_flt;
r->ru_majflt += t->maj_flt;
r->ru_inblock += task_io_get_inblock(t);
r->ru_oublock += task_io_get_oublock(t);
}
void getrusage(struct task_struct *p, int who, struct rusage *r)
{
struct task_struct *t;
unsigned long flags;
u64 tgutime, tgstime, utime, stime;
unsigned long maxrss = 0;
memset((char *)r, 0, sizeof (*r));
utime = stime = 0;
if (who == RUSAGE_THREAD) {
task_cputime_adjusted(current, &utime, &stime);
accumulate_thread_rusage(p, r);
maxrss = p->signal->maxrss;
goto out;
}
if (!lock_task_sighand(p, &flags))
return;
switch (who) {
case RUSAGE_BOTH:
case RUSAGE_CHILDREN:
utime = p->signal->cutime;
stime = p->signal->cstime;
r->ru_nvcsw = p->signal->cnvcsw;
r->ru_nivcsw = p->signal->cnivcsw;
r->ru_minflt = p->signal->cmin_flt;
r->ru_majflt = p->signal->cmaj_flt;
r->ru_inblock = p->signal->cinblock;
r->ru_oublock = p->signal->coublock;
maxrss = p->signal->cmaxrss;
if (who == RUSAGE_CHILDREN)
break;
fallthrough;
case RUSAGE_SELF:
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
utime += tgutime;
stime += tgstime;
r->ru_nvcsw += p->signal->nvcsw;
r->ru_nivcsw += p->signal->nivcsw;
r->ru_minflt += p->signal->min_flt;
r->ru_majflt += p->signal->maj_flt;
r->ru_inblock += p->signal->inblock;
r->ru_oublock += p->signal->oublock;
if (maxrss < p->signal->maxrss)
maxrss = p->signal->maxrss;
t = p;
do {
accumulate_thread_rusage(t, r);
} while_each_thread(p, t);
break;
default:
BUG();
}
unlock_task_sighand(p, &flags);
out:
r->ru_utime = ns_to_kernel_old_timeval(utime);
r->ru_stime = ns_to_kernel_old_timeval(stime);
if (who != RUSAGE_CHILDREN) {
struct mm_struct *mm = get_task_mm(p);
if (mm) {
setmax_mm_hiwater_rss(&maxrss, mm);
mmput(mm);
}
}
r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
}
SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
{
struct rusage r;
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
who != RUSAGE_THREAD)
return -EINVAL;
getrusage(current, who, &r);
return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
{
struct rusage r;
if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
who != RUSAGE_THREAD)
return -EINVAL;
getrusage(current, who, &r);
return put_compat_rusage(&r, ru);
}
#endif
SYSCALL_DEFINE1(umask, int, mask)
{
mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
return mask;
}
static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
{
struct fd exe;
struct inode *inode;
int err;
exe = fdget(fd);
if (!exe.file)
return -EBADF;
inode = file_inode(exe.file);
/*
* Because the original mm->exe_file points to executable file, make
* sure that this one is executable as well, to avoid breaking an
* overall picture.
*/
err = -EACCES;
if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
goto exit;
err = file_permission(exe.file, MAY_EXEC);
if (err)
goto exit;
err = replace_mm_exe_file(mm, exe.file);
exit:
fdput(exe);
return err;
}
/*
* Check arithmetic relations of passed addresses.
*
* WARNING: we don't require any capability here so be very careful
* in what is allowed for modification from userspace.
*/
static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map)
{
unsigned long mmap_max_addr = TASK_SIZE;
int error = -EINVAL, i;
static const unsigned char offsets[] = {
offsetof(struct prctl_mm_map, start_code),
offsetof(struct prctl_mm_map, end_code),
offsetof(struct prctl_mm_map, start_data),
offsetof(struct prctl_mm_map, end_data),
offsetof(struct prctl_mm_map, start_brk),
offsetof(struct prctl_mm_map, brk),
offsetof(struct prctl_mm_map, start_stack),
offsetof(struct prctl_mm_map, arg_start),
offsetof(struct prctl_mm_map, arg_end),
offsetof(struct prctl_mm_map, env_start),
offsetof(struct prctl_mm_map, env_end),
};
/*
* Make sure the members are not somewhere outside
* of allowed address space.
*/
for (i = 0; i < ARRAY_SIZE(offsets); i++) {
u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
if ((unsigned long)val >= mmap_max_addr ||
(unsigned long)val < mmap_min_addr)
goto out;
}
/*
* Make sure the pairs are ordered.
*/
#define __prctl_check_order(__m1, __op, __m2) \
((unsigned long)prctl_map->__m1 __op \
(unsigned long)prctl_map->__m2) ? 0 : -EINVAL
error = __prctl_check_order(start_code, <, end_code);
error |= __prctl_check_order(start_data,<=, end_data);
error |= __prctl_check_order(start_brk, <=, brk);
error |= __prctl_check_order(arg_start, <=, arg_end);
error |= __prctl_check_order(env_start, <=, env_end);
if (error)
goto out;
#undef __prctl_check_order
error = -EINVAL;
/*
* Neither we should allow to override limits if they set.
*/
if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
prctl_map->start_brk, prctl_map->end_data,
prctl_map->start_data))
goto out;
error = 0;
out:
return error;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
{
struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
unsigned long user_auxv[AT_VECTOR_SIZE];
struct mm_struct *mm = current->mm;
int error;
BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
if (opt == PR_SET_MM_MAP_SIZE)
return put_user((unsigned int)sizeof(prctl_map),
(unsigned int __user *)addr);
if (data_size != sizeof(prctl_map))
return -EINVAL;
if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
return -EFAULT;
error = validate_prctl_map_addr(&prctl_map);
if (error)
return error;
if (prctl_map.auxv_size) {
/*
* Someone is trying to cheat the auxv vector.
*/
if (!prctl_map.auxv ||
prctl_map.auxv_size > sizeof(mm->saved_auxv))
return -EINVAL;
memset(user_auxv, 0, sizeof(user_auxv));
if (copy_from_user(user_auxv,
(const void __user *)prctl_map.auxv,
prctl_map.auxv_size))
return -EFAULT;
/* Last entry must be AT_NULL as specification requires */
user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
}
if (prctl_map.exe_fd != (u32)-1) {
/*
* Check if the current user is checkpoint/restore capable.
* At the time of this writing, it checks for CAP_SYS_ADMIN
* or CAP_CHECKPOINT_RESTORE.
* Note that a user with access to ptrace can masquerade an
* arbitrary program as any executable, even setuid ones.
* This may have implications in the tomoyo subsystem.
*/
if (!checkpoint_restore_ns_capable(current_user_ns()))
return -EPERM;
error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
if (error)
return error;
}
/*
* arg_lock protects concurrent updates but we still need mmap_lock for
* read to exclude races with sys_brk.
*/
mmap_read_lock(mm);
/*
* We don't validate if these members are pointing to
* real present VMAs because application may have correspond
* VMAs already unmapped and kernel uses these members for statistics
* output in procfs mostly, except
*
* - @start_brk/@brk which are used in do_brk_flags but kernel lookups
* for VMAs when updating these members so anything wrong written
* here cause kernel to swear at userspace program but won't lead
* to any problem in kernel itself
*/
spin_lock(&mm->arg_lock);
mm->start_code = prctl_map.start_code;
mm->end_code = prctl_map.end_code;
mm->start_data = prctl_map.start_data;
mm->end_data = prctl_map.end_data;
mm->start_brk = prctl_map.start_brk;
mm->brk = prctl_map.brk;
mm->start_stack = prctl_map.start_stack;
mm->arg_start = prctl_map.arg_start;
mm->arg_end = prctl_map.arg_end;
mm->env_start = prctl_map.env_start;
mm->env_end = prctl_map.env_end;
spin_unlock(&mm->arg_lock);
/*
* Note this update of @saved_auxv is lockless thus
* if someone reads this member in procfs while we're
* updating -- it may get partly updated results. It's
* known and acceptable trade off: we leave it as is to
* not introduce additional locks here making the kernel
* more complex.
*/
if (prctl_map.auxv_size)
memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
mmap_read_unlock(mm);
return 0;
}
#endif /* CONFIG_CHECKPOINT_RESTORE */
static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
unsigned long len)
{
/*
* This doesn't move the auxiliary vector itself since it's pinned to
* mm_struct, but it permits filling the vector with new values. It's
* up to the caller to provide sane values here, otherwise userspace
* tools which use this vector might be unhappy.
*/
unsigned long user_auxv[AT_VECTOR_SIZE] = {};
if (len > sizeof(user_auxv))
return -EINVAL;
if (copy_from_user(user_auxv, (const void __user *)addr, len))
return -EFAULT;
/* Make sure the last entry is always AT_NULL */
user_auxv[AT_VECTOR_SIZE - 2] = 0;
user_auxv[AT_VECTOR_SIZE - 1] = 0;
BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
task_lock(current);
memcpy(mm->saved_auxv, user_auxv, len);
task_unlock(current);
return 0;
}
static int prctl_set_mm(int opt, unsigned long addr,
unsigned long arg4, unsigned long arg5)
{
struct mm_struct *mm = current->mm;
struct prctl_mm_map prctl_map = {
.auxv = NULL,
.auxv_size = 0,
.exe_fd = -1,
};
struct vm_area_struct *vma;
int error;
if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
opt != PR_SET_MM_MAP &&
opt != PR_SET_MM_MAP_SIZE)))
return -EINVAL;
#ifdef CONFIG_CHECKPOINT_RESTORE
if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
#endif
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (opt == PR_SET_MM_EXE_FILE)
return prctl_set_mm_exe_file(mm, (unsigned int)addr);
if (opt == PR_SET_MM_AUXV)
return prctl_set_auxv(mm, addr, arg4);
if (addr >= TASK_SIZE || addr < mmap_min_addr)
return -EINVAL;
error = -EINVAL;
/*
* arg_lock protects concurrent updates of arg boundaries, we need
* mmap_lock for a) concurrent sys_brk, b) finding VMA for addr
* validation.
*/
mmap_read_lock(mm);
vma = find_vma(mm, addr);
spin_lock(&mm->arg_lock);
prctl_map.start_code = mm->start_code;
prctl_map.end_code = mm->end_code;
prctl_map.start_data = mm->start_data;
prctl_map.end_data = mm->end_data;
prctl_map.start_brk = mm->start_brk;
prctl_map.brk = mm->brk;
prctl_map.start_stack = mm->start_stack;
prctl_map.arg_start = mm->arg_start;
prctl_map.arg_end = mm->arg_end;
prctl_map.env_start = mm->env_start;
prctl_map.env_end = mm->env_end;
switch (opt) {
case PR_SET_MM_START_CODE:
prctl_map.start_code = addr;
break;
case PR_SET_MM_END_CODE:
prctl_map.end_code = addr;
break;
case PR_SET_MM_START_DATA:
prctl_map.start_data = addr;
break;
case PR_SET_MM_END_DATA:
prctl_map.end_data = addr;
break;
case PR_SET_MM_START_STACK:
prctl_map.start_stack = addr;
break;
case PR_SET_MM_START_BRK:
prctl_map.start_brk = addr;
break;
case PR_SET_MM_BRK:
prctl_map.brk = addr;
break;
case PR_SET_MM_ARG_START:
prctl_map.arg_start = addr;
break;
case PR_SET_MM_ARG_END:
prctl_map.arg_end = addr;
break;
case PR_SET_MM_ENV_START:
prctl_map.env_start = addr;
break;
case PR_SET_MM_ENV_END:
prctl_map.env_end = addr;
break;
default:
goto out;
}
error = validate_prctl_map_addr(&prctl_map);
if (error)
goto out;
switch (opt) {
/*
* If command line arguments and environment
* are placed somewhere else on stack, we can
* set them up here, ARG_START/END to setup
* command line arguments and ENV_START/END
* for environment.
*/
case PR_SET_MM_START_STACK:
case PR_SET_MM_ARG_START:
case PR_SET_MM_ARG_END:
case PR_SET_MM_ENV_START:
case PR_SET_MM_ENV_END:
if (!vma) {
error = -EFAULT;
goto out;
}
}
mm->start_code = prctl_map.start_code;
mm->end_code = prctl_map.end_code;
mm->start_data = prctl_map.start_data;
mm->end_data = prctl_map.end_data;
mm->start_brk = prctl_map.start_brk;
mm->brk = prctl_map.brk;
mm->start_stack = prctl_map.start_stack;
mm->arg_start = prctl_map.arg_start;
mm->arg_end = prctl_map.arg_end;
mm->env_start = prctl_map.env_start;
mm->env_end = prctl_map.env_end;
error = 0;
out:
spin_unlock(&mm->arg_lock);
mmap_read_unlock(mm);
return error;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
{
return put_user(me->clear_child_tid, tid_addr);
}
#else
static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
{
return -EINVAL;
}
#endif
static int propagate_has_child_subreaper(struct task_struct *p, void *data)
{
/*
* If task has has_child_subreaper - all its descendants
* already have these flag too and new descendants will
* inherit it on fork, skip them.
*
* If we've found child_reaper - skip descendants in
* it's subtree as they will never get out pidns.
*/
if (p->signal->has_child_subreaper ||
is_child_reaper(task_pid(p)))
return 0;
p->signal->has_child_subreaper = 1;
return 1;
}
int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
{
return -EINVAL;
}
int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
unsigned long ctrl)
{
return -EINVAL;
}
#define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE)
#ifdef CONFIG_ANON_VMA_NAME
#define ANON_VMA_NAME_MAX_LEN 80
#define ANON_VMA_NAME_INVALID_CHARS "\\`$[]"
static inline bool is_valid_name_char(char ch)
{
/* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */
return ch > 0x1f && ch < 0x7f &&
!strchr(ANON_VMA_NAME_INVALID_CHARS, ch);
}
static int prctl_set_vma(unsigned long opt, unsigned long addr,
unsigned long size, unsigned long arg)
{
struct mm_struct *mm = current->mm;
const char __user *uname;
struct anon_vma_name *anon_name = NULL;
int error;
switch (opt) {
case PR_SET_VMA_ANON_NAME:
uname = (const char __user *)arg;
if (uname) {
char *name, *pch;
name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN);
if (IS_ERR(name))
return PTR_ERR(name);
for (pch = name; *pch != '\0'; pch++) {
if (!is_valid_name_char(*pch)) {
kfree(name);
return -EINVAL;
}
}
/* anon_vma has its own copy */
anon_name = anon_vma_name_alloc(name);
kfree(name);
if (!anon_name)
return -ENOMEM;
}
mmap_write_lock(mm);
error = madvise_set_anon_name(mm, addr, size, anon_name);
mmap_write_unlock(mm);
anon_vma_name_put(anon_name);
break;
default:
error = -EINVAL;
}
return error;
}
#else /* CONFIG_ANON_VMA_NAME */
static int prctl_set_vma(unsigned long opt, unsigned long start,
unsigned long size, unsigned long arg)
{
return -EINVAL;
}
#endif /* CONFIG_ANON_VMA_NAME */
static inline int prctl_set_mdwe(unsigned long bits, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
if (arg3 || arg4 || arg5)
return -EINVAL;
if (bits & ~(PR_MDWE_REFUSE_EXEC_GAIN))
return -EINVAL;
if (bits & PR_MDWE_REFUSE_EXEC_GAIN)
set_bit(MMF_HAS_MDWE, ¤t->mm->flags);
else if (test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
return -EPERM; /* Cannot unset the flag */
return 0;
}
static inline int prctl_get_mdwe(unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
return test_bit(MMF_HAS_MDWE, ¤t->mm->flags) ?
PR_MDWE_REFUSE_EXEC_GAIN : 0;
}
static int prctl_get_auxv(void __user *addr, unsigned long len)
{
struct mm_struct *mm = current->mm;
unsigned long size = min_t(unsigned long, sizeof(mm->saved_auxv), len);
if (size && copy_to_user(addr, mm->saved_auxv, size))
return -EFAULT;
return sizeof(mm->saved_auxv);
}
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
struct task_struct *me = current;
unsigned char comm[sizeof(me->comm)];
long error;
error = security_task_prctl(option, arg2, arg3, arg4, arg5);
if (error != -ENOSYS)
return error;
error = 0;
switch (option) {
case PR_SET_PDEATHSIG:
if (!valid_signal(arg2)) {
error = -EINVAL;
break;
}
me->pdeath_signal = arg2;
break;
case PR_GET_PDEATHSIG:
error = put_user(me->pdeath_signal, (int __user *)arg2);
break;
case PR_GET_DUMPABLE:
error = get_dumpable(me->mm);
break;
case PR_SET_DUMPABLE:
if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
error = -EINVAL;
break;
}
set_dumpable(me->mm, arg2);
break;
case PR_SET_UNALIGN:
error = SET_UNALIGN_CTL(me, arg2);
break;
case PR_GET_UNALIGN:
error = GET_UNALIGN_CTL(me, arg2);
break;
case PR_SET_FPEMU:
error = SET_FPEMU_CTL(me, arg2);
break;
case PR_GET_FPEMU:
error = GET_FPEMU_CTL(me, arg2);
break;
case PR_SET_FPEXC:
error = SET_FPEXC_CTL(me, arg2);
break;
case PR_GET_FPEXC:
error = GET_FPEXC_CTL(me, arg2);
break;
case PR_GET_TIMING:
error = PR_TIMING_STATISTICAL;
break;
case PR_SET_TIMING:
if (arg2 != PR_TIMING_STATISTICAL)
error = -EINVAL;
break;
case PR_SET_NAME:
comm[sizeof(me->comm) - 1] = 0;
if (strncpy_from_user(comm, (char __user *)arg2,
sizeof(me->comm) - 1) < 0)
return -EFAULT;
set_task_comm(me, comm);
proc_comm_connector(me);
break;
case PR_GET_NAME:
get_task_comm(comm, me);
if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
return -EFAULT;
break;
case PR_GET_ENDIAN:
error = GET_ENDIAN(me, arg2);
break;
case PR_SET_ENDIAN:
error = SET_ENDIAN(me, arg2);
break;
case PR_GET_SECCOMP:
error = prctl_get_seccomp();
break;
case PR_SET_SECCOMP:
error = prctl_set_seccomp(arg2, (char __user *)arg3);
break;
case PR_GET_TSC:
error = GET_TSC_CTL(arg2);
break;
case PR_SET_TSC:
error = SET_TSC_CTL(arg2);
break;
case PR_TASK_PERF_EVENTS_DISABLE:
error = perf_event_task_disable();
break;
case PR_TASK_PERF_EVENTS_ENABLE:
error = perf_event_task_enable();
break;
case PR_GET_TIMERSLACK:
if (current->timer_slack_ns > ULONG_MAX)
error = ULONG_MAX;
else
error = current->timer_slack_ns;
break;
case PR_SET_TIMERSLACK:
if (arg2 <= 0)
current->timer_slack_ns =
current->default_timer_slack_ns;
else
current->timer_slack_ns = arg2;
break;
case PR_MCE_KILL:
if (arg4 | arg5)
return -EINVAL;
switch (arg2) {
case PR_MCE_KILL_CLEAR:
if (arg3 != 0)
return -EINVAL;
current->flags &= ~PF_MCE_PROCESS;
break;
case PR_MCE_KILL_SET:
current->flags |= PF_MCE_PROCESS;
if (arg3 == PR_MCE_KILL_EARLY)
current->flags |= PF_MCE_EARLY;
else if (arg3 == PR_MCE_KILL_LATE)
current->flags &= ~PF_MCE_EARLY;
else if (arg3 == PR_MCE_KILL_DEFAULT)
current->flags &=
~(PF_MCE_EARLY|PF_MCE_PROCESS);
else
return -EINVAL;
break;
default:
return -EINVAL;
}
break;
case PR_MCE_KILL_GET:
if (arg2 | arg3 | arg4 | arg5)
return -EINVAL;
if (current->flags & PF_MCE_PROCESS)
error = (current->flags & PF_MCE_EARLY) ?
PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
else
error = PR_MCE_KILL_DEFAULT;
break;
case PR_SET_MM:
error = prctl_set_mm(arg2, arg3, arg4, arg5);
break;
case PR_GET_TID_ADDRESS:
error = prctl_get_tid_address(me, (int __user * __user *)arg2);
break;
case PR_SET_CHILD_SUBREAPER:
me->signal->is_child_subreaper = !!arg2;
if (!arg2)
break;
walk_process_tree(me, propagate_has_child_subreaper, NULL);
break;
case PR_GET_CHILD_SUBREAPER:
error = put_user(me->signal->is_child_subreaper,
(int __user *)arg2);
break;
case PR_SET_NO_NEW_PRIVS:
if (arg2 != 1 || arg3 || arg4 || arg5)
return -EINVAL;
task_set_no_new_privs(current);
break;
case PR_GET_NO_NEW_PRIVS:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
return task_no_new_privs(current) ? 1 : 0;
case PR_GET_THP_DISABLE:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags);
break;
case PR_SET_THP_DISABLE:
if (arg3 || arg4 || arg5)
return -EINVAL;
if (mmap_write_lock_killable(me->mm))
return -EINTR;
if (arg2)
set_bit(MMF_DISABLE_THP, &me->mm->flags);
else
clear_bit(MMF_DISABLE_THP, &me->mm->flags);
mmap_write_unlock(me->mm);
break;
case PR_MPX_ENABLE_MANAGEMENT:
case PR_MPX_DISABLE_MANAGEMENT:
/* No longer implemented: */
return -EINVAL;
case PR_SET_FP_MODE:
error = SET_FP_MODE(me, arg2);
break;
case PR_GET_FP_MODE:
error = GET_FP_MODE(me);
break;
case PR_SVE_SET_VL:
error = SVE_SET_VL(arg2);
break;
case PR_SVE_GET_VL:
error = SVE_GET_VL();
break;
case PR_SME_SET_VL:
error = SME_SET_VL(arg2);
break;
case PR_SME_GET_VL:
error = SME_GET_VL();
break;
case PR_GET_SPECULATION_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = arch_prctl_spec_ctrl_get(me, arg2);
break;
case PR_SET_SPECULATION_CTRL:
if (arg4 || arg5)
return -EINVAL;
error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
break;
case PR_PAC_RESET_KEYS:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = PAC_RESET_KEYS(me, arg2);
break;
case PR_PAC_SET_ENABLED_KEYS:
if (arg4 || arg5)
return -EINVAL;
error = PAC_SET_ENABLED_KEYS(me, arg2, arg3);
break;
case PR_PAC_GET_ENABLED_KEYS:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = PAC_GET_ENABLED_KEYS(me);
break;
case PR_SET_TAGGED_ADDR_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;
error = SET_TAGGED_ADDR_CTRL(arg2);
break;
case PR_GET_TAGGED_ADDR_CTRL:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = GET_TAGGED_ADDR_CTRL();
break;
case PR_SET_IO_FLUSHER:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (arg3 || arg4 || arg5)
return -EINVAL;
if (arg2 == 1)
current->flags |= PR_IO_FLUSHER;
else if (!arg2)
current->flags &= ~PR_IO_FLUSHER;
else
return -EINVAL;
break;
case PR_GET_IO_FLUSHER:
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
break;
case PR_SET_SYSCALL_USER_DISPATCH:
error = set_syscall_user_dispatch(arg2, arg3, arg4,
(char __user *) arg5);
break;
#ifdef CONFIG_SCHED_CORE
case PR_SCHED_CORE:
error = sched_core_share_pid(arg2, arg3, arg4, arg5);
break;
#endif
case PR_SET_MDWE:
error = prctl_set_mdwe(arg2, arg3, arg4, arg5);
break;
case PR_GET_MDWE:
error = prctl_get_mdwe(arg2, arg3, arg4, arg5);
break;
case PR_SET_VMA:
error = prctl_set_vma(arg2, arg3, arg4, arg5);
break;
case PR_GET_AUXV:
if (arg4 || arg5)
return -EINVAL;
error = prctl_get_auxv((void __user *)arg2, arg3);
break;
#ifdef CONFIG_KSM
case PR_SET_MEMORY_MERGE:
if (arg3 || arg4 || arg5)
return -EINVAL;
if (mmap_write_lock_killable(me->mm))
return -EINTR;
if (arg2)
error = ksm_enable_merge_any(me->mm);
else
error = ksm_disable_merge_any(me->mm);
mmap_write_unlock(me->mm);
break;
case PR_GET_MEMORY_MERGE:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = !!test_bit(MMF_VM_MERGE_ANY, &me->mm->flags);
break;
#endif
case PR_RISCV_V_SET_CONTROL:
error = RISCV_V_SET_CONTROL(arg2);
break;
case PR_RISCV_V_GET_CONTROL:
error = RISCV_V_GET_CONTROL();
break;
default:
error = -EINVAL;
break;
}
return error;
}
SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
struct getcpu_cache __user *, unused)
{
int err = 0;
int cpu = raw_smp_processor_id();
if (cpup)
err |= put_user(cpu, cpup);
if (nodep)
err |= put_user(cpu_to_node(cpu), nodep);
return err ? -EFAULT : 0;
}
/**
* do_sysinfo - fill in sysinfo struct
* @info: pointer to buffer to fill
*/
static int do_sysinfo(struct sysinfo *info)
{
unsigned long mem_total, sav_total;
unsigned int mem_unit, bitcount;
struct timespec64 tp;
memset(info, 0, sizeof(struct sysinfo));
ktime_get_boottime_ts64(&tp);
timens_add_boottime(&tp);
info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
info->procs = nr_threads;
si_meminfo(info);
si_swapinfo(info);
/*
* If the sum of all the available memory (i.e. ram + swap)
* is less than can be stored in a 32 bit unsigned long then
* we can be binary compatible with 2.2.x kernels. If not,
* well, in that case 2.2.x was broken anyways...
*
* -Erik Andersen <[email protected]>
*/
mem_total = info->totalram + info->totalswap;
if (mem_total < info->totalram || mem_total < info->totalswap)
goto out;
bitcount = 0;
mem_unit = info->mem_unit;
while (mem_unit > 1) {
bitcount++;
mem_unit >>= 1;
sav_total = mem_total;
mem_total <<= 1;
if (mem_total < sav_total)
goto out;
}
/*
* If mem_total did not overflow, multiply all memory values by
* info->mem_unit and set it to 1. This leaves things compatible
* with 2.2.x, and also retains compatibility with earlier 2.4.x
* kernels...
*/
info->mem_unit = 1;
info->totalram <<= bitcount;
info->freeram <<= bitcount;
info->sharedram <<= bitcount;
info->bufferram <<= bitcount;
info->totalswap <<= bitcount;
info->freeswap <<= bitcount;
info->totalhigh <<= bitcount;
info->freehigh <<= bitcount;
out:
return 0;
}
SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
{
struct sysinfo val;
do_sysinfo(&val);
if (copy_to_user(info, &val, sizeof(struct sysinfo)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
struct compat_sysinfo {
s32 uptime;
u32 loads[3];
u32 totalram;
u32 freeram;
u32 sharedram;
u32 bufferram;
u32 totalswap;
u32 freeswap;
u16 procs;
u16 pad;
u32 totalhigh;
u32 freehigh;
u32 mem_unit;
char _f[20-2*sizeof(u32)-sizeof(int)];
};
COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
{
struct sysinfo s;
struct compat_sysinfo s_32;
do_sysinfo(&s);
/* Check to see if any memory value is too large for 32-bit and scale
* down if needed
*/
if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
int bitcount = 0;
while (s.mem_unit < PAGE_SIZE) {
s.mem_unit <<= 1;
bitcount++;
}
s.totalram >>= bitcount;
s.freeram >>= bitcount;
s.sharedram >>= bitcount;
s.bufferram >>= bitcount;
s.totalswap >>= bitcount;
s.freeswap >>= bitcount;
s.totalhigh >>= bitcount;
s.freehigh >>= bitcount;
}
memset(&s_32, 0, sizeof(s_32));
s_32.uptime = s.uptime;
s_32.loads[0] = s.loads[0];
s_32.loads[1] = s.loads[1];
s_32.loads[2] = s.loads[2];
s_32.totalram = s.totalram;
s_32.freeram = s.freeram;
s_32.sharedram = s.sharedram;
s_32.bufferram = s.bufferram;
s_32.totalswap = s.totalswap;
s_32.freeswap = s.freeswap;
s_32.procs = s.procs;
s_32.totalhigh = s.totalhigh;
s_32.freehigh = s.freehigh;
s_32.mem_unit = s.mem_unit;
if (copy_to_user(info, &s_32, sizeof(s_32)))
return -EFAULT;
return 0;
}
#endif /* CONFIG_COMPAT */
| linux-master | kernel/sys.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/compat.c
*
* Kernel compatibililty routines for e.g. 32 bit syscall support
* on 64 bit kernels.
*
* Copyright (C) 2002-2003 Stephen Rothwell, IBM Corporation
*/
#include <linux/linkage.h>
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/signal.h>
#include <linux/sched.h> /* for MAX_SCHEDULE_TIMEOUT */
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/migrate.h>
#include <linux/posix-timers.h>
#include <linux/times.h>
#include <linux/ptrace.h>
#include <linux/gfp.h>
#include <linux/uaccess.h>
#ifdef __ARCH_WANT_SYS_SIGPROCMASK
/*
* sys_sigprocmask SIG_SETMASK sets the first (compat) word of the
* blocked set of signals to the supplied signal set
*/
static inline void compat_sig_setmask(sigset_t *blocked, compat_sigset_word set)
{
memcpy(blocked->sig, &set, sizeof(set));
}
COMPAT_SYSCALL_DEFINE3(sigprocmask, int, how,
compat_old_sigset_t __user *, nset,
compat_old_sigset_t __user *, oset)
{
old_sigset_t old_set, new_set;
sigset_t new_blocked;
old_set = current->blocked.sig[0];
if (nset) {
if (get_user(new_set, nset))
return -EFAULT;
new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
new_blocked = current->blocked;
switch (how) {
case SIG_BLOCK:
sigaddsetmask(&new_blocked, new_set);
break;
case SIG_UNBLOCK:
sigdelsetmask(&new_blocked, new_set);
break;
case SIG_SETMASK:
compat_sig_setmask(&new_blocked, new_set);
break;
default:
return -EINVAL;
}
set_current_blocked(&new_blocked);
}
if (oset) {
if (put_user(old_set, oset))
return -EFAULT;
}
return 0;
}
#endif
int put_compat_rusage(const struct rusage *r, struct compat_rusage __user *ru)
{
struct compat_rusage r32;
memset(&r32, 0, sizeof(r32));
r32.ru_utime.tv_sec = r->ru_utime.tv_sec;
r32.ru_utime.tv_usec = r->ru_utime.tv_usec;
r32.ru_stime.tv_sec = r->ru_stime.tv_sec;
r32.ru_stime.tv_usec = r->ru_stime.tv_usec;
r32.ru_maxrss = r->ru_maxrss;
r32.ru_ixrss = r->ru_ixrss;
r32.ru_idrss = r->ru_idrss;
r32.ru_isrss = r->ru_isrss;
r32.ru_minflt = r->ru_minflt;
r32.ru_majflt = r->ru_majflt;
r32.ru_nswap = r->ru_nswap;
r32.ru_inblock = r->ru_inblock;
r32.ru_oublock = r->ru_oublock;
r32.ru_msgsnd = r->ru_msgsnd;
r32.ru_msgrcv = r->ru_msgrcv;
r32.ru_nsignals = r->ru_nsignals;
r32.ru_nvcsw = r->ru_nvcsw;
r32.ru_nivcsw = r->ru_nivcsw;
if (copy_to_user(ru, &r32, sizeof(r32)))
return -EFAULT;
return 0;
}
static int compat_get_user_cpu_mask(compat_ulong_t __user *user_mask_ptr,
unsigned len, struct cpumask *new_mask)
{
unsigned long *k;
if (len < cpumask_size())
memset(new_mask, 0, cpumask_size());
else if (len > cpumask_size())
len = cpumask_size();
k = cpumask_bits(new_mask);
return compat_get_bitmap(k, user_mask_ptr, len * 8);
}
COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
unsigned int, len,
compat_ulong_t __user *, user_mask_ptr)
{
cpumask_var_t new_mask;
int retval;
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
return -ENOMEM;
retval = compat_get_user_cpu_mask(user_mask_ptr, len, new_mask);
if (retval)
goto out;
retval = sched_setaffinity(pid, new_mask);
out:
free_cpumask_var(new_mask);
return retval;
}
COMPAT_SYSCALL_DEFINE3(sched_getaffinity, compat_pid_t, pid, unsigned int, len,
compat_ulong_t __user *, user_mask_ptr)
{
int ret;
cpumask_var_t mask;
if ((len * BITS_PER_BYTE) < nr_cpu_ids)
return -EINVAL;
if (len & (sizeof(compat_ulong_t)-1))
return -EINVAL;
if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
return -ENOMEM;
ret = sched_getaffinity(pid, mask);
if (ret == 0) {
unsigned int retlen = min(len, cpumask_size());
if (compat_put_bitmap(user_mask_ptr, cpumask_bits(mask), retlen * 8))
ret = -EFAULT;
else
ret = retlen;
}
free_cpumask_var(mask);
return ret;
}
/*
* We currently only need the following fields from the sigevent
* structure: sigev_value, sigev_signo, sig_notify and (sometimes
* sigev_notify_thread_id). The others are handled in user mode.
* We also assume that copying sigev_value.sival_int is sufficient
* to keep all the bits of sigev_value.sival_ptr intact.
*/
int get_compat_sigevent(struct sigevent *event,
const struct compat_sigevent __user *u_event)
{
memset(event, 0, sizeof(*event));
return (!access_ok(u_event, sizeof(*u_event)) ||
__get_user(event->sigev_value.sival_int,
&u_event->sigev_value.sival_int) ||
__get_user(event->sigev_signo, &u_event->sigev_signo) ||
__get_user(event->sigev_notify, &u_event->sigev_notify) ||
__get_user(event->sigev_notify_thread_id,
&u_event->sigev_notify_thread_id))
? -EFAULT : 0;
}
long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
unsigned long bitmap_size)
{
unsigned long nr_compat_longs;
/* align bitmap up to nearest compat_long_t boundary */
bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
if (!user_read_access_begin(umask, bitmap_size / 8))
return -EFAULT;
while (nr_compat_longs > 1) {
compat_ulong_t l1, l2;
unsafe_get_user(l1, umask++, Efault);
unsafe_get_user(l2, umask++, Efault);
*mask++ = ((unsigned long)l2 << BITS_PER_COMPAT_LONG) | l1;
nr_compat_longs -= 2;
}
if (nr_compat_longs)
unsafe_get_user(*mask, umask++, Efault);
user_read_access_end();
return 0;
Efault:
user_read_access_end();
return -EFAULT;
}
long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
unsigned long bitmap_size)
{
unsigned long nr_compat_longs;
/* align bitmap up to nearest compat_long_t boundary */
bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG);
nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size);
if (!user_write_access_begin(umask, bitmap_size / 8))
return -EFAULT;
while (nr_compat_longs > 1) {
unsigned long m = *mask++;
unsafe_put_user((compat_ulong_t)m, umask++, Efault);
unsafe_put_user(m >> BITS_PER_COMPAT_LONG, umask++, Efault);
nr_compat_longs -= 2;
}
if (nr_compat_longs)
unsafe_put_user((compat_ulong_t)*mask, umask++, Efault);
user_write_access_end();
return 0;
Efault:
user_write_access_end();
return -EFAULT;
}
int
get_compat_sigset(sigset_t *set, const compat_sigset_t __user *compat)
{
#ifdef __BIG_ENDIAN
compat_sigset_t v;
if (copy_from_user(&v, compat, sizeof(compat_sigset_t)))
return -EFAULT;
switch (_NSIG_WORDS) {
case 4: set->sig[3] = v.sig[6] | (((long)v.sig[7]) << 32 );
fallthrough;
case 3: set->sig[2] = v.sig[4] | (((long)v.sig[5]) << 32 );
fallthrough;
case 2: set->sig[1] = v.sig[2] | (((long)v.sig[3]) << 32 );
fallthrough;
case 1: set->sig[0] = v.sig[0] | (((long)v.sig[1]) << 32 );
}
#else
if (copy_from_user(set, compat, sizeof(compat_sigset_t)))
return -EFAULT;
#endif
return 0;
}
EXPORT_SYMBOL_GPL(get_compat_sigset);
| linux-master | kernel/compat.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* audit_watch.c -- watching inodes
*
* Copyright 2003-2009 Red Hat, Inc.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright 2005 IBM Corporation
*/
#include <linux/file.h>
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/refcount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
#include "audit.h"
/*
* Reference counting:
*
* audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
* event. Each audit_watch holds a reference to its associated parent.
*
* audit_watch: if added to lists, lifetime is from audit_init_watch() to
* audit_remove_watch(). Additionally, an audit_watch may exist
* temporarily to assist in searching existing filter data. Each
* audit_krule holds a reference to its associated watch.
*/
struct audit_watch {
refcount_t count; /* reference count */
dev_t dev; /* associated superblock device */
char *path; /* insertion path */
unsigned long ino; /* associated inode number */
struct audit_parent *parent; /* associated parent */
struct list_head wlist; /* entry in parent->watches list */
struct list_head rules; /* anchor for krule->rlist */
};
struct audit_parent {
struct list_head watches; /* anchor for audit_watch->wlist */
struct fsnotify_mark mark; /* fsnotify mark on the inode */
};
/* fsnotify handle. */
static struct fsnotify_group *audit_watch_group;
/* fsnotify events we care about. */
#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
FS_MOVE_SELF | FS_UNMOUNT)
static void audit_free_parent(struct audit_parent *parent)
{
WARN_ON(!list_empty(&parent->watches));
kfree(parent);
}
static void audit_watch_free_mark(struct fsnotify_mark *entry)
{
struct audit_parent *parent;
parent = container_of(entry, struct audit_parent, mark);
audit_free_parent(parent);
}
static void audit_get_parent(struct audit_parent *parent)
{
if (likely(parent))
fsnotify_get_mark(&parent->mark);
}
static void audit_put_parent(struct audit_parent *parent)
{
if (likely(parent))
fsnotify_put_mark(&parent->mark);
}
/*
* Find and return the audit_parent on the given inode. If found a reference
* is taken on this parent.
*/
static inline struct audit_parent *audit_find_parent(struct inode *inode)
{
struct audit_parent *parent = NULL;
struct fsnotify_mark *entry;
entry = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_watch_group);
if (entry)
parent = container_of(entry, struct audit_parent, mark);
return parent;
}
void audit_get_watch(struct audit_watch *watch)
{
refcount_inc(&watch->count);
}
void audit_put_watch(struct audit_watch *watch)
{
if (refcount_dec_and_test(&watch->count)) {
WARN_ON(watch->parent);
WARN_ON(!list_empty(&watch->rules));
kfree(watch->path);
kfree(watch);
}
}
static void audit_remove_watch(struct audit_watch *watch)
{
list_del(&watch->wlist);
audit_put_parent(watch->parent);
watch->parent = NULL;
audit_put_watch(watch); /* match initial get */
}
char *audit_watch_path(struct audit_watch *watch)
{
return watch->path;
}
int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
{
return (watch->ino != AUDIT_INO_UNSET) &&
(watch->ino == ino) &&
(watch->dev == dev);
}
/* Initialize a parent watch entry. */
static struct audit_parent *audit_init_parent(const struct path *path)
{
struct inode *inode = d_backing_inode(path->dentry);
struct audit_parent *parent;
int ret;
parent = kzalloc(sizeof(*parent), GFP_KERNEL);
if (unlikely(!parent))
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&parent->watches);
fsnotify_init_mark(&parent->mark, audit_watch_group);
parent->mark.mask = AUDIT_FS_WATCH;
ret = fsnotify_add_inode_mark(&parent->mark, inode, 0);
if (ret < 0) {
audit_free_parent(parent);
return ERR_PTR(ret);
}
return parent;
}
/* Initialize a watch entry. */
static struct audit_watch *audit_init_watch(char *path)
{
struct audit_watch *watch;
watch = kzalloc(sizeof(*watch), GFP_KERNEL);
if (unlikely(!watch))
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&watch->rules);
refcount_set(&watch->count, 1);
watch->path = path;
watch->dev = AUDIT_DEV_UNSET;
watch->ino = AUDIT_INO_UNSET;
return watch;
}
/* Translate a watch string to kernel representation. */
int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
{
struct audit_watch *watch;
if (!audit_watch_group)
return -EOPNOTSUPP;
if (path[0] != '/' || path[len-1] == '/' ||
(krule->listnr != AUDIT_FILTER_EXIT &&
krule->listnr != AUDIT_FILTER_URING_EXIT) ||
op != Audit_equal ||
krule->inode_f || krule->watch || krule->tree)
return -EINVAL;
watch = audit_init_watch(path);
if (IS_ERR(watch))
return PTR_ERR(watch);
krule->watch = watch;
return 0;
}
/* Duplicate the given audit watch. The new watch's rules list is initialized
* to an empty list and wlist is undefined. */
static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
{
char *path;
struct audit_watch *new;
path = kstrdup(old->path, GFP_KERNEL);
if (unlikely(!path))
return ERR_PTR(-ENOMEM);
new = audit_init_watch(path);
if (IS_ERR(new)) {
kfree(path);
goto out;
}
new->dev = old->dev;
new->ino = old->ino;
audit_get_parent(old->parent);
new->parent = old->parent;
out:
return new;
}
static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
{
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
if (!ab)
return;
audit_log_session_info(ab);
audit_log_format(ab, "op=%s path=", op);
audit_log_untrustedstring(ab, w->path);
audit_log_key(ab, r->filterkey);
audit_log_format(ab, " list=%d res=1", r->listnr);
audit_log_end(ab);
}
/* Update inode info in audit rules based on filesystem event. */
static void audit_update_watch(struct audit_parent *parent,
const struct qstr *dname, dev_t dev,
unsigned long ino, unsigned invalidating)
{
struct audit_watch *owatch, *nwatch, *nextw;
struct audit_krule *r, *nextr;
struct audit_entry *oentry, *nentry;
mutex_lock(&audit_filter_mutex);
/* Run all of the watches on this parent looking for the one that
* matches the given dname */
list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
if (audit_compare_dname_path(dname, owatch->path,
AUDIT_NAME_FULL))
continue;
/* If the update involves invalidating rules, do the inode-based
* filtering now, so we don't omit records. */
if (invalidating && !audit_dummy_context())
audit_filter_inodes(current, audit_context());
/* updating ino will likely change which audit_hash_list we
* are on so we need a new watch for the new list */
nwatch = audit_dupe_watch(owatch);
if (IS_ERR(nwatch)) {
mutex_unlock(&audit_filter_mutex);
audit_panic("error updating watch, skipping");
return;
}
nwatch->dev = dev;
nwatch->ino = ino;
list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
oentry = container_of(r, struct audit_entry, rule);
list_del(&oentry->rule.rlist);
list_del_rcu(&oentry->list);
nentry = audit_dupe_rule(&oentry->rule);
if (IS_ERR(nentry)) {
list_del(&oentry->rule.list);
audit_panic("error updating watch, removing");
} else {
int h = audit_hash_ino((u32)ino);
/*
* nentry->rule.watch == oentry->rule.watch so
* we must drop that reference and set it to our
* new watch.
*/
audit_put_watch(nentry->rule.watch);
audit_get_watch(nwatch);
nentry->rule.watch = nwatch;
list_add(&nentry->rule.rlist, &nwatch->rules);
list_add_rcu(&nentry->list, &audit_inode_hash[h]);
list_replace(&oentry->rule.list,
&nentry->rule.list);
}
if (oentry->rule.exe)
audit_remove_mark(oentry->rule.exe);
call_rcu(&oentry->rcu, audit_free_rule_rcu);
}
audit_remove_watch(owatch);
goto add_watch_to_parent; /* event applies to a single watch */
}
mutex_unlock(&audit_filter_mutex);
return;
add_watch_to_parent:
list_add(&nwatch->wlist, &parent->watches);
mutex_unlock(&audit_filter_mutex);
return;
}
/* Remove all watches & rules associated with a parent that is going away. */
static void audit_remove_parent_watches(struct audit_parent *parent)
{
struct audit_watch *w, *nextw;
struct audit_krule *r, *nextr;
struct audit_entry *e;
mutex_lock(&audit_filter_mutex);
list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
e = container_of(r, struct audit_entry, rule);
audit_watch_log_rule_change(r, w, "remove_rule");
if (e->rule.exe)
audit_remove_mark(e->rule.exe);
list_del(&r->rlist);
list_del(&r->list);
list_del_rcu(&e->list);
call_rcu(&e->rcu, audit_free_rule_rcu);
}
audit_remove_watch(w);
}
mutex_unlock(&audit_filter_mutex);
fsnotify_destroy_mark(&parent->mark, audit_watch_group);
}
/* Get path information necessary for adding watches. */
static int audit_get_nd(struct audit_watch *watch, struct path *parent)
{
struct dentry *d = kern_path_locked(watch->path, parent);
if (IS_ERR(d))
return PTR_ERR(d);
if (d_is_positive(d)) {
/* update watch filter fields */
watch->dev = d->d_sb->s_dev;
watch->ino = d_backing_inode(d)->i_ino;
}
inode_unlock(d_backing_inode(parent->dentry));
dput(d);
return 0;
}
/* Associate the given rule with an existing parent.
* Caller must hold audit_filter_mutex. */
static void audit_add_to_parent(struct audit_krule *krule,
struct audit_parent *parent)
{
struct audit_watch *w, *watch = krule->watch;
int watch_found = 0;
BUG_ON(!mutex_is_locked(&audit_filter_mutex));
list_for_each_entry(w, &parent->watches, wlist) {
if (strcmp(watch->path, w->path))
continue;
watch_found = 1;
/* put krule's ref to temporary watch */
audit_put_watch(watch);
audit_get_watch(w);
krule->watch = watch = w;
audit_put_parent(parent);
break;
}
if (!watch_found) {
watch->parent = parent;
audit_get_watch(watch);
list_add(&watch->wlist, &parent->watches);
}
list_add(&krule->rlist, &watch->rules);
}
/* Find a matching watch entry, or add this one.
* Caller must hold audit_filter_mutex. */
int audit_add_watch(struct audit_krule *krule, struct list_head **list)
{
struct audit_watch *watch = krule->watch;
struct audit_parent *parent;
struct path parent_path;
int h, ret = 0;
/*
* When we will be calling audit_add_to_parent, krule->watch might have
* been updated and watch might have been freed.
* So we need to keep a reference of watch.
*/
audit_get_watch(watch);
mutex_unlock(&audit_filter_mutex);
/* Avoid calling path_lookup under audit_filter_mutex. */
ret = audit_get_nd(watch, &parent_path);
/* caller expects mutex locked */
mutex_lock(&audit_filter_mutex);
if (ret) {
audit_put_watch(watch);
return ret;
}
/* either find an old parent or attach a new one */
parent = audit_find_parent(d_backing_inode(parent_path.dentry));
if (!parent) {
parent = audit_init_parent(&parent_path);
if (IS_ERR(parent)) {
ret = PTR_ERR(parent);
goto error;
}
}
audit_add_to_parent(krule, parent);
h = audit_hash_ino((u32)watch->ino);
*list = &audit_inode_hash[h];
error:
path_put(&parent_path);
audit_put_watch(watch);
return ret;
}
void audit_remove_watch_rule(struct audit_krule *krule)
{
struct audit_watch *watch = krule->watch;
struct audit_parent *parent = watch->parent;
list_del(&krule->rlist);
if (list_empty(&watch->rules)) {
/*
* audit_remove_watch() drops our reference to 'parent' which
* can get freed. Grab our own reference to be safe.
*/
audit_get_parent(parent);
audit_remove_watch(watch);
if (list_empty(&parent->watches))
fsnotify_destroy_mark(&parent->mark, audit_watch_group);
audit_put_parent(parent);
}
}
/* Update watch data in audit rules based on fsnotify events. */
static int audit_watch_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
struct inode *inode, struct inode *dir,
const struct qstr *dname, u32 cookie)
{
struct audit_parent *parent;
parent = container_of(inode_mark, struct audit_parent, mark);
if (WARN_ON_ONCE(inode_mark->group != audit_watch_group))
return 0;
if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
else if (mask & (FS_DELETE|FS_MOVED_FROM))
audit_update_watch(parent, dname, AUDIT_DEV_UNSET, AUDIT_INO_UNSET, 1);
else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
audit_remove_parent_watches(parent);
return 0;
}
static const struct fsnotify_ops audit_watch_fsnotify_ops = {
.handle_inode_event = audit_watch_handle_event,
.free_mark = audit_watch_free_mark,
};
static int __init audit_watch_init(void)
{
audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops, 0);
if (IS_ERR(audit_watch_group)) {
audit_watch_group = NULL;
audit_panic("cannot create audit fsnotify group");
}
return 0;
}
device_initcall(audit_watch_init);
int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
{
struct audit_fsnotify_mark *audit_mark;
char *pathname;
pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
if (!pathname)
return -ENOMEM;
audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
if (IS_ERR(audit_mark)) {
kfree(pathname);
return PTR_ERR(audit_mark);
}
new->exe = audit_mark;
return 0;
}
int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
{
struct file *exe_file;
unsigned long ino;
dev_t dev;
exe_file = get_task_exe_file(tsk);
if (!exe_file)
return 0;
ino = file_inode(exe_file)->i_ino;
dev = file_inode(exe_file)->i_sb->s_dev;
fput(exe_file);
return audit_mark_compare(mark, ino, dev);
}
| linux-master | kernel/audit_watch.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* umd - User mode driver support
*/
#include <linux/shmem_fs.h>
#include <linux/pipe_fs_i.h>
#include <linux/mount.h>
#include <linux/fs_struct.h>
#include <linux/task_work.h>
#include <linux/usermode_driver.h>
static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *name)
{
struct file_system_type *type;
struct vfsmount *mnt;
struct file *file;
ssize_t written;
loff_t pos = 0;
type = get_fs_type("tmpfs");
if (!type)
return ERR_PTR(-ENODEV);
mnt = kern_mount(type);
put_filesystem(type);
if (IS_ERR(mnt))
return mnt;
file = file_open_root_mnt(mnt, name, O_CREAT | O_WRONLY, 0700);
if (IS_ERR(file)) {
kern_unmount(mnt);
return ERR_CAST(file);
}
written = kernel_write(file, data, len, &pos);
if (written != len) {
int err = written;
if (err >= 0)
err = -ENOMEM;
filp_close(file, NULL);
kern_unmount(mnt);
return ERR_PTR(err);
}
fput(file);
/* Flush delayed fput so exec can open the file read-only */
flush_delayed_fput();
task_work_run();
return mnt;
}
/**
* umd_load_blob - Remember a blob of bytes for fork_usermode_driver
* @info: information about usermode driver
* @data: a blob of bytes that can be executed as a file
* @len: The lentgh of the blob
*
*/
int umd_load_blob(struct umd_info *info, const void *data, size_t len)
{
struct vfsmount *mnt;
if (WARN_ON_ONCE(info->wd.dentry || info->wd.mnt))
return -EBUSY;
mnt = blob_to_mnt(data, len, info->driver_name);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
info->wd.mnt = mnt;
info->wd.dentry = mnt->mnt_root;
return 0;
}
EXPORT_SYMBOL_GPL(umd_load_blob);
/**
* umd_unload_blob - Disassociate @info from a previously loaded blob
* @info: information about usermode driver
*
*/
int umd_unload_blob(struct umd_info *info)
{
if (WARN_ON_ONCE(!info->wd.mnt ||
!info->wd.dentry ||
info->wd.mnt->mnt_root != info->wd.dentry))
return -EINVAL;
kern_unmount(info->wd.mnt);
info->wd.mnt = NULL;
info->wd.dentry = NULL;
return 0;
}
EXPORT_SYMBOL_GPL(umd_unload_blob);
static int umd_setup(struct subprocess_info *info, struct cred *new)
{
struct umd_info *umd_info = info->data;
struct file *from_umh[2];
struct file *to_umh[2];
int err;
/* create pipe to send data to umh */
err = create_pipe_files(to_umh, 0);
if (err)
return err;
err = replace_fd(0, to_umh[0], 0);
fput(to_umh[0]);
if (err < 0) {
fput(to_umh[1]);
return err;
}
/* create pipe to receive data from umh */
err = create_pipe_files(from_umh, 0);
if (err) {
fput(to_umh[1]);
replace_fd(0, NULL, 0);
return err;
}
err = replace_fd(1, from_umh[1], 0);
fput(from_umh[1]);
if (err < 0) {
fput(to_umh[1]);
replace_fd(0, NULL, 0);
fput(from_umh[0]);
return err;
}
set_fs_pwd(current->fs, &umd_info->wd);
umd_info->pipe_to_umh = to_umh[1];
umd_info->pipe_from_umh = from_umh[0];
umd_info->tgid = get_pid(task_tgid(current));
return 0;
}
static void umd_cleanup(struct subprocess_info *info)
{
struct umd_info *umd_info = info->data;
/* cleanup if umh_setup() was successful but exec failed */
if (info->retval)
umd_cleanup_helper(umd_info);
}
/**
* umd_cleanup_helper - release the resources which were allocated in umd_setup
* @info: information about usermode driver
*/
void umd_cleanup_helper(struct umd_info *info)
{
fput(info->pipe_to_umh);
fput(info->pipe_from_umh);
put_pid(info->tgid);
info->tgid = NULL;
}
EXPORT_SYMBOL_GPL(umd_cleanup_helper);
/**
* fork_usermode_driver - fork a usermode driver
* @info: information about usermode driver (shouldn't be NULL)
*
* Returns either negative error or zero which indicates success in
* executing a usermode driver. In such case 'struct umd_info *info'
* is populated with two pipes and a tgid of the process. The caller is
* responsible for health check of the user process, killing it via
* tgid, and closing the pipes when user process is no longer needed.
*/
int fork_usermode_driver(struct umd_info *info)
{
struct subprocess_info *sub_info;
const char *argv[] = { info->driver_name, NULL };
int err;
if (WARN_ON_ONCE(info->tgid))
return -EBUSY;
err = -ENOMEM;
sub_info = call_usermodehelper_setup(info->driver_name,
(char **)argv, NULL, GFP_KERNEL,
umd_setup, umd_cleanup, info);
if (!sub_info)
goto out;
err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
out:
return err;
}
EXPORT_SYMBOL_GPL(fork_usermode_driver);
| linux-master | kernel/usermode_driver.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/resource.c
*
* Copyright (C) 1999 Linus Torvalds
* Copyright (C) 1999 Martin Mares <[email protected]>
*
* Arbitrary resource management.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/pseudo_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/resource_ext.h>
#include <uapi/linux/magic.h>
#include <asm/io.h>
struct resource ioport_resource = {
.name = "PCI IO",
.start = 0,
.end = IO_SPACE_LIMIT,
.flags = IORESOURCE_IO,
};
EXPORT_SYMBOL(ioport_resource);
struct resource iomem_resource = {
.name = "PCI mem",
.start = 0,
.end = -1,
.flags = IORESOURCE_MEM,
};
EXPORT_SYMBOL(iomem_resource);
/* constraints to be met while allocating resources */
struct resource_constraint {
resource_size_t min, max, align;
resource_size_t (*alignf)(void *, const struct resource *,
resource_size_t, resource_size_t);
void *alignf_data;
};
static DEFINE_RWLOCK(resource_lock);
static struct resource *next_resource(struct resource *p)
{
if (p->child)
return p->child;
while (!p->sibling && p->parent)
p = p->parent;
return p->sibling;
}
static struct resource *next_resource_skip_children(struct resource *p)
{
while (!p->sibling && p->parent)
p = p->parent;
return p->sibling;
}
#define for_each_resource(_root, _p, _skip_children) \
for ((_p) = (_root)->child; (_p); \
(_p) = (_skip_children) ? next_resource_skip_children(_p) : \
next_resource(_p))
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
(*pos)++;
return (void *)next_resource(p);
}
#ifdef CONFIG_PROC_FS
enum { MAX_IORES_LEVEL = 5 };
static void *r_start(struct seq_file *m, loff_t *pos)
__acquires(resource_lock)
{
struct resource *p = pde_data(file_inode(m->file));
loff_t l = 0;
read_lock(&resource_lock);
for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
;
return p;
}
static void r_stop(struct seq_file *m, void *v)
__releases(resource_lock)
{
read_unlock(&resource_lock);
}
static int r_show(struct seq_file *m, void *v)
{
struct resource *root = pde_data(file_inode(m->file));
struct resource *r = v, *p;
unsigned long long start, end;
int width = root->end < 0x10000 ? 4 : 8;
int depth;
for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
if (p->parent == root)
break;
if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
start = r->start;
end = r->end;
} else {
start = end = 0;
}
seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
depth * 2, "",
width, start,
width, end,
r->name ? r->name : "<BAD>");
return 0;
}
static const struct seq_operations resource_op = {
.start = r_start,
.next = r_next,
.stop = r_stop,
.show = r_show,
};
static int __init ioresources_init(void)
{
proc_create_seq_data("ioports", 0, NULL, &resource_op,
&ioport_resource);
proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
return 0;
}
__initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
static void free_resource(struct resource *res)
{
/**
* If the resource was allocated using memblock early during boot
* we'll leak it here: we can only return full pages back to the
* buddy and trying to be smart and reusing them eventually in
* alloc_resource() overcomplicates resource handling.
*/
if (res && PageSlab(virt_to_head_page(res)))
kfree(res);
}
static struct resource *alloc_resource(gfp_t flags)
{
return kzalloc(sizeof(struct resource), flags);
}
/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
resource_size_t start = new->start;
resource_size_t end = new->end;
struct resource *tmp, **p;
if (end < start)
return root;
if (start < root->start)
return root;
if (end > root->end)
return root;
p = &root->child;
for (;;) {
tmp = *p;
if (!tmp || tmp->start > end) {
new->sibling = tmp;
*p = new;
new->parent = root;
return NULL;
}
p = &tmp->sibling;
if (tmp->end < start)
continue;
return tmp;
}
}
static int __release_resource(struct resource *old, bool release_child)
{
struct resource *tmp, **p, *chd;
p = &old->parent->child;
for (;;) {
tmp = *p;
if (!tmp)
break;
if (tmp == old) {
if (release_child || !(tmp->child)) {
*p = tmp->sibling;
} else {
for (chd = tmp->child;; chd = chd->sibling) {
chd->parent = tmp->parent;
if (!(chd->sibling))
break;
}
*p = tmp->child;
chd->sibling = tmp->sibling;
}
old->parent = NULL;
return 0;
}
p = &tmp->sibling;
}
return -EINVAL;
}
static void __release_child_resources(struct resource *r)
{
struct resource *tmp, *p;
resource_size_t size;
p = r->child;
r->child = NULL;
while (p) {
tmp = p;
p = p->sibling;
tmp->parent = NULL;
tmp->sibling = NULL;
__release_child_resources(tmp);
printk(KERN_DEBUG "release child resource %pR\n", tmp);
/* need to restore size, and keep flags */
size = resource_size(tmp);
tmp->start = 0;
tmp->end = size - 1;
}
}
void release_child_resources(struct resource *r)
{
write_lock(&resource_lock);
__release_child_resources(r);
write_unlock(&resource_lock);
}
/**
* request_resource_conflict - request and reserve an I/O or memory resource
* @root: root resource descriptor
* @new: resource descriptor desired by caller
*
* Returns 0 for success, conflict resource on error.
*/
struct resource *request_resource_conflict(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
return conflict;
}
/**
* request_resource - request and reserve an I/O or memory resource
* @root: root resource descriptor
* @new: resource descriptor desired by caller
*
* Returns 0 for success, negative error code on error.
*/
int request_resource(struct resource *root, struct resource *new)
{
struct resource *conflict;
conflict = request_resource_conflict(root, new);
return conflict ? -EBUSY : 0;
}
EXPORT_SYMBOL(request_resource);
/**
* release_resource - release a previously reserved resource
* @old: resource pointer
*/
int release_resource(struct resource *old)
{
int retval;
write_lock(&resource_lock);
retval = __release_resource(old, true);
write_unlock(&resource_lock);
return retval;
}
EXPORT_SYMBOL(release_resource);
/**
* find_next_iomem_res - Finds the lowest iomem resource that covers part of
* [@start..@end].
*
* If a resource is found, returns 0 and @*res is overwritten with the part
* of the resource that's within [@start..@end]; if none is found, returns
* -ENODEV. Returns -EINVAL for invalid parameters.
*
* @start: start address of the resource searched for
* @end: end address of same resource
* @flags: flags which the resource must have
* @desc: descriptor the resource must have
* @res: return ptr, if resource found
*
* The caller must specify @start, @end, @flags, and @desc
* (which may be IORES_DESC_NONE).
*/
static int find_next_iomem_res(resource_size_t start, resource_size_t end,
unsigned long flags, unsigned long desc,
struct resource *res)
{
struct resource *p;
if (!res)
return -EINVAL;
if (start >= end)
return -EINVAL;
read_lock(&resource_lock);
for (p = iomem_resource.child; p; p = next_resource(p)) {
/* If we passed the resource we are looking for, stop */
if (p->start > end) {
p = NULL;
break;
}
/* Skip until we find a range that matches what we look for */
if (p->end < start)
continue;
if ((p->flags & flags) != flags)
continue;
if ((desc != IORES_DESC_NONE) && (desc != p->desc))
continue;
/* Found a match, break */
break;
}
if (p) {
/* copy data */
*res = (struct resource) {
.start = max(start, p->start),
.end = min(end, p->end),
.flags = p->flags,
.desc = p->desc,
.parent = p->parent,
};
}
read_unlock(&resource_lock);
return p ? 0 : -ENODEV;
}
static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
unsigned long flags, unsigned long desc,
void *arg,
int (*func)(struct resource *, void *))
{
struct resource res;
int ret = -EINVAL;
while (start < end &&
!find_next_iomem_res(start, end, flags, desc, &res)) {
ret = (*func)(&res, arg);
if (ret)
break;
start = res.end + 1;
}
return ret;
}
/**
* walk_iomem_res_desc - Walks through iomem resources and calls func()
* with matching resource ranges.
* *
* @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
* @flags: I/O resource flags
* @start: start addr
* @end: end addr
* @arg: function argument for the callback @func
* @func: callback function that is called for each qualifying resource area
*
* All the memory ranges which overlap start,end and also match flags and
* desc are valid candidates.
*
* NOTE: For a new descriptor search, define a new IORES_DESC in
* <linux/ioport.h> and set it in 'desc' of a target resource entry.
*/
int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
u64 end, void *arg, int (*func)(struct resource *, void *))
{
return __walk_iomem_res_desc(start, end, flags, desc, arg, func);
}
EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
/*
* This function calls the @func callback against all memory ranges of type
* System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
* Now, this function is only for System RAM, it deals with full ranges and
* not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
* ranges.
*/
int walk_system_ram_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *))
{
unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
func);
}
/*
* This function calls the @func callback against all memory ranges, which
* are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
*/
int walk_mem_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *))
{
unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
func);
}
/*
* This function calls the @func callback against all memory ranges of type
* System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
* It is to be used only for System RAM.
*/
int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *))
{
resource_size_t start, end;
unsigned long flags;
struct resource res;
unsigned long pfn, end_pfn;
int ret = -EINVAL;
start = (u64) start_pfn << PAGE_SHIFT;
end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
while (start < end &&
!find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
pfn = PFN_UP(res.start);
end_pfn = PFN_DOWN(res.end + 1);
if (end_pfn > pfn)
ret = (*func)(pfn, end_pfn - pfn, arg);
if (ret)
break;
start = res.end + 1;
}
return ret;
}
static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
{
return 1;
}
/*
* This generic page_is_ram() returns true if specified address is
* registered as System RAM in iomem_resource list.
*/
int __weak page_is_ram(unsigned long pfn)
{
return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
}
EXPORT_SYMBOL_GPL(page_is_ram);
static int __region_intersects(struct resource *parent, resource_size_t start,
size_t size, unsigned long flags,
unsigned long desc)
{
struct resource res;
int type = 0; int other = 0;
struct resource *p;
res.start = start;
res.end = start + size - 1;
for (p = parent->child; p ; p = p->sibling) {
bool is_type = (((p->flags & flags) == flags) &&
((desc == IORES_DESC_NONE) ||
(desc == p->desc)));
if (resource_overlaps(p, &res))
is_type ? type++ : other++;
}
if (type == 0)
return REGION_DISJOINT;
if (other == 0)
return REGION_INTERSECTS;
return REGION_MIXED;
}
/**
* region_intersects() - determine intersection of region with known resources
* @start: region start address
* @size: size of region
* @flags: flags of resource (in iomem_resource)
* @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
*
* Check if the specified region partially overlaps or fully eclipses a
* resource identified by @flags and @desc (optional with IORES_DESC_NONE).
* Return REGION_DISJOINT if the region does not overlap @flags/@desc,
* return REGION_MIXED if the region overlaps @flags/@desc and another
* resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
* and no other defined resource. Note that REGION_INTERSECTS is also
* returned in the case when the specified region overlaps RAM and undefined
* memory holes.
*
* region_intersect() is used by memory remapping functions to ensure
* the user is not remapping RAM and is a vast speed up over walking
* through the resource table page by page.
*/
int region_intersects(resource_size_t start, size_t size, unsigned long flags,
unsigned long desc)
{
int ret;
read_lock(&resource_lock);
ret = __region_intersects(&iomem_resource, start, size, flags, desc);
read_unlock(&resource_lock);
return ret;
}
EXPORT_SYMBOL_GPL(region_intersects);
void __weak arch_remove_reservations(struct resource *avail)
{
}
static resource_size_t simple_align_resource(void *data,
const struct resource *avail,
resource_size_t size,
resource_size_t align)
{
return avail->start;
}
static void resource_clip(struct resource *res, resource_size_t min,
resource_size_t max)
{
if (res->start < min)
res->start = min;
if (res->end > max)
res->end = max;
}
/*
* Find empty slot in the resource tree with the given range and
* alignment constraints
*/
static int __find_resource(struct resource *root, struct resource *old,
struct resource *new,
resource_size_t size,
struct resource_constraint *constraint)
{
struct resource *this = root->child;
struct resource tmp = *new, avail, alloc;
tmp.start = root->start;
/*
* Skip past an allocated resource that starts at 0, since the assignment
* of this->start - 1 to tmp->end below would cause an underflow.
*/
if (this && this->start == root->start) {
tmp.start = (this == old) ? old->start : this->end + 1;
this = this->sibling;
}
for(;;) {
if (this)
tmp.end = (this == old) ? this->end : this->start - 1;
else
tmp.end = root->end;
if (tmp.end < tmp.start)
goto next;
resource_clip(&tmp, constraint->min, constraint->max);
arch_remove_reservations(&tmp);
/* Check for overflow after ALIGN() */
avail.start = ALIGN(tmp.start, constraint->align);
avail.end = tmp.end;
avail.flags = new->flags & ~IORESOURCE_UNSET;
if (avail.start >= tmp.start) {
alloc.flags = avail.flags;
alloc.start = constraint->alignf(constraint->alignf_data, &avail,
size, constraint->align);
alloc.end = alloc.start + size - 1;
if (alloc.start <= alloc.end &&
resource_contains(&avail, &alloc)) {
new->start = alloc.start;
new->end = alloc.end;
return 0;
}
}
next: if (!this || this->end == root->end)
break;
if (this != old)
tmp.start = this->end + 1;
this = this->sibling;
}
return -EBUSY;
}
/*
* Find empty slot in the resource tree given range and alignment.
*/
static int find_resource(struct resource *root, struct resource *new,
resource_size_t size,
struct resource_constraint *constraint)
{
return __find_resource(root, NULL, new, size, constraint);
}
/**
* reallocate_resource - allocate a slot in the resource tree given range & alignment.
* The resource will be relocated if the new size cannot be reallocated in the
* current location.
*
* @root: root resource descriptor
* @old: resource descriptor desired by caller
* @newsize: new size of the resource descriptor
* @constraint: the size and alignment constraints to be met.
*/
static int reallocate_resource(struct resource *root, struct resource *old,
resource_size_t newsize,
struct resource_constraint *constraint)
{
int err=0;
struct resource new = *old;
struct resource *conflict;
write_lock(&resource_lock);
if ((err = __find_resource(root, old, &new, newsize, constraint)))
goto out;
if (resource_contains(&new, old)) {
old->start = new.start;
old->end = new.end;
goto out;
}
if (old->child) {
err = -EBUSY;
goto out;
}
if (resource_contains(old, &new)) {
old->start = new.start;
old->end = new.end;
} else {
__release_resource(old, true);
*old = new;
conflict = __request_resource(root, old);
BUG_ON(conflict);
}
out:
write_unlock(&resource_lock);
return err;
}
/**
* allocate_resource - allocate empty slot in the resource tree given range & alignment.
* The resource will be reallocated with a new size if it was already allocated
* @root: root resource descriptor
* @new: resource descriptor desired by caller
* @size: requested resource region size
* @min: minimum boundary to allocate
* @max: maximum boundary to allocate
* @align: alignment requested, in bytes
* @alignf: alignment function, optional, called if not NULL
* @alignf_data: arbitrary data to pass to the @alignf function
*/
int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,
resource_size_t (*alignf)(void *,
const struct resource *,
resource_size_t,
resource_size_t),
void *alignf_data)
{
int err;
struct resource_constraint constraint;
if (!alignf)
alignf = simple_align_resource;
constraint.min = min;
constraint.max = max;
constraint.align = align;
constraint.alignf = alignf;
constraint.alignf_data = alignf_data;
if ( new->parent ) {
/* resource is already allocated, try reallocating with
the new constraints */
return reallocate_resource(root, new, size, &constraint);
}
write_lock(&resource_lock);
err = find_resource(root, new, size, &constraint);
if (err >= 0 && __request_resource(root, new))
err = -EBUSY;
write_unlock(&resource_lock);
return err;
}
EXPORT_SYMBOL(allocate_resource);
/**
* lookup_resource - find an existing resource by a resource start address
* @root: root resource descriptor
* @start: resource start address
*
* Returns a pointer to the resource if found, NULL otherwise
*/
struct resource *lookup_resource(struct resource *root, resource_size_t start)
{
struct resource *res;
read_lock(&resource_lock);
for (res = root->child; res; res = res->sibling) {
if (res->start == start)
break;
}
read_unlock(&resource_lock);
return res;
}
/*
* Insert a resource into the resource tree. If successful, return NULL,
* otherwise return the conflicting resource (compare to __request_resource())
*/
static struct resource * __insert_resource(struct resource *parent, struct resource *new)
{
struct resource *first, *next;
for (;; parent = first) {
first = __request_resource(parent, new);
if (!first)
return first;
if (first == parent)
return first;
if (WARN_ON(first == new)) /* duplicated insertion */
return first;
if ((first->start > new->start) || (first->end < new->end))
break;
if ((first->start == new->start) && (first->end == new->end))
break;
}
for (next = first; ; next = next->sibling) {
/* Partial overlap? Bad, and unfixable */
if (next->start < new->start || next->end > new->end)
return next;
if (!next->sibling)
break;
if (next->sibling->start > new->end)
break;
}
new->parent = parent;
new->sibling = next->sibling;
new->child = first;
next->sibling = NULL;
for (next = first; next; next = next->sibling)
next->parent = new;
if (parent->child == first) {
parent->child = new;
} else {
next = parent->child;
while (next->sibling != first)
next = next->sibling;
next->sibling = new;
}
return NULL;
}
/**
* insert_resource_conflict - Inserts resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, conflict resource if the resource can't be inserted.
*
* This function is equivalent to request_resource_conflict when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
*
* This function is intended for producers of resources, such as FW modules
* and bus drivers.
*/
struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __insert_resource(parent, new);
write_unlock(&resource_lock);
return conflict;
}
/**
* insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
* This function is intended for producers of resources, such as FW modules
* and bus drivers.
*/
int insert_resource(struct resource *parent, struct resource *new)
{
struct resource *conflict;
conflict = insert_resource_conflict(parent, new);
return conflict ? -EBUSY : 0;
}
EXPORT_SYMBOL_GPL(insert_resource);
/**
* insert_resource_expand_to_fit - Insert a resource into the resource tree
* @root: root resource descriptor
* @new: new resource to insert
*
* Insert a resource into the resource tree, possibly expanding it in order
* to make it encompass any conflicting resources.
*/
void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
{
if (new->parent)
return;
write_lock(&resource_lock);
for (;;) {
struct resource *conflict;
conflict = __insert_resource(root, new);
if (!conflict)
break;
if (conflict == root)
break;
/* Ok, expand resource to cover the conflict, then try again .. */
if (conflict->start < new->start)
new->start = conflict->start;
if (conflict->end > new->end)
new->end = conflict->end;
pr_info("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
}
write_unlock(&resource_lock);
}
/*
* Not for general consumption, only early boot memory map parsing, PCI
* resource discovery, and late discovery of CXL resources are expected
* to use this interface. The former are built-in and only the latter,
* CXL, is a module.
*/
EXPORT_SYMBOL_NS_GPL(insert_resource_expand_to_fit, CXL);
/**
* remove_resource - Remove a resource in the resource tree
* @old: resource to remove
*
* Returns 0 on success, -EINVAL if the resource is not valid.
*
* This function removes a resource previously inserted by insert_resource()
* or insert_resource_conflict(), and moves the children (if any) up to
* where they were before. insert_resource() and insert_resource_conflict()
* insert a new resource, and move any conflicting resources down to the
* children of the new resource.
*
* insert_resource(), insert_resource_conflict() and remove_resource() are
* intended for producers of resources, such as FW modules and bus drivers.
*/
int remove_resource(struct resource *old)
{
int retval;
write_lock(&resource_lock);
retval = __release_resource(old, false);
write_unlock(&resource_lock);
return retval;
}
EXPORT_SYMBOL_GPL(remove_resource);
static int __adjust_resource(struct resource *res, resource_size_t start,
resource_size_t size)
{
struct resource *tmp, *parent = res->parent;
resource_size_t end = start + size - 1;
int result = -EBUSY;
if (!parent)
goto skip;
if ((start < parent->start) || (end > parent->end))
goto out;
if (res->sibling && (res->sibling->start <= end))
goto out;
tmp = parent->child;
if (tmp != res) {
while (tmp->sibling != res)
tmp = tmp->sibling;
if (start <= tmp->end)
goto out;
}
skip:
for (tmp = res->child; tmp; tmp = tmp->sibling)
if ((tmp->start < start) || (tmp->end > end))
goto out;
res->start = start;
res->end = end;
result = 0;
out:
return result;
}
/**
* adjust_resource - modify a resource's start and size
* @res: resource to modify
* @start: new start value
* @size: new size
*
* Given an existing resource, change its start and size to match the
* arguments. Returns 0 on success, -EBUSY if it can't fit.
* Existing children of the resource are assumed to be immutable.
*/
int adjust_resource(struct resource *res, resource_size_t start,
resource_size_t size)
{
int result;
write_lock(&resource_lock);
result = __adjust_resource(res, start, size);
write_unlock(&resource_lock);
return result;
}
EXPORT_SYMBOL(adjust_resource);
static void __init
__reserve_region_with_split(struct resource *root, resource_size_t start,
resource_size_t end, const char *name)
{
struct resource *parent = root;
struct resource *conflict;
struct resource *res = alloc_resource(GFP_ATOMIC);
struct resource *next_res = NULL;
int type = resource_type(root);
if (!res)
return;
res->name = name;
res->start = start;
res->end = end;
res->flags = type | IORESOURCE_BUSY;
res->desc = IORES_DESC_NONE;
while (1) {
conflict = __request_resource(parent, res);
if (!conflict) {
if (!next_res)
break;
res = next_res;
next_res = NULL;
continue;
}
/* conflict covered whole area */
if (conflict->start <= res->start &&
conflict->end >= res->end) {
free_resource(res);
WARN_ON(next_res);
break;
}
/* failed, split and try again */
if (conflict->start > res->start) {
end = res->end;
res->end = conflict->start - 1;
if (conflict->end < end) {
next_res = alloc_resource(GFP_ATOMIC);
if (!next_res) {
free_resource(res);
break;
}
next_res->name = name;
next_res->start = conflict->end + 1;
next_res->end = end;
next_res->flags = type | IORESOURCE_BUSY;
next_res->desc = IORES_DESC_NONE;
}
} else {
res->start = conflict->end + 1;
}
}
}
void __init
reserve_region_with_split(struct resource *root, resource_size_t start,
resource_size_t end, const char *name)
{
int abort = 0;
write_lock(&resource_lock);
if (root->start > start || root->end < end) {
pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
(unsigned long long)start, (unsigned long long)end,
root);
if (start > root->end || end < root->start)
abort = 1;
else {
if (end > root->end)
end = root->end;
if (start < root->start)
start = root->start;
pr_err("fixing request to [0x%llx-0x%llx]\n",
(unsigned long long)start,
(unsigned long long)end);
}
dump_stack();
}
if (!abort)
__reserve_region_with_split(root, start, end, name);
write_unlock(&resource_lock);
}
/**
* resource_alignment - calculate resource's alignment
* @res: resource pointer
*
* Returns alignment on success, 0 (invalid alignment) on failure.
*/
resource_size_t resource_alignment(struct resource *res)
{
switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
case IORESOURCE_SIZEALIGN:
return resource_size(res);
case IORESOURCE_STARTALIGN:
return res->start;
default:
return 0;
}
}
/*
* This is compatibility stuff for IO resources.
*
* Note how this, unlike the above, knows about
* the IO flag meanings (busy etc).
*
* request_region creates a new busy region.
*
* release_region releases a matching busy region.
*/
static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
static struct inode *iomem_inode;
#ifdef CONFIG_IO_STRICT_DEVMEM
static void revoke_iomem(struct resource *res)
{
/* pairs with smp_store_release() in iomem_init_inode() */
struct inode *inode = smp_load_acquire(&iomem_inode);
/*
* Check that the initialization has completed. Losing the race
* is ok because it means drivers are claiming resources before
* the fs_initcall level of init and prevent iomem_get_mapping users
* from establishing mappings.
*/
if (!inode)
return;
/*
* The expectation is that the driver has successfully marked
* the resource busy by this point, so devmem_is_allowed()
* should start returning false, however for performance this
* does not iterate the entire resource range.
*/
if (devmem_is_allowed(PHYS_PFN(res->start)) &&
devmem_is_allowed(PHYS_PFN(res->end))) {
/*
* *cringe* iomem=relaxed says "go ahead, what's the
* worst that can happen?"
*/
return;
}
unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
}
#else
static void revoke_iomem(struct resource *res) {}
#endif
struct address_space *iomem_get_mapping(void)
{
/*
* This function is only called from file open paths, hence guaranteed
* that fs_initcalls have completed and no need to check for NULL. But
* since revoke_iomem can be called before the initcall we still need
* the barrier to appease checkers.
*/
return smp_load_acquire(&iomem_inode)->i_mapping;
}
static int __request_region_locked(struct resource *res, struct resource *parent,
resource_size_t start, resource_size_t n,
const char *name, int flags)
{
DECLARE_WAITQUEUE(wait, current);
res->name = name;
res->start = start;
res->end = start + n - 1;
for (;;) {
struct resource *conflict;
res->flags = resource_type(parent) | resource_ext_type(parent);
res->flags |= IORESOURCE_BUSY | flags;
res->desc = parent->desc;
conflict = __request_resource(parent, res);
if (!conflict)
break;
/*
* mm/hmm.c reserves physical addresses which then
* become unavailable to other users. Conflicts are
* not expected. Warn to aid debugging if encountered.
*/
if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
pr_warn("Unaddressable device %s %pR conflicts with %pR",
conflict->name, conflict, res);
}
if (conflict != parent) {
if (!(conflict->flags & IORESOURCE_BUSY)) {
parent = conflict;
continue;
}
}
if (conflict->flags & flags & IORESOURCE_MUXED) {
add_wait_queue(&muxed_resource_wait, &wait);
write_unlock(&resource_lock);
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
remove_wait_queue(&muxed_resource_wait, &wait);
write_lock(&resource_lock);
continue;
}
/* Uhhuh, that didn't work out.. */
return -EBUSY;
}
return 0;
}
/**
* __request_region - create a new busy resource region
* @parent: parent resource descriptor
* @start: resource start address
* @n: resource region size
* @name: reserving caller's ID string
* @flags: IO resource flags
*/
struct resource *__request_region(struct resource *parent,
resource_size_t start, resource_size_t n,
const char *name, int flags)
{
struct resource *res = alloc_resource(GFP_KERNEL);
int ret;
if (!res)
return NULL;
write_lock(&resource_lock);
ret = __request_region_locked(res, parent, start, n, name, flags);
write_unlock(&resource_lock);
if (ret) {
free_resource(res);
return NULL;
}
if (parent == &iomem_resource)
revoke_iomem(res);
return res;
}
EXPORT_SYMBOL(__request_region);
/**
* __release_region - release a previously reserved resource region
* @parent: parent resource descriptor
* @start: resource start address
* @n: resource region size
*
* The described resource region must match a currently busy region.
*/
void __release_region(struct resource *parent, resource_size_t start,
resource_size_t n)
{
struct resource **p;
resource_size_t end;
p = &parent->child;
end = start + n - 1;
write_lock(&resource_lock);
for (;;) {
struct resource *res = *p;
if (!res)
break;
if (res->start <= start && res->end >= end) {
if (!(res->flags & IORESOURCE_BUSY)) {
p = &res->child;
continue;
}
if (res->start != start || res->end != end)
break;
*p = res->sibling;
write_unlock(&resource_lock);
if (res->flags & IORESOURCE_MUXED)
wake_up(&muxed_resource_wait);
free_resource(res);
return;
}
p = &res->sibling;
}
write_unlock(&resource_lock);
pr_warn("Trying to free nonexistent resource <%pa-%pa>\n", &start, &end);
}
EXPORT_SYMBOL(__release_region);
#ifdef CONFIG_MEMORY_HOTREMOVE
/**
* release_mem_region_adjustable - release a previously reserved memory region
* @start: resource start address
* @size: resource region size
*
* This interface is intended for memory hot-delete. The requested region
* is released from a currently busy memory resource. The requested region
* must either match exactly or fit into a single busy resource entry. In
* the latter case, the remaining resource is adjusted accordingly.
* Existing children of the busy memory resource must be immutable in the
* request.
*
* Note:
* - Additional release conditions, such as overlapping region, can be
* supported after they are confirmed as valid cases.
* - When a busy memory resource gets split into two entries, the code
* assumes that all children remain in the lower address entry for
* simplicity. Enhance this logic when necessary.
*/
void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
{
struct resource *parent = &iomem_resource;
struct resource *new_res = NULL;
bool alloc_nofail = false;
struct resource **p;
struct resource *res;
resource_size_t end;
end = start + size - 1;
if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
return;
/*
* We free up quite a lot of memory on memory hotunplug (esp., memap),
* just before releasing the region. This is highly unlikely to
* fail - let's play save and make it never fail as the caller cannot
* perform any error handling (e.g., trying to re-add memory will fail
* similarly).
*/
retry:
new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
p = &parent->child;
write_lock(&resource_lock);
while ((res = *p)) {
if (res->start >= end)
break;
/* look for the next resource if it does not fit into */
if (res->start > start || res->end < end) {
p = &res->sibling;
continue;
}
if (!(res->flags & IORESOURCE_MEM))
break;
if (!(res->flags & IORESOURCE_BUSY)) {
p = &res->child;
continue;
}
/* found the target resource; let's adjust accordingly */
if (res->start == start && res->end == end) {
/* free the whole entry */
*p = res->sibling;
free_resource(res);
} else if (res->start == start && res->end != end) {
/* adjust the start */
WARN_ON_ONCE(__adjust_resource(res, end + 1,
res->end - end));
} else if (res->start != start && res->end == end) {
/* adjust the end */
WARN_ON_ONCE(__adjust_resource(res, res->start,
start - res->start));
} else {
/* split into two entries - we need a new resource */
if (!new_res) {
new_res = alloc_resource(GFP_ATOMIC);
if (!new_res) {
alloc_nofail = true;
write_unlock(&resource_lock);
goto retry;
}
}
new_res->name = res->name;
new_res->start = end + 1;
new_res->end = res->end;
new_res->flags = res->flags;
new_res->desc = res->desc;
new_res->parent = res->parent;
new_res->sibling = res->sibling;
new_res->child = NULL;
if (WARN_ON_ONCE(__adjust_resource(res, res->start,
start - res->start)))
break;
res->sibling = new_res;
new_res = NULL;
}
break;
}
write_unlock(&resource_lock);
free_resource(new_res);
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
#ifdef CONFIG_MEMORY_HOTPLUG
static bool system_ram_resources_mergeable(struct resource *r1,
struct resource *r2)
{
/* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
return r1->flags == r2->flags && r1->end + 1 == r2->start &&
r1->name == r2->name && r1->desc == r2->desc &&
!r1->child && !r2->child;
}
/**
* merge_system_ram_resource - mark the System RAM resource mergeable and try to
* merge it with adjacent, mergeable resources
* @res: resource descriptor
*
* This interface is intended for memory hotplug, whereby lots of contiguous
* system ram resources are added (e.g., via add_memory*()) by a driver, and
* the actual resource boundaries are not of interest (e.g., it might be
* relevant for DIMMs). Only resources that are marked mergeable, that have the
* same parent, and that don't have any children are considered. All mergeable
* resources must be immutable during the request.
*
* Note:
* - The caller has to make sure that no pointers to resources that are
* marked mergeable are used anymore after this call - the resource might
* be freed and the pointer might be stale!
* - release_mem_region_adjustable() will split on demand on memory hotunplug
*/
void merge_system_ram_resource(struct resource *res)
{
const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
struct resource *cur;
if (WARN_ON_ONCE((res->flags & flags) != flags))
return;
write_lock(&resource_lock);
res->flags |= IORESOURCE_SYSRAM_MERGEABLE;
/* Try to merge with next item in the list. */
cur = res->sibling;
if (cur && system_ram_resources_mergeable(res, cur)) {
res->end = cur->end;
res->sibling = cur->sibling;
free_resource(cur);
}
/* Try to merge with previous item in the list. */
cur = res->parent->child;
while (cur && cur->sibling != res)
cur = cur->sibling;
if (cur && system_ram_resources_mergeable(cur, res)) {
cur->end = res->end;
cur->sibling = res->sibling;
free_resource(res);
}
write_unlock(&resource_lock);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
/*
* Managed region resource
*/
static void devm_resource_release(struct device *dev, void *ptr)
{
struct resource **r = ptr;
release_resource(*r);
}
/**
* devm_request_resource() - request and reserve an I/O or memory resource
* @dev: device for which to request the resource
* @root: root of the resource tree from which to request the resource
* @new: descriptor of the resource to request
*
* This is a device-managed version of request_resource(). There is usually
* no need to release resources requested by this function explicitly since
* that will be taken care of when the device is unbound from its driver.
* If for some reason the resource needs to be released explicitly, because
* of ordering issues for example, drivers must call devm_release_resource()
* rather than the regular release_resource().
*
* When a conflict is detected between any existing resources and the newly
* requested resource, an error message will be printed.
*
* Returns 0 on success or a negative error code on failure.
*/
int devm_request_resource(struct device *dev, struct resource *root,
struct resource *new)
{
struct resource *conflict, **ptr;
ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
*ptr = new;
conflict = request_resource_conflict(root, new);
if (conflict) {
dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
new, conflict->name, conflict);
devres_free(ptr);
return -EBUSY;
}
devres_add(dev, ptr);
return 0;
}
EXPORT_SYMBOL(devm_request_resource);
static int devm_resource_match(struct device *dev, void *res, void *data)
{
struct resource **ptr = res;
return *ptr == data;
}
/**
* devm_release_resource() - release a previously requested resource
* @dev: device for which to release the resource
* @new: descriptor of the resource to release
*
* Releases a resource previously requested using devm_request_resource().
*/
void devm_release_resource(struct device *dev, struct resource *new)
{
WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
new));
}
EXPORT_SYMBOL(devm_release_resource);
struct region_devres {
struct resource *parent;
resource_size_t start;
resource_size_t n;
};
static void devm_region_release(struct device *dev, void *res)
{
struct region_devres *this = res;
__release_region(this->parent, this->start, this->n);
}
static int devm_region_match(struct device *dev, void *res, void *match_data)
{
struct region_devres *this = res, *match = match_data;
return this->parent == match->parent &&
this->start == match->start && this->n == match->n;
}
struct resource *
__devm_request_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n, const char *name)
{
struct region_devres *dr = NULL;
struct resource *res;
dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
GFP_KERNEL);
if (!dr)
return NULL;
dr->parent = parent;
dr->start = start;
dr->n = n;
res = __request_region(parent, start, n, name, 0);
if (res)
devres_add(dev, dr);
else
devres_free(dr);
return res;
}
EXPORT_SYMBOL(__devm_request_region);
void __devm_release_region(struct device *dev, struct resource *parent,
resource_size_t start, resource_size_t n)
{
struct region_devres match_data = { parent, start, n };
__release_region(parent, start, n);
WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
&match_data));
}
EXPORT_SYMBOL(__devm_release_region);
/*
* Reserve I/O ports or memory based on "reserve=" kernel parameter.
*/
#define MAXRESERVE 4
static int __init reserve_setup(char *str)
{
static int reserved;
static struct resource reserve[MAXRESERVE];
for (;;) {
unsigned int io_start, io_num;
int x = reserved;
struct resource *parent;
if (get_option(&str, &io_start) != 2)
break;
if (get_option(&str, &io_num) == 0)
break;
if (x < MAXRESERVE) {
struct resource *res = reserve + x;
/*
* If the region starts below 0x10000, we assume it's
* I/O port space; otherwise assume it's memory.
*/
if (io_start < 0x10000) {
res->flags = IORESOURCE_IO;
parent = &ioport_resource;
} else {
res->flags = IORESOURCE_MEM;
parent = &iomem_resource;
}
res->name = "reserved";
res->start = io_start;
res->end = io_start + io_num - 1;
res->flags |= IORESOURCE_BUSY;
res->desc = IORES_DESC_NONE;
res->child = NULL;
if (request_resource(parent, res) == 0)
reserved = x+1;
}
}
return 1;
}
__setup("reserve=", reserve_setup);
/*
* Check if the requested addr and size spans more than any slot in the
* iomem resource tree.
*/
int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
{
struct resource *p = &iomem_resource;
resource_size_t end = addr + size - 1;
int err = 0;
loff_t l;
read_lock(&resource_lock);
for (p = p->child; p ; p = r_next(NULL, p, &l)) {
/*
* We can probably skip the resources without
* IORESOURCE_IO attribute?
*/
if (p->start > end)
continue;
if (p->end < addr)
continue;
if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
PFN_DOWN(p->end) >= PFN_DOWN(end))
continue;
/*
* if a resource is "BUSY", it's not a hardware resource
* but a driver mapping of such a resource; we don't want
* to warn for those; some drivers legitimately map only
* partial hardware resources. (example: vesafb)
*/
if (p->flags & IORESOURCE_BUSY)
continue;
pr_warn("resource sanity check: requesting [mem %pa-%pa], which spans more than %s %pR\n",
&addr, &end, p->name, p);
err = -1;
break;
}
read_unlock(&resource_lock);
return err;
}
#ifdef CONFIG_STRICT_DEVMEM
static int strict_iomem_checks = 1;
#else
static int strict_iomem_checks;
#endif
/*
* Check if an address is exclusive to the kernel and must not be mapped to
* user space, for example, via /dev/mem.
*
* Returns true if exclusive to the kernel, otherwise returns false.
*/
bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size)
{
const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
IORESOURCE_EXCLUSIVE;
bool skip_children = false, err = false;
struct resource *p;
read_lock(&resource_lock);
for_each_resource(root, p, skip_children) {
if (p->start >= addr + size)
break;
if (p->end < addr) {
skip_children = true;
continue;
}
skip_children = false;
/*
* IORESOURCE_SYSTEM_RAM resources are exclusive if
* IORESOURCE_EXCLUSIVE is set, even if they
* are not busy and even if "iomem=relaxed" is set. The
* responsible driver dynamically adds/removes system RAM within
* such an area and uncontrolled access is dangerous.
*/
if ((p->flags & exclusive_system_ram) == exclusive_system_ram) {
err = true;
break;
}
/*
* A resource is exclusive if IORESOURCE_EXCLUSIVE is set
* or CONFIG_IO_STRICT_DEVMEM is enabled and the
* resource is busy.
*/
if (!strict_iomem_checks || !(p->flags & IORESOURCE_BUSY))
continue;
if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
|| p->flags & IORESOURCE_EXCLUSIVE) {
err = true;
break;
}
}
read_unlock(&resource_lock);
return err;
}
bool iomem_is_exclusive(u64 addr)
{
return resource_is_exclusive(&iomem_resource, addr & PAGE_MASK,
PAGE_SIZE);
}
struct resource_entry *resource_list_create_entry(struct resource *res,
size_t extra_size)
{
struct resource_entry *entry;
entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
if (entry) {
INIT_LIST_HEAD(&entry->node);
entry->res = res ? res : &entry->__res;
}
return entry;
}
EXPORT_SYMBOL(resource_list_create_entry);
void resource_list_free(struct list_head *head)
{
struct resource_entry *entry, *tmp;
list_for_each_entry_safe(entry, tmp, head, node)
resource_list_destroy_entry(entry);
}
EXPORT_SYMBOL(resource_list_free);
#ifdef CONFIG_GET_FREE_REGION
#define GFR_DESCENDING (1UL << 0)
#define GFR_REQUEST_REGION (1UL << 1)
#define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
static resource_size_t gfr_start(struct resource *base, resource_size_t size,
resource_size_t align, unsigned long flags)
{
if (flags & GFR_DESCENDING) {
resource_size_t end;
end = min_t(resource_size_t, base->end,
(1ULL << MAX_PHYSMEM_BITS) - 1);
return end - size + 1;
}
return ALIGN(base->start, align);
}
static bool gfr_continue(struct resource *base, resource_size_t addr,
resource_size_t size, unsigned long flags)
{
if (flags & GFR_DESCENDING)
return addr > size && addr >= base->start;
/*
* In the ascend case be careful that the last increment by
* @size did not wrap 0.
*/
return addr > addr - size &&
addr <= min_t(resource_size_t, base->end,
(1ULL << MAX_PHYSMEM_BITS) - 1);
}
static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
unsigned long flags)
{
if (flags & GFR_DESCENDING)
return addr - size;
return addr + size;
}
static void remove_free_mem_region(void *_res)
{
struct resource *res = _res;
if (res->parent)
remove_resource(res);
free_resource(res);
}
static struct resource *
get_free_mem_region(struct device *dev, struct resource *base,
resource_size_t size, const unsigned long align,
const char *name, const unsigned long desc,
const unsigned long flags)
{
resource_size_t addr;
struct resource *res;
struct region_devres *dr = NULL;
size = ALIGN(size, align);
res = alloc_resource(GFP_KERNEL);
if (!res)
return ERR_PTR(-ENOMEM);
if (dev && (flags & GFR_REQUEST_REGION)) {
dr = devres_alloc(devm_region_release,
sizeof(struct region_devres), GFP_KERNEL);
if (!dr) {
free_resource(res);
return ERR_PTR(-ENOMEM);
}
} else if (dev) {
if (devm_add_action_or_reset(dev, remove_free_mem_region, res))
return ERR_PTR(-ENOMEM);
}
write_lock(&resource_lock);
for (addr = gfr_start(base, size, align, flags);
gfr_continue(base, addr, size, flags);
addr = gfr_next(addr, size, flags)) {
if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
REGION_DISJOINT)
continue;
if (flags & GFR_REQUEST_REGION) {
if (__request_region_locked(res, &iomem_resource, addr,
size, name, 0))
break;
if (dev) {
dr->parent = &iomem_resource;
dr->start = addr;
dr->n = size;
devres_add(dev, dr);
}
res->desc = desc;
write_unlock(&resource_lock);
/*
* A driver is claiming this region so revoke any
* mappings.
*/
revoke_iomem(res);
} else {
res->start = addr;
res->end = addr + size - 1;
res->name = name;
res->desc = desc;
res->flags = IORESOURCE_MEM;
/*
* Only succeed if the resource hosts an exclusive
* range after the insert
*/
if (__insert_resource(base, res) || res->child)
break;
write_unlock(&resource_lock);
}
return res;
}
write_unlock(&resource_lock);
if (flags & GFR_REQUEST_REGION) {
free_resource(res);
devres_free(dr);
} else if (dev)
devm_release_action(dev, remove_free_mem_region, res);
return ERR_PTR(-ERANGE);
}
/**
* devm_request_free_mem_region - find free region for device private memory
*
* @dev: device struct to bind the resource to
* @size: size in bytes of the device memory to add
* @base: resource tree to look in
*
* This function tries to find an empty range of physical address big enough to
* contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
* memory, which in turn allocates struct pages.
*/
struct resource *devm_request_free_mem_region(struct device *dev,
struct resource *base, unsigned long size)
{
unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
return get_free_mem_region(dev, base, size, GFR_DEFAULT_ALIGN,
dev_name(dev),
IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
}
EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
struct resource *request_free_mem_region(struct resource *base,
unsigned long size, const char *name)
{
unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
return get_free_mem_region(NULL, base, size, GFR_DEFAULT_ALIGN, name,
IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
}
EXPORT_SYMBOL_GPL(request_free_mem_region);
/**
* alloc_free_mem_region - find a free region relative to @base
* @base: resource that will parent the new resource
* @size: size in bytes of memory to allocate from @base
* @align: alignment requirements for the allocation
* @name: resource name
*
* Buses like CXL, that can dynamically instantiate new memory regions,
* need a method to allocate physical address space for those regions.
* Allocate and insert a new resource to cover a free, unclaimed by a
* descendant of @base, range in the span of @base.
*/
struct resource *alloc_free_mem_region(struct resource *base,
unsigned long size, unsigned long align,
const char *name)
{
/* Default of ascending direction and insert resource */
unsigned long flags = 0;
return get_free_mem_region(NULL, base, size, align, name,
IORES_DESC_NONE, flags);
}
EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
#endif /* CONFIG_GET_FREE_REGION */
static int __init strict_iomem(char *str)
{
if (strstr(str, "relaxed"))
strict_iomem_checks = 0;
if (strstr(str, "strict"))
strict_iomem_checks = 1;
return 1;
}
static int iomem_fs_init_fs_context(struct fs_context *fc)
{
return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
}
static struct file_system_type iomem_fs_type = {
.name = "iomem",
.owner = THIS_MODULE,
.init_fs_context = iomem_fs_init_fs_context,
.kill_sb = kill_anon_super,
};
static int __init iomem_init_inode(void)
{
static struct vfsmount *iomem_vfs_mount;
static int iomem_fs_cnt;
struct inode *inode;
int rc;
rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt);
if (rc < 0) {
pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc);
return rc;
}
inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb);
if (IS_ERR(inode)) {
rc = PTR_ERR(inode);
pr_err("Cannot allocate inode for iomem: %d\n", rc);
simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt);
return rc;
}
/*
* Publish iomem revocation inode initialized.
* Pairs with smp_load_acquire() in revoke_iomem().
*/
smp_store_release(&iomem_inode, inode);
return 0;
}
fs_initcall(iomem_init_inode);
__setup("iomem=", strict_iomem);
| linux-master | kernel/resource.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* kernel/stop_machine.c
*
* Copyright (C) 2008, 2005 IBM Corporation.
* Copyright (C) 2008, 2005 Rusty Russell [email protected]
* Copyright (C) 2010 SUSE Linux Products GmbH
* Copyright (C) 2010 Tejun Heo <[email protected]>
*/
#include <linux/compiler.h>
#include <linux/completion.h>
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/stop_machine.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/smpboot.h>
#include <linux/atomic.h>
#include <linux/nmi.h>
#include <linux/sched/wake_q.h>
/*
* Structure to determine completion condition and record errors. May
* be shared by works on different cpus.
*/
struct cpu_stop_done {
atomic_t nr_todo; /* nr left to execute */
int ret; /* collected return value */
struct completion completion; /* fired if nr_todo reaches 0 */
};
/* the actual stopper, one per every possible cpu, enabled on online cpus */
struct cpu_stopper {
struct task_struct *thread;
raw_spinlock_t lock;
bool enabled; /* is this stopper enabled? */
struct list_head works; /* list of pending works */
struct cpu_stop_work stop_work; /* for stop_cpus */
unsigned long caller;
cpu_stop_fn_t fn;
};
static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper);
static bool stop_machine_initialized = false;
void print_stop_info(const char *log_lvl, struct task_struct *task)
{
/*
* If @task is a stopper task, it cannot migrate and task_cpu() is
* stable.
*/
struct cpu_stopper *stopper = per_cpu_ptr(&cpu_stopper, task_cpu(task));
if (task != stopper->thread)
return;
printk("%sStopper: %pS <- %pS\n", log_lvl, stopper->fn, (void *)stopper->caller);
}
/* static data for stop_cpus */
static DEFINE_MUTEX(stop_cpus_mutex);
static bool stop_cpus_in_progress;
static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo)
{
memset(done, 0, sizeof(*done));
atomic_set(&done->nr_todo, nr_todo);
init_completion(&done->completion);
}
/* signal completion unless @done is NULL */
static void cpu_stop_signal_done(struct cpu_stop_done *done)
{
if (atomic_dec_and_test(&done->nr_todo))
complete(&done->completion);
}
static void __cpu_stop_queue_work(struct cpu_stopper *stopper,
struct cpu_stop_work *work,
struct wake_q_head *wakeq)
{
list_add_tail(&work->list, &stopper->works);
wake_q_add(wakeq, stopper->thread);
}
/* queue @work to @stopper. if offline, @work is completed immediately */
static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
DEFINE_WAKE_Q(wakeq);
unsigned long flags;
bool enabled;
preempt_disable();
raw_spin_lock_irqsave(&stopper->lock, flags);
enabled = stopper->enabled;
if (enabled)
__cpu_stop_queue_work(stopper, work, &wakeq);
else if (work->done)
cpu_stop_signal_done(work->done);
raw_spin_unlock_irqrestore(&stopper->lock, flags);
wake_up_q(&wakeq);
preempt_enable();
return enabled;
}
/**
* stop_one_cpu - stop a cpu
* @cpu: cpu to stop
* @fn: function to execute
* @arg: argument to @fn
*
* Execute @fn(@arg) on @cpu. @fn is run in a process context with
* the highest priority preempting any task on the cpu and
* monopolizing it. This function returns after the execution is
* complete.
*
* This function doesn't guarantee @cpu stays online till @fn
* completes. If @cpu goes down in the middle, execution may happen
* partially or fully on different cpus. @fn should either be ready
* for that or the caller should ensure that @cpu stays online until
* this function completes.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* -ENOENT if @fn(@arg) was not executed because @cpu was offline;
* otherwise, the return value of @fn.
*/
int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
{
struct cpu_stop_done done;
struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done, .caller = _RET_IP_ };
cpu_stop_init_done(&done, 1);
if (!cpu_stop_queue_work(cpu, &work))
return -ENOENT;
/*
* In case @cpu == smp_proccessor_id() we can avoid a sleep+wakeup
* cycle by doing a preemption:
*/
cond_resched();
wait_for_completion(&done.completion);
return done.ret;
}
/* This controls the threads on each CPU. */
enum multi_stop_state {
/* Dummy starting state for thread. */
MULTI_STOP_NONE,
/* Awaiting everyone to be scheduled. */
MULTI_STOP_PREPARE,
/* Disable interrupts. */
MULTI_STOP_DISABLE_IRQ,
/* Run the function */
MULTI_STOP_RUN,
/* Exit */
MULTI_STOP_EXIT,
};
struct multi_stop_data {
cpu_stop_fn_t fn;
void *data;
/* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */
unsigned int num_threads;
const struct cpumask *active_cpus;
enum multi_stop_state state;
atomic_t thread_ack;
};
static void set_state(struct multi_stop_data *msdata,
enum multi_stop_state newstate)
{
/* Reset ack counter. */
atomic_set(&msdata->thread_ack, msdata->num_threads);
smp_wmb();
WRITE_ONCE(msdata->state, newstate);
}
/* Last one to ack a state moves to the next state. */
static void ack_state(struct multi_stop_data *msdata)
{
if (atomic_dec_and_test(&msdata->thread_ack))
set_state(msdata, msdata->state + 1);
}
notrace void __weak stop_machine_yield(const struct cpumask *cpumask)
{
cpu_relax();
}
/* This is the cpu_stop function which stops the CPU. */
static int multi_cpu_stop(void *data)
{
struct multi_stop_data *msdata = data;
enum multi_stop_state newstate, curstate = MULTI_STOP_NONE;
int cpu = smp_processor_id(), err = 0;
const struct cpumask *cpumask;
unsigned long flags;
bool is_active;
/*
* When called from stop_machine_from_inactive_cpu(), irq might
* already be disabled. Save the state and restore it on exit.
*/
local_save_flags(flags);
if (!msdata->active_cpus) {
cpumask = cpu_online_mask;
is_active = cpu == cpumask_first(cpumask);
} else {
cpumask = msdata->active_cpus;
is_active = cpumask_test_cpu(cpu, cpumask);
}
/* Simple state machine */
do {
/* Chill out and ensure we re-read multi_stop_state. */
stop_machine_yield(cpumask);
newstate = READ_ONCE(msdata->state);
if (newstate != curstate) {
curstate = newstate;
switch (curstate) {
case MULTI_STOP_DISABLE_IRQ:
local_irq_disable();
hard_irq_disable();
break;
case MULTI_STOP_RUN:
if (is_active)
err = msdata->fn(msdata->data);
break;
default:
break;
}
ack_state(msdata);
} else if (curstate > MULTI_STOP_PREPARE) {
/*
* At this stage all other CPUs we depend on must spin
* in the same loop. Any reason for hard-lockup should
* be detected and reported on their side.
*/
touch_nmi_watchdog();
}
rcu_momentary_dyntick_idle();
} while (curstate != MULTI_STOP_EXIT);
local_irq_restore(flags);
return err;
}
static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1,
int cpu2, struct cpu_stop_work *work2)
{
struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1);
struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2);
DEFINE_WAKE_Q(wakeq);
int err;
retry:
/*
* The waking up of stopper threads has to happen in the same
* scheduling context as the queueing. Otherwise, there is a
* possibility of one of the above stoppers being woken up by another
* CPU, and preempting us. This will cause us to not wake up the other
* stopper forever.
*/
preempt_disable();
raw_spin_lock_irq(&stopper1->lock);
raw_spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
if (!stopper1->enabled || !stopper2->enabled) {
err = -ENOENT;
goto unlock;
}
/*
* Ensure that if we race with __stop_cpus() the stoppers won't get
* queued up in reverse order leading to system deadlock.
*
* We can't miss stop_cpus_in_progress if queue_stop_cpus_work() has
* queued a work on cpu1 but not on cpu2, we hold both locks.
*
* It can be falsely true but it is safe to spin until it is cleared,
* queue_stop_cpus_work() does everything under preempt_disable().
*/
if (unlikely(stop_cpus_in_progress)) {
err = -EDEADLK;
goto unlock;
}
err = 0;
__cpu_stop_queue_work(stopper1, work1, &wakeq);
__cpu_stop_queue_work(stopper2, work2, &wakeq);
unlock:
raw_spin_unlock(&stopper2->lock);
raw_spin_unlock_irq(&stopper1->lock);
if (unlikely(err == -EDEADLK)) {
preempt_enable();
while (stop_cpus_in_progress)
cpu_relax();
goto retry;
}
wake_up_q(&wakeq);
preempt_enable();
return err;
}
/**
* stop_two_cpus - stops two cpus
* @cpu1: the cpu to stop
* @cpu2: the other cpu to stop
* @fn: function to execute
* @arg: argument to @fn
*
* Stops both the current and specified CPU and runs @fn on one of them.
*
* returns when both are completed.
*/
int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg)
{
struct cpu_stop_done done;
struct cpu_stop_work work1, work2;
struct multi_stop_data msdata;
msdata = (struct multi_stop_data){
.fn = fn,
.data = arg,
.num_threads = 2,
.active_cpus = cpumask_of(cpu1),
};
work1 = work2 = (struct cpu_stop_work){
.fn = multi_cpu_stop,
.arg = &msdata,
.done = &done,
.caller = _RET_IP_,
};
cpu_stop_init_done(&done, 2);
set_state(&msdata, MULTI_STOP_PREPARE);
if (cpu1 > cpu2)
swap(cpu1, cpu2);
if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2))
return -ENOENT;
wait_for_completion(&done.completion);
return done.ret;
}
/**
* stop_one_cpu_nowait - stop a cpu but don't wait for completion
* @cpu: cpu to stop
* @fn: function to execute
* @arg: argument to @fn
* @work_buf: pointer to cpu_stop_work structure
*
* Similar to stop_one_cpu() but doesn't wait for completion. The
* caller is responsible for ensuring @work_buf is currently unused
* and will remain untouched until stopper starts executing @fn.
*
* CONTEXT:
* Don't care.
*
* RETURNS:
* true if cpu_stop_work was queued successfully and @fn will be called,
* false otherwise.
*/
bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
struct cpu_stop_work *work_buf)
{
*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, .caller = _RET_IP_, };
return cpu_stop_queue_work(cpu, work_buf);
}
static bool queue_stop_cpus_work(const struct cpumask *cpumask,
cpu_stop_fn_t fn, void *arg,
struct cpu_stop_done *done)
{
struct cpu_stop_work *work;
unsigned int cpu;
bool queued = false;
/*
* Disable preemption while queueing to avoid getting
* preempted by a stopper which might wait for other stoppers
* to enter @fn which can lead to deadlock.
*/
preempt_disable();
stop_cpus_in_progress = true;
barrier();
for_each_cpu(cpu, cpumask) {
work = &per_cpu(cpu_stopper.stop_work, cpu);
work->fn = fn;
work->arg = arg;
work->done = done;
work->caller = _RET_IP_;
if (cpu_stop_queue_work(cpu, work))
queued = true;
}
barrier();
stop_cpus_in_progress = false;
preempt_enable();
return queued;
}
static int __stop_cpus(const struct cpumask *cpumask,
cpu_stop_fn_t fn, void *arg)
{
struct cpu_stop_done done;
cpu_stop_init_done(&done, cpumask_weight(cpumask));
if (!queue_stop_cpus_work(cpumask, fn, arg, &done))
return -ENOENT;
wait_for_completion(&done.completion);
return done.ret;
}
/**
* stop_cpus - stop multiple cpus
* @cpumask: cpus to stop
* @fn: function to execute
* @arg: argument to @fn
*
* Execute @fn(@arg) on online cpus in @cpumask. On each target cpu,
* @fn is run in a process context with the highest priority
* preempting any task on the cpu and monopolizing it. This function
* returns after all executions are complete.
*
* This function doesn't guarantee the cpus in @cpumask stay online
* till @fn completes. If some cpus go down in the middle, execution
* on the cpu may happen partially or fully on different cpus. @fn
* should either be ready for that or the caller should ensure that
* the cpus stay online until this function completes.
*
* All stop_cpus() calls are serialized making it safe for @fn to wait
* for all cpus to start executing it.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* -ENOENT if @fn(@arg) was not executed at all because all cpus in
* @cpumask were offline; otherwise, 0 if all executions of @fn
* returned 0, any non zero return value if any returned non zero.
*/
static int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg)
{
int ret;
/* static works are used, process one request at a time */
mutex_lock(&stop_cpus_mutex);
ret = __stop_cpus(cpumask, fn, arg);
mutex_unlock(&stop_cpus_mutex);
return ret;
}
static int cpu_stop_should_run(unsigned int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
unsigned long flags;
int run;
raw_spin_lock_irqsave(&stopper->lock, flags);
run = !list_empty(&stopper->works);
raw_spin_unlock_irqrestore(&stopper->lock, flags);
return run;
}
static void cpu_stopper_thread(unsigned int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
struct cpu_stop_work *work;
repeat:
work = NULL;
raw_spin_lock_irq(&stopper->lock);
if (!list_empty(&stopper->works)) {
work = list_first_entry(&stopper->works,
struct cpu_stop_work, list);
list_del_init(&work->list);
}
raw_spin_unlock_irq(&stopper->lock);
if (work) {
cpu_stop_fn_t fn = work->fn;
void *arg = work->arg;
struct cpu_stop_done *done = work->done;
int ret;
/* cpu stop callbacks must not sleep, make in_atomic() == T */
stopper->caller = work->caller;
stopper->fn = fn;
preempt_count_inc();
ret = fn(arg);
if (done) {
if (ret)
done->ret = ret;
cpu_stop_signal_done(done);
}
preempt_count_dec();
stopper->fn = NULL;
stopper->caller = 0;
WARN_ONCE(preempt_count(),
"cpu_stop: %ps(%p) leaked preempt count\n", fn, arg);
goto repeat;
}
}
void stop_machine_park(int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
/*
* Lockless. cpu_stopper_thread() will take stopper->lock and flush
* the pending works before it parks, until then it is fine to queue
* the new works.
*/
stopper->enabled = false;
kthread_park(stopper->thread);
}
static void cpu_stop_create(unsigned int cpu)
{
sched_set_stop_task(cpu, per_cpu(cpu_stopper.thread, cpu));
}
static void cpu_stop_park(unsigned int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
WARN_ON(!list_empty(&stopper->works));
}
void stop_machine_unpark(int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
stopper->enabled = true;
kthread_unpark(stopper->thread);
}
static struct smp_hotplug_thread cpu_stop_threads = {
.store = &cpu_stopper.thread,
.thread_should_run = cpu_stop_should_run,
.thread_fn = cpu_stopper_thread,
.thread_comm = "migration/%u",
.create = cpu_stop_create,
.park = cpu_stop_park,
.selfparking = true,
};
static int __init cpu_stop_init(void)
{
unsigned int cpu;
for_each_possible_cpu(cpu) {
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
raw_spin_lock_init(&stopper->lock);
INIT_LIST_HEAD(&stopper->works);
}
BUG_ON(smpboot_register_percpu_thread(&cpu_stop_threads));
stop_machine_unpark(raw_smp_processor_id());
stop_machine_initialized = true;
return 0;
}
early_initcall(cpu_stop_init);
int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data,
const struct cpumask *cpus)
{
struct multi_stop_data msdata = {
.fn = fn,
.data = data,
.num_threads = num_online_cpus(),
.active_cpus = cpus,
};
lockdep_assert_cpus_held();
if (!stop_machine_initialized) {
/*
* Handle the case where stop_machine() is called
* early in boot before stop_machine() has been
* initialized.
*/
unsigned long flags;
int ret;
WARN_ON_ONCE(msdata.num_threads != 1);
local_irq_save(flags);
hard_irq_disable();
ret = (*fn)(data);
local_irq_restore(flags);
return ret;
}
/* Set the initial state and stop all online cpus. */
set_state(&msdata, MULTI_STOP_PREPARE);
return stop_cpus(cpu_online_mask, multi_cpu_stop, &msdata);
}
int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus)
{
int ret;
/* No CPUs can come up or down during this. */
cpus_read_lock();
ret = stop_machine_cpuslocked(fn, data, cpus);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(stop_machine);
#ifdef CONFIG_SCHED_SMT
int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data)
{
const struct cpumask *smt_mask = cpu_smt_mask(cpu);
struct multi_stop_data msdata = {
.fn = fn,
.data = data,
.num_threads = cpumask_weight(smt_mask),
.active_cpus = smt_mask,
};
lockdep_assert_cpus_held();
/* Set the initial state and stop all online cpus. */
set_state(&msdata, MULTI_STOP_PREPARE);
return stop_cpus(smt_mask, multi_cpu_stop, &msdata);
}
EXPORT_SYMBOL_GPL(stop_core_cpuslocked);
#endif
/**
* stop_machine_from_inactive_cpu - stop_machine() from inactive CPU
* @fn: the function to run
* @data: the data ptr for the @fn()
* @cpus: the cpus to run the @fn() on (NULL = any online cpu)
*
* This is identical to stop_machine() but can be called from a CPU which
* is not active. The local CPU is in the process of hotplug (so no other
* CPU hotplug can start) and not marked active and doesn't have enough
* context to sleep.
*
* This function provides stop_machine() functionality for such state by
* using busy-wait for synchronization and executing @fn directly for local
* CPU.
*
* CONTEXT:
* Local CPU is inactive. Temporarily stops all active CPUs.
*
* RETURNS:
* 0 if all executions of @fn returned 0, any non zero return value if any
* returned non zero.
*/
int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data,
const struct cpumask *cpus)
{
struct multi_stop_data msdata = { .fn = fn, .data = data,
.active_cpus = cpus };
struct cpu_stop_done done;
int ret;
/* Local CPU must be inactive and CPU hotplug in progress. */
BUG_ON(cpu_active(raw_smp_processor_id()));
msdata.num_threads = num_active_cpus() + 1; /* +1 for local */
/* No proper task established and can't sleep - busy wait for lock. */
while (!mutex_trylock(&stop_cpus_mutex))
cpu_relax();
/* Schedule work on other CPUs and execute directly for local CPU */
set_state(&msdata, MULTI_STOP_PREPARE);
cpu_stop_init_done(&done, num_active_cpus());
queue_stop_cpus_work(cpu_active_mask, multi_cpu_stop, &msdata,
&done);
ret = multi_cpu_stop(&msdata);
/* Busy wait for completion. */
while (!completion_done(&done.completion))
cpu_relax();
mutex_unlock(&stop_cpus_mutex);
return ret ?: done.ret;
}
| linux-master | kernel/stop_machine.c |
// SPDX-License-Identifier: GPL-2.0
#include "audit.h"
#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/kthread.h>
#include <linux/refcount.h>
#include <linux/slab.h>
struct audit_tree;
struct audit_chunk;
struct audit_tree {
refcount_t count;
int goner;
struct audit_chunk *root;
struct list_head chunks;
struct list_head rules;
struct list_head list;
struct list_head same_root;
struct rcu_head head;
char pathname[];
};
struct audit_chunk {
struct list_head hash;
unsigned long key;
struct fsnotify_mark *mark;
struct list_head trees; /* with root here */
int count;
atomic_long_t refs;
struct rcu_head head;
struct audit_node {
struct list_head list;
struct audit_tree *owner;
unsigned index; /* index; upper bit indicates 'will prune' */
} owners[];
};
struct audit_tree_mark {
struct fsnotify_mark mark;
struct audit_chunk *chunk;
};
static LIST_HEAD(tree_list);
static LIST_HEAD(prune_list);
static struct task_struct *prune_thread;
/*
* One struct chunk is attached to each inode of interest through
* audit_tree_mark (fsnotify mark). We replace struct chunk on tagging /
* untagging, the mark is stable as long as there is chunk attached. The
* association between mark and chunk is protected by hash_lock and
* audit_tree_group->mark_mutex. Thus as long as we hold
* audit_tree_group->mark_mutex and check that the mark is alive by
* FSNOTIFY_MARK_FLAG_ATTACHED flag check, we are sure the mark points to
* the current chunk.
*
* Rules have pointer to struct audit_tree.
* Rules have struct list_head rlist forming a list of rules over
* the same tree.
* References to struct chunk are collected at audit_inode{,_child}()
* time and used in AUDIT_TREE rule matching.
* These references are dropped at the same time we are calling
* audit_free_names(), etc.
*
* Cyclic lists galore:
* tree.chunks anchors chunk.owners[].list hash_lock
* tree.rules anchors rule.rlist audit_filter_mutex
* chunk.trees anchors tree.same_root hash_lock
* chunk.hash is a hash with middle bits of watch.inode as
* a hash function. RCU, hash_lock
*
* tree is refcounted; one reference for "some rules on rules_list refer to
* it", one for each chunk with pointer to it.
*
* chunk is refcounted by embedded .refs. Mark associated with the chunk holds
* one chunk reference. This reference is dropped either when a mark is going
* to be freed (corresponding inode goes away) or when chunk attached to the
* mark gets replaced. This reference must be dropped using
* audit_mark_put_chunk() to make sure the reference is dropped only after RCU
* grace period as it protects RCU readers of the hash table.
*
* node.index allows to get from node.list to containing chunk.
* MSB of that sucker is stolen to mark taggings that we might have to
* revert - several operations have very unpleasant cleanup logics and
* that makes a difference. Some.
*/
static struct fsnotify_group *audit_tree_group;
static struct kmem_cache *audit_tree_mark_cachep __read_mostly;
static struct audit_tree *alloc_tree(const char *s)
{
struct audit_tree *tree;
tree = kmalloc(struct_size(tree, pathname, strlen(s) + 1), GFP_KERNEL);
if (tree) {
refcount_set(&tree->count, 1);
tree->goner = 0;
INIT_LIST_HEAD(&tree->chunks);
INIT_LIST_HEAD(&tree->rules);
INIT_LIST_HEAD(&tree->list);
INIT_LIST_HEAD(&tree->same_root);
tree->root = NULL;
strcpy(tree->pathname, s);
}
return tree;
}
static inline void get_tree(struct audit_tree *tree)
{
refcount_inc(&tree->count);
}
static inline void put_tree(struct audit_tree *tree)
{
if (refcount_dec_and_test(&tree->count))
kfree_rcu(tree, head);
}
/* to avoid bringing the entire thing in audit.h */
const char *audit_tree_path(struct audit_tree *tree)
{
return tree->pathname;
}
static void free_chunk(struct audit_chunk *chunk)
{
int i;
for (i = 0; i < chunk->count; i++) {
if (chunk->owners[i].owner)
put_tree(chunk->owners[i].owner);
}
kfree(chunk);
}
void audit_put_chunk(struct audit_chunk *chunk)
{
if (atomic_long_dec_and_test(&chunk->refs))
free_chunk(chunk);
}
static void __put_chunk(struct rcu_head *rcu)
{
struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
audit_put_chunk(chunk);
}
/*
* Drop reference to the chunk that was held by the mark. This is the reference
* that gets dropped after we've removed the chunk from the hash table and we
* use it to make sure chunk cannot be freed before RCU grace period expires.
*/
static void audit_mark_put_chunk(struct audit_chunk *chunk)
{
call_rcu(&chunk->head, __put_chunk);
}
static inline struct audit_tree_mark *audit_mark(struct fsnotify_mark *mark)
{
return container_of(mark, struct audit_tree_mark, mark);
}
static struct audit_chunk *mark_chunk(struct fsnotify_mark *mark)
{
return audit_mark(mark)->chunk;
}
static void audit_tree_destroy_watch(struct fsnotify_mark *mark)
{
kmem_cache_free(audit_tree_mark_cachep, audit_mark(mark));
}
static struct fsnotify_mark *alloc_mark(void)
{
struct audit_tree_mark *amark;
amark = kmem_cache_zalloc(audit_tree_mark_cachep, GFP_KERNEL);
if (!amark)
return NULL;
fsnotify_init_mark(&amark->mark, audit_tree_group);
amark->mark.mask = FS_IN_IGNORED;
return &amark->mark;
}
static struct audit_chunk *alloc_chunk(int count)
{
struct audit_chunk *chunk;
int i;
chunk = kzalloc(struct_size(chunk, owners, count), GFP_KERNEL);
if (!chunk)
return NULL;
INIT_LIST_HEAD(&chunk->hash);
INIT_LIST_HEAD(&chunk->trees);
chunk->count = count;
atomic_long_set(&chunk->refs, 1);
for (i = 0; i < count; i++) {
INIT_LIST_HEAD(&chunk->owners[i].list);
chunk->owners[i].index = i;
}
return chunk;
}
enum {HASH_SIZE = 128};
static struct list_head chunk_hash_heads[HASH_SIZE];
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(hash_lock);
/* Function to return search key in our hash from inode. */
static unsigned long inode_to_key(const struct inode *inode)
{
/* Use address pointed to by connector->obj as the key */
return (unsigned long)&inode->i_fsnotify_marks;
}
static inline struct list_head *chunk_hash(unsigned long key)
{
unsigned long n = key / L1_CACHE_BYTES;
return chunk_hash_heads + n % HASH_SIZE;
}
/* hash_lock & mark->group->mark_mutex is held by caller */
static void insert_hash(struct audit_chunk *chunk)
{
struct list_head *list;
/*
* Make sure chunk is fully initialized before making it visible in the
* hash. Pairs with a data dependency barrier in READ_ONCE() in
* audit_tree_lookup().
*/
smp_wmb();
WARN_ON_ONCE(!chunk->key);
list = chunk_hash(chunk->key);
list_add_rcu(&chunk->hash, list);
}
/* called under rcu_read_lock */
struct audit_chunk *audit_tree_lookup(const struct inode *inode)
{
unsigned long key = inode_to_key(inode);
struct list_head *list = chunk_hash(key);
struct audit_chunk *p;
list_for_each_entry_rcu(p, list, hash) {
/*
* We use a data dependency barrier in READ_ONCE() to make sure
* the chunk we see is fully initialized.
*/
if (READ_ONCE(p->key) == key) {
atomic_long_inc(&p->refs);
return p;
}
}
return NULL;
}
bool audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
{
int n;
for (n = 0; n < chunk->count; n++)
if (chunk->owners[n].owner == tree)
return true;
return false;
}
/* tagging and untagging inodes with trees */
static struct audit_chunk *find_chunk(struct audit_node *p)
{
int index = p->index & ~(1U<<31);
p -= index;
return container_of(p, struct audit_chunk, owners[0]);
}
static void replace_mark_chunk(struct fsnotify_mark *mark,
struct audit_chunk *chunk)
{
struct audit_chunk *old;
assert_spin_locked(&hash_lock);
old = mark_chunk(mark);
audit_mark(mark)->chunk = chunk;
if (chunk)
chunk->mark = mark;
if (old)
old->mark = NULL;
}
static void replace_chunk(struct audit_chunk *new, struct audit_chunk *old)
{
struct audit_tree *owner;
int i, j;
new->key = old->key;
list_splice_init(&old->trees, &new->trees);
list_for_each_entry(owner, &new->trees, same_root)
owner->root = new;
for (i = j = 0; j < old->count; i++, j++) {
if (!old->owners[j].owner) {
i--;
continue;
}
owner = old->owners[j].owner;
new->owners[i].owner = owner;
new->owners[i].index = old->owners[j].index - j + i;
if (!owner) /* result of earlier fallback */
continue;
get_tree(owner);
list_replace_init(&old->owners[j].list, &new->owners[i].list);
}
replace_mark_chunk(old->mark, new);
/*
* Make sure chunk is fully initialized before making it visible in the
* hash. Pairs with a data dependency barrier in READ_ONCE() in
* audit_tree_lookup().
*/
smp_wmb();
list_replace_rcu(&old->hash, &new->hash);
}
static void remove_chunk_node(struct audit_chunk *chunk, struct audit_node *p)
{
struct audit_tree *owner = p->owner;
if (owner->root == chunk) {
list_del_init(&owner->same_root);
owner->root = NULL;
}
list_del_init(&p->list);
p->owner = NULL;
put_tree(owner);
}
static int chunk_count_trees(struct audit_chunk *chunk)
{
int i;
int ret = 0;
for (i = 0; i < chunk->count; i++)
if (chunk->owners[i].owner)
ret++;
return ret;
}
static void untag_chunk(struct audit_chunk *chunk, struct fsnotify_mark *mark)
{
struct audit_chunk *new;
int size;
fsnotify_group_lock(audit_tree_group);
/*
* mark_mutex stabilizes chunk attached to the mark so we can check
* whether it didn't change while we've dropped hash_lock.
*/
if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) ||
mark_chunk(mark) != chunk)
goto out_mutex;
size = chunk_count_trees(chunk);
if (!size) {
spin_lock(&hash_lock);
list_del_init(&chunk->trees);
list_del_rcu(&chunk->hash);
replace_mark_chunk(mark, NULL);
spin_unlock(&hash_lock);
fsnotify_detach_mark(mark);
fsnotify_group_unlock(audit_tree_group);
audit_mark_put_chunk(chunk);
fsnotify_free_mark(mark);
return;
}
new = alloc_chunk(size);
if (!new)
goto out_mutex;
spin_lock(&hash_lock);
/*
* This has to go last when updating chunk as once replace_chunk() is
* called, new RCU readers can see the new chunk.
*/
replace_chunk(new, chunk);
spin_unlock(&hash_lock);
fsnotify_group_unlock(audit_tree_group);
audit_mark_put_chunk(chunk);
return;
out_mutex:
fsnotify_group_unlock(audit_tree_group);
}
/* Call with group->mark_mutex held, releases it */
static int create_chunk(struct inode *inode, struct audit_tree *tree)
{
struct fsnotify_mark *mark;
struct audit_chunk *chunk = alloc_chunk(1);
if (!chunk) {
fsnotify_group_unlock(audit_tree_group);
return -ENOMEM;
}
mark = alloc_mark();
if (!mark) {
fsnotify_group_unlock(audit_tree_group);
kfree(chunk);
return -ENOMEM;
}
if (fsnotify_add_inode_mark_locked(mark, inode, 0)) {
fsnotify_group_unlock(audit_tree_group);
fsnotify_put_mark(mark);
kfree(chunk);
return -ENOSPC;
}
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
fsnotify_detach_mark(mark);
fsnotify_group_unlock(audit_tree_group);
fsnotify_free_mark(mark);
fsnotify_put_mark(mark);
kfree(chunk);
return 0;
}
replace_mark_chunk(mark, chunk);
chunk->owners[0].index = (1U << 31);
chunk->owners[0].owner = tree;
get_tree(tree);
list_add(&chunk->owners[0].list, &tree->chunks);
if (!tree->root) {
tree->root = chunk;
list_add(&tree->same_root, &chunk->trees);
}
chunk->key = inode_to_key(inode);
/*
* Inserting into the hash table has to go last as once we do that RCU
* readers can see the chunk.
*/
insert_hash(chunk);
spin_unlock(&hash_lock);
fsnotify_group_unlock(audit_tree_group);
/*
* Drop our initial reference. When mark we point to is getting freed,
* we get notification through ->freeing_mark callback and cleanup
* chunk pointing to this mark.
*/
fsnotify_put_mark(mark);
return 0;
}
/* the first tagged inode becomes root of tree */
static int tag_chunk(struct inode *inode, struct audit_tree *tree)
{
struct fsnotify_mark *mark;
struct audit_chunk *chunk, *old;
struct audit_node *p;
int n;
fsnotify_group_lock(audit_tree_group);
mark = fsnotify_find_mark(&inode->i_fsnotify_marks, audit_tree_group);
if (!mark)
return create_chunk(inode, tree);
/*
* Found mark is guaranteed to be attached and mark_mutex protects mark
* from getting detached and thus it makes sure there is chunk attached
* to the mark.
*/
/* are we already there? */
spin_lock(&hash_lock);
old = mark_chunk(mark);
for (n = 0; n < old->count; n++) {
if (old->owners[n].owner == tree) {
spin_unlock(&hash_lock);
fsnotify_group_unlock(audit_tree_group);
fsnotify_put_mark(mark);
return 0;
}
}
spin_unlock(&hash_lock);
chunk = alloc_chunk(old->count + 1);
if (!chunk) {
fsnotify_group_unlock(audit_tree_group);
fsnotify_put_mark(mark);
return -ENOMEM;
}
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
fsnotify_group_unlock(audit_tree_group);
fsnotify_put_mark(mark);
kfree(chunk);
return 0;
}
p = &chunk->owners[chunk->count - 1];
p->index = (chunk->count - 1) | (1U<<31);
p->owner = tree;
get_tree(tree);
list_add(&p->list, &tree->chunks);
if (!tree->root) {
tree->root = chunk;
list_add(&tree->same_root, &chunk->trees);
}
/*
* This has to go last when updating chunk as once replace_chunk() is
* called, new RCU readers can see the new chunk.
*/
replace_chunk(chunk, old);
spin_unlock(&hash_lock);
fsnotify_group_unlock(audit_tree_group);
fsnotify_put_mark(mark); /* pair to fsnotify_find_mark */
audit_mark_put_chunk(old);
return 0;
}
static void audit_tree_log_remove_rule(struct audit_context *context,
struct audit_krule *rule)
{
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return;
audit_log_format(ab, "op=remove_rule dir=");
audit_log_untrustedstring(ab, rule->tree->pathname);
audit_log_key(ab, rule->filterkey);
audit_log_format(ab, " list=%d res=1", rule->listnr);
audit_log_end(ab);
}
static void kill_rules(struct audit_context *context, struct audit_tree *tree)
{
struct audit_krule *rule, *next;
struct audit_entry *entry;
list_for_each_entry_safe(rule, next, &tree->rules, rlist) {
entry = container_of(rule, struct audit_entry, rule);
list_del_init(&rule->rlist);
if (rule->tree) {
/* not a half-baked one */
audit_tree_log_remove_rule(context, rule);
if (entry->rule.exe)
audit_remove_mark(entry->rule.exe);
rule->tree = NULL;
list_del_rcu(&entry->list);
list_del(&entry->rule.list);
call_rcu(&entry->rcu, audit_free_rule_rcu);
}
}
}
/*
* Remove tree from chunks. If 'tagged' is set, remove tree only from tagged
* chunks. The function expects tagged chunks are all at the beginning of the
* chunks list.
*/
static void prune_tree_chunks(struct audit_tree *victim, bool tagged)
{
spin_lock(&hash_lock);
while (!list_empty(&victim->chunks)) {
struct audit_node *p;
struct audit_chunk *chunk;
struct fsnotify_mark *mark;
p = list_first_entry(&victim->chunks, struct audit_node, list);
/* have we run out of marked? */
if (tagged && !(p->index & (1U<<31)))
break;
chunk = find_chunk(p);
mark = chunk->mark;
remove_chunk_node(chunk, p);
/* Racing with audit_tree_freeing_mark()? */
if (!mark)
continue;
fsnotify_get_mark(mark);
spin_unlock(&hash_lock);
untag_chunk(chunk, mark);
fsnotify_put_mark(mark);
spin_lock(&hash_lock);
}
spin_unlock(&hash_lock);
}
/*
* finish killing struct audit_tree
*/
static void prune_one(struct audit_tree *victim)
{
prune_tree_chunks(victim, false);
put_tree(victim);
}
/* trim the uncommitted chunks from tree */
static void trim_marked(struct audit_tree *tree)
{
struct list_head *p, *q;
spin_lock(&hash_lock);
if (tree->goner) {
spin_unlock(&hash_lock);
return;
}
/* reorder */
for (p = tree->chunks.next; p != &tree->chunks; p = q) {
struct audit_node *node = list_entry(p, struct audit_node, list);
q = p->next;
if (node->index & (1U<<31)) {
list_del_init(p);
list_add(p, &tree->chunks);
}
}
spin_unlock(&hash_lock);
prune_tree_chunks(tree, true);
spin_lock(&hash_lock);
if (!tree->root && !tree->goner) {
tree->goner = 1;
spin_unlock(&hash_lock);
mutex_lock(&audit_filter_mutex);
kill_rules(audit_context(), tree);
list_del_init(&tree->list);
mutex_unlock(&audit_filter_mutex);
prune_one(tree);
} else {
spin_unlock(&hash_lock);
}
}
static void audit_schedule_prune(void);
/* called with audit_filter_mutex */
int audit_remove_tree_rule(struct audit_krule *rule)
{
struct audit_tree *tree;
tree = rule->tree;
if (tree) {
spin_lock(&hash_lock);
list_del_init(&rule->rlist);
if (list_empty(&tree->rules) && !tree->goner) {
tree->root = NULL;
list_del_init(&tree->same_root);
tree->goner = 1;
list_move(&tree->list, &prune_list);
rule->tree = NULL;
spin_unlock(&hash_lock);
audit_schedule_prune();
return 1;
}
rule->tree = NULL;
spin_unlock(&hash_lock);
return 1;
}
return 0;
}
static int compare_root(struct vfsmount *mnt, void *arg)
{
return inode_to_key(d_backing_inode(mnt->mnt_root)) ==
(unsigned long)arg;
}
void audit_trim_trees(void)
{
struct list_head cursor;
mutex_lock(&audit_filter_mutex);
list_add(&cursor, &tree_list);
while (cursor.next != &tree_list) {
struct audit_tree *tree;
struct path path;
struct vfsmount *root_mnt;
struct audit_node *node;
int err;
tree = container_of(cursor.next, struct audit_tree, list);
get_tree(tree);
list_move(&cursor, &tree->list);
mutex_unlock(&audit_filter_mutex);
err = kern_path(tree->pathname, 0, &path);
if (err)
goto skip_it;
root_mnt = collect_mounts(&path);
path_put(&path);
if (IS_ERR(root_mnt))
goto skip_it;
spin_lock(&hash_lock);
list_for_each_entry(node, &tree->chunks, list) {
struct audit_chunk *chunk = find_chunk(node);
/* this could be NULL if the watch is dying else where... */
node->index |= 1U<<31;
if (iterate_mounts(compare_root,
(void *)(chunk->key),
root_mnt))
node->index &= ~(1U<<31);
}
spin_unlock(&hash_lock);
trim_marked(tree);
drop_collected_mounts(root_mnt);
skip_it:
put_tree(tree);
mutex_lock(&audit_filter_mutex);
}
list_del(&cursor);
mutex_unlock(&audit_filter_mutex);
}
int audit_make_tree(struct audit_krule *rule, char *pathname, u32 op)
{
if (pathname[0] != '/' ||
(rule->listnr != AUDIT_FILTER_EXIT &&
rule->listnr != AUDIT_FILTER_URING_EXIT) ||
op != Audit_equal ||
rule->inode_f || rule->watch || rule->tree)
return -EINVAL;
rule->tree = alloc_tree(pathname);
if (!rule->tree)
return -ENOMEM;
return 0;
}
void audit_put_tree(struct audit_tree *tree)
{
put_tree(tree);
}
static int tag_mount(struct vfsmount *mnt, void *arg)
{
return tag_chunk(d_backing_inode(mnt->mnt_root), arg);
}
/*
* That gets run when evict_chunk() ends up needing to kill audit_tree.
* Runs from a separate thread.
*/
static int prune_tree_thread(void *unused)
{
for (;;) {
if (list_empty(&prune_list)) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
audit_ctl_lock();
mutex_lock(&audit_filter_mutex);
while (!list_empty(&prune_list)) {
struct audit_tree *victim;
victim = list_entry(prune_list.next,
struct audit_tree, list);
list_del_init(&victim->list);
mutex_unlock(&audit_filter_mutex);
prune_one(victim);
mutex_lock(&audit_filter_mutex);
}
mutex_unlock(&audit_filter_mutex);
audit_ctl_unlock();
}
return 0;
}
static int audit_launch_prune(void)
{
if (prune_thread)
return 0;
prune_thread = kthread_run(prune_tree_thread, NULL,
"audit_prune_tree");
if (IS_ERR(prune_thread)) {
pr_err("cannot start thread audit_prune_tree");
prune_thread = NULL;
return -ENOMEM;
}
return 0;
}
/* called with audit_filter_mutex */
int audit_add_tree_rule(struct audit_krule *rule)
{
struct audit_tree *seed = rule->tree, *tree;
struct path path;
struct vfsmount *mnt;
int err;
rule->tree = NULL;
list_for_each_entry(tree, &tree_list, list) {
if (!strcmp(seed->pathname, tree->pathname)) {
put_tree(seed);
rule->tree = tree;
list_add(&rule->rlist, &tree->rules);
return 0;
}
}
tree = seed;
list_add(&tree->list, &tree_list);
list_add(&rule->rlist, &tree->rules);
/* do not set rule->tree yet */
mutex_unlock(&audit_filter_mutex);
if (unlikely(!prune_thread)) {
err = audit_launch_prune();
if (err)
goto Err;
}
err = kern_path(tree->pathname, 0, &path);
if (err)
goto Err;
mnt = collect_mounts(&path);
path_put(&path);
if (IS_ERR(mnt)) {
err = PTR_ERR(mnt);
goto Err;
}
get_tree(tree);
err = iterate_mounts(tag_mount, tree, mnt);
drop_collected_mounts(mnt);
if (!err) {
struct audit_node *node;
spin_lock(&hash_lock);
list_for_each_entry(node, &tree->chunks, list)
node->index &= ~(1U<<31);
spin_unlock(&hash_lock);
} else {
trim_marked(tree);
goto Err;
}
mutex_lock(&audit_filter_mutex);
if (list_empty(&rule->rlist)) {
put_tree(tree);
return -ENOENT;
}
rule->tree = tree;
put_tree(tree);
return 0;
Err:
mutex_lock(&audit_filter_mutex);
list_del_init(&tree->list);
list_del_init(&tree->rules);
put_tree(tree);
return err;
}
int audit_tag_tree(char *old, char *new)
{
struct list_head cursor, barrier;
int failed = 0;
struct path path1, path2;
struct vfsmount *tagged;
int err;
err = kern_path(new, 0, &path2);
if (err)
return err;
tagged = collect_mounts(&path2);
path_put(&path2);
if (IS_ERR(tagged))
return PTR_ERR(tagged);
err = kern_path(old, 0, &path1);
if (err) {
drop_collected_mounts(tagged);
return err;
}
mutex_lock(&audit_filter_mutex);
list_add(&barrier, &tree_list);
list_add(&cursor, &barrier);
while (cursor.next != &tree_list) {
struct audit_tree *tree;
int good_one = 0;
tree = container_of(cursor.next, struct audit_tree, list);
get_tree(tree);
list_move(&cursor, &tree->list);
mutex_unlock(&audit_filter_mutex);
err = kern_path(tree->pathname, 0, &path2);
if (!err) {
good_one = path_is_under(&path1, &path2);
path_put(&path2);
}
if (!good_one) {
put_tree(tree);
mutex_lock(&audit_filter_mutex);
continue;
}
failed = iterate_mounts(tag_mount, tree, tagged);
if (failed) {
put_tree(tree);
mutex_lock(&audit_filter_mutex);
break;
}
mutex_lock(&audit_filter_mutex);
spin_lock(&hash_lock);
if (!tree->goner) {
list_move(&tree->list, &tree_list);
}
spin_unlock(&hash_lock);
put_tree(tree);
}
while (barrier.prev != &tree_list) {
struct audit_tree *tree;
tree = container_of(barrier.prev, struct audit_tree, list);
get_tree(tree);
list_move(&tree->list, &barrier);
mutex_unlock(&audit_filter_mutex);
if (!failed) {
struct audit_node *node;
spin_lock(&hash_lock);
list_for_each_entry(node, &tree->chunks, list)
node->index &= ~(1U<<31);
spin_unlock(&hash_lock);
} else {
trim_marked(tree);
}
put_tree(tree);
mutex_lock(&audit_filter_mutex);
}
list_del(&barrier);
list_del(&cursor);
mutex_unlock(&audit_filter_mutex);
path_put(&path1);
drop_collected_mounts(tagged);
return failed;
}
static void audit_schedule_prune(void)
{
wake_up_process(prune_thread);
}
/*
* ... and that one is done if evict_chunk() decides to delay until the end
* of syscall. Runs synchronously.
*/
void audit_kill_trees(struct audit_context *context)
{
struct list_head *list = &context->killed_trees;
audit_ctl_lock();
mutex_lock(&audit_filter_mutex);
while (!list_empty(list)) {
struct audit_tree *victim;
victim = list_entry(list->next, struct audit_tree, list);
kill_rules(context, victim);
list_del_init(&victim->list);
mutex_unlock(&audit_filter_mutex);
prune_one(victim);
mutex_lock(&audit_filter_mutex);
}
mutex_unlock(&audit_filter_mutex);
audit_ctl_unlock();
}
/*
* Here comes the stuff asynchronous to auditctl operations
*/
static void evict_chunk(struct audit_chunk *chunk)
{
struct audit_tree *owner;
struct list_head *postponed = audit_killed_trees();
int need_prune = 0;
int n;
mutex_lock(&audit_filter_mutex);
spin_lock(&hash_lock);
while (!list_empty(&chunk->trees)) {
owner = list_entry(chunk->trees.next,
struct audit_tree, same_root);
owner->goner = 1;
owner->root = NULL;
list_del_init(&owner->same_root);
spin_unlock(&hash_lock);
if (!postponed) {
kill_rules(audit_context(), owner);
list_move(&owner->list, &prune_list);
need_prune = 1;
} else {
list_move(&owner->list, postponed);
}
spin_lock(&hash_lock);
}
list_del_rcu(&chunk->hash);
for (n = 0; n < chunk->count; n++)
list_del_init(&chunk->owners[n].list);
spin_unlock(&hash_lock);
mutex_unlock(&audit_filter_mutex);
if (need_prune)
audit_schedule_prune();
}
static int audit_tree_handle_event(struct fsnotify_mark *mark, u32 mask,
struct inode *inode, struct inode *dir,
const struct qstr *file_name, u32 cookie)
{
return 0;
}
static void audit_tree_freeing_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group)
{
struct audit_chunk *chunk;
fsnotify_group_lock(mark->group);
spin_lock(&hash_lock);
chunk = mark_chunk(mark);
replace_mark_chunk(mark, NULL);
spin_unlock(&hash_lock);
fsnotify_group_unlock(mark->group);
if (chunk) {
evict_chunk(chunk);
audit_mark_put_chunk(chunk);
}
/*
* We are guaranteed to have at least one reference to the mark from
* either the inode or the caller of fsnotify_destroy_mark().
*/
BUG_ON(refcount_read(&mark->refcnt) < 1);
}
static const struct fsnotify_ops audit_tree_ops = {
.handle_inode_event = audit_tree_handle_event,
.freeing_mark = audit_tree_freeing_mark,
.free_mark = audit_tree_destroy_watch,
};
static int __init audit_tree_init(void)
{
int i;
audit_tree_mark_cachep = KMEM_CACHE(audit_tree_mark, SLAB_PANIC);
audit_tree_group = fsnotify_alloc_group(&audit_tree_ops, 0);
if (IS_ERR(audit_tree_group))
audit_panic("cannot initialize fsnotify group for rectree watches");
for (i = 0; i < HASH_SIZE; i++)
INIT_LIST_HEAD(&chunk_hash_heads[i]);
return 0;
}
__initcall(audit_tree_init);
| linux-master | kernel/audit_tree.c |
/* CPU control.
* (C) 2001, 2002, 2003, 2004 Rusty Russell
*
* This code is licenced under the GPL.
*/
#include <linux/sched/mm.h>
#include <linux/proc_fs.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/notifier.h>
#include <linux/sched/signal.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/isolation.h>
#include <linux/sched/task.h>
#include <linux/sched/smt.h>
#include <linux/unistd.h>
#include <linux/cpu.h>
#include <linux/oom.h>
#include <linux/rcupdate.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/bug.h>
#include <linux/kthread.h>
#include <linux/stop_machine.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/suspend.h>
#include <linux/lockdep.h>
#include <linux/tick.h>
#include <linux/irq.h>
#include <linux/nmi.h>
#include <linux/smpboot.h>
#include <linux/relay.h>
#include <linux/slab.h>
#include <linux/scs.h>
#include <linux/percpu-rwsem.h>
#include <linux/cpuset.h>
#include <linux/random.h>
#include <linux/cc_platform.h>
#include <trace/events/power.h>
#define CREATE_TRACE_POINTS
#include <trace/events/cpuhp.h>
#include "smpboot.h"
/**
* struct cpuhp_cpu_state - Per cpu hotplug state storage
* @state: The current cpu state
* @target: The target state
* @fail: Current CPU hotplug callback state
* @thread: Pointer to the hotplug thread
* @should_run: Thread should execute
* @rollback: Perform a rollback
* @single: Single callback invocation
* @bringup: Single callback bringup or teardown selector
* @cpu: CPU number
* @node: Remote CPU node; for multi-instance, do a
* single entry callback for install/remove
* @last: For multi-instance rollback, remember how far we got
* @cb_state: The state for a single callback (install/uninstall)
* @result: Result of the operation
* @ap_sync_state: State for AP synchronization
* @done_up: Signal completion to the issuer of the task for cpu-up
* @done_down: Signal completion to the issuer of the task for cpu-down
*/
struct cpuhp_cpu_state {
enum cpuhp_state state;
enum cpuhp_state target;
enum cpuhp_state fail;
#ifdef CONFIG_SMP
struct task_struct *thread;
bool should_run;
bool rollback;
bool single;
bool bringup;
struct hlist_node *node;
struct hlist_node *last;
enum cpuhp_state cb_state;
int result;
atomic_t ap_sync_state;
struct completion done_up;
struct completion done_down;
#endif
};
static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
.fail = CPUHP_INVALID,
};
#ifdef CONFIG_SMP
cpumask_t cpus_booted_once_mask;
#endif
#if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
static struct lockdep_map cpuhp_state_up_map =
STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
static struct lockdep_map cpuhp_state_down_map =
STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
static inline void cpuhp_lock_acquire(bool bringup)
{
lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
}
static inline void cpuhp_lock_release(bool bringup)
{
lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
}
#else
static inline void cpuhp_lock_acquire(bool bringup) { }
static inline void cpuhp_lock_release(bool bringup) { }
#endif
/**
* struct cpuhp_step - Hotplug state machine step
* @name: Name of the step
* @startup: Startup function of the step
* @teardown: Teardown function of the step
* @cant_stop: Bringup/teardown can't be stopped at this step
* @multi_instance: State has multiple instances which get added afterwards
*/
struct cpuhp_step {
const char *name;
union {
int (*single)(unsigned int cpu);
int (*multi)(unsigned int cpu,
struct hlist_node *node);
} startup;
union {
int (*single)(unsigned int cpu);
int (*multi)(unsigned int cpu,
struct hlist_node *node);
} teardown;
/* private: */
struct hlist_head list;
/* public: */
bool cant_stop;
bool multi_instance;
};
static DEFINE_MUTEX(cpuhp_state_mutex);
static struct cpuhp_step cpuhp_hp_states[];
static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
{
return cpuhp_hp_states + state;
}
static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step)
{
return bringup ? !step->startup.single : !step->teardown.single;
}
/**
* cpuhp_invoke_callback - Invoke the callbacks for a given state
* @cpu: The cpu for which the callback should be invoked
* @state: The state to do callbacks for
* @bringup: True if the bringup callback should be invoked
* @node: For multi-instance, do a single entry callback for install/remove
* @lastp: For multi-instance rollback, remember how far we got
*
* Called from cpu hotplug and from the state register machinery.
*
* Return: %0 on success or a negative errno code
*/
static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
bool bringup, struct hlist_node *node,
struct hlist_node **lastp)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
struct cpuhp_step *step = cpuhp_get_step(state);
int (*cbm)(unsigned int cpu, struct hlist_node *node);
int (*cb)(unsigned int cpu);
int ret, cnt;
if (st->fail == state) {
st->fail = CPUHP_INVALID;
return -EAGAIN;
}
if (cpuhp_step_empty(bringup, step)) {
WARN_ON_ONCE(1);
return 0;
}
if (!step->multi_instance) {
WARN_ON_ONCE(lastp && *lastp);
cb = bringup ? step->startup.single : step->teardown.single;
trace_cpuhp_enter(cpu, st->target, state, cb);
ret = cb(cpu);
trace_cpuhp_exit(cpu, st->state, state, ret);
return ret;
}
cbm = bringup ? step->startup.multi : step->teardown.multi;
/* Single invocation for instance add/remove */
if (node) {
WARN_ON_ONCE(lastp && *lastp);
trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
ret = cbm(cpu, node);
trace_cpuhp_exit(cpu, st->state, state, ret);
return ret;
}
/* State transition. Invoke on all instances */
cnt = 0;
hlist_for_each(node, &step->list) {
if (lastp && node == *lastp)
break;
trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
ret = cbm(cpu, node);
trace_cpuhp_exit(cpu, st->state, state, ret);
if (ret) {
if (!lastp)
goto err;
*lastp = node;
return ret;
}
cnt++;
}
if (lastp)
*lastp = NULL;
return 0;
err:
/* Rollback the instances if one failed */
cbm = !bringup ? step->startup.multi : step->teardown.multi;
if (!cbm)
return ret;
hlist_for_each(node, &step->list) {
if (!cnt--)
break;
trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
ret = cbm(cpu, node);
trace_cpuhp_exit(cpu, st->state, state, ret);
/*
* Rollback must not fail,
*/
WARN_ON_ONCE(ret);
}
return ret;
}
#ifdef CONFIG_SMP
static bool cpuhp_is_ap_state(enum cpuhp_state state)
{
/*
* The extra check for CPUHP_TEARDOWN_CPU is only for documentation
* purposes as that state is handled explicitly in cpu_down.
*/
return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
}
static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
{
struct completion *done = bringup ? &st->done_up : &st->done_down;
wait_for_completion(done);
}
static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
{
struct completion *done = bringup ? &st->done_up : &st->done_down;
complete(done);
}
/*
* The former STARTING/DYING states, ran with IRQs disabled and must not fail.
*/
static bool cpuhp_is_atomic_state(enum cpuhp_state state)
{
return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;
}
/* Synchronization state management */
enum cpuhp_sync_state {
SYNC_STATE_DEAD,
SYNC_STATE_KICKED,
SYNC_STATE_SHOULD_DIE,
SYNC_STATE_ALIVE,
SYNC_STATE_SHOULD_ONLINE,
SYNC_STATE_ONLINE,
};
#ifdef CONFIG_HOTPLUG_CORE_SYNC
/**
* cpuhp_ap_update_sync_state - Update synchronization state during bringup/teardown
* @state: The synchronization state to set
*
* No synchronization point. Just update of the synchronization state, but implies
* a full barrier so that the AP changes are visible before the control CPU proceeds.
*/
static inline void cpuhp_ap_update_sync_state(enum cpuhp_sync_state state)
{
atomic_t *st = this_cpu_ptr(&cpuhp_state.ap_sync_state);
(void)atomic_xchg(st, state);
}
void __weak arch_cpuhp_sync_state_poll(void) { cpu_relax(); }
static bool cpuhp_wait_for_sync_state(unsigned int cpu, enum cpuhp_sync_state state,
enum cpuhp_sync_state next_state)
{
atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
ktime_t now, end, start = ktime_get();
int sync;
end = start + 10ULL * NSEC_PER_SEC;
sync = atomic_read(st);
while (1) {
if (sync == state) {
if (!atomic_try_cmpxchg(st, &sync, next_state))
continue;
return true;
}
now = ktime_get();
if (now > end) {
/* Timeout. Leave the state unchanged */
return false;
} else if (now - start < NSEC_PER_MSEC) {
/* Poll for one millisecond */
arch_cpuhp_sync_state_poll();
} else {
usleep_range_state(USEC_PER_MSEC, 2 * USEC_PER_MSEC, TASK_UNINTERRUPTIBLE);
}
sync = atomic_read(st);
}
return true;
}
#else /* CONFIG_HOTPLUG_CORE_SYNC */
static inline void cpuhp_ap_update_sync_state(enum cpuhp_sync_state state) { }
#endif /* !CONFIG_HOTPLUG_CORE_SYNC */
#ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD
/**
* cpuhp_ap_report_dead - Update synchronization state to DEAD
*
* No synchronization point. Just update of the synchronization state.
*/
void cpuhp_ap_report_dead(void)
{
cpuhp_ap_update_sync_state(SYNC_STATE_DEAD);
}
void __weak arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) { }
/*
* Late CPU shutdown synchronization point. Cannot use cpuhp_state::done_down
* because the AP cannot issue complete() at this stage.
*/
static void cpuhp_bp_sync_dead(unsigned int cpu)
{
atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
int sync = atomic_read(st);
do {
/* CPU can have reported dead already. Don't overwrite that! */
if (sync == SYNC_STATE_DEAD)
break;
} while (!atomic_try_cmpxchg(st, &sync, SYNC_STATE_SHOULD_DIE));
if (cpuhp_wait_for_sync_state(cpu, SYNC_STATE_DEAD, SYNC_STATE_DEAD)) {
/* CPU reached dead state. Invoke the cleanup function */
arch_cpuhp_cleanup_dead_cpu(cpu);
return;
}
/* No further action possible. Emit message and give up. */
pr_err("CPU%u failed to report dead state\n", cpu);
}
#else /* CONFIG_HOTPLUG_CORE_SYNC_DEAD */
static inline void cpuhp_bp_sync_dead(unsigned int cpu) { }
#endif /* !CONFIG_HOTPLUG_CORE_SYNC_DEAD */
#ifdef CONFIG_HOTPLUG_CORE_SYNC_FULL
/**
* cpuhp_ap_sync_alive - Synchronize AP with the control CPU once it is alive
*
* Updates the AP synchronization state to SYNC_STATE_ALIVE and waits
* for the BP to release it.
*/
void cpuhp_ap_sync_alive(void)
{
atomic_t *st = this_cpu_ptr(&cpuhp_state.ap_sync_state);
cpuhp_ap_update_sync_state(SYNC_STATE_ALIVE);
/* Wait for the control CPU to release it. */
while (atomic_read(st) != SYNC_STATE_SHOULD_ONLINE)
cpu_relax();
}
static bool cpuhp_can_boot_ap(unsigned int cpu)
{
atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
int sync = atomic_read(st);
again:
switch (sync) {
case SYNC_STATE_DEAD:
/* CPU is properly dead */
break;
case SYNC_STATE_KICKED:
/* CPU did not come up in previous attempt */
break;
case SYNC_STATE_ALIVE:
/* CPU is stuck cpuhp_ap_sync_alive(). */
break;
default:
/* CPU failed to report online or dead and is in limbo state. */
return false;
}
/* Prepare for booting */
if (!atomic_try_cmpxchg(st, &sync, SYNC_STATE_KICKED))
goto again;
return true;
}
void __weak arch_cpuhp_cleanup_kick_cpu(unsigned int cpu) { }
/*
* Early CPU bringup synchronization point. Cannot use cpuhp_state::done_up
* because the AP cannot issue complete() so early in the bringup.
*/
static int cpuhp_bp_sync_alive(unsigned int cpu)
{
int ret = 0;
if (!IS_ENABLED(CONFIG_HOTPLUG_CORE_SYNC_FULL))
return 0;
if (!cpuhp_wait_for_sync_state(cpu, SYNC_STATE_ALIVE, SYNC_STATE_SHOULD_ONLINE)) {
pr_err("CPU%u failed to report alive state\n", cpu);
ret = -EIO;
}
/* Let the architecture cleanup the kick alive mechanics. */
arch_cpuhp_cleanup_kick_cpu(cpu);
return ret;
}
#else /* CONFIG_HOTPLUG_CORE_SYNC_FULL */
static inline int cpuhp_bp_sync_alive(unsigned int cpu) { return 0; }
static inline bool cpuhp_can_boot_ap(unsigned int cpu) { return true; }
#endif /* !CONFIG_HOTPLUG_CORE_SYNC_FULL */
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
static DEFINE_MUTEX(cpu_add_remove_lock);
bool cpuhp_tasks_frozen;
EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
/*
* The following two APIs (cpu_maps_update_begin/done) must be used when
* attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
*/
void cpu_maps_update_begin(void)
{
mutex_lock(&cpu_add_remove_lock);
}
void cpu_maps_update_done(void)
{
mutex_unlock(&cpu_add_remove_lock);
}
/*
* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
* Should always be manipulated under cpu_add_remove_lock
*/
static int cpu_hotplug_disabled;
#ifdef CONFIG_HOTPLUG_CPU
DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
void cpus_read_lock(void)
{
percpu_down_read(&cpu_hotplug_lock);
}
EXPORT_SYMBOL_GPL(cpus_read_lock);
int cpus_read_trylock(void)
{
return percpu_down_read_trylock(&cpu_hotplug_lock);
}
EXPORT_SYMBOL_GPL(cpus_read_trylock);
void cpus_read_unlock(void)
{
percpu_up_read(&cpu_hotplug_lock);
}
EXPORT_SYMBOL_GPL(cpus_read_unlock);
void cpus_write_lock(void)
{
percpu_down_write(&cpu_hotplug_lock);
}
void cpus_write_unlock(void)
{
percpu_up_write(&cpu_hotplug_lock);
}
void lockdep_assert_cpus_held(void)
{
/*
* We can't have hotplug operations before userspace starts running,
* and some init codepaths will knowingly not take the hotplug lock.
* This is all valid, so mute lockdep until it makes sense to report
* unheld locks.
*/
if (system_state < SYSTEM_RUNNING)
return;
percpu_rwsem_assert_held(&cpu_hotplug_lock);
}
#ifdef CONFIG_LOCKDEP
int lockdep_is_cpus_held(void)
{
return percpu_rwsem_is_held(&cpu_hotplug_lock);
}
#endif
static void lockdep_acquire_cpus_lock(void)
{
rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
}
static void lockdep_release_cpus_lock(void)
{
rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_);
}
/*
* Wait for currently running CPU hotplug operations to complete (if any) and
* disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
* the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
* hotplug path before performing hotplug operations. So acquiring that lock
* guarantees mutual exclusion from any currently running hotplug operations.
*/
void cpu_hotplug_disable(void)
{
cpu_maps_update_begin();
cpu_hotplug_disabled++;
cpu_maps_update_done();
}
EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
static void __cpu_hotplug_enable(void)
{
if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
return;
cpu_hotplug_disabled--;
}
void cpu_hotplug_enable(void)
{
cpu_maps_update_begin();
__cpu_hotplug_enable();
cpu_maps_update_done();
}
EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
#else
static void lockdep_acquire_cpus_lock(void)
{
}
static void lockdep_release_cpus_lock(void)
{
}
#endif /* CONFIG_HOTPLUG_CPU */
/*
* Architectures that need SMT-specific errata handling during SMT hotplug
* should override this.
*/
void __weak arch_smt_update(void) { }
#ifdef CONFIG_HOTPLUG_SMT
enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
static unsigned int cpu_smt_max_threads __ro_after_init;
unsigned int cpu_smt_num_threads __read_mostly = UINT_MAX;
void __init cpu_smt_disable(bool force)
{
if (!cpu_smt_possible())
return;
if (force) {
pr_info("SMT: Force disabled\n");
cpu_smt_control = CPU_SMT_FORCE_DISABLED;
} else {
pr_info("SMT: disabled\n");
cpu_smt_control = CPU_SMT_DISABLED;
}
cpu_smt_num_threads = 1;
}
/*
* The decision whether SMT is supported can only be done after the full
* CPU identification. Called from architecture code.
*/
void __init cpu_smt_set_num_threads(unsigned int num_threads,
unsigned int max_threads)
{
WARN_ON(!num_threads || (num_threads > max_threads));
if (max_threads == 1)
cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
cpu_smt_max_threads = max_threads;
/*
* If SMT has been disabled via the kernel command line or SMT is
* not supported, set cpu_smt_num_threads to 1 for consistency.
* If enabled, take the architecture requested number of threads
* to bring up into account.
*/
if (cpu_smt_control != CPU_SMT_ENABLED)
cpu_smt_num_threads = 1;
else if (num_threads < cpu_smt_num_threads)
cpu_smt_num_threads = num_threads;
}
static int __init smt_cmdline_disable(char *str)
{
cpu_smt_disable(str && !strcmp(str, "force"));
return 0;
}
early_param("nosmt", smt_cmdline_disable);
/*
* For Archicture supporting partial SMT states check if the thread is allowed.
* Otherwise this has already been checked through cpu_smt_max_threads when
* setting the SMT level.
*/
static inline bool cpu_smt_thread_allowed(unsigned int cpu)
{
#ifdef CONFIG_SMT_NUM_THREADS_DYNAMIC
return topology_smt_thread_allowed(cpu);
#else
return true;
#endif
}
static inline bool cpu_smt_allowed(unsigned int cpu)
{
if (cpu_smt_control == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
return true;
if (topology_is_primary_thread(cpu))
return true;
/*
* On x86 it's required to boot all logical CPUs at least once so
* that the init code can get a chance to set CR4.MCE on each
* CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any
* core will shutdown the machine.
*/
return !cpumask_test_cpu(cpu, &cpus_booted_once_mask);
}
/* Returns true if SMT is supported and not forcefully (irreversibly) disabled */
bool cpu_smt_possible(void)
{
return cpu_smt_control != CPU_SMT_FORCE_DISABLED &&
cpu_smt_control != CPU_SMT_NOT_SUPPORTED;
}
EXPORT_SYMBOL_GPL(cpu_smt_possible);
#else
static inline bool cpu_smt_allowed(unsigned int cpu) { return true; }
#endif
static inline enum cpuhp_state
cpuhp_set_state(int cpu, struct cpuhp_cpu_state *st, enum cpuhp_state target)
{
enum cpuhp_state prev_state = st->state;
bool bringup = st->state < target;
st->rollback = false;
st->last = NULL;
st->target = target;
st->single = false;
st->bringup = bringup;
if (cpu_dying(cpu) != !bringup)
set_cpu_dying(cpu, !bringup);
return prev_state;
}
static inline void
cpuhp_reset_state(int cpu, struct cpuhp_cpu_state *st,
enum cpuhp_state prev_state)
{
bool bringup = !st->bringup;
st->target = prev_state;
/*
* Already rolling back. No need invert the bringup value or to change
* the current state.
*/
if (st->rollback)
return;
st->rollback = true;
/*
* If we have st->last we need to undo partial multi_instance of this
* state first. Otherwise start undo at the previous state.
*/
if (!st->last) {
if (st->bringup)
st->state--;
else
st->state++;
}
st->bringup = bringup;
if (cpu_dying(cpu) != !bringup)
set_cpu_dying(cpu, !bringup);
}
/* Regular hotplug invocation of the AP hotplug thread */
static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st)
{
if (!st->single && st->state == st->target)
return;
st->result = 0;
/*
* Make sure the above stores are visible before should_run becomes
* true. Paired with the mb() above in cpuhp_thread_fun()
*/
smp_mb();
st->should_run = true;
wake_up_process(st->thread);
wait_for_ap_thread(st, st->bringup);
}
static int cpuhp_kick_ap(int cpu, struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
enum cpuhp_state prev_state;
int ret;
prev_state = cpuhp_set_state(cpu, st, target);
__cpuhp_kick_ap(st);
if ((ret = st->result)) {
cpuhp_reset_state(cpu, st, prev_state);
__cpuhp_kick_ap(st);
}
return ret;
}
static int bringup_wait_for_ap_online(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
/* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
wait_for_ap_thread(st, true);
if (WARN_ON_ONCE((!cpu_online(cpu))))
return -ECANCELED;
/* Unpark the hotplug thread of the target cpu */
kthread_unpark(st->thread);
/*
* SMT soft disabling on X86 requires to bring the CPU out of the
* BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The
* CPU marked itself as booted_once in notify_cpu_starting() so the
* cpu_smt_allowed() check will now return false if this is not the
* primary sibling.
*/
if (!cpu_smt_allowed(cpu))
return -ECANCELED;
return 0;
}
#ifdef CONFIG_HOTPLUG_SPLIT_STARTUP
static int cpuhp_kick_ap_alive(unsigned int cpu)
{
if (!cpuhp_can_boot_ap(cpu))
return -EAGAIN;
return arch_cpuhp_kick_ap_alive(cpu, idle_thread_get(cpu));
}
static int cpuhp_bringup_ap(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int ret;
/*
* Some architectures have to walk the irq descriptors to
* setup the vector space for the cpu which comes online.
* Prevent irq alloc/free across the bringup.
*/
irq_lock_sparse();
ret = cpuhp_bp_sync_alive(cpu);
if (ret)
goto out_unlock;
ret = bringup_wait_for_ap_online(cpu);
if (ret)
goto out_unlock;
irq_unlock_sparse();
if (st->target <= CPUHP_AP_ONLINE_IDLE)
return 0;
return cpuhp_kick_ap(cpu, st, st->target);
out_unlock:
irq_unlock_sparse();
return ret;
}
#else
static int bringup_cpu(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
struct task_struct *idle = idle_thread_get(cpu);
int ret;
if (!cpuhp_can_boot_ap(cpu))
return -EAGAIN;
/*
* Some architectures have to walk the irq descriptors to
* setup the vector space for the cpu which comes online.
*
* Prevent irq alloc/free across the bringup by acquiring the
* sparse irq lock. Hold it until the upcoming CPU completes the
* startup in cpuhp_online_idle() which allows to avoid
* intermediate synchronization points in the architecture code.
*/
irq_lock_sparse();
ret = __cpu_up(cpu, idle);
if (ret)
goto out_unlock;
ret = cpuhp_bp_sync_alive(cpu);
if (ret)
goto out_unlock;
ret = bringup_wait_for_ap_online(cpu);
if (ret)
goto out_unlock;
irq_unlock_sparse();
if (st->target <= CPUHP_AP_ONLINE_IDLE)
return 0;
return cpuhp_kick_ap(cpu, st, st->target);
out_unlock:
irq_unlock_sparse();
return ret;
}
#endif
static int finish_cpu(unsigned int cpu)
{
struct task_struct *idle = idle_thread_get(cpu);
struct mm_struct *mm = idle->active_mm;
/*
* idle_task_exit() will have switched to &init_mm, now
* clean up any remaining active_mm state.
*/
if (mm != &init_mm)
idle->active_mm = &init_mm;
mmdrop_lazy_tlb(mm);
return 0;
}
/*
* Hotplug state machine related functions
*/
/*
* Get the next state to run. Empty ones will be skipped. Returns true if a
* state must be run.
*
* st->state will be modified ahead of time, to match state_to_run, as if it
* has already ran.
*/
static bool cpuhp_next_state(bool bringup,
enum cpuhp_state *state_to_run,
struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
do {
if (bringup) {
if (st->state >= target)
return false;
*state_to_run = ++st->state;
} else {
if (st->state <= target)
return false;
*state_to_run = st->state--;
}
if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run)))
break;
} while (true);
return true;
}
static int __cpuhp_invoke_callback_range(bool bringup,
unsigned int cpu,
struct cpuhp_cpu_state *st,
enum cpuhp_state target,
bool nofail)
{
enum cpuhp_state state;
int ret = 0;
while (cpuhp_next_state(bringup, &state, st, target)) {
int err;
err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL);
if (!err)
continue;
if (nofail) {
pr_warn("CPU %u %s state %s (%d) failed (%d)\n",
cpu, bringup ? "UP" : "DOWN",
cpuhp_get_step(st->state)->name,
st->state, err);
ret = -1;
} else {
ret = err;
break;
}
}
return ret;
}
static inline int cpuhp_invoke_callback_range(bool bringup,
unsigned int cpu,
struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
return __cpuhp_invoke_callback_range(bringup, cpu, st, target, false);
}
static inline void cpuhp_invoke_callback_range_nofail(bool bringup,
unsigned int cpu,
struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
__cpuhp_invoke_callback_range(bringup, cpu, st, target, true);
}
static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st)
{
if (IS_ENABLED(CONFIG_HOTPLUG_CPU))
return true;
/*
* When CPU hotplug is disabled, then taking the CPU down is not
* possible because takedown_cpu() and the architecture and
* subsystem specific mechanisms are not available. So the CPU
* which would be completely unplugged again needs to stay around
* in the current state.
*/
return st->state <= CPUHP_BRINGUP_CPU;
}
static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
enum cpuhp_state prev_state = st->state;
int ret = 0;
ret = cpuhp_invoke_callback_range(true, cpu, st, target);
if (ret) {
pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n",
ret, cpu, cpuhp_get_step(st->state)->name,
st->state);
cpuhp_reset_state(cpu, st, prev_state);
if (can_rollback_cpu(st))
WARN_ON(cpuhp_invoke_callback_range(false, cpu, st,
prev_state));
}
return ret;
}
/*
* The cpu hotplug threads manage the bringup and teardown of the cpus
*/
static int cpuhp_should_run(unsigned int cpu)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
return st->should_run;
}
/*
* Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
* callbacks when a state gets [un]installed at runtime.
*
* Each invocation of this function by the smpboot thread does a single AP
* state callback.
*
* It has 3 modes of operation:
* - single: runs st->cb_state
* - up: runs ++st->state, while st->state < st->target
* - down: runs st->state--, while st->state > st->target
*
* When complete or on error, should_run is cleared and the completion is fired.
*/
static void cpuhp_thread_fun(unsigned int cpu)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
bool bringup = st->bringup;
enum cpuhp_state state;
if (WARN_ON_ONCE(!st->should_run))
return;
/*
* ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
* that if we see ->should_run we also see the rest of the state.
*/
smp_mb();
/*
* The BP holds the hotplug lock, but we're now running on the AP,
* ensure that anybody asserting the lock is held, will actually find
* it so.
*/
lockdep_acquire_cpus_lock();
cpuhp_lock_acquire(bringup);
if (st->single) {
state = st->cb_state;
st->should_run = false;
} else {
st->should_run = cpuhp_next_state(bringup, &state, st, st->target);
if (!st->should_run)
goto end;
}
WARN_ON_ONCE(!cpuhp_is_ap_state(state));
if (cpuhp_is_atomic_state(state)) {
local_irq_disable();
st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
local_irq_enable();
/*
* STARTING/DYING must not fail!
*/
WARN_ON_ONCE(st->result);
} else {
st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
}
if (st->result) {
/*
* If we fail on a rollback, we're up a creek without no
* paddle, no way forward, no way back. We loose, thanks for
* playing.
*/
WARN_ON_ONCE(st->rollback);
st->should_run = false;
}
end:
cpuhp_lock_release(bringup);
lockdep_release_cpus_lock();
if (!st->should_run)
complete_ap_thread(st, bringup);
}
/* Invoke a single callback on a remote cpu */
static int
cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
struct hlist_node *node)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int ret;
if (!cpu_online(cpu))
return 0;
cpuhp_lock_acquire(false);
cpuhp_lock_release(false);
cpuhp_lock_acquire(true);
cpuhp_lock_release(true);
/*
* If we are up and running, use the hotplug thread. For early calls
* we invoke the thread function directly.
*/
if (!st->thread)
return cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
st->rollback = false;
st->last = NULL;
st->node = node;
st->bringup = bringup;
st->cb_state = state;
st->single = true;
__cpuhp_kick_ap(st);
/*
* If we failed and did a partial, do a rollback.
*/
if ((ret = st->result) && st->last) {
st->rollback = true;
st->bringup = !bringup;
__cpuhp_kick_ap(st);
}
/*
* Clean up the leftovers so the next hotplug operation wont use stale
* data.
*/
st->node = st->last = NULL;
return ret;
}
static int cpuhp_kick_ap_work(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
enum cpuhp_state prev_state = st->state;
int ret;
cpuhp_lock_acquire(false);
cpuhp_lock_release(false);
cpuhp_lock_acquire(true);
cpuhp_lock_release(true);
trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
ret = cpuhp_kick_ap(cpu, st, st->target);
trace_cpuhp_exit(cpu, st->state, prev_state, ret);
return ret;
}
static struct smp_hotplug_thread cpuhp_threads = {
.store = &cpuhp_state.thread,
.thread_should_run = cpuhp_should_run,
.thread_fn = cpuhp_thread_fun,
.thread_comm = "cpuhp/%u",
.selfparking = true,
};
static __init void cpuhp_init_state(void)
{
struct cpuhp_cpu_state *st;
int cpu;
for_each_possible_cpu(cpu) {
st = per_cpu_ptr(&cpuhp_state, cpu);
init_completion(&st->done_up);
init_completion(&st->done_down);
}
}
void __init cpuhp_threads_init(void)
{
cpuhp_init_state();
BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads));
kthread_unpark(this_cpu_read(cpuhp_state.thread));
}
/*
*
* Serialize hotplug trainwrecks outside of the cpu_hotplug_lock
* protected region.
*
* The operation is still serialized against concurrent CPU hotplug via
* cpu_add_remove_lock, i.e. CPU map protection. But it is _not_
* serialized against other hotplug related activity like adding or
* removing of state callbacks and state instances, which invoke either the
* startup or the teardown callback of the affected state.
*
* This is required for subsystems which are unfixable vs. CPU hotplug and
* evade lock inversion problems by scheduling work which has to be
* completed _before_ cpu_up()/_cpu_down() returns.
*
* Don't even think about adding anything to this for any new code or even
* drivers. It's only purpose is to keep existing lock order trainwrecks
* working.
*
* For cpu_down() there might be valid reasons to finish cleanups which are
* not required to be done under cpu_hotplug_lock, but that's a different
* story and would be not invoked via this.
*/
static void cpu_up_down_serialize_trainwrecks(bool tasks_frozen)
{
/*
* cpusets delegate hotplug operations to a worker to "solve" the
* lock order problems. Wait for the worker, but only if tasks are
* _not_ frozen (suspend, hibernate) as that would wait forever.
*
* The wait is required because otherwise the hotplug operation
* returns with inconsistent state, which could even be observed in
* user space when a new CPU is brought up. The CPU plug uevent
* would be delivered and user space reacting on it would fail to
* move tasks to the newly plugged CPU up to the point where the
* work has finished because up to that point the newly plugged CPU
* is not assignable in cpusets/cgroups. On unplug that's not
* necessarily a visible issue, but it is still inconsistent state,
* which is the real problem which needs to be "fixed". This can't
* prevent the transient state between scheduling the work and
* returning from waiting for it.
*/
if (!tasks_frozen)
cpuset_wait_for_hotplug();
}
#ifdef CONFIG_HOTPLUG_CPU
#ifndef arch_clear_mm_cpumask_cpu
#define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
#endif
/**
* clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
* @cpu: a CPU id
*
* This function walks all processes, finds a valid mm struct for each one and
* then clears a corresponding bit in mm's cpumask. While this all sounds
* trivial, there are various non-obvious corner cases, which this function
* tries to solve in a safe manner.
*
* Also note that the function uses a somewhat relaxed locking scheme, so it may
* be called only for an already offlined CPU.
*/
void clear_tasks_mm_cpumask(int cpu)
{
struct task_struct *p;
/*
* This function is called after the cpu is taken down and marked
* offline, so its not like new tasks will ever get this cpu set in
* their mm mask. -- Peter Zijlstra
* Thus, we may use rcu_read_lock() here, instead of grabbing
* full-fledged tasklist_lock.
*/
WARN_ON(cpu_online(cpu));
rcu_read_lock();
for_each_process(p) {
struct task_struct *t;
/*
* Main thread might exit, but other threads may still have
* a valid mm. Find one.
*/
t = find_lock_task_mm(p);
if (!t)
continue;
arch_clear_mm_cpumask_cpu(cpu, t->mm);
task_unlock(t);
}
rcu_read_unlock();
}
/* Take this CPU down. */
static int take_cpu_down(void *_param)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
int err, cpu = smp_processor_id();
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
if (err < 0)
return err;
/*
* Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going
* down, that the current state is CPUHP_TEARDOWN_CPU - 1.
*/
WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1));
/*
* Invoke the former CPU_DYING callbacks. DYING must not fail!
*/
cpuhp_invoke_callback_range_nofail(false, cpu, st, target);
/* Give up timekeeping duties */
tick_handover_do_timer();
/* Remove CPU from timer broadcasting */
tick_offline_cpu(cpu);
/* Park the stopper thread */
stop_machine_park(cpu);
return 0;
}
static int takedown_cpu(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int err;
/* Park the smpboot threads */
kthread_park(st->thread);
/*
* Prevent irq alloc/free while the dying cpu reorganizes the
* interrupt affinities.
*/
irq_lock_sparse();
/*
* So now all preempt/rcu users must observe !cpu_active().
*/
err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
if (err) {
/* CPU refused to die */
irq_unlock_sparse();
/* Unpark the hotplug thread so we can rollback there */
kthread_unpark(st->thread);
return err;
}
BUG_ON(cpu_online(cpu));
/*
* The teardown callback for CPUHP_AP_SCHED_STARTING will have removed
* all runnable tasks from the CPU, there's only the idle task left now
* that the migration thread is done doing the stop_machine thing.
*
* Wait for the stop thread to go away.
*/
wait_for_ap_thread(st, false);
BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
/* Interrupts are moved away from the dying cpu, reenable alloc/free */
irq_unlock_sparse();
hotplug_cpu__broadcast_tick_pull(cpu);
/* This actually kills the CPU. */
__cpu_die(cpu);
cpuhp_bp_sync_dead(cpu);
tick_cleanup_dead_cpu(cpu);
rcutree_migrate_callbacks(cpu);
return 0;
}
static void cpuhp_complete_idle_dead(void *arg)
{
struct cpuhp_cpu_state *st = arg;
complete_ap_thread(st, false);
}
void cpuhp_report_idle_dead(void)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
BUG_ON(st->state != CPUHP_AP_OFFLINE);
rcu_report_dead(smp_processor_id());
st->state = CPUHP_AP_IDLE_DEAD;
/*
* We cannot call complete after rcu_report_dead() so we delegate it
* to an online cpu.
*/
smp_call_function_single(cpumask_first(cpu_online_mask),
cpuhp_complete_idle_dead, st, 0);
}
static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
enum cpuhp_state target)
{
enum cpuhp_state prev_state = st->state;
int ret = 0;
ret = cpuhp_invoke_callback_range(false, cpu, st, target);
if (ret) {
pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n",
ret, cpu, cpuhp_get_step(st->state)->name,
st->state);
cpuhp_reset_state(cpu, st, prev_state);
if (st->state < prev_state)
WARN_ON(cpuhp_invoke_callback_range(true, cpu, st,
prev_state));
}
return ret;
}
/* Requires cpu_add_remove_lock to be held */
static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
enum cpuhp_state target)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int prev_state, ret = 0;
if (num_online_cpus() == 1)
return -EBUSY;
if (!cpu_present(cpu))
return -EINVAL;
cpus_write_lock();
cpuhp_tasks_frozen = tasks_frozen;
prev_state = cpuhp_set_state(cpu, st, target);
/*
* If the current CPU state is in the range of the AP hotplug thread,
* then we need to kick the thread.
*/
if (st->state > CPUHP_TEARDOWN_CPU) {
st->target = max((int)target, CPUHP_TEARDOWN_CPU);
ret = cpuhp_kick_ap_work(cpu);
/*
* The AP side has done the error rollback already. Just
* return the error code..
*/
if (ret)
goto out;
/*
* We might have stopped still in the range of the AP hotplug
* thread. Nothing to do anymore.
*/
if (st->state > CPUHP_TEARDOWN_CPU)
goto out;
st->target = target;
}
/*
* The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
* to do the further cleanups.
*/
ret = cpuhp_down_callbacks(cpu, st, target);
if (ret && st->state < prev_state) {
if (st->state == CPUHP_TEARDOWN_CPU) {
cpuhp_reset_state(cpu, st, prev_state);
__cpuhp_kick_ap(st);
} else {
WARN(1, "DEAD callback error for CPU%d", cpu);
}
}
out:
cpus_write_unlock();
/*
* Do post unplug cleanup. This is still protected against
* concurrent CPU hotplug via cpu_add_remove_lock.
*/
lockup_detector_cleanup();
arch_smt_update();
cpu_up_down_serialize_trainwrecks(tasks_frozen);
return ret;
}
struct cpu_down_work {
unsigned int cpu;
enum cpuhp_state target;
};
static long __cpu_down_maps_locked(void *arg)
{
struct cpu_down_work *work = arg;
return _cpu_down(work->cpu, 0, work->target);
}
static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
{
struct cpu_down_work work = { .cpu = cpu, .target = target, };
/*
* If the platform does not support hotplug, report it explicitly to
* differentiate it from a transient offlining failure.
*/
if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED))
return -EOPNOTSUPP;
if (cpu_hotplug_disabled)
return -EBUSY;
/*
* Ensure that the control task does not run on the to be offlined
* CPU to prevent a deadlock against cfs_b->period_timer.
*/
cpu = cpumask_any_but(cpu_online_mask, cpu);
if (cpu >= nr_cpu_ids)
return -EBUSY;
return work_on_cpu(cpu, __cpu_down_maps_locked, &work);
}
static int cpu_down(unsigned int cpu, enum cpuhp_state target)
{
int err;
cpu_maps_update_begin();
err = cpu_down_maps_locked(cpu, target);
cpu_maps_update_done();
return err;
}
/**
* cpu_device_down - Bring down a cpu device
* @dev: Pointer to the cpu device to offline
*
* This function is meant to be used by device core cpu subsystem only.
*
* Other subsystems should use remove_cpu() instead.
*
* Return: %0 on success or a negative errno code
*/
int cpu_device_down(struct device *dev)
{
return cpu_down(dev->id, CPUHP_OFFLINE);
}
int remove_cpu(unsigned int cpu)
{
int ret;
lock_device_hotplug();
ret = device_offline(get_cpu_device(cpu));
unlock_device_hotplug();
return ret;
}
EXPORT_SYMBOL_GPL(remove_cpu);
void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
{
unsigned int cpu;
int error;
cpu_maps_update_begin();
/*
* Make certain the cpu I'm about to reboot on is online.
*
* This is inline to what migrate_to_reboot_cpu() already do.
*/
if (!cpu_online(primary_cpu))
primary_cpu = cpumask_first(cpu_online_mask);
for_each_online_cpu(cpu) {
if (cpu == primary_cpu)
continue;
error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
if (error) {
pr_err("Failed to offline CPU%d - error=%d",
cpu, error);
break;
}
}
/*
* Ensure all but the reboot CPU are offline.
*/
BUG_ON(num_online_cpus() > 1);
/*
* Make sure the CPUs won't be enabled by someone else after this
* point. Kexec will reboot to a new kernel shortly resetting
* everything along the way.
*/
cpu_hotplug_disabled++;
cpu_maps_update_done();
}
#else
#define takedown_cpu NULL
#endif /*CONFIG_HOTPLUG_CPU*/
/**
* notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
* @cpu: cpu that just started
*
* It must be called by the arch code on the new cpu, before the new cpu
* enables interrupts and before the "boot" cpu returns from __cpu_up().
*/
void notify_cpu_starting(unsigned int cpu)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
cpumask_set_cpu(cpu, &cpus_booted_once_mask);
/*
* STARTING must not fail!
*/
cpuhp_invoke_callback_range_nofail(true, cpu, st, target);
}
/*
* Called from the idle task. Wake up the controlling task which brings the
* hotplug thread of the upcoming CPU up and then delegates the rest of the
* online bringup to the hotplug thread.
*/
void cpuhp_online_idle(enum cpuhp_state state)
{
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
/* Happens for the boot cpu */
if (state != CPUHP_AP_ONLINE_IDLE)
return;
cpuhp_ap_update_sync_state(SYNC_STATE_ONLINE);
/*
* Unpark the stopper thread before we start the idle loop (and start
* scheduling); this ensures the stopper task is always available.
*/
stop_machine_unpark(smp_processor_id());
st->state = CPUHP_AP_ONLINE_IDLE;
complete_ap_thread(st, true);
}
/* Requires cpu_add_remove_lock to be held */
static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
struct task_struct *idle;
int ret = 0;
cpus_write_lock();
if (!cpu_present(cpu)) {
ret = -EINVAL;
goto out;
}
/*
* The caller of cpu_up() might have raced with another
* caller. Nothing to do.
*/
if (st->state >= target)
goto out;
if (st->state == CPUHP_OFFLINE) {
/* Let it fail before we try to bring the cpu up */
idle = idle_thread_get(cpu);
if (IS_ERR(idle)) {
ret = PTR_ERR(idle);
goto out;
}
/*
* Reset stale stack state from the last time this CPU was online.
*/
scs_task_reset(idle);
kasan_unpoison_task_stack(idle);
}
cpuhp_tasks_frozen = tasks_frozen;
cpuhp_set_state(cpu, st, target);
/*
* If the current CPU state is in the range of the AP hotplug thread,
* then we need to kick the thread once more.
*/
if (st->state > CPUHP_BRINGUP_CPU) {
ret = cpuhp_kick_ap_work(cpu);
/*
* The AP side has done the error rollback already. Just
* return the error code..
*/
if (ret)
goto out;
}
/*
* Try to reach the target state. We max out on the BP at
* CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
* responsible for bringing it up to the target state.
*/
target = min((int)target, CPUHP_BRINGUP_CPU);
ret = cpuhp_up_callbacks(cpu, st, target);
out:
cpus_write_unlock();
arch_smt_update();
cpu_up_down_serialize_trainwrecks(tasks_frozen);
return ret;
}
static int cpu_up(unsigned int cpu, enum cpuhp_state target)
{
int err = 0;
if (!cpu_possible(cpu)) {
pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
cpu);
#if defined(CONFIG_IA64)
pr_err("please check additional_cpus= boot parameter\n");
#endif
return -EINVAL;
}
err = try_online_node(cpu_to_node(cpu));
if (err)
return err;
cpu_maps_update_begin();
if (cpu_hotplug_disabled) {
err = -EBUSY;
goto out;
}
if (!cpu_smt_allowed(cpu)) {
err = -EPERM;
goto out;
}
err = _cpu_up(cpu, 0, target);
out:
cpu_maps_update_done();
return err;
}
/**
* cpu_device_up - Bring up a cpu device
* @dev: Pointer to the cpu device to online
*
* This function is meant to be used by device core cpu subsystem only.
*
* Other subsystems should use add_cpu() instead.
*
* Return: %0 on success or a negative errno code
*/
int cpu_device_up(struct device *dev)
{
return cpu_up(dev->id, CPUHP_ONLINE);
}
int add_cpu(unsigned int cpu)
{
int ret;
lock_device_hotplug();
ret = device_online(get_cpu_device(cpu));
unlock_device_hotplug();
return ret;
}
EXPORT_SYMBOL_GPL(add_cpu);
/**
* bringup_hibernate_cpu - Bring up the CPU that we hibernated on
* @sleep_cpu: The cpu we hibernated on and should be brought up.
*
* On some architectures like arm64, we can hibernate on any CPU, but on
* wake up the CPU we hibernated on might be offline as a side effect of
* using maxcpus= for example.
*
* Return: %0 on success or a negative errno code
*/
int bringup_hibernate_cpu(unsigned int sleep_cpu)
{
int ret;
if (!cpu_online(sleep_cpu)) {
pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
ret = cpu_up(sleep_cpu, CPUHP_ONLINE);
if (ret) {
pr_err("Failed to bring hibernate-CPU up!\n");
return ret;
}
}
return 0;
}
static void __init cpuhp_bringup_mask(const struct cpumask *mask, unsigned int ncpus,
enum cpuhp_state target)
{
unsigned int cpu;
for_each_cpu(cpu, mask) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
if (cpu_up(cpu, target) && can_rollback_cpu(st)) {
/*
* If this failed then cpu_up() might have only
* rolled back to CPUHP_BP_KICK_AP for the final
* online. Clean it up. NOOP if already rolled back.
*/
WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, CPUHP_OFFLINE));
}
if (!--ncpus)
break;
}
}
#ifdef CONFIG_HOTPLUG_PARALLEL
static bool __cpuhp_parallel_bringup __ro_after_init = true;
static int __init parallel_bringup_parse_param(char *arg)
{
return kstrtobool(arg, &__cpuhp_parallel_bringup);
}
early_param("cpuhp.parallel", parallel_bringup_parse_param);
static inline bool cpuhp_smt_aware(void)
{
return cpu_smt_max_threads > 1;
}
static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
{
return cpu_primary_thread_mask;
}
/*
* On architectures which have enabled parallel bringup this invokes all BP
* prepare states for each of the to be onlined APs first. The last state
* sends the startup IPI to the APs. The APs proceed through the low level
* bringup code in parallel and then wait for the control CPU to release
* them one by one for the final onlining procedure.
*
* This avoids waiting for each AP to respond to the startup IPI in
* CPUHP_BRINGUP_CPU.
*/
static bool __init cpuhp_bringup_cpus_parallel(unsigned int ncpus)
{
const struct cpumask *mask = cpu_present_mask;
if (__cpuhp_parallel_bringup)
__cpuhp_parallel_bringup = arch_cpuhp_init_parallel_bringup();
if (!__cpuhp_parallel_bringup)
return false;
if (cpuhp_smt_aware()) {
const struct cpumask *pmask = cpuhp_get_primary_thread_mask();
static struct cpumask tmp_mask __initdata;
/*
* X86 requires to prevent that SMT siblings stopped while
* the primary thread does a microcode update for various
* reasons. Bring the primary threads up first.
*/
cpumask_and(&tmp_mask, mask, pmask);
cpuhp_bringup_mask(&tmp_mask, ncpus, CPUHP_BP_KICK_AP);
cpuhp_bringup_mask(&tmp_mask, ncpus, CPUHP_ONLINE);
/* Account for the online CPUs */
ncpus -= num_online_cpus();
if (!ncpus)
return true;
/* Create the mask for secondary CPUs */
cpumask_andnot(&tmp_mask, mask, pmask);
mask = &tmp_mask;
}
/* Bring the not-yet started CPUs up */
cpuhp_bringup_mask(mask, ncpus, CPUHP_BP_KICK_AP);
cpuhp_bringup_mask(mask, ncpus, CPUHP_ONLINE);
return true;
}
#else
static inline bool cpuhp_bringup_cpus_parallel(unsigned int ncpus) { return false; }
#endif /* CONFIG_HOTPLUG_PARALLEL */
void __init bringup_nonboot_cpus(unsigned int setup_max_cpus)
{
/* Try parallel bringup optimization if enabled */
if (cpuhp_bringup_cpus_parallel(setup_max_cpus))
return;
/* Full per CPU serialized bringup */
cpuhp_bringup_mask(cpu_present_mask, setup_max_cpus, CPUHP_ONLINE);
}
#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_var_t frozen_cpus;
int freeze_secondary_cpus(int primary)
{
int cpu, error = 0;
cpu_maps_update_begin();
if (primary == -1) {
primary = cpumask_first(cpu_online_mask);
if (!housekeeping_cpu(primary, HK_TYPE_TIMER))
primary = housekeeping_any_cpu(HK_TYPE_TIMER);
} else {
if (!cpu_online(primary))
primary = cpumask_first(cpu_online_mask);
}
/*
* We take down all of the non-boot CPUs in one shot to avoid races
* with the userspace trying to use the CPU hotplug at the same time
*/
cpumask_clear(frozen_cpus);
pr_info("Disabling non-boot CPUs ...\n");
for_each_online_cpu(cpu) {
if (cpu == primary)
continue;
if (pm_wakeup_pending()) {
pr_info("Wakeup pending. Abort CPU freeze\n");
error = -EBUSY;
break;
}
trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
if (!error)
cpumask_set_cpu(cpu, frozen_cpus);
else {
pr_err("Error taking CPU%d down: %d\n", cpu, error);
break;
}
}
if (!error)
BUG_ON(num_online_cpus() > 1);
else
pr_err("Non-boot CPUs are not disabled\n");
/*
* Make sure the CPUs won't be enabled by someone else. We need to do
* this even in case of failure as all freeze_secondary_cpus() users are
* supposed to do thaw_secondary_cpus() on the failure path.
*/
cpu_hotplug_disabled++;
cpu_maps_update_done();
return error;
}
void __weak arch_thaw_secondary_cpus_begin(void)
{
}
void __weak arch_thaw_secondary_cpus_end(void)
{
}
void thaw_secondary_cpus(void)
{
int cpu, error;
/* Allow everyone to use the CPU hotplug again */
cpu_maps_update_begin();
__cpu_hotplug_enable();
if (cpumask_empty(frozen_cpus))
goto out;
pr_info("Enabling non-boot CPUs ...\n");
arch_thaw_secondary_cpus_begin();
for_each_cpu(cpu, frozen_cpus) {
trace_suspend_resume(TPS("CPU_ON"), cpu, true);
error = _cpu_up(cpu, 1, CPUHP_ONLINE);
trace_suspend_resume(TPS("CPU_ON"), cpu, false);
if (!error) {
pr_info("CPU%d is up\n", cpu);
continue;
}
pr_warn("Error taking CPU%d up: %d\n", cpu, error);
}
arch_thaw_secondary_cpus_end();
cpumask_clear(frozen_cpus);
out:
cpu_maps_update_done();
}
static int __init alloc_frozen_cpus(void)
{
if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
return -ENOMEM;
return 0;
}
core_initcall(alloc_frozen_cpus);
/*
* When callbacks for CPU hotplug notifications are being executed, we must
* ensure that the state of the system with respect to the tasks being frozen
* or not, as reported by the notification, remains unchanged *throughout the
* duration* of the execution of the callbacks.
* Hence we need to prevent the freezer from racing with regular CPU hotplug.
*
* This synchronization is implemented by mutually excluding regular CPU
* hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
* Hibernate notifications.
*/
static int
cpu_hotplug_pm_callback(struct notifier_block *nb,
unsigned long action, void *ptr)
{
switch (action) {
case PM_SUSPEND_PREPARE:
case PM_HIBERNATION_PREPARE:
cpu_hotplug_disable();
break;
case PM_POST_SUSPEND:
case PM_POST_HIBERNATION:
cpu_hotplug_enable();
break;
default:
return NOTIFY_DONE;
}
return NOTIFY_OK;
}
static int __init cpu_hotplug_pm_sync_init(void)
{
/*
* cpu_hotplug_pm_callback has higher priority than x86
* bsp_pm_callback which depends on cpu_hotplug_pm_callback
* to disable cpu hotplug to avoid cpu hotplug race.
*/
pm_notifier(cpu_hotplug_pm_callback, 0);
return 0;
}
core_initcall(cpu_hotplug_pm_sync_init);
#endif /* CONFIG_PM_SLEEP_SMP */
int __boot_cpu_id;
#endif /* CONFIG_SMP */
/* Boot processor state steps */
static struct cpuhp_step cpuhp_hp_states[] = {
[CPUHP_OFFLINE] = {
.name = "offline",
.startup.single = NULL,
.teardown.single = NULL,
},
#ifdef CONFIG_SMP
[CPUHP_CREATE_THREADS]= {
.name = "threads:prepare",
.startup.single = smpboot_create_threads,
.teardown.single = NULL,
.cant_stop = true,
},
[CPUHP_PERF_PREPARE] = {
.name = "perf:prepare",
.startup.single = perf_event_init_cpu,
.teardown.single = perf_event_exit_cpu,
},
[CPUHP_RANDOM_PREPARE] = {
.name = "random:prepare",
.startup.single = random_prepare_cpu,
.teardown.single = NULL,
},
[CPUHP_WORKQUEUE_PREP] = {
.name = "workqueue:prepare",
.startup.single = workqueue_prepare_cpu,
.teardown.single = NULL,
},
[CPUHP_HRTIMERS_PREPARE] = {
.name = "hrtimers:prepare",
.startup.single = hrtimers_prepare_cpu,
.teardown.single = hrtimers_dead_cpu,
},
[CPUHP_SMPCFD_PREPARE] = {
.name = "smpcfd:prepare",
.startup.single = smpcfd_prepare_cpu,
.teardown.single = smpcfd_dead_cpu,
},
[CPUHP_RELAY_PREPARE] = {
.name = "relay:prepare",
.startup.single = relay_prepare_cpu,
.teardown.single = NULL,
},
[CPUHP_SLAB_PREPARE] = {
.name = "slab:prepare",
.startup.single = slab_prepare_cpu,
.teardown.single = slab_dead_cpu,
},
[CPUHP_RCUTREE_PREP] = {
.name = "RCU/tree:prepare",
.startup.single = rcutree_prepare_cpu,
.teardown.single = rcutree_dead_cpu,
},
/*
* On the tear-down path, timers_dead_cpu() must be invoked
* before blk_mq_queue_reinit_notify() from notify_dead(),
* otherwise a RCU stall occurs.
*/
[CPUHP_TIMERS_PREPARE] = {
.name = "timers:prepare",
.startup.single = timers_prepare_cpu,
.teardown.single = timers_dead_cpu,
},
#ifdef CONFIG_HOTPLUG_SPLIT_STARTUP
/*
* Kicks the AP alive. AP will wait in cpuhp_ap_sync_alive() until
* the next step will release it.
*/
[CPUHP_BP_KICK_AP] = {
.name = "cpu:kick_ap",
.startup.single = cpuhp_kick_ap_alive,
},
/*
* Waits for the AP to reach cpuhp_ap_sync_alive() and then
* releases it for the complete bringup.
*/
[CPUHP_BRINGUP_CPU] = {
.name = "cpu:bringup",
.startup.single = cpuhp_bringup_ap,
.teardown.single = finish_cpu,
.cant_stop = true,
},
#else
/*
* All-in-one CPU bringup state which includes the kick alive.
*/
[CPUHP_BRINGUP_CPU] = {
.name = "cpu:bringup",
.startup.single = bringup_cpu,
.teardown.single = finish_cpu,
.cant_stop = true,
},
#endif
/* Final state before CPU kills itself */
[CPUHP_AP_IDLE_DEAD] = {
.name = "idle:dead",
},
/*
* Last state before CPU enters the idle loop to die. Transient state
* for synchronization.
*/
[CPUHP_AP_OFFLINE] = {
.name = "ap:offline",
.cant_stop = true,
},
/* First state is scheduler control. Interrupts are disabled */
[CPUHP_AP_SCHED_STARTING] = {
.name = "sched:starting",
.startup.single = sched_cpu_starting,
.teardown.single = sched_cpu_dying,
},
[CPUHP_AP_RCUTREE_DYING] = {
.name = "RCU/tree:dying",
.startup.single = NULL,
.teardown.single = rcutree_dying_cpu,
},
[CPUHP_AP_SMPCFD_DYING] = {
.name = "smpcfd:dying",
.startup.single = NULL,
.teardown.single = smpcfd_dying_cpu,
},
/* Entry state on starting. Interrupts enabled from here on. Transient
* state for synchronsization */
[CPUHP_AP_ONLINE] = {
.name = "ap:online",
},
/*
* Handled on control processor until the plugged processor manages
* this itself.
*/
[CPUHP_TEARDOWN_CPU] = {
.name = "cpu:teardown",
.startup.single = NULL,
.teardown.single = takedown_cpu,
.cant_stop = true,
},
[CPUHP_AP_SCHED_WAIT_EMPTY] = {
.name = "sched:waitempty",
.startup.single = NULL,
.teardown.single = sched_cpu_wait_empty,
},
/* Handle smpboot threads park/unpark */
[CPUHP_AP_SMPBOOT_THREADS] = {
.name = "smpboot/threads:online",
.startup.single = smpboot_unpark_threads,
.teardown.single = smpboot_park_threads,
},
[CPUHP_AP_IRQ_AFFINITY_ONLINE] = {
.name = "irq/affinity:online",
.startup.single = irq_affinity_online_cpu,
.teardown.single = NULL,
},
[CPUHP_AP_PERF_ONLINE] = {
.name = "perf:online",
.startup.single = perf_event_init_cpu,
.teardown.single = perf_event_exit_cpu,
},
[CPUHP_AP_WATCHDOG_ONLINE] = {
.name = "lockup_detector:online",
.startup.single = lockup_detector_online_cpu,
.teardown.single = lockup_detector_offline_cpu,
},
[CPUHP_AP_WORKQUEUE_ONLINE] = {
.name = "workqueue:online",
.startup.single = workqueue_online_cpu,
.teardown.single = workqueue_offline_cpu,
},
[CPUHP_AP_RANDOM_ONLINE] = {
.name = "random:online",
.startup.single = random_online_cpu,
.teardown.single = NULL,
},
[CPUHP_AP_RCUTREE_ONLINE] = {
.name = "RCU/tree:online",
.startup.single = rcutree_online_cpu,
.teardown.single = rcutree_offline_cpu,
},
#endif
/*
* The dynamically registered state space is here
*/
#ifdef CONFIG_SMP
/* Last state is scheduler control setting the cpu active */
[CPUHP_AP_ACTIVE] = {
.name = "sched:active",
.startup.single = sched_cpu_activate,
.teardown.single = sched_cpu_deactivate,
},
#endif
/* CPU is fully up and running. */
[CPUHP_ONLINE] = {
.name = "online",
.startup.single = NULL,
.teardown.single = NULL,
},
};
/* Sanity check for callbacks */
static int cpuhp_cb_check(enum cpuhp_state state)
{
if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE)
return -EINVAL;
return 0;
}
/*
* Returns a free for dynamic slot assignment of the Online state. The states
* are protected by the cpuhp_slot_states mutex and an empty slot is identified
* by having no name assigned.
*/
static int cpuhp_reserve_state(enum cpuhp_state state)
{
enum cpuhp_state i, end;
struct cpuhp_step *step;
switch (state) {
case CPUHP_AP_ONLINE_DYN:
step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN;
end = CPUHP_AP_ONLINE_DYN_END;
break;
case CPUHP_BP_PREPARE_DYN:
step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN;
end = CPUHP_BP_PREPARE_DYN_END;
break;
default:
return -EINVAL;
}
for (i = state; i <= end; i++, step++) {
if (!step->name)
return i;
}
WARN(1, "No more dynamic states available for CPU hotplug\n");
return -ENOSPC;
}
static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu),
bool multi_instance)
{
/* (Un)Install the callbacks for further cpu hotplug operations */
struct cpuhp_step *sp;
int ret = 0;
/*
* If name is NULL, then the state gets removed.
*
* CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on
* the first allocation from these dynamic ranges, so the removal
* would trigger a new allocation and clear the wrong (already
* empty) state, leaving the callbacks of the to be cleared state
* dangling, which causes wreckage on the next hotplug operation.
*/
if (name && (state == CPUHP_AP_ONLINE_DYN ||
state == CPUHP_BP_PREPARE_DYN)) {
ret = cpuhp_reserve_state(state);
if (ret < 0)
return ret;
state = ret;
}
sp = cpuhp_get_step(state);
if (name && sp->name)
return -EBUSY;
sp->startup.single = startup;
sp->teardown.single = teardown;
sp->name = name;
sp->multi_instance = multi_instance;
INIT_HLIST_HEAD(&sp->list);
return ret;
}
static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
{
return cpuhp_get_step(state)->teardown.single;
}
/*
* Call the startup/teardown function for a step either on the AP or
* on the current CPU.
*/
static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
struct hlist_node *node)
{
struct cpuhp_step *sp = cpuhp_get_step(state);
int ret;
/*
* If there's nothing to do, we done.
* Relies on the union for multi_instance.
*/
if (cpuhp_step_empty(bringup, sp))
return 0;
/*
* The non AP bound callbacks can fail on bringup. On teardown
* e.g. module removal we crash for now.
*/
#ifdef CONFIG_SMP
if (cpuhp_is_ap_state(state))
ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node);
else
ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
#else
ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
#endif
BUG_ON(ret && !bringup);
return ret;
}
/*
* Called from __cpuhp_setup_state on a recoverable failure.
*
* Note: The teardown callbacks for rollback are not allowed to fail!
*/
static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
struct hlist_node *node)
{
int cpu;
/* Roll back the already executed steps on the other cpus */
for_each_present_cpu(cpu) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int cpustate = st->state;
if (cpu >= failedcpu)
break;
/* Did we invoke the startup call on that cpu ? */
if (cpustate >= state)
cpuhp_issue_call(cpu, state, false, node);
}
}
int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
struct hlist_node *node,
bool invoke)
{
struct cpuhp_step *sp;
int cpu;
int ret;
lockdep_assert_cpus_held();
sp = cpuhp_get_step(state);
if (sp->multi_instance == false)
return -EINVAL;
mutex_lock(&cpuhp_state_mutex);
if (!invoke || !sp->startup.multi)
goto add_node;
/*
* Try to call the startup callback for each present cpu
* depending on the hotplug state of the cpu.
*/
for_each_present_cpu(cpu) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int cpustate = st->state;
if (cpustate < state)
continue;
ret = cpuhp_issue_call(cpu, state, true, node);
if (ret) {
if (sp->teardown.multi)
cpuhp_rollback_install(cpu, state, node);
goto unlock;
}
}
add_node:
ret = 0;
hlist_add_head(node, &sp->list);
unlock:
mutex_unlock(&cpuhp_state_mutex);
return ret;
}
int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
bool invoke)
{
int ret;
cpus_read_lock();
ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
/**
* __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state
* @state: The state to setup
* @name: Name of the step
* @invoke: If true, the startup function is invoked for cpus where
* cpu state >= @state
* @startup: startup callback function
* @teardown: teardown callback function
* @multi_instance: State is set up for multiple instances which get
* added afterwards.
*
* The caller needs to hold cpus read locked while calling this function.
* Return:
* On success:
* Positive state number if @state is CPUHP_AP_ONLINE_DYN;
* 0 for all other states
* On failure: proper (negative) error code
*/
int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
const char *name, bool invoke,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu),
bool multi_instance)
{
int cpu, ret = 0;
bool dynstate;
lockdep_assert_cpus_held();
if (cpuhp_cb_check(state) || !name)
return -EINVAL;
mutex_lock(&cpuhp_state_mutex);
ret = cpuhp_store_callbacks(state, name, startup, teardown,
multi_instance);
dynstate = state == CPUHP_AP_ONLINE_DYN;
if (ret > 0 && dynstate) {
state = ret;
ret = 0;
}
if (ret || !invoke || !startup)
goto out;
/*
* Try to call the startup callback for each present cpu
* depending on the hotplug state of the cpu.
*/
for_each_present_cpu(cpu) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int cpustate = st->state;
if (cpustate < state)
continue;
ret = cpuhp_issue_call(cpu, state, true, NULL);
if (ret) {
if (teardown)
cpuhp_rollback_install(cpu, state, NULL);
cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
goto out;
}
}
out:
mutex_unlock(&cpuhp_state_mutex);
/*
* If the requested state is CPUHP_AP_ONLINE_DYN, return the
* dynamically allocated state in case of success.
*/
if (!ret && dynstate)
return state;
return ret;
}
EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked);
int __cpuhp_setup_state(enum cpuhp_state state,
const char *name, bool invoke,
int (*startup)(unsigned int cpu),
int (*teardown)(unsigned int cpu),
bool multi_instance)
{
int ret;
cpus_read_lock();
ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup,
teardown, multi_instance);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL(__cpuhp_setup_state);
int __cpuhp_state_remove_instance(enum cpuhp_state state,
struct hlist_node *node, bool invoke)
{
struct cpuhp_step *sp = cpuhp_get_step(state);
int cpu;
BUG_ON(cpuhp_cb_check(state));
if (!sp->multi_instance)
return -EINVAL;
cpus_read_lock();
mutex_lock(&cpuhp_state_mutex);
if (!invoke || !cpuhp_get_teardown_cb(state))
goto remove;
/*
* Call the teardown callback for each present cpu depending
* on the hotplug state of the cpu. This function is not
* allowed to fail currently!
*/
for_each_present_cpu(cpu) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int cpustate = st->state;
if (cpustate >= state)
cpuhp_issue_call(cpu, state, false, node);
}
remove:
hlist_del(node);
mutex_unlock(&cpuhp_state_mutex);
cpus_read_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
/**
* __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state
* @state: The state to remove
* @invoke: If true, the teardown function is invoked for cpus where
* cpu state >= @state
*
* The caller needs to hold cpus read locked while calling this function.
* The teardown callback is currently not allowed to fail. Think
* about module removal!
*/
void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke)
{
struct cpuhp_step *sp = cpuhp_get_step(state);
int cpu;
BUG_ON(cpuhp_cb_check(state));
lockdep_assert_cpus_held();
mutex_lock(&cpuhp_state_mutex);
if (sp->multi_instance) {
WARN(!hlist_empty(&sp->list),
"Error: Removing state %d which has instances left.\n",
state);
goto remove;
}
if (!invoke || !cpuhp_get_teardown_cb(state))
goto remove;
/*
* Call the teardown callback for each present cpu depending
* on the hotplug state of the cpu. This function is not
* allowed to fail currently!
*/
for_each_present_cpu(cpu) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int cpustate = st->state;
if (cpustate >= state)
cpuhp_issue_call(cpu, state, false, NULL);
}
remove:
cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
mutex_unlock(&cpuhp_state_mutex);
}
EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked);
void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
{
cpus_read_lock();
__cpuhp_remove_state_cpuslocked(state, invoke);
cpus_read_unlock();
}
EXPORT_SYMBOL(__cpuhp_remove_state);
#ifdef CONFIG_HOTPLUG_SMT
static void cpuhp_offline_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = true;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
}
static void cpuhp_online_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = false;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
}
int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
{
int cpu, ret = 0;
cpu_maps_update_begin();
for_each_online_cpu(cpu) {
if (topology_is_primary_thread(cpu))
continue;
/*
* Disable can be called with CPU_SMT_ENABLED when changing
* from a higher to lower number of SMT threads per core.
*/
if (ctrlval == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
continue;
ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
if (ret)
break;
/*
* As this needs to hold the cpu maps lock it's impossible
* to call device_offline() because that ends up calling
* cpu_down() which takes cpu maps lock. cpu maps lock
* needs to be held as this might race against in kernel
* abusers of the hotplug machinery (thermal management).
*
* So nothing would update device:offline state. That would
* leave the sysfs entry stale and prevent onlining after
* smt control has been changed to 'off' again. This is
* called under the sysfs hotplug lock, so it is properly
* serialized against the regular offline usage.
*/
cpuhp_offline_cpu_device(cpu);
}
if (!ret)
cpu_smt_control = ctrlval;
cpu_maps_update_done();
return ret;
}
int cpuhp_smt_enable(void)
{
int cpu, ret = 0;
cpu_maps_update_begin();
cpu_smt_control = CPU_SMT_ENABLED;
for_each_present_cpu(cpu) {
/* Skip online CPUs and CPUs on offline nodes */
if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
continue;
if (!cpu_smt_thread_allowed(cpu))
continue;
ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
if (ret)
break;
/* See comment in cpuhp_smt_disable() */
cpuhp_online_cpu_device(cpu);
}
cpu_maps_update_done();
return ret;
}
#endif
#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
static ssize_t state_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
return sprintf(buf, "%d\n", st->state);
}
static DEVICE_ATTR_RO(state);
static ssize_t target_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
struct cpuhp_step *sp;
int target, ret;
ret = kstrtoint(buf, 10, &target);
if (ret)
return ret;
#ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL
if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE)
return -EINVAL;
#else
if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE)
return -EINVAL;
#endif
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
mutex_lock(&cpuhp_state_mutex);
sp = cpuhp_get_step(target);
ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
mutex_unlock(&cpuhp_state_mutex);
if (ret)
goto out;
if (st->state < target)
ret = cpu_up(dev->id, target);
else if (st->state > target)
ret = cpu_down(dev->id, target);
else if (WARN_ON(st->target != target))
st->target = target;
out:
unlock_device_hotplug();
return ret ? ret : count;
}
static ssize_t target_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
return sprintf(buf, "%d\n", st->target);
}
static DEVICE_ATTR_RW(target);
static ssize_t fail_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
struct cpuhp_step *sp;
int fail, ret;
ret = kstrtoint(buf, 10, &fail);
if (ret)
return ret;
if (fail == CPUHP_INVALID) {
st->fail = fail;
return count;
}
if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE)
return -EINVAL;
/*
* Cannot fail STARTING/DYING callbacks.
*/
if (cpuhp_is_atomic_state(fail))
return -EINVAL;
/*
* DEAD callbacks cannot fail...
* ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter
* triggering STARTING callbacks, a failure in this state would
* hinder rollback.
*/
if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU)
return -EINVAL;
/*
* Cannot fail anything that doesn't have callbacks.
*/
mutex_lock(&cpuhp_state_mutex);
sp = cpuhp_get_step(fail);
if (!sp->startup.single && !sp->teardown.single)
ret = -EINVAL;
mutex_unlock(&cpuhp_state_mutex);
if (ret)
return ret;
st->fail = fail;
return count;
}
static ssize_t fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
return sprintf(buf, "%d\n", st->fail);
}
static DEVICE_ATTR_RW(fail);
static struct attribute *cpuhp_cpu_attrs[] = {
&dev_attr_state.attr,
&dev_attr_target.attr,
&dev_attr_fail.attr,
NULL
};
static const struct attribute_group cpuhp_cpu_attr_group = {
.attrs = cpuhp_cpu_attrs,
.name = "hotplug",
NULL
};
static ssize_t states_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
ssize_t cur, res = 0;
int i;
mutex_lock(&cpuhp_state_mutex);
for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
struct cpuhp_step *sp = cpuhp_get_step(i);
if (sp->name) {
cur = sprintf(buf, "%3d: %s\n", i, sp->name);
buf += cur;
res += cur;
}
}
mutex_unlock(&cpuhp_state_mutex);
return res;
}
static DEVICE_ATTR_RO(states);
static struct attribute *cpuhp_cpu_root_attrs[] = {
&dev_attr_states.attr,
NULL
};
static const struct attribute_group cpuhp_cpu_root_attr_group = {
.attrs = cpuhp_cpu_root_attrs,
.name = "hotplug",
NULL
};
#ifdef CONFIG_HOTPLUG_SMT
static bool cpu_smt_num_threads_valid(unsigned int threads)
{
if (IS_ENABLED(CONFIG_SMT_NUM_THREADS_DYNAMIC))
return threads >= 1 && threads <= cpu_smt_max_threads;
return threads == 1 || threads == cpu_smt_max_threads;
}
static ssize_t
__store_smt_control(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
int ctrlval, ret, num_threads, orig_threads;
bool force_off;
if (cpu_smt_control == CPU_SMT_FORCE_DISABLED)
return -EPERM;
if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
return -ENODEV;
if (sysfs_streq(buf, "on")) {
ctrlval = CPU_SMT_ENABLED;
num_threads = cpu_smt_max_threads;
} else if (sysfs_streq(buf, "off")) {
ctrlval = CPU_SMT_DISABLED;
num_threads = 1;
} else if (sysfs_streq(buf, "forceoff")) {
ctrlval = CPU_SMT_FORCE_DISABLED;
num_threads = 1;
} else if (kstrtoint(buf, 10, &num_threads) == 0) {
if (num_threads == 1)
ctrlval = CPU_SMT_DISABLED;
else if (cpu_smt_num_threads_valid(num_threads))
ctrlval = CPU_SMT_ENABLED;
else
return -EINVAL;
} else {
return -EINVAL;
}
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
orig_threads = cpu_smt_num_threads;
cpu_smt_num_threads = num_threads;
force_off = ctrlval != cpu_smt_control && ctrlval == CPU_SMT_FORCE_DISABLED;
if (num_threads > orig_threads)
ret = cpuhp_smt_enable();
else if (num_threads < orig_threads || force_off)
ret = cpuhp_smt_disable(ctrlval);
unlock_device_hotplug();
return ret ? ret : count;
}
#else /* !CONFIG_HOTPLUG_SMT */
static ssize_t
__store_smt_control(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
return -ENODEV;
}
#endif /* CONFIG_HOTPLUG_SMT */
static const char *smt_states[] = {
[CPU_SMT_ENABLED] = "on",
[CPU_SMT_DISABLED] = "off",
[CPU_SMT_FORCE_DISABLED] = "forceoff",
[CPU_SMT_NOT_SUPPORTED] = "notsupported",
[CPU_SMT_NOT_IMPLEMENTED] = "notimplemented",
};
static ssize_t control_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
const char *state = smt_states[cpu_smt_control];
#ifdef CONFIG_HOTPLUG_SMT
/*
* If SMT is enabled but not all threads are enabled then show the
* number of threads. If all threads are enabled show "on". Otherwise
* show the state name.
*/
if (cpu_smt_control == CPU_SMT_ENABLED &&
cpu_smt_num_threads != cpu_smt_max_threads)
return sysfs_emit(buf, "%d\n", cpu_smt_num_threads);
#endif
return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
}
static ssize_t control_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
return __store_smt_control(dev, attr, buf, count);
}
static DEVICE_ATTR_RW(control);
static ssize_t active_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active());
}
static DEVICE_ATTR_RO(active);
static struct attribute *cpuhp_smt_attrs[] = {
&dev_attr_control.attr,
&dev_attr_active.attr,
NULL
};
static const struct attribute_group cpuhp_smt_attr_group = {
.attrs = cpuhp_smt_attrs,
.name = "smt",
NULL
};
static int __init cpu_smt_sysfs_init(void)
{
struct device *dev_root;
int ret = -ENODEV;
dev_root = bus_get_dev_root(&cpu_subsys);
if (dev_root) {
ret = sysfs_create_group(&dev_root->kobj, &cpuhp_smt_attr_group);
put_device(dev_root);
}
return ret;
}
static int __init cpuhp_sysfs_init(void)
{
struct device *dev_root;
int cpu, ret;
ret = cpu_smt_sysfs_init();
if (ret)
return ret;
dev_root = bus_get_dev_root(&cpu_subsys);
if (dev_root) {
ret = sysfs_create_group(&dev_root->kobj, &cpuhp_cpu_root_attr_group);
put_device(dev_root);
if (ret)
return ret;
}
for_each_possible_cpu(cpu) {
struct device *dev = get_cpu_device(cpu);
if (!dev)
continue;
ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
if (ret)
return ret;
}
return 0;
}
device_initcall(cpuhp_sysfs_init);
#endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */
/*
* cpu_bit_bitmap[] is a special, "compressed" data structure that
* represents all NR_CPUS bits binary values of 1<<nr.
*
* It is used by cpumask_of() to get a constant address to a CPU
* mask value that has a single bit set only.
*/
/* cpu_bit_bitmap[0] is empty - so we can back into it */
#define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
#define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
#define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
#define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
MASK_DECLARE_8(0), MASK_DECLARE_8(8),
MASK_DECLARE_8(16), MASK_DECLARE_8(24),
#if BITS_PER_LONG > 32
MASK_DECLARE_8(32), MASK_DECLARE_8(40),
MASK_DECLARE_8(48), MASK_DECLARE_8(56),
#endif
};
EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
EXPORT_SYMBOL(cpu_all_bits);
#ifdef CONFIG_INIT_ALL_POSSIBLE
struct cpumask __cpu_possible_mask __read_mostly
= {CPU_BITS_ALL};
#else
struct cpumask __cpu_possible_mask __read_mostly;
#endif
EXPORT_SYMBOL(__cpu_possible_mask);
struct cpumask __cpu_online_mask __read_mostly;
EXPORT_SYMBOL(__cpu_online_mask);
struct cpumask __cpu_present_mask __read_mostly;
EXPORT_SYMBOL(__cpu_present_mask);
struct cpumask __cpu_active_mask __read_mostly;
EXPORT_SYMBOL(__cpu_active_mask);
struct cpumask __cpu_dying_mask __read_mostly;
EXPORT_SYMBOL(__cpu_dying_mask);
atomic_t __num_online_cpus __read_mostly;
EXPORT_SYMBOL(__num_online_cpus);
void init_cpu_present(const struct cpumask *src)
{
cpumask_copy(&__cpu_present_mask, src);
}
void init_cpu_possible(const struct cpumask *src)
{
cpumask_copy(&__cpu_possible_mask, src);
}
void init_cpu_online(const struct cpumask *src)
{
cpumask_copy(&__cpu_online_mask, src);
}
void set_cpu_online(unsigned int cpu, bool online)
{
/*
* atomic_inc/dec() is required to handle the horrid abuse of this
* function by the reboot and kexec code which invoke it from
* IPI/NMI broadcasts when shutting down CPUs. Invocation from
* regular CPU hotplug is properly serialized.
*
* Note, that the fact that __num_online_cpus is of type atomic_t
* does not protect readers which are not serialized against
* concurrent hotplug operations.
*/
if (online) {
if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask))
atomic_inc(&__num_online_cpus);
} else {
if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask))
atomic_dec(&__num_online_cpus);
}
}
/*
* Activate the first processor.
*/
void __init boot_cpu_init(void)
{
int cpu = smp_processor_id();
/* Mark the boot cpu "present", "online" etc for SMP and UP case */
set_cpu_online(cpu, true);
set_cpu_active(cpu, true);
set_cpu_present(cpu, true);
set_cpu_possible(cpu, true);
#ifdef CONFIG_SMP
__boot_cpu_id = cpu;
#endif
}
/*
* Must be called _AFTER_ setting up the per_cpu areas
*/
void __init boot_cpu_hotplug_init(void)
{
#ifdef CONFIG_SMP
cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask);
atomic_set(this_cpu_ptr(&cpuhp_state.ap_sync_state), SYNC_STATE_ONLINE);
#endif
this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
this_cpu_write(cpuhp_state.target, CPUHP_ONLINE);
}
/*
* These are used for a global "mitigations=" cmdline option for toggling
* optional CPU mitigations.
*/
enum cpu_mitigations {
CPU_MITIGATIONS_OFF,
CPU_MITIGATIONS_AUTO,
CPU_MITIGATIONS_AUTO_NOSMT,
};
static enum cpu_mitigations cpu_mitigations __ro_after_init =
CPU_MITIGATIONS_AUTO;
static int __init mitigations_parse_cmdline(char *arg)
{
if (!strcmp(arg, "off"))
cpu_mitigations = CPU_MITIGATIONS_OFF;
else if (!strcmp(arg, "auto"))
cpu_mitigations = CPU_MITIGATIONS_AUTO;
else if (!strcmp(arg, "auto,nosmt"))
cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
else
pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
arg);
return 0;
}
early_param("mitigations", mitigations_parse_cmdline);
/* mitigations=off */
bool cpu_mitigations_off(void)
{
return cpu_mitigations == CPU_MITIGATIONS_OFF;
}
EXPORT_SYMBOL_GPL(cpu_mitigations_off);
/* mitigations=auto,nosmt */
bool cpu_mitigations_auto_nosmt(void)
{
return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
}
EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt);
| linux-master | kernel/cpu.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* delayacct.c - per-task delay accounting
*
* Copyright (C) Shailabh Nagar, IBM Corp. 2006
*/
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/sched/cputime.h>
#include <linux/sched/clock.h>
#include <linux/slab.h>
#include <linux/taskstats.h>
#include <linux/sysctl.h>
#include <linux/delayacct.h>
#include <linux/module.h>
DEFINE_STATIC_KEY_FALSE(delayacct_key);
int delayacct_on __read_mostly; /* Delay accounting turned on/off */
struct kmem_cache *delayacct_cache;
static void set_delayacct(bool enabled)
{
if (enabled) {
static_branch_enable(&delayacct_key);
delayacct_on = 1;
} else {
delayacct_on = 0;
static_branch_disable(&delayacct_key);
}
}
static int __init delayacct_setup_enable(char *str)
{
delayacct_on = 1;
return 1;
}
__setup("delayacct", delayacct_setup_enable);
void delayacct_init(void)
{
delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
delayacct_tsk_init(&init_task);
set_delayacct(delayacct_on);
}
#ifdef CONFIG_PROC_SYSCTL
static int sysctl_delayacct(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
int state = delayacct_on;
struct ctl_table t;
int err;
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
t = *table;
t.data = &state;
err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
if (err < 0)
return err;
if (write)
set_delayacct(state);
return err;
}
static struct ctl_table kern_delayacct_table[] = {
{
.procname = "task_delayacct",
.data = NULL,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = sysctl_delayacct,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{ }
};
static __init int kernel_delayacct_sysctls_init(void)
{
register_sysctl_init("kernel", kern_delayacct_table);
return 0;
}
late_initcall(kernel_delayacct_sysctls_init);
#endif
void __delayacct_tsk_init(struct task_struct *tsk)
{
tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
if (tsk->delays)
raw_spin_lock_init(&tsk->delays->lock);
}
/*
* Finish delay accounting for a statistic using its timestamps (@start),
* accumalator (@total) and @count
*/
static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count)
{
s64 ns = local_clock() - *start;
unsigned long flags;
if (ns > 0) {
raw_spin_lock_irqsave(lock, flags);
*total += ns;
(*count)++;
raw_spin_unlock_irqrestore(lock, flags);
}
}
void __delayacct_blkio_start(void)
{
current->delays->blkio_start = local_clock();
}
/*
* We cannot rely on the `current` macro, as we haven't yet switched back to
* the process being woken.
*/
void __delayacct_blkio_end(struct task_struct *p)
{
delayacct_end(&p->delays->lock,
&p->delays->blkio_start,
&p->delays->blkio_delay,
&p->delays->blkio_count);
}
int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
{
u64 utime, stime, stimescaled, utimescaled;
unsigned long long t2, t3;
unsigned long flags, t1;
s64 tmp;
task_cputime(tsk, &utime, &stime);
tmp = (s64)d->cpu_run_real_total;
tmp += utime + stime;
d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
task_cputime_scaled(tsk, &utimescaled, &stimescaled);
tmp = (s64)d->cpu_scaled_run_real_total;
tmp += utimescaled + stimescaled;
d->cpu_scaled_run_real_total =
(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
/*
* No locking available for sched_info (and too expensive to add one)
* Mitigate by taking snapshot of values
*/
t1 = tsk->sched_info.pcount;
t2 = tsk->sched_info.run_delay;
t3 = tsk->se.sum_exec_runtime;
d->cpu_count += t1;
tmp = (s64)d->cpu_delay_total + t2;
d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
tmp = (s64)d->cpu_run_virtual_total + t3;
d->cpu_run_virtual_total =
(tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
if (!tsk->delays)
return 0;
/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
raw_spin_lock_irqsave(&tsk->delays->lock, flags);
tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
tmp = d->compact_delay_total + tsk->delays->compact_delay;
d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;
tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay;
d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp;
tmp = d->irq_delay_total + tsk->delays->irq_delay;
d->irq_delay_total = (tmp < d->irq_delay_total) ? 0 : tmp;
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
d->freepages_count += tsk->delays->freepages_count;
d->thrashing_count += tsk->delays->thrashing_count;
d->compact_count += tsk->delays->compact_count;
d->wpcopy_count += tsk->delays->wpcopy_count;
d->irq_count += tsk->delays->irq_count;
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return 0;
}
__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
{
__u64 ret;
unsigned long flags;
raw_spin_lock_irqsave(&tsk->delays->lock, flags);
ret = nsec_to_clock_t(tsk->delays->blkio_delay);
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return ret;
}
void __delayacct_freepages_start(void)
{
current->delays->freepages_start = local_clock();
}
void __delayacct_freepages_end(void)
{
delayacct_end(¤t->delays->lock,
¤t->delays->freepages_start,
¤t->delays->freepages_delay,
¤t->delays->freepages_count);
}
void __delayacct_thrashing_start(bool *in_thrashing)
{
*in_thrashing = !!current->in_thrashing;
if (*in_thrashing)
return;
current->in_thrashing = 1;
current->delays->thrashing_start = local_clock();
}
void __delayacct_thrashing_end(bool *in_thrashing)
{
if (*in_thrashing)
return;
current->in_thrashing = 0;
delayacct_end(¤t->delays->lock,
¤t->delays->thrashing_start,
¤t->delays->thrashing_delay,
¤t->delays->thrashing_count);
}
void __delayacct_swapin_start(void)
{
current->delays->swapin_start = local_clock();
}
void __delayacct_swapin_end(void)
{
delayacct_end(¤t->delays->lock,
¤t->delays->swapin_start,
¤t->delays->swapin_delay,
¤t->delays->swapin_count);
}
void __delayacct_compact_start(void)
{
current->delays->compact_start = local_clock();
}
void __delayacct_compact_end(void)
{
delayacct_end(¤t->delays->lock,
¤t->delays->compact_start,
¤t->delays->compact_delay,
¤t->delays->compact_count);
}
void __delayacct_wpcopy_start(void)
{
current->delays->wpcopy_start = local_clock();
}
void __delayacct_wpcopy_end(void)
{
delayacct_end(¤t->delays->lock,
¤t->delays->wpcopy_start,
¤t->delays->wpcopy_delay,
¤t->delays->wpcopy_count);
}
void __delayacct_irq(struct task_struct *task, u32 delta)
{
unsigned long flags;
raw_spin_lock_irqsave(&task->delays->lock, flags);
task->delays->irq_delay += delta;
task->delays->irq_count++;
raw_spin_unlock_irqrestore(&task->delays->lock, flags);
}
| linux-master | kernel/delayacct.c |
// SPDX-License-Identifier: GPL-2.0
#define pr_fmt(fmt) "kcov: " fmt
#define DISABLE_BRANCH_PROFILING
#include <linux/atomic.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/hashtable.h>
#include <linux/init.h>
#include <linux/kmsan-checks.h>
#include <linux/mm.h>
#include <linux/preempt.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/kcov.h>
#include <linux/refcount.h>
#include <linux/log2.h>
#include <asm/setup.h>
#define kcov_debug(fmt, ...) pr_debug("%s: " fmt, __func__, ##__VA_ARGS__)
/* Number of 64-bit words written per one comparison: */
#define KCOV_WORDS_PER_CMP 4
/*
* kcov descriptor (one per opened debugfs file).
* State transitions of the descriptor:
* - initial state after open()
* - then there must be a single ioctl(KCOV_INIT_TRACE) call
* - then, mmap() call (several calls are allowed but not useful)
* - then, ioctl(KCOV_ENABLE, arg), where arg is
* KCOV_TRACE_PC - to trace only the PCs
* or
* KCOV_TRACE_CMP - to trace only the comparison operands
* - then, ioctl(KCOV_DISABLE) to disable the task.
* Enabling/disabling ioctls can be repeated (only one task a time allowed).
*/
struct kcov {
/*
* Reference counter. We keep one for:
* - opened file descriptor
* - task with enabled coverage (we can't unwire it from another task)
* - each code section for remote coverage collection
*/
refcount_t refcount;
/* The lock protects mode, size, area and t. */
spinlock_t lock;
enum kcov_mode mode;
/* Size of arena (in long's). */
unsigned int size;
/* Coverage buffer shared with user space. */
void *area;
/* Task for which we collect coverage, or NULL. */
struct task_struct *t;
/* Collecting coverage from remote (background) threads. */
bool remote;
/* Size of remote area (in long's). */
unsigned int remote_size;
/*
* Sequence is incremented each time kcov is reenabled, used by
* kcov_remote_stop(), see the comment there.
*/
int sequence;
};
struct kcov_remote_area {
struct list_head list;
unsigned int size;
};
struct kcov_remote {
u64 handle;
struct kcov *kcov;
struct hlist_node hnode;
};
static DEFINE_SPINLOCK(kcov_remote_lock);
static DEFINE_HASHTABLE(kcov_remote_map, 4);
static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas);
struct kcov_percpu_data {
void *irq_area;
local_lock_t lock;
unsigned int saved_mode;
unsigned int saved_size;
void *saved_area;
struct kcov *saved_kcov;
int saved_sequence;
};
static DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data) = {
.lock = INIT_LOCAL_LOCK(lock),
};
/* Must be called with kcov_remote_lock locked. */
static struct kcov_remote *kcov_remote_find(u64 handle)
{
struct kcov_remote *remote;
hash_for_each_possible(kcov_remote_map, remote, hnode, handle) {
if (remote->handle == handle)
return remote;
}
return NULL;
}
/* Must be called with kcov_remote_lock locked. */
static struct kcov_remote *kcov_remote_add(struct kcov *kcov, u64 handle)
{
struct kcov_remote *remote;
if (kcov_remote_find(handle))
return ERR_PTR(-EEXIST);
remote = kmalloc(sizeof(*remote), GFP_ATOMIC);
if (!remote)
return ERR_PTR(-ENOMEM);
remote->handle = handle;
remote->kcov = kcov;
hash_add(kcov_remote_map, &remote->hnode, handle);
return remote;
}
/* Must be called with kcov_remote_lock locked. */
static struct kcov_remote_area *kcov_remote_area_get(unsigned int size)
{
struct kcov_remote_area *area;
struct list_head *pos;
list_for_each(pos, &kcov_remote_areas) {
area = list_entry(pos, struct kcov_remote_area, list);
if (area->size == size) {
list_del(&area->list);
return area;
}
}
return NULL;
}
/* Must be called with kcov_remote_lock locked. */
static void kcov_remote_area_put(struct kcov_remote_area *area,
unsigned int size)
{
INIT_LIST_HEAD(&area->list);
area->size = size;
list_add(&area->list, &kcov_remote_areas);
/*
* KMSAN doesn't instrument this file, so it may not know area->list
* is initialized. Unpoison it explicitly to avoid reports in
* kcov_remote_area_get().
*/
kmsan_unpoison_memory(&area->list, sizeof(area->list));
}
static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
{
unsigned int mode;
/*
* We are interested in code coverage as a function of a syscall inputs,
* so we ignore code executed in interrupts, unless we are in a remote
* coverage collection section in a softirq.
*/
if (!in_task() && !(in_serving_softirq() && t->kcov_softirq))
return false;
mode = READ_ONCE(t->kcov_mode);
/*
* There is some code that runs in interrupts but for which
* in_interrupt() returns false (e.g. preempt_schedule_irq()).
* READ_ONCE()/barrier() effectively provides load-acquire wrt
* interrupts, there are paired barrier()/WRITE_ONCE() in
* kcov_start().
*/
barrier();
return mode == needed_mode;
}
static notrace unsigned long canonicalize_ip(unsigned long ip)
{
#ifdef CONFIG_RANDOMIZE_BASE
ip -= kaslr_offset();
#endif
return ip;
}
/*
* Entry point from instrumented code.
* This is called once per basic-block/edge.
*/
void notrace __sanitizer_cov_trace_pc(void)
{
struct task_struct *t;
unsigned long *area;
unsigned long ip = canonicalize_ip(_RET_IP_);
unsigned long pos;
t = current;
if (!check_kcov_mode(KCOV_MODE_TRACE_PC, t))
return;
area = t->kcov_area;
/* The first 64-bit word is the number of subsequent PCs. */
pos = READ_ONCE(area[0]) + 1;
if (likely(pos < t->kcov_size)) {
/* Previously we write pc before updating pos. However, some
* early interrupt code could bypass check_kcov_mode() check
* and invoke __sanitizer_cov_trace_pc(). If such interrupt is
* raised between writing pc and updating pos, the pc could be
* overitten by the recursive __sanitizer_cov_trace_pc().
* Update pos before writing pc to avoid such interleaving.
*/
WRITE_ONCE(area[0], pos);
barrier();
area[pos] = ip;
}
}
EXPORT_SYMBOL(__sanitizer_cov_trace_pc);
#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
static void notrace write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip)
{
struct task_struct *t;
u64 *area;
u64 count, start_index, end_pos, max_pos;
t = current;
if (!check_kcov_mode(KCOV_MODE_TRACE_CMP, t))
return;
ip = canonicalize_ip(ip);
/*
* We write all comparison arguments and types as u64.
* The buffer was allocated for t->kcov_size unsigned longs.
*/
area = (u64 *)t->kcov_area;
max_pos = t->kcov_size * sizeof(unsigned long);
count = READ_ONCE(area[0]);
/* Every record is KCOV_WORDS_PER_CMP 64-bit words. */
start_index = 1 + count * KCOV_WORDS_PER_CMP;
end_pos = (start_index + KCOV_WORDS_PER_CMP) * sizeof(u64);
if (likely(end_pos <= max_pos)) {
/* See comment in __sanitizer_cov_trace_pc(). */
WRITE_ONCE(area[0], count + 1);
barrier();
area[start_index] = type;
area[start_index + 1] = arg1;
area[start_index + 2] = arg2;
area[start_index + 3] = ip;
}
}
void notrace __sanitizer_cov_trace_cmp1(u8 arg1, u8 arg2)
{
write_comp_data(KCOV_CMP_SIZE(0), arg1, arg2, _RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_cmp1);
void notrace __sanitizer_cov_trace_cmp2(u16 arg1, u16 arg2)
{
write_comp_data(KCOV_CMP_SIZE(1), arg1, arg2, _RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_cmp2);
void notrace __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2)
{
write_comp_data(KCOV_CMP_SIZE(2), arg1, arg2, _RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_cmp4);
void notrace __sanitizer_cov_trace_cmp8(kcov_u64 arg1, kcov_u64 arg2)
{
write_comp_data(KCOV_CMP_SIZE(3), arg1, arg2, _RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_cmp8);
void notrace __sanitizer_cov_trace_const_cmp1(u8 arg1, u8 arg2)
{
write_comp_data(KCOV_CMP_SIZE(0) | KCOV_CMP_CONST, arg1, arg2,
_RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp1);
void notrace __sanitizer_cov_trace_const_cmp2(u16 arg1, u16 arg2)
{
write_comp_data(KCOV_CMP_SIZE(1) | KCOV_CMP_CONST, arg1, arg2,
_RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp2);
void notrace __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2)
{
write_comp_data(KCOV_CMP_SIZE(2) | KCOV_CMP_CONST, arg1, arg2,
_RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp4);
void notrace __sanitizer_cov_trace_const_cmp8(kcov_u64 arg1, kcov_u64 arg2)
{
write_comp_data(KCOV_CMP_SIZE(3) | KCOV_CMP_CONST, arg1, arg2,
_RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp8);
void notrace __sanitizer_cov_trace_switch(kcov_u64 val, void *arg)
{
u64 i;
u64 *cases = arg;
u64 count = cases[0];
u64 size = cases[1];
u64 type = KCOV_CMP_CONST;
switch (size) {
case 8:
type |= KCOV_CMP_SIZE(0);
break;
case 16:
type |= KCOV_CMP_SIZE(1);
break;
case 32:
type |= KCOV_CMP_SIZE(2);
break;
case 64:
type |= KCOV_CMP_SIZE(3);
break;
default:
return;
}
for (i = 0; i < count; i++)
write_comp_data(type, cases[i + 2], val, _RET_IP_);
}
EXPORT_SYMBOL(__sanitizer_cov_trace_switch);
#endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */
static void kcov_start(struct task_struct *t, struct kcov *kcov,
unsigned int size, void *area, enum kcov_mode mode,
int sequence)
{
kcov_debug("t = %px, size = %u, area = %px\n", t, size, area);
t->kcov = kcov;
/* Cache in task struct for performance. */
t->kcov_size = size;
t->kcov_area = area;
t->kcov_sequence = sequence;
/* See comment in check_kcov_mode(). */
barrier();
WRITE_ONCE(t->kcov_mode, mode);
}
static void kcov_stop(struct task_struct *t)
{
WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
barrier();
t->kcov = NULL;
t->kcov_size = 0;
t->kcov_area = NULL;
}
static void kcov_task_reset(struct task_struct *t)
{
kcov_stop(t);
t->kcov_sequence = 0;
t->kcov_handle = 0;
}
void kcov_task_init(struct task_struct *t)
{
kcov_task_reset(t);
t->kcov_handle = current->kcov_handle;
}
static void kcov_reset(struct kcov *kcov)
{
kcov->t = NULL;
kcov->mode = KCOV_MODE_INIT;
kcov->remote = false;
kcov->remote_size = 0;
kcov->sequence++;
}
static void kcov_remote_reset(struct kcov *kcov)
{
int bkt;
struct kcov_remote *remote;
struct hlist_node *tmp;
unsigned long flags;
spin_lock_irqsave(&kcov_remote_lock, flags);
hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) {
if (remote->kcov != kcov)
continue;
hash_del(&remote->hnode);
kfree(remote);
}
/* Do reset before unlock to prevent races with kcov_remote_start(). */
kcov_reset(kcov);
spin_unlock_irqrestore(&kcov_remote_lock, flags);
}
static void kcov_disable(struct task_struct *t, struct kcov *kcov)
{
kcov_task_reset(t);
if (kcov->remote)
kcov_remote_reset(kcov);
else
kcov_reset(kcov);
}
static void kcov_get(struct kcov *kcov)
{
refcount_inc(&kcov->refcount);
}
static void kcov_put(struct kcov *kcov)
{
if (refcount_dec_and_test(&kcov->refcount)) {
kcov_remote_reset(kcov);
vfree(kcov->area);
kfree(kcov);
}
}
void kcov_task_exit(struct task_struct *t)
{
struct kcov *kcov;
unsigned long flags;
kcov = t->kcov;
if (kcov == NULL)
return;
spin_lock_irqsave(&kcov->lock, flags);
kcov_debug("t = %px, kcov->t = %px\n", t, kcov->t);
/*
* For KCOV_ENABLE devices we want to make sure that t->kcov->t == t,
* which comes down to:
* WARN_ON(!kcov->remote && kcov->t != t);
*
* For KCOV_REMOTE_ENABLE devices, the exiting task is either:
*
* 1. A remote task between kcov_remote_start() and kcov_remote_stop().
* In this case we should print a warning right away, since a task
* shouldn't be exiting when it's in a kcov coverage collection
* section. Here t points to the task that is collecting remote
* coverage, and t->kcov->t points to the thread that created the
* kcov device. Which means that to detect this case we need to
* check that t != t->kcov->t, and this gives us the following:
* WARN_ON(kcov->remote && kcov->t != t);
*
* 2. The task that created kcov exiting without calling KCOV_DISABLE,
* and then again we make sure that t->kcov->t == t:
* WARN_ON(kcov->remote && kcov->t != t);
*
* By combining all three checks into one we get:
*/
if (WARN_ON(kcov->t != t)) {
spin_unlock_irqrestore(&kcov->lock, flags);
return;
}
/* Just to not leave dangling references behind. */
kcov_disable(t, kcov);
spin_unlock_irqrestore(&kcov->lock, flags);
kcov_put(kcov);
}
static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
{
int res = 0;
struct kcov *kcov = vma->vm_file->private_data;
unsigned long size, off;
struct page *page;
unsigned long flags;
spin_lock_irqsave(&kcov->lock, flags);
size = kcov->size * sizeof(unsigned long);
if (kcov->area == NULL || vma->vm_pgoff != 0 ||
vma->vm_end - vma->vm_start != size) {
res = -EINVAL;
goto exit;
}
spin_unlock_irqrestore(&kcov->lock, flags);
vm_flags_set(vma, VM_DONTEXPAND);
for (off = 0; off < size; off += PAGE_SIZE) {
page = vmalloc_to_page(kcov->area + off);
res = vm_insert_page(vma, vma->vm_start + off, page);
if (res) {
pr_warn_once("kcov: vm_insert_page() failed\n");
return res;
}
}
return 0;
exit:
spin_unlock_irqrestore(&kcov->lock, flags);
return res;
}
static int kcov_open(struct inode *inode, struct file *filep)
{
struct kcov *kcov;
kcov = kzalloc(sizeof(*kcov), GFP_KERNEL);
if (!kcov)
return -ENOMEM;
kcov->mode = KCOV_MODE_DISABLED;
kcov->sequence = 1;
refcount_set(&kcov->refcount, 1);
spin_lock_init(&kcov->lock);
filep->private_data = kcov;
return nonseekable_open(inode, filep);
}
static int kcov_close(struct inode *inode, struct file *filep)
{
kcov_put(filep->private_data);
return 0;
}
static int kcov_get_mode(unsigned long arg)
{
if (arg == KCOV_TRACE_PC)
return KCOV_MODE_TRACE_PC;
else if (arg == KCOV_TRACE_CMP)
#ifdef CONFIG_KCOV_ENABLE_COMPARISONS
return KCOV_MODE_TRACE_CMP;
#else
return -ENOTSUPP;
#endif
else
return -EINVAL;
}
/*
* Fault in a lazily-faulted vmalloc area before it can be used by
* __santizer_cov_trace_pc(), to avoid recursion issues if any code on the
* vmalloc fault handling path is instrumented.
*/
static void kcov_fault_in_area(struct kcov *kcov)
{
unsigned long stride = PAGE_SIZE / sizeof(unsigned long);
unsigned long *area = kcov->area;
unsigned long offset;
for (offset = 0; offset < kcov->size; offset += stride)
READ_ONCE(area[offset]);
}
static inline bool kcov_check_handle(u64 handle, bool common_valid,
bool uncommon_valid, bool zero_valid)
{
if (handle & ~(KCOV_SUBSYSTEM_MASK | KCOV_INSTANCE_MASK))
return false;
switch (handle & KCOV_SUBSYSTEM_MASK) {
case KCOV_SUBSYSTEM_COMMON:
return (handle & KCOV_INSTANCE_MASK) ?
common_valid : zero_valid;
case KCOV_SUBSYSTEM_USB:
return uncommon_valid;
default:
return false;
}
return false;
}
static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
unsigned long arg)
{
struct task_struct *t;
unsigned long flags, unused;
int mode, i;
struct kcov_remote_arg *remote_arg;
struct kcov_remote *remote;
switch (cmd) {
case KCOV_ENABLE:
/*
* Enable coverage for the current task.
* At this point user must have been enabled trace mode,
* and mmapped the file. Coverage collection is disabled only
* at task exit or voluntary by KCOV_DISABLE. After that it can
* be enabled for another task.
*/
if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
return -EINVAL;
t = current;
if (kcov->t != NULL || t->kcov != NULL)
return -EBUSY;
mode = kcov_get_mode(arg);
if (mode < 0)
return mode;
kcov_fault_in_area(kcov);
kcov->mode = mode;
kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode,
kcov->sequence);
kcov->t = t;
/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
kcov_get(kcov);
return 0;
case KCOV_DISABLE:
/* Disable coverage for the current task. */
unused = arg;
if (unused != 0 || current->kcov != kcov)
return -EINVAL;
t = current;
if (WARN_ON(kcov->t != t))
return -EINVAL;
kcov_disable(t, kcov);
kcov_put(kcov);
return 0;
case KCOV_REMOTE_ENABLE:
if (kcov->mode != KCOV_MODE_INIT || !kcov->area)
return -EINVAL;
t = current;
if (kcov->t != NULL || t->kcov != NULL)
return -EBUSY;
remote_arg = (struct kcov_remote_arg *)arg;
mode = kcov_get_mode(remote_arg->trace_mode);
if (mode < 0)
return mode;
if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long))
return -EINVAL;
kcov->mode = mode;
t->kcov = kcov;
kcov->t = t;
kcov->remote = true;
kcov->remote_size = remote_arg->area_size;
spin_lock_irqsave(&kcov_remote_lock, flags);
for (i = 0; i < remote_arg->num_handles; i++) {
if (!kcov_check_handle(remote_arg->handles[i],
false, true, false)) {
spin_unlock_irqrestore(&kcov_remote_lock,
flags);
kcov_disable(t, kcov);
return -EINVAL;
}
remote = kcov_remote_add(kcov, remote_arg->handles[i]);
if (IS_ERR(remote)) {
spin_unlock_irqrestore(&kcov_remote_lock,
flags);
kcov_disable(t, kcov);
return PTR_ERR(remote);
}
}
if (remote_arg->common_handle) {
if (!kcov_check_handle(remote_arg->common_handle,
true, false, false)) {
spin_unlock_irqrestore(&kcov_remote_lock,
flags);
kcov_disable(t, kcov);
return -EINVAL;
}
remote = kcov_remote_add(kcov,
remote_arg->common_handle);
if (IS_ERR(remote)) {
spin_unlock_irqrestore(&kcov_remote_lock,
flags);
kcov_disable(t, kcov);
return PTR_ERR(remote);
}
t->kcov_handle = remote_arg->common_handle;
}
spin_unlock_irqrestore(&kcov_remote_lock, flags);
/* Put either in kcov_task_exit() or in KCOV_DISABLE. */
kcov_get(kcov);
return 0;
default:
return -ENOTTY;
}
}
static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
{
struct kcov *kcov;
int res;
struct kcov_remote_arg *remote_arg = NULL;
unsigned int remote_num_handles;
unsigned long remote_arg_size;
unsigned long size, flags;
void *area;
kcov = filep->private_data;
switch (cmd) {
case KCOV_INIT_TRACE:
/*
* Enable kcov in trace mode and setup buffer size.
* Must happen before anything else.
*
* First check the size argument - it must be at least 2
* to hold the current position and one PC.
*/
size = arg;
if (size < 2 || size > INT_MAX / sizeof(unsigned long))
return -EINVAL;
area = vmalloc_user(size * sizeof(unsigned long));
if (area == NULL)
return -ENOMEM;
spin_lock_irqsave(&kcov->lock, flags);
if (kcov->mode != KCOV_MODE_DISABLED) {
spin_unlock_irqrestore(&kcov->lock, flags);
vfree(area);
return -EBUSY;
}
kcov->area = area;
kcov->size = size;
kcov->mode = KCOV_MODE_INIT;
spin_unlock_irqrestore(&kcov->lock, flags);
return 0;
case KCOV_REMOTE_ENABLE:
if (get_user(remote_num_handles, (unsigned __user *)(arg +
offsetof(struct kcov_remote_arg, num_handles))))
return -EFAULT;
if (remote_num_handles > KCOV_REMOTE_MAX_HANDLES)
return -EINVAL;
remote_arg_size = struct_size(remote_arg, handles,
remote_num_handles);
remote_arg = memdup_user((void __user *)arg, remote_arg_size);
if (IS_ERR(remote_arg))
return PTR_ERR(remote_arg);
if (remote_arg->num_handles != remote_num_handles) {
kfree(remote_arg);
return -EINVAL;
}
arg = (unsigned long)remote_arg;
fallthrough;
default:
/*
* All other commands can be normally executed under a spin lock, so we
* obtain and release it here in order to simplify kcov_ioctl_locked().
*/
spin_lock_irqsave(&kcov->lock, flags);
res = kcov_ioctl_locked(kcov, cmd, arg);
spin_unlock_irqrestore(&kcov->lock, flags);
kfree(remote_arg);
return res;
}
}
static const struct file_operations kcov_fops = {
.open = kcov_open,
.unlocked_ioctl = kcov_ioctl,
.compat_ioctl = kcov_ioctl,
.mmap = kcov_mmap,
.release = kcov_close,
};
/*
* kcov_remote_start() and kcov_remote_stop() can be used to annotate a section
* of code in a kernel background thread or in a softirq to allow kcov to be
* used to collect coverage from that part of code.
*
* The handle argument of kcov_remote_start() identifies a code section that is
* used for coverage collection. A userspace process passes this handle to
* KCOV_REMOTE_ENABLE ioctl to make the used kcov device start collecting
* coverage for the code section identified by this handle.
*
* The usage of these annotations in the kernel code is different depending on
* the type of the kernel thread whose code is being annotated.
*
* For global kernel threads that are spawned in a limited number of instances
* (e.g. one USB hub_event() worker thread is spawned per USB HCD) and for
* softirqs, each instance must be assigned a unique 4-byte instance id. The
* instance id is then combined with a 1-byte subsystem id to get a handle via
* kcov_remote_handle(subsystem_id, instance_id).
*
* For local kernel threads that are spawned from system calls handler when a
* user interacts with some kernel interface (e.g. vhost workers), a handle is
* passed from a userspace process as the common_handle field of the
* kcov_remote_arg struct (note, that the user must generate a handle by using
* kcov_remote_handle() with KCOV_SUBSYSTEM_COMMON as the subsystem id and an
* arbitrary 4-byte non-zero number as the instance id). This common handle
* then gets saved into the task_struct of the process that issued the
* KCOV_REMOTE_ENABLE ioctl. When this process issues system calls that spawn
* kernel threads, the common handle must be retrieved via kcov_common_handle()
* and passed to the spawned threads via custom annotations. Those kernel
* threads must in turn be annotated with kcov_remote_start(common_handle) and
* kcov_remote_stop(). All of the threads that are spawned by the same process
* obtain the same handle, hence the name "common".
*
* See Documentation/dev-tools/kcov.rst for more details.
*
* Internally, kcov_remote_start() looks up the kcov device associated with the
* provided handle, allocates an area for coverage collection, and saves the
* pointers to kcov and area into the current task_struct to allow coverage to
* be collected via __sanitizer_cov_trace_pc().
* In turns kcov_remote_stop() clears those pointers from task_struct to stop
* collecting coverage and copies all collected coverage into the kcov area.
*/
static inline bool kcov_mode_enabled(unsigned int mode)
{
return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED;
}
static void kcov_remote_softirq_start(struct task_struct *t)
{
struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data);
unsigned int mode;
mode = READ_ONCE(t->kcov_mode);
barrier();
if (kcov_mode_enabled(mode)) {
data->saved_mode = mode;
data->saved_size = t->kcov_size;
data->saved_area = t->kcov_area;
data->saved_sequence = t->kcov_sequence;
data->saved_kcov = t->kcov;
kcov_stop(t);
}
}
static void kcov_remote_softirq_stop(struct task_struct *t)
{
struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data);
if (data->saved_kcov) {
kcov_start(t, data->saved_kcov, data->saved_size,
data->saved_area, data->saved_mode,
data->saved_sequence);
data->saved_mode = 0;
data->saved_size = 0;
data->saved_area = NULL;
data->saved_sequence = 0;
data->saved_kcov = NULL;
}
}
void kcov_remote_start(u64 handle)
{
struct task_struct *t = current;
struct kcov_remote *remote;
struct kcov *kcov;
unsigned int mode;
void *area;
unsigned int size;
int sequence;
unsigned long flags;
if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
return;
if (!in_task() && !in_serving_softirq())
return;
local_lock_irqsave(&kcov_percpu_data.lock, flags);
/*
* Check that kcov_remote_start() is not called twice in background
* threads nor called by user tasks (with enabled kcov).
*/
mode = READ_ONCE(t->kcov_mode);
if (WARN_ON(in_task() && kcov_mode_enabled(mode))) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
/*
* Check that kcov_remote_start() is not called twice in softirqs.
* Note, that kcov_remote_start() can be called from a softirq that
* happened while collecting coverage from a background thread.
*/
if (WARN_ON(in_serving_softirq() && t->kcov_softirq)) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
spin_lock(&kcov_remote_lock);
remote = kcov_remote_find(handle);
if (!remote) {
spin_unlock(&kcov_remote_lock);
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
kcov_debug("handle = %llx, context: %s\n", handle,
in_task() ? "task" : "softirq");
kcov = remote->kcov;
/* Put in kcov_remote_stop(). */
kcov_get(kcov);
/*
* Read kcov fields before unlock to prevent races with
* KCOV_DISABLE / kcov_remote_reset().
*/
mode = kcov->mode;
sequence = kcov->sequence;
if (in_task()) {
size = kcov->remote_size;
area = kcov_remote_area_get(size);
} else {
size = CONFIG_KCOV_IRQ_AREA_SIZE;
area = this_cpu_ptr(&kcov_percpu_data)->irq_area;
}
spin_unlock(&kcov_remote_lock);
/* Can only happen when in_task(). */
if (!area) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
area = vmalloc(size * sizeof(unsigned long));
if (!area) {
kcov_put(kcov);
return;
}
local_lock_irqsave(&kcov_percpu_data.lock, flags);
}
/* Reset coverage size. */
*(u64 *)area = 0;
if (in_serving_softirq()) {
kcov_remote_softirq_start(t);
t->kcov_softirq = 1;
}
kcov_start(t, kcov, size, area, mode, sequence);
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
}
EXPORT_SYMBOL(kcov_remote_start);
static void kcov_move_area(enum kcov_mode mode, void *dst_area,
unsigned int dst_area_size, void *src_area)
{
u64 word_size = sizeof(unsigned long);
u64 count_size, entry_size_log;
u64 dst_len, src_len;
void *dst_entries, *src_entries;
u64 dst_occupied, dst_free, bytes_to_move, entries_moved;
kcov_debug("%px %u <= %px %lu\n",
dst_area, dst_area_size, src_area, *(unsigned long *)src_area);
switch (mode) {
case KCOV_MODE_TRACE_PC:
dst_len = READ_ONCE(*(unsigned long *)dst_area);
src_len = *(unsigned long *)src_area;
count_size = sizeof(unsigned long);
entry_size_log = __ilog2_u64(sizeof(unsigned long));
break;
case KCOV_MODE_TRACE_CMP:
dst_len = READ_ONCE(*(u64 *)dst_area);
src_len = *(u64 *)src_area;
count_size = sizeof(u64);
BUILD_BUG_ON(!is_power_of_2(KCOV_WORDS_PER_CMP));
entry_size_log = __ilog2_u64(sizeof(u64) * KCOV_WORDS_PER_CMP);
break;
default:
WARN_ON(1);
return;
}
/* As arm can't divide u64 integers use log of entry size. */
if (dst_len > ((dst_area_size * word_size - count_size) >>
entry_size_log))
return;
dst_occupied = count_size + (dst_len << entry_size_log);
dst_free = dst_area_size * word_size - dst_occupied;
bytes_to_move = min(dst_free, src_len << entry_size_log);
dst_entries = dst_area + dst_occupied;
src_entries = src_area + count_size;
memcpy(dst_entries, src_entries, bytes_to_move);
entries_moved = bytes_to_move >> entry_size_log;
switch (mode) {
case KCOV_MODE_TRACE_PC:
WRITE_ONCE(*(unsigned long *)dst_area, dst_len + entries_moved);
break;
case KCOV_MODE_TRACE_CMP:
WRITE_ONCE(*(u64 *)dst_area, dst_len + entries_moved);
break;
default:
break;
}
}
/* See the comment before kcov_remote_start() for usage details. */
void kcov_remote_stop(void)
{
struct task_struct *t = current;
struct kcov *kcov;
unsigned int mode;
void *area;
unsigned int size;
int sequence;
unsigned long flags;
if (!in_task() && !in_serving_softirq())
return;
local_lock_irqsave(&kcov_percpu_data.lock, flags);
mode = READ_ONCE(t->kcov_mode);
barrier();
if (!kcov_mode_enabled(mode)) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
/*
* When in softirq, check if the corresponding kcov_remote_start()
* actually found the remote handle and started collecting coverage.
*/
if (in_serving_softirq() && !t->kcov_softirq) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
/* Make sure that kcov_softirq is only set when in softirq. */
if (WARN_ON(!in_serving_softirq() && t->kcov_softirq)) {
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
return;
}
kcov = t->kcov;
area = t->kcov_area;
size = t->kcov_size;
sequence = t->kcov_sequence;
kcov_stop(t);
if (in_serving_softirq()) {
t->kcov_softirq = 0;
kcov_remote_softirq_stop(t);
}
spin_lock(&kcov->lock);
/*
* KCOV_DISABLE could have been called between kcov_remote_start()
* and kcov_remote_stop(), hence the sequence check.
*/
if (sequence == kcov->sequence && kcov->remote)
kcov_move_area(kcov->mode, kcov->area, kcov->size, area);
spin_unlock(&kcov->lock);
if (in_task()) {
spin_lock(&kcov_remote_lock);
kcov_remote_area_put(area, size);
spin_unlock(&kcov_remote_lock);
}
local_unlock_irqrestore(&kcov_percpu_data.lock, flags);
/* Get in kcov_remote_start(). */
kcov_put(kcov);
}
EXPORT_SYMBOL(kcov_remote_stop);
/* See the comment before kcov_remote_start() for usage details. */
u64 kcov_common_handle(void)
{
if (!in_task())
return 0;
return current->kcov_handle;
}
EXPORT_SYMBOL(kcov_common_handle);
static int __init kcov_init(void)
{
int cpu;
for_each_possible_cpu(cpu) {
void *area = vmalloc_node(CONFIG_KCOV_IRQ_AREA_SIZE *
sizeof(unsigned long), cpu_to_node(cpu));
if (!area)
return -ENOMEM;
per_cpu_ptr(&kcov_percpu_data, cpu)->irq_area = area;
}
/*
* The kcov debugfs file won't ever get removed and thus,
* there is no need to protect it against removal races. The
* use of debugfs_create_file_unsafe() is actually safe here.
*/
debugfs_create_file_unsafe("kcov", 0600, NULL, NULL, &kcov_fops);
return 0;
}
device_initcall(kcov_init);
| linux-master | kernel/kcov.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/static_call.h>
long __static_call_return0(void)
{
return 0;
}
EXPORT_SYMBOL_GPL(__static_call_return0);
| linux-master | kernel/static_call.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* sysctl.c: General linux system control interface
*
* Begun 24 March 1995, Stephen Tweedie
* Added /proc support, Dec 1995
* Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
* Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
* Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
* Dynamic registration fixes, Stephen Tweedie.
* Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
* Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
* Horn.
* Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
* Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
* Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
* Wendling.
* The list_for_each() macro wasn't appropriate for the sysctl loop.
* Removed it and replaced it with older style, 03/23/00, Bill Wendling
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/bitmap.h>
#include <linux/signal.h>
#include <linux/panic.h>
#include <linux/printk.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/ctype.h>
#include <linux/kmemleak.h>
#include <linux/filter.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/net.h>
#include <linux/sysrq.h>
#include <linux/highuid.h>
#include <linux/writeback.h>
#include <linux/ratelimit.h>
#include <linux/hugetlb.h>
#include <linux/initrd.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/limits.h>
#include <linux/dcache.h>
#include <linux/syscalls.h>
#include <linux/vmstat.h>
#include <linux/nfs_fs.h>
#include <linux/acpi.h>
#include <linux/reboot.h>
#include <linux/ftrace.h>
#include <linux/perf_event.h>
#include <linux/oom.h>
#include <linux/kmod.h>
#include <linux/capability.h>
#include <linux/binfmts.h>
#include <linux/sched/sysctl.h>
#include <linux/mount.h>
#include <linux/userfaultfd_k.h>
#include <linux/pid.h>
#include "../lib/kstrtox.h"
#include <linux/uaccess.h>
#include <asm/processor.h>
#ifdef CONFIG_X86
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/io.h>
#endif
#ifdef CONFIG_SPARC
#include <asm/setup.h>
#endif
#ifdef CONFIG_RT_MUTEXES
#include <linux/rtmutex.h>
#endif
/* shared constants to be used in various sysctls */
const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
EXPORT_SYMBOL(sysctl_vals);
const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
EXPORT_SYMBOL_GPL(sysctl_long_vals);
#if defined(CONFIG_SYSCTL)
/* Constants used for minimum and maximum */
#ifdef CONFIG_PERF_EVENTS
static const int six_hundred_forty_kb = 640 * 1024;
#endif
static const int ngroups_max = NGROUPS_MAX;
static const int cap_last_cap = CAP_LAST_CAP;
#ifdef CONFIG_PROC_SYSCTL
/**
* enum sysctl_writes_mode - supported sysctl write modes
*
* @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
* to be written, and multiple writes on the same sysctl file descriptor
* will rewrite the sysctl value, regardless of file position. No warning
* is issued when the initial position is not 0.
* @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
* not 0.
* @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
* file position 0 and the value must be fully contained in the buffer
* sent to the write syscall. If dealing with strings respect the file
* position, but restrict this to the max length of the buffer, anything
* passed the max length will be ignored. Multiple writes will append
* to the buffer.
*
* These write modes control how current file position affects the behavior of
* updating sysctl values through the proc interface on each write.
*/
enum sysctl_writes_mode {
SYSCTL_WRITES_LEGACY = -1,
SYSCTL_WRITES_WARN = 0,
SYSCTL_WRITES_STRICT = 1,
};
static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
#endif /* CONFIG_PROC_SYSCTL */
#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
int sysctl_legacy_va_layout;
#endif
#endif /* CONFIG_SYSCTL */
/*
* /proc/sys support
*/
#ifdef CONFIG_PROC_SYSCTL
static int _proc_do_string(char *data, int maxlen, int write,
char *buffer, size_t *lenp, loff_t *ppos)
{
size_t len;
char c, *p;
if (!data || !maxlen || !*lenp) {
*lenp = 0;
return 0;
}
if (write) {
if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
/* Only continue writes not past the end of buffer. */
len = strlen(data);
if (len > maxlen - 1)
len = maxlen - 1;
if (*ppos > len)
return 0;
len = *ppos;
} else {
/* Start writing from beginning of buffer. */
len = 0;
}
*ppos += *lenp;
p = buffer;
while ((p - buffer) < *lenp && len < maxlen - 1) {
c = *(p++);
if (c == 0 || c == '\n')
break;
data[len++] = c;
}
data[len] = 0;
} else {
len = strlen(data);
if (len > maxlen)
len = maxlen;
if (*ppos > len) {
*lenp = 0;
return 0;
}
data += *ppos;
len -= *ppos;
if (len > *lenp)
len = *lenp;
if (len)
memcpy(buffer, data, len);
if (len < *lenp) {
buffer[len] = '\n';
len++;
}
*lenp = len;
*ppos += len;
}
return 0;
}
static void warn_sysctl_write(struct ctl_table *table)
{
pr_warn_once("%s wrote to %s when file position was not 0!\n"
"This will not be supported in the future. To silence this\n"
"warning, set kernel.sysctl_writes_strict = -1\n",
current->comm, table->procname);
}
/**
* proc_first_pos_non_zero_ignore - check if first position is allowed
* @ppos: file position
* @table: the sysctl table
*
* Returns true if the first position is non-zero and the sysctl_writes_strict
* mode indicates this is not allowed for numeric input types. String proc
* handlers can ignore the return value.
*/
static bool proc_first_pos_non_zero_ignore(loff_t *ppos,
struct ctl_table *table)
{
if (!*ppos)
return false;
switch (sysctl_writes_strict) {
case SYSCTL_WRITES_STRICT:
return true;
case SYSCTL_WRITES_WARN:
warn_sysctl_write(table);
return false;
default:
return false;
}
}
/**
* proc_dostring - read a string sysctl
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes a string from/to the user buffer. If the kernel
* buffer provided is not large enough to hold the string, the
* string is truncated. The copied string is %NULL-terminated.
* If the string is being read by the user process, it is copied
* and a newline '\n' is added. It is truncated if the buffer is
* not large enough.
*
* Returns 0 on success.
*/
int proc_dostring(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
if (write)
proc_first_pos_non_zero_ignore(ppos, table);
return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
ppos);
}
static void proc_skip_spaces(char **buf, size_t *size)
{
while (*size) {
if (!isspace(**buf))
break;
(*size)--;
(*buf)++;
}
}
static void proc_skip_char(char **buf, size_t *size, const char v)
{
while (*size) {
if (**buf != v)
break;
(*size)--;
(*buf)++;
}
}
/**
* strtoul_lenient - parse an ASCII formatted integer from a buffer and only
* fail on overflow
*
* @cp: kernel buffer containing the string to parse
* @endp: pointer to store the trailing characters
* @base: the base to use
* @res: where the parsed integer will be stored
*
* In case of success 0 is returned and @res will contain the parsed integer,
* @endp will hold any trailing characters.
* This function will fail the parse on overflow. If there wasn't an overflow
* the function will defer the decision what characters count as invalid to the
* caller.
*/
static int strtoul_lenient(const char *cp, char **endp, unsigned int base,
unsigned long *res)
{
unsigned long long result;
unsigned int rv;
cp = _parse_integer_fixup_radix(cp, &base);
rv = _parse_integer(cp, base, &result);
if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result))
return -ERANGE;
cp += rv;
if (endp)
*endp = (char *)cp;
*res = (unsigned long)result;
return 0;
}
#define TMPBUFLEN 22
/**
* proc_get_long - reads an ASCII formatted integer from a user buffer
*
* @buf: a kernel buffer
* @size: size of the kernel buffer
* @val: this is where the number will be stored
* @neg: set to %TRUE if number is negative
* @perm_tr: a vector which contains the allowed trailers
* @perm_tr_len: size of the perm_tr vector
* @tr: pointer to store the trailer character
*
* In case of success %0 is returned and @buf and @size are updated with
* the amount of bytes read. If @tr is non-NULL and a trailing
* character exists (size is non-zero after returning from this
* function), @tr is updated with the trailing character.
*/
static int proc_get_long(char **buf, size_t *size,
unsigned long *val, bool *neg,
const char *perm_tr, unsigned perm_tr_len, char *tr)
{
char *p, tmp[TMPBUFLEN];
ssize_t len = *size;
if (len <= 0)
return -EINVAL;
if (len > TMPBUFLEN - 1)
len = TMPBUFLEN - 1;
memcpy(tmp, *buf, len);
tmp[len] = 0;
p = tmp;
if (*p == '-' && *size > 1) {
*neg = true;
p++;
} else
*neg = false;
if (!isdigit(*p))
return -EINVAL;
if (strtoul_lenient(p, &p, 0, val))
return -EINVAL;
len = p - tmp;
/* We don't know if the next char is whitespace thus we may accept
* invalid integers (e.g. 1234...a) or two integers instead of one
* (e.g. 123...1). So lets not allow such large numbers. */
if (len == TMPBUFLEN - 1)
return -EINVAL;
if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
return -EINVAL;
if (tr && (len < *size))
*tr = *p;
*buf += len;
*size -= len;
return 0;
}
/**
* proc_put_long - converts an integer to a decimal ASCII formatted string
*
* @buf: the user buffer
* @size: the size of the user buffer
* @val: the integer to be converted
* @neg: sign of the number, %TRUE for negative
*
* In case of success @buf and @size are updated with the amount of bytes
* written.
*/
static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
{
int len;
char tmp[TMPBUFLEN], *p = tmp;
sprintf(p, "%s%lu", neg ? "-" : "", val);
len = strlen(tmp);
if (len > *size)
len = *size;
memcpy(*buf, tmp, len);
*size -= len;
*buf += len;
}
#undef TMPBUFLEN
static void proc_put_char(void **buf, size_t *size, char c)
{
if (*size) {
char **buffer = (char **)buf;
**buffer = c;
(*size)--;
(*buffer)++;
*buf = *buffer;
}
}
static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
if (write) {
if (*negp) {
if (*lvalp > (unsigned long) INT_MAX + 1)
return -EINVAL;
WRITE_ONCE(*valp, -*lvalp);
} else {
if (*lvalp > (unsigned long) INT_MAX)
return -EINVAL;
WRITE_ONCE(*valp, *lvalp);
}
} else {
int val = READ_ONCE(*valp);
if (val < 0) {
*negp = true;
*lvalp = -(unsigned long)val;
} else {
*negp = false;
*lvalp = (unsigned long)val;
}
}
return 0;
}
static int do_proc_douintvec_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
if (write) {
if (*lvalp > UINT_MAX)
return -EINVAL;
WRITE_ONCE(*valp, *lvalp);
} else {
unsigned int val = READ_ONCE(*valp);
*lvalp = (unsigned long)val;
}
return 0;
}
static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
int write, void *buffer,
size_t *lenp, loff_t *ppos,
int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
int write, void *data),
void *data)
{
int *i, vleft, first = 1, err = 0;
size_t left;
char *p;
if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
i = (int *) tbl_data;
vleft = table->maxlen / sizeof(*i);
left = *lenp;
if (!conv)
conv = do_proc_dointvec_conv;
if (write) {
if (proc_first_pos_non_zero_ignore(ppos, table))
goto out;
if (left > PAGE_SIZE - 1)
left = PAGE_SIZE - 1;
p = buffer;
}
for (; left && vleft--; i++, first=0) {
unsigned long lval;
bool neg;
if (write) {
proc_skip_spaces(&p, &left);
if (!left)
break;
err = proc_get_long(&p, &left, &lval, &neg,
proc_wspace_sep,
sizeof(proc_wspace_sep), NULL);
if (err)
break;
if (conv(&neg, &lval, i, 1, data)) {
err = -EINVAL;
break;
}
} else {
if (conv(&neg, &lval, i, 0, data)) {
err = -EINVAL;
break;
}
if (!first)
proc_put_char(&buffer, &left, '\t');
proc_put_long(&buffer, &left, lval, neg);
}
}
if (!write && !first && left && !err)
proc_put_char(&buffer, &left, '\n');
if (write && !err && left)
proc_skip_spaces(&p, &left);
if (write && first)
return err ? : -EINVAL;
*lenp -= left;
out:
*ppos += *lenp;
return err;
}
static int do_proc_dointvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos,
int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
int write, void *data),
void *data)
{
return __do_proc_dointvec(table->data, table, write,
buffer, lenp, ppos, conv, data);
}
static int do_proc_douintvec_w(unsigned int *tbl_data,
struct ctl_table *table,
void *buffer,
size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp,
unsigned int *valp,
int write, void *data),
void *data)
{
unsigned long lval;
int err = 0;
size_t left;
bool neg;
char *p = buffer;
left = *lenp;
if (proc_first_pos_non_zero_ignore(ppos, table))
goto bail_early;
if (left > PAGE_SIZE - 1)
left = PAGE_SIZE - 1;
proc_skip_spaces(&p, &left);
if (!left) {
err = -EINVAL;
goto out_free;
}
err = proc_get_long(&p, &left, &lval, &neg,
proc_wspace_sep,
sizeof(proc_wspace_sep), NULL);
if (err || neg) {
err = -EINVAL;
goto out_free;
}
if (conv(&lval, tbl_data, 1, data)) {
err = -EINVAL;
goto out_free;
}
if (!err && left)
proc_skip_spaces(&p, &left);
out_free:
if (err)
return -EINVAL;
return 0;
/* This is in keeping with old __do_proc_dointvec() */
bail_early:
*ppos += *lenp;
return err;
}
static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp,
unsigned int *valp,
int write, void *data),
void *data)
{
unsigned long lval;
int err = 0;
size_t left;
left = *lenp;
if (conv(&lval, tbl_data, 0, data)) {
err = -EINVAL;
goto out;
}
proc_put_long(&buffer, &left, lval, false);
if (!left)
goto out;
proc_put_char(&buffer, &left, '\n');
out:
*lenp -= left;
*ppos += *lenp;
return err;
}
static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
int write, void *buffer,
size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp,
unsigned int *valp,
int write, void *data),
void *data)
{
unsigned int *i, vleft;
if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
i = (unsigned int *) tbl_data;
vleft = table->maxlen / sizeof(*i);
/*
* Arrays are not supported, keep this simple. *Do not* add
* support for them.
*/
if (vleft != 1) {
*lenp = 0;
return -EINVAL;
}
if (!conv)
conv = do_proc_douintvec_conv;
if (write)
return do_proc_douintvec_w(i, table, buffer, lenp, ppos,
conv, data);
return do_proc_douintvec_r(i, buffer, lenp, ppos, conv, data);
}
int do_proc_douintvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp,
unsigned int *valp,
int write, void *data),
void *data)
{
return __do_proc_douintvec(table->data, table, write,
buffer, lenp, ppos, conv, data);
}
/**
* proc_dobool - read/write a bool
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes one integer value from/to the user buffer,
* treated as an ASCII string.
*
* table->data must point to a bool variable and table->maxlen must
* be sizeof(bool).
*
* Returns 0 on success.
*/
int proc_dobool(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
struct ctl_table tmp;
bool *data = table->data;
int res, val;
/* Do not support arrays yet. */
if (table->maxlen != sizeof(bool))
return -EINVAL;
tmp = *table;
tmp.maxlen = sizeof(val);
tmp.data = &val;
val = READ_ONCE(*data);
res = proc_dointvec(&tmp, write, buffer, lenp, ppos);
if (res)
return res;
if (write)
WRITE_ONCE(*data, val);
return 0;
}
/**
* proc_dointvec - read a vector of integers
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
* values from/to the user buffer, treated as an ASCII string.
*
* Returns 0 on success.
*/
int proc_dointvec(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
}
/**
* proc_douintvec - read a vector of unsigned integers
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
* values from/to the user buffer, treated as an ASCII string.
*
* Returns 0 on success.
*/
int proc_douintvec(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
return do_proc_douintvec(table, write, buffer, lenp, ppos,
do_proc_douintvec_conv, NULL);
}
/*
* Taint values can only be increased
* This means we can safely use a temporary.
*/
static int proc_taint(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
unsigned long tmptaint = get_taint();
int err;
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
t = *table;
t.data = &tmptaint;
err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
if (err < 0)
return err;
if (write) {
int i;
/*
* If we are relying on panic_on_taint not producing
* false positives due to userspace input, bail out
* before setting the requested taint flags.
*/
if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
return -EINVAL;
/*
* Poor man's atomic or. Not worth adding a primitive
* to everyone's atomic.h for this
*/
for (i = 0; i < TAINT_FLAGS_COUNT; i++)
if ((1UL << i) & tmptaint)
add_taint(i, LOCKDEP_STILL_OK);
}
return err;
}
/**
* struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
* @min: pointer to minimum allowable value
* @max: pointer to maximum allowable value
*
* The do_proc_dointvec_minmax_conv_param structure provides the
* minimum and maximum values for doing range checking for those sysctl
* parameters that use the proc_dointvec_minmax() handler.
*/
struct do_proc_dointvec_minmax_conv_param {
int *min;
int *max;
};
static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
int tmp, ret;
struct do_proc_dointvec_minmax_conv_param *param = data;
/*
* If writing, first do so via a temporary local int so we can
* bounds-check it before touching *valp.
*/
int *ip = write ? &tmp : valp;
ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
if (ret)
return ret;
if (write) {
if ((param->min && *param->min > tmp) ||
(param->max && *param->max < tmp))
return -EINVAL;
WRITE_ONCE(*valp, tmp);
}
return 0;
}
/**
* proc_dointvec_minmax - read a vector of integers with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
* values from/to the user buffer, treated as an ASCII string.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max).
*
* Returns 0 on success or -EINVAL on write when the range check fails.
*/
int proc_dointvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct do_proc_dointvec_minmax_conv_param param = {
.min = (int *) table->extra1,
.max = (int *) table->extra2,
};
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_minmax_conv, ¶m);
}
/**
* struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
* @min: pointer to minimum allowable value
* @max: pointer to maximum allowable value
*
* The do_proc_douintvec_minmax_conv_param structure provides the
* minimum and maximum values for doing range checking for those sysctl
* parameters that use the proc_douintvec_minmax() handler.
*/
struct do_proc_douintvec_minmax_conv_param {
unsigned int *min;
unsigned int *max;
};
static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
int ret;
unsigned int tmp;
struct do_proc_douintvec_minmax_conv_param *param = data;
/* write via temporary local uint for bounds-checking */
unsigned int *up = write ? &tmp : valp;
ret = do_proc_douintvec_conv(lvalp, up, write, data);
if (ret)
return ret;
if (write) {
if ((param->min && *param->min > tmp) ||
(param->max && *param->max < tmp))
return -ERANGE;
WRITE_ONCE(*valp, tmp);
}
return 0;
}
/**
* proc_douintvec_minmax - read a vector of unsigned ints with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
* values from/to the user buffer, treated as an ASCII string. Negative
* strings are not allowed.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max). There is a final sanity
* check for UINT_MAX to avoid having to support wrap around uses from
* userspace.
*
* Returns 0 on success or -ERANGE on write when the range check fails.
*/
int proc_douintvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct do_proc_douintvec_minmax_conv_param param = {
.min = (unsigned int *) table->extra1,
.max = (unsigned int *) table->extra2,
};
return do_proc_douintvec(table, write, buffer, lenp, ppos,
do_proc_douintvec_minmax_conv, ¶m);
}
/**
* proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(u8) unsigned chars
* values from/to the user buffer, treated as an ASCII string. Negative
* strings are not allowed.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max).
*
* Returns 0 on success or an error on write when the range check fails.
*/
int proc_dou8vec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table tmp;
unsigned int min = 0, max = 255U, val;
u8 *data = table->data;
struct do_proc_douintvec_minmax_conv_param param = {
.min = &min,
.max = &max,
};
int res;
/* Do not support arrays yet. */
if (table->maxlen != sizeof(u8))
return -EINVAL;
if (table->extra1) {
min = *(unsigned int *) table->extra1;
if (min > 255U)
return -EINVAL;
}
if (table->extra2) {
max = *(unsigned int *) table->extra2;
if (max > 255U)
return -EINVAL;
}
tmp = *table;
tmp.maxlen = sizeof(val);
tmp.data = &val;
val = READ_ONCE(*data);
res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
do_proc_douintvec_minmax_conv, ¶m);
if (res)
return res;
if (write)
WRITE_ONCE(*data, val);
return 0;
}
EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
#ifdef CONFIG_MAGIC_SYSRQ
static int sysrq_sysctl_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int tmp, ret;
tmp = sysrq_mask();
ret = __do_proc_dointvec(&tmp, table, write, buffer,
lenp, ppos, NULL, NULL);
if (ret || !write)
return ret;
if (write)
sysrq_toggle_support(tmp);
return 0;
}
#endif
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
int write, void *buffer, size_t *lenp, loff_t *ppos,
unsigned long convmul, unsigned long convdiv)
{
unsigned long *i, *min, *max;
int vleft, first = 1, err = 0;
size_t left;
char *p;
if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
i = data;
min = table->extra1;
max = table->extra2;
vleft = table->maxlen / sizeof(unsigned long);
left = *lenp;
if (write) {
if (proc_first_pos_non_zero_ignore(ppos, table))
goto out;
if (left > PAGE_SIZE - 1)
left = PAGE_SIZE - 1;
p = buffer;
}
for (; left && vleft--; i++, first = 0) {
unsigned long val;
if (write) {
bool neg;
proc_skip_spaces(&p, &left);
if (!left)
break;
err = proc_get_long(&p, &left, &val, &neg,
proc_wspace_sep,
sizeof(proc_wspace_sep), NULL);
if (err || neg) {
err = -EINVAL;
break;
}
val = convmul * val / convdiv;
if ((min && val < *min) || (max && val > *max)) {
err = -EINVAL;
break;
}
WRITE_ONCE(*i, val);
} else {
val = convdiv * READ_ONCE(*i) / convmul;
if (!first)
proc_put_char(&buffer, &left, '\t');
proc_put_long(&buffer, &left, val, false);
}
}
if (!write && !first && left && !err)
proc_put_char(&buffer, &left, '\n');
if (write && !err)
proc_skip_spaces(&p, &left);
if (write && first)
return err ? : -EINVAL;
*lenp -= left;
out:
*ppos += *lenp;
return err;
}
static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
unsigned long convdiv)
{
return __do_proc_doulongvec_minmax(table->data, table, write,
buffer, lenp, ppos, convmul, convdiv);
}
/**
* proc_doulongvec_minmax - read a vector of long integers with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
* values from/to the user buffer, treated as an ASCII string.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max).
*
* Returns 0 on success.
*/
int proc_doulongvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
}
/**
* proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
* values from/to the user buffer, treated as an ASCII string. The values
* are treated as milliseconds, and converted to jiffies when they are stored.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max).
*
* Returns 0 on success.
*/
int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return do_proc_doulongvec_minmax(table, write, buffer,
lenp, ppos, HZ, 1000l);
}
static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
if (write) {
if (*lvalp > INT_MAX / HZ)
return 1;
if (*negp)
WRITE_ONCE(*valp, -*lvalp * HZ);
else
WRITE_ONCE(*valp, *lvalp * HZ);
} else {
int val = READ_ONCE(*valp);
unsigned long lval;
if (val < 0) {
*negp = true;
lval = -(unsigned long)val;
} else {
*negp = false;
lval = (unsigned long)val;
}
*lvalp = lval / HZ;
}
return 0;
}
static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
if (write) {
if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
return 1;
*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
} else {
int val = *valp;
unsigned long lval;
if (val < 0) {
*negp = true;
lval = -(unsigned long)val;
} else {
*negp = false;
lval = (unsigned long)val;
}
*lvalp = jiffies_to_clock_t(lval);
}
return 0;
}
static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
if (write) {
unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
if (jif > INT_MAX)
return 1;
WRITE_ONCE(*valp, (int)jif);
} else {
int val = READ_ONCE(*valp);
unsigned long lval;
if (val < 0) {
*negp = true;
lval = -(unsigned long)val;
} else {
*negp = false;
lval = (unsigned long)val;
}
*lvalp = jiffies_to_msecs(lval);
}
return 0;
}
static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
int *valp, int write, void *data)
{
int tmp, ret;
struct do_proc_dointvec_minmax_conv_param *param = data;
/*
* If writing, first do so via a temporary local int so we can
* bounds-check it before touching *valp.
*/
int *ip = write ? &tmp : valp;
ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, write, data);
if (ret)
return ret;
if (write) {
if ((param->min && *param->min > tmp) ||
(param->max && *param->max < tmp))
return -EINVAL;
*valp = tmp;
}
return 0;
}
/**
* proc_dointvec_jiffies - read a vector of integers as seconds
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
* values from/to the user buffer, treated as an ASCII string.
* The values read are assumed to be in seconds, and are converted into
* jiffies.
*
* Returns 0 on success.
*/
int proc_dointvec_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return do_proc_dointvec(table,write,buffer,lenp,ppos,
do_proc_dointvec_jiffies_conv,NULL);
}
int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct do_proc_dointvec_minmax_conv_param param = {
.min = (int *) table->extra1,
.max = (int *) table->extra2,
};
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_ms_jiffies_minmax_conv, ¶m);
}
/**
* proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: pointer to the file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
* values from/to the user buffer, treated as an ASCII string.
* The values read are assumed to be in 1/USER_HZ seconds, and
* are converted into jiffies.
*
* Returns 0 on success.
*/
int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_userhz_jiffies_conv, NULL);
}
/**
* proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
* @ppos: the current position in the file
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) integer
* values from/to the user buffer, treated as an ASCII string.
* The values read are assumed to be in 1/1000 seconds, and
* are converted into jiffies.
*
* Returns 0 on success.
*/
int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_ms_jiffies_conv, NULL);
}
static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
struct pid *new_pid;
pid_t tmp;
int r;
tmp = pid_vnr(cad_pid);
r = __do_proc_dointvec(&tmp, table, write, buffer,
lenp, ppos, NULL, NULL);
if (r || !write)
return r;
new_pid = find_get_pid(tmp);
if (!new_pid)
return -ESRCH;
put_pid(xchg(&cad_pid, new_pid));
return 0;
}
/**
* proc_do_large_bitmap - read/write from/to a large bitmap
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* The bitmap is stored at table->data and the bitmap length (in bits)
* in table->maxlen.
*
* We use a range comma separated format (e.g. 1,3-4,10-10) so that
* large bitmaps may be represented in a compact manner. Writing into
* the file will clear the bitmap then update it with the given input.
*
* Returns 0 on success.
*/
int proc_do_large_bitmap(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int err = 0;
size_t left = *lenp;
unsigned long bitmap_len = table->maxlen;
unsigned long *bitmap = *(unsigned long **) table->data;
unsigned long *tmp_bitmap = NULL;
char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
*lenp = 0;
return 0;
}
if (write) {
char *p = buffer;
size_t skipped = 0;
if (left > PAGE_SIZE - 1) {
left = PAGE_SIZE - 1;
/* How much of the buffer we'll skip this pass */
skipped = *lenp - left;
}
tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
if (!tmp_bitmap)
return -ENOMEM;
proc_skip_char(&p, &left, '\n');
while (!err && left) {
unsigned long val_a, val_b;
bool neg;
size_t saved_left;
/* In case we stop parsing mid-number, we can reset */
saved_left = left;
err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
sizeof(tr_a), &c);
/*
* If we consumed the entirety of a truncated buffer or
* only one char is left (may be a "-"), then stop here,
* reset, & come back for more.
*/
if ((left <= 1) && skipped) {
left = saved_left;
break;
}
if (err)
break;
if (val_a >= bitmap_len || neg) {
err = -EINVAL;
break;
}
val_b = val_a;
if (left) {
p++;
left--;
}
if (c == '-') {
err = proc_get_long(&p, &left, &val_b,
&neg, tr_b, sizeof(tr_b),
&c);
/*
* If we consumed all of a truncated buffer or
* then stop here, reset, & come back for more.
*/
if (!left && skipped) {
left = saved_left;
break;
}
if (err)
break;
if (val_b >= bitmap_len || neg ||
val_a > val_b) {
err = -EINVAL;
break;
}
if (left) {
p++;
left--;
}
}
bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
proc_skip_char(&p, &left, '\n');
}
left += skipped;
} else {
unsigned long bit_a, bit_b = 0;
bool first = 1;
while (left) {
bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
if (bit_a >= bitmap_len)
break;
bit_b = find_next_zero_bit(bitmap, bitmap_len,
bit_a + 1) - 1;
if (!first)
proc_put_char(&buffer, &left, ',');
proc_put_long(&buffer, &left, bit_a, false);
if (bit_a != bit_b) {
proc_put_char(&buffer, &left, '-');
proc_put_long(&buffer, &left, bit_b, false);
}
first = 0; bit_b++;
}
proc_put_char(&buffer, &left, '\n');
}
if (!err) {
if (write) {
if (*ppos)
bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
else
bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
}
*lenp -= left;
*ppos += *lenp;
}
bitmap_free(tmp_bitmap);
return err;
}
#else /* CONFIG_PROC_SYSCTL */
int proc_dostring(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dobool(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_douintvec(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_douintvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dou8vec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_doulongvec_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_do_large_bitmap(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
#endif /* CONFIG_PROC_SYSCTL */
#if defined(CONFIG_SYSCTL)
int proc_do_static_key(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct static_key *key = (struct static_key *)table->data;
static DEFINE_MUTEX(static_key_mutex);
int val, ret;
struct ctl_table tmp = {
.data = &val,
.maxlen = sizeof(val),
.mode = table->mode,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
};
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
mutex_lock(&static_key_mutex);
val = static_key_enabled(key);
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
if (write && !ret) {
if (val)
static_key_enable(key);
else
static_key_disable(key);
}
mutex_unlock(&static_key_mutex);
return ret;
}
static struct ctl_table kern_table[] = {
{
.procname = "panic",
.data = &panic_timeout,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#ifdef CONFIG_PROC_SYSCTL
{
.procname = "tainted",
.maxlen = sizeof(long),
.mode = 0644,
.proc_handler = proc_taint,
},
{
.procname = "sysctl_writes_strict",
.data = &sysctl_writes_strict,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_NEG_ONE,
.extra2 = SYSCTL_ONE,
},
#endif
{
.procname = "print-fatal-signals",
.data = &print_fatal_signals,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#ifdef CONFIG_SPARC
{
.procname = "reboot-cmd",
.data = reboot_command,
.maxlen = 256,
.mode = 0644,
.proc_handler = proc_dostring,
},
{
.procname = "stop-a",
.data = &stop_a_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "scons-poweroff",
.data = &scons_pwroff,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_SPARC64
{
.procname = "tsb-ratio",
.data = &sysctl_tsb_ratio,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_PARISC
{
.procname = "soft-power",
.data = &pwrsw_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
{
.procname = "unaligned-trap",
.data = &unaligned_enabled,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_STACK_TRACER
{
.procname = "stack_tracer_enabled",
.data = &stack_tracer_enabled,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = stack_trace_sysctl,
},
#endif
#ifdef CONFIG_TRACING
{
.procname = "ftrace_dump_on_oops",
.data = &ftrace_dump_on_oops,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "traceoff_on_warning",
.data = &__disable_trace_on_warning,
.maxlen = sizeof(__disable_trace_on_warning),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "tracepoint_printk",
.data = &tracepoint_printk,
.maxlen = sizeof(tracepoint_printk),
.mode = 0644,
.proc_handler = tracepoint_printk_sysctl,
},
#endif
#ifdef CONFIG_MODULES
{
.procname = "modprobe",
.data = &modprobe_path,
.maxlen = KMOD_PATH_LEN,
.mode = 0644,
.proc_handler = proc_dostring,
},
{
.procname = "modules_disabled",
.data = &modules_disabled,
.maxlen = sizeof(int),
.mode = 0644,
/* only handle a transition from default "0" to "1" */
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_ONE,
},
#endif
#ifdef CONFIG_UEVENT_HELPER
{
.procname = "hotplug",
.data = &uevent_helper,
.maxlen = UEVENT_HELPER_PATH_LEN,
.mode = 0644,
.proc_handler = proc_dostring,
},
#endif
#ifdef CONFIG_MAGIC_SYSRQ
{
.procname = "sysrq",
.data = NULL,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = sysrq_sysctl_handler,
},
#endif
#ifdef CONFIG_PROC_SYSCTL
{
.procname = "cad_pid",
.data = NULL,
.maxlen = sizeof (int),
.mode = 0600,
.proc_handler = proc_do_cad_pid,
},
#endif
{
.procname = "threads-max",
.data = NULL,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = sysctl_max_threads,
},
{
.procname = "overflowuid",
.data = &overflowuid,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_MAXOLDUID,
},
{
.procname = "overflowgid",
.data = &overflowgid,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_MAXOLDUID,
},
#ifdef CONFIG_S390
{
.procname = "userprocess_debug",
.data = &show_unhandled_signals,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
{
.procname = "pid_max",
.data = &pid_max,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &pid_max_min,
.extra2 = &pid_max_max,
},
{
.procname = "panic_on_oops",
.data = &panic_on_oops,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "panic_print",
.data = &panic_print,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "ngroups_max",
.data = (void *)&ngroups_max,
.maxlen = sizeof (int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
{
.procname = "cap_last_cap",
.data = (void *)&cap_last_cap,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
{
.procname = "unknown_nmi_panic",
.data = &unknown_nmi_panic,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
defined(CONFIG_DEBUG_STACKOVERFLOW)
{
.procname = "panic_on_stackoverflow",
.data = &sysctl_panic_on_stackoverflow,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#if defined(CONFIG_X86)
{
.procname = "panic_on_unrecovered_nmi",
.data = &panic_on_unrecovered_nmi,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "panic_on_io_nmi",
.data = &panic_on_io_nmi,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "bootloader_type",
.data = &bootloader_type,
.maxlen = sizeof (int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
{
.procname = "bootloader_version",
.data = &bootloader_version,
.maxlen = sizeof (int),
.mode = 0444,
.proc_handler = proc_dointvec,
},
{
.procname = "io_delay_type",
.data = &io_delay_type,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#if defined(CONFIG_MMU)
{
.procname = "randomize_va_space",
.data = &randomize_va_space,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#if defined(CONFIG_S390) && defined(CONFIG_SMP)
{
.procname = "spin_retry",
.data = &spin_retry,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#if defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
{
.procname = "acpi_video_flags",
.data = &acpi_realmode_flags,
.maxlen = sizeof (unsigned long),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
#endif
#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
{
.procname = "ignore-unaligned-usertrap",
.data = &no_unaligned_warning,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_IA64
{
.procname = "unaligned-dump-stack",
.data = &unaligned_dump_stack,
.maxlen = sizeof (int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_RT_MUTEXES
{
.procname = "max_lock_depth",
.data = &max_lock_depth,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
#ifdef CONFIG_PERF_EVENTS
/*
* User-space scripts rely on the existence of this file
* as a feature check for perf_events being enabled.
*
* So it's an ABI, do not remove!
*/
{
.procname = "perf_event_paranoid",
.data = &sysctl_perf_event_paranoid,
.maxlen = sizeof(sysctl_perf_event_paranoid),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "perf_event_mlock_kb",
.data = &sysctl_perf_event_mlock,
.maxlen = sizeof(sysctl_perf_event_mlock),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "perf_event_max_sample_rate",
.data = &sysctl_perf_event_sample_rate,
.maxlen = sizeof(sysctl_perf_event_sample_rate),
.mode = 0644,
.proc_handler = perf_proc_update_handler,
.extra1 = SYSCTL_ONE,
},
{
.procname = "perf_cpu_time_max_percent",
.data = &sysctl_perf_cpu_time_max_percent,
.maxlen = sizeof(sysctl_perf_cpu_time_max_percent),
.mode = 0644,
.proc_handler = perf_cpu_time_max_percent_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
},
{
.procname = "perf_event_max_stack",
.data = &sysctl_perf_event_max_stack,
.maxlen = sizeof(sysctl_perf_event_max_stack),
.mode = 0644,
.proc_handler = perf_event_max_stack_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = (void *)&six_hundred_forty_kb,
},
{
.procname = "perf_event_max_contexts_per_stack",
.data = &sysctl_perf_event_max_contexts_per_stack,
.maxlen = sizeof(sysctl_perf_event_max_contexts_per_stack),
.mode = 0644,
.proc_handler = perf_event_max_stack_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_THOUSAND,
},
#endif
{
.procname = "panic_on_warn",
.data = &panic_on_warn,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#ifdef CONFIG_TREE_RCU
{
.procname = "panic_on_rcu_stall",
.data = &sysctl_panic_on_rcu_stall,
.maxlen = sizeof(sysctl_panic_on_rcu_stall),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "max_rcu_stall_to_panic",
.data = &sysctl_max_rcu_stall_to_panic,
.maxlen = sizeof(sysctl_max_rcu_stall_to_panic),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_INT_MAX,
},
#endif
{ }
};
static struct ctl_table vm_table[] = {
{
.procname = "overcommit_memory",
.data = &sysctl_overcommit_memory,
.maxlen = sizeof(sysctl_overcommit_memory),
.mode = 0644,
.proc_handler = overcommit_policy_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{
.procname = "overcommit_ratio",
.data = &sysctl_overcommit_ratio,
.maxlen = sizeof(sysctl_overcommit_ratio),
.mode = 0644,
.proc_handler = overcommit_ratio_handler,
},
{
.procname = "overcommit_kbytes",
.data = &sysctl_overcommit_kbytes,
.maxlen = sizeof(sysctl_overcommit_kbytes),
.mode = 0644,
.proc_handler = overcommit_kbytes_handler,
},
{
.procname = "page-cluster",
.data = &page_cluster,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = (void *)&page_cluster_max,
},
{
.procname = "dirtytime_expire_seconds",
.data = &dirtytime_expire_interval,
.maxlen = sizeof(dirtytime_expire_interval),
.mode = 0644,
.proc_handler = dirtytime_interval_handler,
.extra1 = SYSCTL_ZERO,
},
{
.procname = "swappiness",
.data = &vm_swappiness,
.maxlen = sizeof(vm_swappiness),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO_HUNDRED,
},
#ifdef CONFIG_NUMA
{
.procname = "numa_stat",
.data = &sysctl_vm_numa_stat,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = sysctl_vm_numa_stat_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif
{
.procname = "drop_caches",
.data = &sysctl_drop_caches,
.maxlen = sizeof(int),
.mode = 0200,
.proc_handler = drop_caches_sysctl_handler,
.extra1 = SYSCTL_ONE,
.extra2 = SYSCTL_FOUR,
},
{
.procname = "page_lock_unfairness",
.data = &sysctl_page_lock_unfairness,
.maxlen = sizeof(sysctl_page_lock_unfairness),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#ifdef CONFIG_MMU
{
.procname = "max_map_count",
.data = &sysctl_max_map_count,
.maxlen = sizeof(sysctl_max_map_count),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#else
{
.procname = "nr_trim_pages",
.data = &sysctl_nr_trim_pages,
.maxlen = sizeof(sysctl_nr_trim_pages),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#endif
{
.procname = "vfs_cache_pressure",
.data = &sysctl_vfs_cache_pressure,
.maxlen = sizeof(sysctl_vfs_cache_pressure),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
{
.procname = "legacy_va_layout",
.data = &sysctl_legacy_va_layout,
.maxlen = sizeof(sysctl_legacy_va_layout),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#endif
#ifdef CONFIG_NUMA
{
.procname = "zone_reclaim_mode",
.data = &node_reclaim_mode,
.maxlen = sizeof(node_reclaim_mode),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#endif
#ifdef CONFIG_SMP
{
.procname = "stat_interval",
.data = &sysctl_stat_interval,
.maxlen = sizeof(sysctl_stat_interval),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "stat_refresh",
.data = NULL,
.maxlen = 0,
.mode = 0600,
.proc_handler = vmstat_refresh,
},
#endif
#ifdef CONFIG_MMU
{
.procname = "mmap_min_addr",
.data = &dac_mmap_min_addr,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = mmap_min_addr_handler,
},
#endif
#if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
(defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
{
.procname = "vdso_enabled",
#ifdef CONFIG_X86_32
.data = &vdso32_enabled,
.maxlen = sizeof(vdso32_enabled),
#else
.data = &vdso_enabled,
.maxlen = sizeof(vdso_enabled),
#endif
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
},
#endif
{
.procname = "user_reserve_kbytes",
.data = &sysctl_user_reserve_kbytes,
.maxlen = sizeof(sysctl_user_reserve_kbytes),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{
.procname = "admin_reserve_kbytes",
.data = &sysctl_admin_reserve_kbytes,
.maxlen = sizeof(sysctl_admin_reserve_kbytes),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
{
.procname = "mmap_rnd_bits",
.data = &mmap_rnd_bits,
.maxlen = sizeof(mmap_rnd_bits),
.mode = 0600,
.proc_handler = proc_dointvec_minmax,
.extra1 = (void *)&mmap_rnd_bits_min,
.extra2 = (void *)&mmap_rnd_bits_max,
},
#endif
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
{
.procname = "mmap_rnd_compat_bits",
.data = &mmap_rnd_compat_bits,
.maxlen = sizeof(mmap_rnd_compat_bits),
.mode = 0600,
.proc_handler = proc_dointvec_minmax,
.extra1 = (void *)&mmap_rnd_compat_bits_min,
.extra2 = (void *)&mmap_rnd_compat_bits_max,
},
#endif
{ }
};
int __init sysctl_init_bases(void)
{
register_sysctl_init("kernel", kern_table);
register_sysctl_init("vm", vm_table);
return 0;
}
#endif /* CONFIG_SYSCTL */
/*
* No sense putting this after each symbol definition, twice,
* exception granted :-)
*/
EXPORT_SYMBOL(proc_dobool);
EXPORT_SYMBOL(proc_dointvec);
EXPORT_SYMBOL(proc_douintvec);
EXPORT_SYMBOL(proc_dointvec_jiffies);
EXPORT_SYMBOL(proc_dointvec_minmax);
EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
EXPORT_SYMBOL(proc_dostring);
EXPORT_SYMBOL(proc_doulongvec_minmax);
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
EXPORT_SYMBOL(proc_do_large_bitmap);
| linux-master | kernel/sysctl.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/ptrace.c
*
* (C) Copyright 1999 Linus Torvalds
*
* Common interfaces for "ptrace()" which we do not want
* to continually duplicate across every architecture.
*/
#include <linux/capability.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/uio.h>
#include <linux/audit.h>
#include <linux/pid_namespace.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/regset.h>
#include <linux/hw_breakpoint.h>
#include <linux/cn_proc.h>
#include <linux/compat.h>
#include <linux/sched/signal.h>
#include <linux/minmax.h>
#include <linux/syscall_user_dispatch.h>
#include <asm/syscall.h> /* for syscall_get_* */
/*
* Access another process' address space via ptrace.
* Source/target buffer must be kernel space,
* Do not walk the page table directly, use get_user_pages
*/
int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
void *buf, int len, unsigned int gup_flags)
{
struct mm_struct *mm;
int ret;
mm = get_task_mm(tsk);
if (!mm)
return 0;
if (!tsk->ptrace ||
(current != tsk->parent) ||
((get_dumpable(mm) != SUID_DUMP_USER) &&
!ptracer_capable(tsk, mm->user_ns))) {
mmput(mm);
return 0;
}
ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
mmput(mm);
return ret;
}
void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
const struct cred *ptracer_cred)
{
BUG_ON(!list_empty(&child->ptrace_entry));
list_add(&child->ptrace_entry, &new_parent->ptraced);
child->parent = new_parent;
child->ptracer_cred = get_cred(ptracer_cred);
}
/*
* ptrace a task: make the debugger its new parent and
* move it to the ptrace list.
*
* Must be called with the tasklist lock write-held.
*/
static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
{
__ptrace_link(child, new_parent, current_cred());
}
/**
* __ptrace_unlink - unlink ptracee and restore its execution state
* @child: ptracee to be unlinked
*
* Remove @child from the ptrace list, move it back to the original parent,
* and restore the execution state so that it conforms to the group stop
* state.
*
* Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
* exiting. For PTRACE_DETACH, unless the ptracee has been killed between
* ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
* If the ptracer is exiting, the ptracee can be in any state.
*
* After detach, the ptracee should be in a state which conforms to the
* group stop. If the group is stopped or in the process of stopping, the
* ptracee should be put into TASK_STOPPED; otherwise, it should be woken
* up from TASK_TRACED.
*
* If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
* it goes through TRACED -> RUNNING -> STOPPED transition which is similar
* to but in the opposite direction of what happens while attaching to a
* stopped task. However, in this direction, the intermediate RUNNING
* state is not hidden even from the current ptracer and if it immediately
* re-attaches and performs a WNOHANG wait(2), it may fail.
*
* CONTEXT:
* write_lock_irq(tasklist_lock)
*/
void __ptrace_unlink(struct task_struct *child)
{
const struct cred *old_cred;
BUG_ON(!child->ptrace);
clear_task_syscall_work(child, SYSCALL_TRACE);
#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
clear_task_syscall_work(child, SYSCALL_EMU);
#endif
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);
old_cred = child->ptracer_cred;
child->ptracer_cred = NULL;
put_cred(old_cred);
spin_lock(&child->sighand->siglock);
child->ptrace = 0;
/*
* Clear all pending traps and TRAPPING. TRAPPING should be
* cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
*/
task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
task_clear_jobctl_trapping(child);
/*
* Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
* @child isn't dead.
*/
if (!(child->flags & PF_EXITING) &&
(child->signal->flags & SIGNAL_STOP_STOPPED ||
child->signal->group_stop_count)) {
child->jobctl |= JOBCTL_STOP_PENDING;
/*
* This is only possible if this thread was cloned by the
* traced task running in the stopped group, set the signal
* for the future reports.
* FIXME: we should change ptrace_init_task() to handle this
* case.
*/
if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
child->jobctl |= SIGSTOP;
}
/*
* If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
* @child in the butt. Note that @resume should be used iff @child
* is in TASK_TRACED; otherwise, we might unduly disrupt
* TASK_KILLABLE sleeps.
*/
if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
ptrace_signal_wake_up(child, true);
spin_unlock(&child->sighand->siglock);
}
static bool looks_like_a_spurious_pid(struct task_struct *task)
{
if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
return false;
if (task_pid_vnr(task) == task->ptrace_message)
return false;
/*
* The tracee changed its pid but the PTRACE_EVENT_EXEC event
* was not wait()'ed, most probably debugger targets the old
* leader which was destroyed in de_thread().
*/
return true;
}
/*
* Ensure that nothing can wake it up, even SIGKILL
*
* A task is switched to this state while a ptrace operation is in progress;
* such that the ptrace operation is uninterruptible.
*/
static bool ptrace_freeze_traced(struct task_struct *task)
{
bool ret = false;
/* Lockless, nobody but us can set this flag */
if (task->jobctl & JOBCTL_LISTENING)
return ret;
spin_lock_irq(&task->sighand->siglock);
if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
!__fatal_signal_pending(task)) {
task->jobctl |= JOBCTL_PTRACE_FROZEN;
ret = true;
}
spin_unlock_irq(&task->sighand->siglock);
return ret;
}
static void ptrace_unfreeze_traced(struct task_struct *task)
{
unsigned long flags;
/*
* The child may be awake and may have cleared
* JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will
* not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew.
*/
if (lock_task_sighand(task, &flags)) {
task->jobctl &= ~JOBCTL_PTRACE_FROZEN;
if (__fatal_signal_pending(task)) {
task->jobctl &= ~JOBCTL_TRACED;
wake_up_state(task, __TASK_TRACED);
}
unlock_task_sighand(task, &flags);
}
}
/**
* ptrace_check_attach - check whether ptracee is ready for ptrace operation
* @child: ptracee to check for
* @ignore_state: don't check whether @child is currently %TASK_TRACED
*
* Check whether @child is being ptraced by %current and ready for further
* ptrace operations. If @ignore_state is %false, @child also should be in
* %TASK_TRACED state and on return the child is guaranteed to be traced
* and not executing. If @ignore_state is %true, @child can be in any
* state.
*
* CONTEXT:
* Grabs and releases tasklist_lock and @child->sighand->siglock.
*
* RETURNS:
* 0 on success, -ESRCH if %child is not ready.
*/
static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
{
int ret = -ESRCH;
/*
* We take the read lock around doing both checks to close a
* possible race where someone else was tracing our child and
* detached between these two checks. After this locked check,
* we are sure that this is our traced child and that can only
* be changed by us so it's not changing right after this.
*/
read_lock(&tasklist_lock);
if (child->ptrace && child->parent == current) {
/*
* child->sighand can't be NULL, release_task()
* does ptrace_unlink() before __exit_signal().
*/
if (ignore_state || ptrace_freeze_traced(child))
ret = 0;
}
read_unlock(&tasklist_lock);
if (!ret && !ignore_state &&
WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN)))
ret = -ESRCH;
return ret;
}
static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
{
if (mode & PTRACE_MODE_NOAUDIT)
return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
return ns_capable(ns, CAP_SYS_PTRACE);
}
/* Returns 0 on success, -errno on denial. */
static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
const struct cred *cred = current_cred(), *tcred;
struct mm_struct *mm;
kuid_t caller_uid;
kgid_t caller_gid;
if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
return -EPERM;
}
/* May we inspect the given task?
* This check is used both for attaching with ptrace
* and for allowing access to sensitive information in /proc.
*
* ptrace_attach denies several cases that /proc allows
* because setting up the necessary parent/child relationship
* or halting the specified task is impossible.
*/
/* Don't let security modules deny introspection */
if (same_thread_group(task, current))
return 0;
rcu_read_lock();
if (mode & PTRACE_MODE_FSCREDS) {
caller_uid = cred->fsuid;
caller_gid = cred->fsgid;
} else {
/*
* Using the euid would make more sense here, but something
* in userland might rely on the old behavior, and this
* shouldn't be a security problem since
* PTRACE_MODE_REALCREDS implies that the caller explicitly
* used a syscall that requests access to another process
* (and not a filesystem syscall to procfs).
*/
caller_uid = cred->uid;
caller_gid = cred->gid;
}
tcred = __task_cred(task);
if (uid_eq(caller_uid, tcred->euid) &&
uid_eq(caller_uid, tcred->suid) &&
uid_eq(caller_uid, tcred->uid) &&
gid_eq(caller_gid, tcred->egid) &&
gid_eq(caller_gid, tcred->sgid) &&
gid_eq(caller_gid, tcred->gid))
goto ok;
if (ptrace_has_cap(tcred->user_ns, mode))
goto ok;
rcu_read_unlock();
return -EPERM;
ok:
rcu_read_unlock();
/*
* If a task drops privileges and becomes nondumpable (through a syscall
* like setresuid()) while we are trying to access it, we must ensure
* that the dumpability is read after the credentials; otherwise,
* we may be able to attach to a task that we shouldn't be able to
* attach to (as if the task had dropped privileges without becoming
* nondumpable).
* Pairs with a write barrier in commit_creds().
*/
smp_rmb();
mm = task->mm;
if (mm &&
((get_dumpable(mm) != SUID_DUMP_USER) &&
!ptrace_has_cap(mm->user_ns, mode)))
return -EPERM;
return security_ptrace_access_check(task, mode);
}
bool ptrace_may_access(struct task_struct *task, unsigned int mode)
{
int err;
task_lock(task);
err = __ptrace_may_access(task, mode);
task_unlock(task);
return !err;
}
static int check_ptrace_options(unsigned long data)
{
if (data & ~(unsigned long)PTRACE_O_MASK)
return -EINVAL;
if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
!IS_ENABLED(CONFIG_SECCOMP))
return -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
current->ptrace & PT_SUSPEND_SECCOMP)
return -EPERM;
}
return 0;
}
static int ptrace_attach(struct task_struct *task, long request,
unsigned long addr,
unsigned long flags)
{
bool seize = (request == PTRACE_SEIZE);
int retval;
retval = -EIO;
if (seize) {
if (addr != 0)
goto out;
/*
* This duplicates the check in check_ptrace_options() because
* ptrace_attach() and ptrace_setoptions() have historically
* used different error codes for unknown ptrace options.
*/
if (flags & ~(unsigned long)PTRACE_O_MASK)
goto out;
retval = check_ptrace_options(flags);
if (retval)
return retval;
flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
} else {
flags = PT_PTRACED;
}
audit_ptrace(task);
retval = -EPERM;
if (unlikely(task->flags & PF_KTHREAD))
goto out;
if (same_thread_group(task, current))
goto out;
/*
* Protect exec's credential calculations against our interference;
* SUID, SGID and LSM creds get determined differently
* under ptrace.
*/
retval = -ERESTARTNOINTR;
if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
goto out;
task_lock(task);
retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
task_unlock(task);
if (retval)
goto unlock_creds;
write_lock_irq(&tasklist_lock);
retval = -EPERM;
if (unlikely(task->exit_state))
goto unlock_tasklist;
if (task->ptrace)
goto unlock_tasklist;
task->ptrace = flags;
ptrace_link(task, current);
/* SEIZE doesn't trap tracee on attach */
if (!seize)
send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
spin_lock(&task->sighand->siglock);
/*
* If the task is already STOPPED, set JOBCTL_TRAP_STOP and
* TRAPPING, and kick it so that it transits to TRACED. TRAPPING
* will be cleared if the child completes the transition or any
* event which clears the group stop states happens. We'll wait
* for the transition to complete before returning from this
* function.
*
* This hides STOPPED -> RUNNING -> TRACED transition from the
* attaching thread but a different thread in the same group can
* still observe the transient RUNNING state. IOW, if another
* thread's WNOHANG wait(2) on the stopped tracee races against
* ATTACH, the wait(2) may fail due to the transient RUNNING.
*
* The following task_is_stopped() test is safe as both transitions
* in and out of STOPPED are protected by siglock.
*/
if (task_is_stopped(task) &&
task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
task->jobctl &= ~JOBCTL_STOPPED;
signal_wake_up_state(task, __TASK_STOPPED);
}
spin_unlock(&task->sighand->siglock);
retval = 0;
unlock_tasklist:
write_unlock_irq(&tasklist_lock);
unlock_creds:
mutex_unlock(&task->signal->cred_guard_mutex);
out:
if (!retval) {
/*
* We do not bother to change retval or clear JOBCTL_TRAPPING
* if wait_on_bit() was interrupted by SIGKILL. The tracer will
* not return to user-mode, it will exit and clear this bit in
* __ptrace_unlink() if it wasn't already cleared by the tracee;
* and until then nobody can ptrace this task.
*/
wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
proc_ptrace_connector(task, PTRACE_ATTACH);
}
return retval;
}
/**
* ptrace_traceme -- helper for PTRACE_TRACEME
*
* Performs checks and sets PT_PTRACED.
* Should be used by all ptrace implementations for PTRACE_TRACEME.
*/
static int ptrace_traceme(void)
{
int ret = -EPERM;
write_lock_irq(&tasklist_lock);
/* Are we already being traced? */
if (!current->ptrace) {
ret = security_ptrace_traceme(current->parent);
/*
* Check PF_EXITING to ensure ->real_parent has not passed
* exit_ptrace(). Otherwise we don't report the error but
* pretend ->real_parent untraces us right after return.
*/
if (!ret && !(current->real_parent->flags & PF_EXITING)) {
current->ptrace = PT_PTRACED;
ptrace_link(current, current->real_parent);
}
}
write_unlock_irq(&tasklist_lock);
return ret;
}
/*
* Called with irqs disabled, returns true if childs should reap themselves.
*/
static int ignoring_children(struct sighand_struct *sigh)
{
int ret;
spin_lock(&sigh->siglock);
ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
(sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
spin_unlock(&sigh->siglock);
return ret;
}
/*
* Called with tasklist_lock held for writing.
* Unlink a traced task, and clean it up if it was a traced zombie.
* Return true if it needs to be reaped with release_task().
* (We can't call release_task() here because we already hold tasklist_lock.)
*
* If it's a zombie, our attachedness prevented normal parent notification
* or self-reaping. Do notification now if it would have happened earlier.
* If it should reap itself, return true.
*
* If it's our own child, there is no notification to do. But if our normal
* children self-reap, then this child was prevented by ptrace and we must
* reap it now, in that case we must also wake up sub-threads sleeping in
* do_wait().
*/
static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
{
bool dead;
__ptrace_unlink(p);
if (p->exit_state != EXIT_ZOMBIE)
return false;
dead = !thread_group_leader(p);
if (!dead && thread_group_empty(p)) {
if (!same_thread_group(p->real_parent, tracer))
dead = do_notify_parent(p, p->exit_signal);
else if (ignoring_children(tracer->sighand)) {
__wake_up_parent(p, tracer);
dead = true;
}
}
/* Mark it as in the process of being reaped. */
if (dead)
p->exit_state = EXIT_DEAD;
return dead;
}
static int ptrace_detach(struct task_struct *child, unsigned int data)
{
if (!valid_signal(data))
return -EIO;
/* Architecture-specific hardware disable .. */
ptrace_disable(child);
write_lock_irq(&tasklist_lock);
/*
* We rely on ptrace_freeze_traced(). It can't be killed and
* untraced by another thread, it can't be a zombie.
*/
WARN_ON(!child->ptrace || child->exit_state);
/*
* tasklist_lock avoids the race with wait_task_stopped(), see
* the comment in ptrace_resume().
*/
child->exit_code = data;
__ptrace_detach(current, child);
write_unlock_irq(&tasklist_lock);
proc_ptrace_connector(child, PTRACE_DETACH);
return 0;
}
/*
* Detach all tasks we were using ptrace on. Called with tasklist held
* for writing.
*/
void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
{
struct task_struct *p, *n;
list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
if (unlikely(p->ptrace & PT_EXITKILL))
send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
if (__ptrace_detach(tracer, p))
list_add(&p->ptrace_entry, dead);
}
}
int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
{
int copied = 0;
while (len > 0) {
char buf[128];
int this_len, retval;
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
if (!retval) {
if (copied)
break;
return -EIO;
}
if (copy_to_user(dst, buf, retval))
return -EFAULT;
copied += retval;
src += retval;
dst += retval;
len -= retval;
}
return copied;
}
int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
{
int copied = 0;
while (len > 0) {
char buf[128];
int this_len, retval;
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
if (copy_from_user(buf, src, this_len))
return -EFAULT;
retval = ptrace_access_vm(tsk, dst, buf, this_len,
FOLL_FORCE | FOLL_WRITE);
if (!retval) {
if (copied)
break;
return -EIO;
}
copied += retval;
src += retval;
dst += retval;
len -= retval;
}
return copied;
}
static int ptrace_setoptions(struct task_struct *child, unsigned long data)
{
unsigned flags;
int ret;
ret = check_ptrace_options(data);
if (ret)
return ret;
/* Avoid intermediate state when all opts are cleared */
flags = child->ptrace;
flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
flags |= (data << PT_OPT_FLAG_SHIFT);
child->ptrace = flags;
return 0;
}
static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
{
unsigned long flags;
int error = -ESRCH;
if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
if (likely(child->last_siginfo != NULL)) {
copy_siginfo(info, child->last_siginfo);
error = 0;
}
unlock_task_sighand(child, &flags);
}
return error;
}
static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
{
unsigned long flags;
int error = -ESRCH;
if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
if (likely(child->last_siginfo != NULL)) {
copy_siginfo(child->last_siginfo, info);
error = 0;
}
unlock_task_sighand(child, &flags);
}
return error;
}
static int ptrace_peek_siginfo(struct task_struct *child,
unsigned long addr,
unsigned long data)
{
struct ptrace_peeksiginfo_args arg;
struct sigpending *pending;
struct sigqueue *q;
int ret, i;
ret = copy_from_user(&arg, (void __user *) addr,
sizeof(struct ptrace_peeksiginfo_args));
if (ret)
return -EFAULT;
if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
return -EINVAL; /* unknown flags */
if (arg.nr < 0)
return -EINVAL;
/* Ensure arg.off fits in an unsigned long */
if (arg.off > ULONG_MAX)
return 0;
if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
pending = &child->signal->shared_pending;
else
pending = &child->pending;
for (i = 0; i < arg.nr; ) {
kernel_siginfo_t info;
unsigned long off = arg.off + i;
bool found = false;
spin_lock_irq(&child->sighand->siglock);
list_for_each_entry(q, &pending->list, list) {
if (!off--) {
found = true;
copy_siginfo(&info, &q->info);
break;
}
}
spin_unlock_irq(&child->sighand->siglock);
if (!found) /* beyond the end of the list */
break;
#ifdef CONFIG_COMPAT
if (unlikely(in_compat_syscall())) {
compat_siginfo_t __user *uinfo = compat_ptr(data);
if (copy_siginfo_to_user32(uinfo, &info)) {
ret = -EFAULT;
break;
}
} else
#endif
{
siginfo_t __user *uinfo = (siginfo_t __user *) data;
if (copy_siginfo_to_user(uinfo, &info)) {
ret = -EFAULT;
break;
}
}
data += sizeof(siginfo_t);
i++;
if (signal_pending(current))
break;
cond_resched();
}
if (i > 0)
return i;
return ret;
}
#ifdef CONFIG_RSEQ
static long ptrace_get_rseq_configuration(struct task_struct *task,
unsigned long size, void __user *data)
{
struct ptrace_rseq_configuration conf = {
.rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
.rseq_abi_size = task->rseq_len,
.signature = task->rseq_sig,
.flags = 0,
};
size = min_t(unsigned long, size, sizeof(conf));
if (copy_to_user(data, &conf, size))
return -EFAULT;
return sizeof(conf);
}
#endif
#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
#ifdef PTRACE_SINGLEBLOCK
#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
#else
#define is_singleblock(request) 0
#endif
#ifdef PTRACE_SYSEMU
#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
#else
#define is_sysemu_singlestep(request) 0
#endif
static int ptrace_resume(struct task_struct *child, long request,
unsigned long data)
{
if (!valid_signal(data))
return -EIO;
if (request == PTRACE_SYSCALL)
set_task_syscall_work(child, SYSCALL_TRACE);
else
clear_task_syscall_work(child, SYSCALL_TRACE);
#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
set_task_syscall_work(child, SYSCALL_EMU);
else
clear_task_syscall_work(child, SYSCALL_EMU);
#endif
if (is_singleblock(request)) {
if (unlikely(!arch_has_block_step()))
return -EIO;
user_enable_block_step(child);
} else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
if (unlikely(!arch_has_single_step()))
return -EIO;
user_enable_single_step(child);
} else {
user_disable_single_step(child);
}
/*
* Change ->exit_code and ->state under siglock to avoid the race
* with wait_task_stopped() in between; a non-zero ->exit_code will
* wrongly look like another report from tracee.
*
* Note that we need siglock even if ->exit_code == data and/or this
* status was not reported yet, the new status must not be cleared by
* wait_task_stopped() after resume.
*/
spin_lock_irq(&child->sighand->siglock);
child->exit_code = data;
child->jobctl &= ~JOBCTL_TRACED;
wake_up_state(child, __TASK_TRACED);
spin_unlock_irq(&child->sighand->siglock);
return 0;
}
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
static const struct user_regset *
find_regset(const struct user_regset_view *view, unsigned int type)
{
const struct user_regset *regset;
int n;
for (n = 0; n < view->n; ++n) {
regset = view->regsets + n;
if (regset->core_note_type == type)
return regset;
}
return NULL;
}
static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
struct iovec *kiov)
{
const struct user_regset_view *view = task_user_regset_view(task);
const struct user_regset *regset = find_regset(view, type);
int regset_no;
if (!regset || (kiov->iov_len % regset->size) != 0)
return -EINVAL;
regset_no = regset - view->regsets;
kiov->iov_len = min(kiov->iov_len,
(__kernel_size_t) (regset->n * regset->size));
if (req == PTRACE_GETREGSET)
return copy_regset_to_user(task, view, regset_no, 0,
kiov->iov_len, kiov->iov_base);
else
return copy_regset_from_user(task, view, regset_no, 0,
kiov->iov_len, kiov->iov_base);
}
/*
* This is declared in linux/regset.h and defined in machine-dependent
* code. We put the export here, near the primary machine-neutral use,
* to ensure no machine forgets it.
*/
EXPORT_SYMBOL_GPL(task_user_regset_view);
static unsigned long
ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
struct ptrace_syscall_info *info)
{
unsigned long args[ARRAY_SIZE(info->entry.args)];
int i;
info->op = PTRACE_SYSCALL_INFO_ENTRY;
info->entry.nr = syscall_get_nr(child, regs);
syscall_get_arguments(child, regs, args);
for (i = 0; i < ARRAY_SIZE(args); i++)
info->entry.args[i] = args[i];
/* args is the last field in struct ptrace_syscall_info.entry */
return offsetofend(struct ptrace_syscall_info, entry.args);
}
static unsigned long
ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
struct ptrace_syscall_info *info)
{
/*
* As struct ptrace_syscall_info.entry is currently a subset
* of struct ptrace_syscall_info.seccomp, it makes sense to
* initialize that subset using ptrace_get_syscall_info_entry().
* This can be reconsidered in the future if these structures
* diverge significantly enough.
*/
ptrace_get_syscall_info_entry(child, regs, info);
info->op = PTRACE_SYSCALL_INFO_SECCOMP;
info->seccomp.ret_data = child->ptrace_message;
/* ret_data is the last field in struct ptrace_syscall_info.seccomp */
return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
}
static unsigned long
ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
struct ptrace_syscall_info *info)
{
info->op = PTRACE_SYSCALL_INFO_EXIT;
info->exit.rval = syscall_get_error(child, regs);
info->exit.is_error = !!info->exit.rval;
if (!info->exit.is_error)
info->exit.rval = syscall_get_return_value(child, regs);
/* is_error is the last field in struct ptrace_syscall_info.exit */
return offsetofend(struct ptrace_syscall_info, exit.is_error);
}
static int
ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
void __user *datavp)
{
struct pt_regs *regs = task_pt_regs(child);
struct ptrace_syscall_info info = {
.op = PTRACE_SYSCALL_INFO_NONE,
.arch = syscall_get_arch(child),
.instruction_pointer = instruction_pointer(regs),
.stack_pointer = user_stack_pointer(regs),
};
unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
unsigned long write_size;
/*
* This does not need lock_task_sighand() to access
* child->last_siginfo because ptrace_freeze_traced()
* called earlier by ptrace_check_attach() ensures that
* the tracee cannot go away and clear its last_siginfo.
*/
switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
case SIGTRAP | 0x80:
switch (child->ptrace_message) {
case PTRACE_EVENTMSG_SYSCALL_ENTRY:
actual_size = ptrace_get_syscall_info_entry(child, regs,
&info);
break;
case PTRACE_EVENTMSG_SYSCALL_EXIT:
actual_size = ptrace_get_syscall_info_exit(child, regs,
&info);
break;
}
break;
case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
actual_size = ptrace_get_syscall_info_seccomp(child, regs,
&info);
break;
}
write_size = min(actual_size, user_size);
return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
}
#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
int ptrace_request(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
bool seized = child->ptrace & PT_SEIZED;
int ret = -EIO;
kernel_siginfo_t siginfo, *si;
void __user *datavp = (void __user *) data;
unsigned long __user *datalp = datavp;
unsigned long flags;
switch (request) {
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
return generic_ptrace_peekdata(child, addr, data);
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
return generic_ptrace_pokedata(child, addr, data);
#ifdef PTRACE_OLDSETOPTIONS
case PTRACE_OLDSETOPTIONS:
#endif
case PTRACE_SETOPTIONS:
ret = ptrace_setoptions(child, data);
break;
case PTRACE_GETEVENTMSG:
ret = put_user(child->ptrace_message, datalp);
break;
case PTRACE_PEEKSIGINFO:
ret = ptrace_peek_siginfo(child, addr, data);
break;
case PTRACE_GETSIGINFO:
ret = ptrace_getsiginfo(child, &siginfo);
if (!ret)
ret = copy_siginfo_to_user(datavp, &siginfo);
break;
case PTRACE_SETSIGINFO:
ret = copy_siginfo_from_user(&siginfo, datavp);
if (!ret)
ret = ptrace_setsiginfo(child, &siginfo);
break;
case PTRACE_GETSIGMASK: {
sigset_t *mask;
if (addr != sizeof(sigset_t)) {
ret = -EINVAL;
break;
}
if (test_tsk_restore_sigmask(child))
mask = &child->saved_sigmask;
else
mask = &child->blocked;
if (copy_to_user(datavp, mask, sizeof(sigset_t)))
ret = -EFAULT;
else
ret = 0;
break;
}
case PTRACE_SETSIGMASK: {
sigset_t new_set;
if (addr != sizeof(sigset_t)) {
ret = -EINVAL;
break;
}
if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
ret = -EFAULT;
break;
}
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
/*
* Every thread does recalc_sigpending() after resume, so
* retarget_shared_pending() and recalc_sigpending() are not
* called here.
*/
spin_lock_irq(&child->sighand->siglock);
child->blocked = new_set;
spin_unlock_irq(&child->sighand->siglock);
clear_tsk_restore_sigmask(child);
ret = 0;
break;
}
case PTRACE_INTERRUPT:
/*
* Stop tracee without any side-effect on signal or job
* control. At least one trap is guaranteed to happen
* after this request. If @child is already trapped, the
* current trap is not disturbed and another trap will
* happen after the current trap is ended with PTRACE_CONT.
*
* The actual trap might not be PTRACE_EVENT_STOP trap but
* the pending condition is cleared regardless.
*/
if (unlikely(!seized || !lock_task_sighand(child, &flags)))
break;
/*
* INTERRUPT doesn't disturb existing trap sans one
* exception. If ptracer issued LISTEN for the current
* STOP, this INTERRUPT should clear LISTEN and re-trap
* tracee into STOP.
*/
if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
unlock_task_sighand(child, &flags);
ret = 0;
break;
case PTRACE_LISTEN:
/*
* Listen for events. Tracee must be in STOP. It's not
* resumed per-se but is not considered to be in TRACED by
* wait(2) or ptrace(2). If an async event (e.g. group
* stop state change) happens, tracee will enter STOP trap
* again. Alternatively, ptracer can issue INTERRUPT to
* finish listening and re-trap tracee into STOP.
*/
if (unlikely(!seized || !lock_task_sighand(child, &flags)))
break;
si = child->last_siginfo;
if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
child->jobctl |= JOBCTL_LISTENING;
/*
* If NOTIFY is set, it means event happened between
* start of this trap and now. Trigger re-trap.
*/
if (child->jobctl & JOBCTL_TRAP_NOTIFY)
ptrace_signal_wake_up(child, true);
ret = 0;
}
unlock_task_sighand(child, &flags);
break;
case PTRACE_DETACH: /* detach a process that was attached. */
ret = ptrace_detach(child, data);
break;
#ifdef CONFIG_BINFMT_ELF_FDPIC
case PTRACE_GETFDPIC: {
struct mm_struct *mm = get_task_mm(child);
unsigned long tmp = 0;
ret = -ESRCH;
if (!mm)
break;
switch (addr) {
case PTRACE_GETFDPIC_EXEC:
tmp = mm->context.exec_fdpic_loadmap;
break;
case PTRACE_GETFDPIC_INTERP:
tmp = mm->context.interp_fdpic_loadmap;
break;
default:
break;
}
mmput(mm);
ret = put_user(tmp, datalp);
break;
}
#endif
case PTRACE_SINGLESTEP:
#ifdef PTRACE_SINGLEBLOCK
case PTRACE_SINGLEBLOCK:
#endif
#ifdef PTRACE_SYSEMU
case PTRACE_SYSEMU:
case PTRACE_SYSEMU_SINGLESTEP:
#endif
case PTRACE_SYSCALL:
case PTRACE_CONT:
return ptrace_resume(child, request, data);
case PTRACE_KILL:
send_sig_info(SIGKILL, SEND_SIG_NOINFO, child);
return 0;
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
case PTRACE_GETREGSET:
case PTRACE_SETREGSET: {
struct iovec kiov;
struct iovec __user *uiov = datavp;
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(kiov.iov_base, &uiov->iov_base) ||
__get_user(kiov.iov_len, &uiov->iov_len))
return -EFAULT;
ret = ptrace_regset(child, request, addr, &kiov);
if (!ret)
ret = __put_user(kiov.iov_len, &uiov->iov_len);
break;
}
case PTRACE_GET_SYSCALL_INFO:
ret = ptrace_get_syscall_info(child, addr, datavp);
break;
#endif
case PTRACE_SECCOMP_GET_FILTER:
ret = seccomp_get_filter(child, addr, datavp);
break;
case PTRACE_SECCOMP_GET_METADATA:
ret = seccomp_get_metadata(child, addr, datavp);
break;
#ifdef CONFIG_RSEQ
case PTRACE_GET_RSEQ_CONFIGURATION:
ret = ptrace_get_rseq_configuration(child, addr, datavp);
break;
#endif
case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG:
ret = syscall_user_dispatch_set_config(child, addr, datavp);
break;
case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG:
ret = syscall_user_dispatch_get_config(child, addr, datavp);
break;
default:
break;
}
return ret;
}
SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
unsigned long, data)
{
struct task_struct *child;
long ret;
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
goto out;
}
child = find_get_task_by_vpid(pid);
if (!child) {
ret = -ESRCH;
goto out;
}
if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
ret = ptrace_attach(child, request, addr, data);
goto out_put_task_struct;
}
ret = ptrace_check_attach(child, request == PTRACE_KILL ||
request == PTRACE_INTERRUPT);
if (ret < 0)
goto out_put_task_struct;
ret = arch_ptrace(child, request, addr, data);
if (ret || request != PTRACE_DETACH)
ptrace_unfreeze_traced(child);
out_put_task_struct:
put_task_struct(child);
out:
return ret;
}
int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
unsigned long data)
{
unsigned long tmp;
int copied;
copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
if (copied != sizeof(tmp))
return -EIO;
return put_user(tmp, (unsigned long __user *)data);
}
int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
unsigned long data)
{
int copied;
copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
FOLL_FORCE | FOLL_WRITE);
return (copied == sizeof(data)) ? 0 : -EIO;
}
#if defined CONFIG_COMPAT
int compat_ptrace_request(struct task_struct *child, compat_long_t request,
compat_ulong_t addr, compat_ulong_t data)
{
compat_ulong_t __user *datap = compat_ptr(data);
compat_ulong_t word;
kernel_siginfo_t siginfo;
int ret;
switch (request) {
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
ret = ptrace_access_vm(child, addr, &word, sizeof(word),
FOLL_FORCE);
if (ret != sizeof(word))
ret = -EIO;
else
ret = put_user(word, datap);
break;
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = ptrace_access_vm(child, addr, &data, sizeof(data),
FOLL_FORCE | FOLL_WRITE);
ret = (ret != sizeof(data) ? -EIO : 0);
break;
case PTRACE_GETEVENTMSG:
ret = put_user((compat_ulong_t) child->ptrace_message, datap);
break;
case PTRACE_GETSIGINFO:
ret = ptrace_getsiginfo(child, &siginfo);
if (!ret)
ret = copy_siginfo_to_user32(
(struct compat_siginfo __user *) datap,
&siginfo);
break;
case PTRACE_SETSIGINFO:
ret = copy_siginfo_from_user32(
&siginfo, (struct compat_siginfo __user *) datap);
if (!ret)
ret = ptrace_setsiginfo(child, &siginfo);
break;
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
case PTRACE_GETREGSET:
case PTRACE_SETREGSET:
{
struct iovec kiov;
struct compat_iovec __user *uiov =
(struct compat_iovec __user *) datap;
compat_uptr_t ptr;
compat_size_t len;
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(ptr, &uiov->iov_base) ||
__get_user(len, &uiov->iov_len))
return -EFAULT;
kiov.iov_base = compat_ptr(ptr);
kiov.iov_len = len;
ret = ptrace_regset(child, request, addr, &kiov);
if (!ret)
ret = __put_user(kiov.iov_len, &uiov->iov_len);
break;
}
#endif
default:
ret = ptrace_request(child, request, addr, data);
}
return ret;
}
COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
compat_long_t, addr, compat_long_t, data)
{
struct task_struct *child;
long ret;
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
goto out;
}
child = find_get_task_by_vpid(pid);
if (!child) {
ret = -ESRCH;
goto out;
}
if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
ret = ptrace_attach(child, request, addr, data);
goto out_put_task_struct;
}
ret = ptrace_check_attach(child, request == PTRACE_KILL ||
request == PTRACE_INTERRUPT);
if (!ret) {
ret = compat_arch_ptrace(child, request, addr, data);
if (ret || request != PTRACE_DETACH)
ptrace_unfreeze_traced(child);
}
out_put_task_struct:
put_task_struct(child);
out:
return ret;
}
#endif /* CONFIG_COMPAT */
| linux-master | kernel/ptrace.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* The "user cache".
*
* (C) Copyright 1991-2000 Linus Torvalds
*
* We have a per-user structure to keep track of how many
* processes, files etc the user has claimed, in order to be
* able to have per-user limits for system resources.
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/key.h>
#include <linux/sched/user.h>
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
/*
* userns count is 1 for root user, 1 for init_uts_ns,
* and 1 for... ?
*/
struct user_namespace init_user_ns = {
.uid_map = {
.nr_extents = 1,
{
.extent[0] = {
.first = 0,
.lower_first = 0,
.count = 4294967295U,
},
},
},
.gid_map = {
.nr_extents = 1,
{
.extent[0] = {
.first = 0,
.lower_first = 0,
.count = 4294967295U,
},
},
},
.projid_map = {
.nr_extents = 1,
{
.extent[0] = {
.first = 0,
.lower_first = 0,
.count = 4294967295U,
},
},
},
.ns.count = REFCOUNT_INIT(3),
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
.ns.inum = PROC_USER_INIT_INO,
#ifdef CONFIG_USER_NS
.ns.ops = &userns_operations,
#endif
.flags = USERNS_INIT_FLAGS,
#ifdef CONFIG_KEYS
.keyring_name_list = LIST_HEAD_INIT(init_user_ns.keyring_name_list),
.keyring_sem = __RWSEM_INITIALIZER(init_user_ns.keyring_sem),
#endif
};
EXPORT_SYMBOL_GPL(init_user_ns);
/*
* UID task count cache, to get fast user lookup in "alloc_uid"
* when changing user ID's (ie setuid() and friends).
*/
#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 7)
#define UIDHASH_SZ (1 << UIDHASH_BITS)
#define UIDHASH_MASK (UIDHASH_SZ - 1)
#define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
#define uidhashentry(uid) (uidhash_table + __uidhashfn((__kuid_val(uid))))
static struct kmem_cache *uid_cachep;
static struct hlist_head uidhash_table[UIDHASH_SZ];
/*
* The uidhash_lock is mostly taken from process context, but it is
* occasionally also taken from softirq/tasklet context, when
* task-structs get RCU-freed. Hence all locking must be softirq-safe.
* But free_uid() is also called with local interrupts disabled, and running
* local_bh_enable() with local interrupts disabled is an error - we'll run
* softirq callbacks, and they can unconditionally enable interrupts, and
* the caller of free_uid() didn't expect that..
*/
static DEFINE_SPINLOCK(uidhash_lock);
/* root_user.__count is 1, for init task cred */
struct user_struct root_user = {
.__count = REFCOUNT_INIT(1),
.uid = GLOBAL_ROOT_UID,
.ratelimit = RATELIMIT_STATE_INIT(root_user.ratelimit, 0, 0),
};
/*
* These routines must be called with the uidhash spinlock held!
*/
static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
{
hlist_add_head(&up->uidhash_node, hashent);
}
static void uid_hash_remove(struct user_struct *up)
{
hlist_del_init(&up->uidhash_node);
}
static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
{
struct user_struct *user;
hlist_for_each_entry(user, hashent, uidhash_node) {
if (uid_eq(user->uid, uid)) {
refcount_inc(&user->__count);
return user;
}
}
return NULL;
}
static int user_epoll_alloc(struct user_struct *up)
{
#ifdef CONFIG_EPOLL
return percpu_counter_init(&up->epoll_watches, 0, GFP_KERNEL);
#else
return 0;
#endif
}
static void user_epoll_free(struct user_struct *up)
{
#ifdef CONFIG_EPOLL
percpu_counter_destroy(&up->epoll_watches);
#endif
}
/* IRQs are disabled and uidhash_lock is held upon function entry.
* IRQ state (as stored in flags) is restored and uidhash_lock released
* upon function exit.
*/
static void free_user(struct user_struct *up, unsigned long flags)
__releases(&uidhash_lock)
{
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
user_epoll_free(up);
kmem_cache_free(uid_cachep, up);
}
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().
*
* If the user_struct could not be found, return NULL.
*/
struct user_struct *find_user(kuid_t uid)
{
struct user_struct *ret;
unsigned long flags;
spin_lock_irqsave(&uidhash_lock, flags);
ret = uid_hash_find(uid, uidhashentry(uid));
spin_unlock_irqrestore(&uidhash_lock, flags);
return ret;
}
void free_uid(struct user_struct *up)
{
unsigned long flags;
if (!up)
return;
if (refcount_dec_and_lock_irqsave(&up->__count, &uidhash_lock, &flags))
free_user(up, flags);
}
EXPORT_SYMBOL_GPL(free_uid);
struct user_struct *alloc_uid(kuid_t uid)
{
struct hlist_head *hashent = uidhashentry(uid);
struct user_struct *up, *new;
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
spin_unlock_irq(&uidhash_lock);
if (!up) {
new = kmem_cache_zalloc(uid_cachep, GFP_KERNEL);
if (!new)
return NULL;
new->uid = uid;
refcount_set(&new->__count, 1);
if (user_epoll_alloc(new)) {
kmem_cache_free(uid_cachep, new);
return NULL;
}
ratelimit_state_init(&new->ratelimit, HZ, 100);
ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE);
/*
* Before adding this, check whether we raced
* on adding the same user already..
*/
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
user_epoll_free(new);
kmem_cache_free(uid_cachep, new);
} else {
uid_hash_insert(new, hashent);
up = new;
}
spin_unlock_irq(&uidhash_lock);
}
return up;
}
static int __init uid_cache_init(void)
{
int n;
uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
for(n = 0; n < UIDHASH_SZ; ++n)
INIT_HLIST_HEAD(uidhash_table + n);
if (user_epoll_alloc(&root_user))
panic("root_user epoll percpu counter alloc failed");
/* Insert the root user immediately (init already runs as root) */
spin_lock_irq(&uidhash_lock);
uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID));
spin_unlock_irq(&uidhash_lock);
return 0;
}
subsys_initcall(uid_cache_init);
| linux-master | kernel/user.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/fork.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* 'fork.c' contains the help-routines for the 'fork' system call
* (see also entry.S and others).
* Fork is rather simple, once you get the hang of it, but the memory
* management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
*/
#include <linux/anon_inodes.h>
#include <linux/slab.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/mm.h>
#include <linux/sched/coredump.h>
#include <linux/sched/user.h>
#include <linux/sched/numa_balancing.h>
#include <linux/sched/stat.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/seq_file.h>
#include <linux/rtmutex.h>
#include <linux/init.h>
#include <linux/unistd.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/completion.h>
#include <linux/personality.h>
#include <linux/mempolicy.h>
#include <linux/sem.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/iocontext.h>
#include <linux/key.h>
#include <linux/kmsan.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/mmu_notifier.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mm_inline.h>
#include <linux/nsproxy.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/cgroup.h>
#include <linux/security.h>
#include <linux/hugetlb.h>
#include <linux/seccomp.h>
#include <linux/swap.h>
#include <linux/syscalls.h>
#include <linux/jiffies.h>
#include <linux/futex.h>
#include <linux/compat.h>
#include <linux/kthread.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/rcupdate.h>
#include <linux/ptrace.h>
#include <linux/mount.h>
#include <linux/audit.h>
#include <linux/memcontrol.h>
#include <linux/ftrace.h>
#include <linux/proc_fs.h>
#include <linux/profile.h>
#include <linux/rmap.h>
#include <linux/ksm.h>
#include <linux/acct.h>
#include <linux/userfaultfd_k.h>
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/freezer.h>
#include <linux/delayacct.h>
#include <linux/taskstats_kern.h>
#include <linux/tty.h>
#include <linux/fs_struct.h>
#include <linux/magic.h>
#include <linux/perf_event.h>
#include <linux/posix-timers.h>
#include <linux/user-return-notifier.h>
#include <linux/oom.h>
#include <linux/khugepaged.h>
#include <linux/signalfd.h>
#include <linux/uprobes.h>
#include <linux/aio.h>
#include <linux/compiler.h>
#include <linux/sysctl.h>
#include <linux/kcov.h>
#include <linux/livepatch.h>
#include <linux/thread_info.h>
#include <linux/stackleak.h>
#include <linux/kasan.h>
#include <linux/scs.h>
#include <linux/io_uring.h>
#include <linux/bpf.h>
#include <linux/stackprotector.h>
#include <linux/user_events.h>
#include <linux/iommu.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <trace/events/sched.h>
#define CREATE_TRACE_POINTS
#include <trace/events/task.h>
/*
* Minimum number of threads to boot the kernel
*/
#define MIN_THREADS 20
/*
* Maximum number of threads
*/
#define MAX_THREADS FUTEX_TID_MASK
/*
* Protected counters by write_lock_irq(&tasklist_lock)
*/
unsigned long total_forks; /* Handle normal Linux uptimes. */
int nr_threads; /* The idle threads do not count.. */
static int max_threads; /* tunable limit on nr_threads */
#define NAMED_ARRAY_INDEX(x) [x] = __stringify(x)
static const char * const resident_page_types[] = {
NAMED_ARRAY_INDEX(MM_FILEPAGES),
NAMED_ARRAY_INDEX(MM_ANONPAGES),
NAMED_ARRAY_INDEX(MM_SWAPENTS),
NAMED_ARRAY_INDEX(MM_SHMEMPAGES),
};
DEFINE_PER_CPU(unsigned long, process_counts) = 0;
__cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
#ifdef CONFIG_PROVE_RCU
int lockdep_tasklist_lock_is_held(void)
{
return lockdep_is_held(&tasklist_lock);
}
EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
#endif /* #ifdef CONFIG_PROVE_RCU */
int nr_processes(void)
{
int cpu;
int total = 0;
for_each_possible_cpu(cpu)
total += per_cpu(process_counts, cpu);
return total;
}
void __weak arch_release_task_struct(struct task_struct *tsk)
{
}
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
static struct kmem_cache *task_struct_cachep;
static inline struct task_struct *alloc_task_struct_node(int node)
{
return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
}
static inline void free_task_struct(struct task_struct *tsk)
{
kmem_cache_free(task_struct_cachep, tsk);
}
#endif
#ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
/*
* Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
* kmemcache based allocator.
*/
# if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
# ifdef CONFIG_VMAP_STACK
/*
* vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
* flush. Try to minimize the number of calls by caching stacks.
*/
#define NR_CACHED_STACKS 2
static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
struct vm_stack {
struct rcu_head rcu;
struct vm_struct *stack_vm_area;
};
static bool try_release_thread_stack_to_cache(struct vm_struct *vm)
{
unsigned int i;
for (i = 0; i < NR_CACHED_STACKS; i++) {
if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL)
continue;
return true;
}
return false;
}
static void thread_stack_free_rcu(struct rcu_head *rh)
{
struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu);
if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area))
return;
vfree(vm_stack);
}
static void thread_stack_delayed_free(struct task_struct *tsk)
{
struct vm_stack *vm_stack = tsk->stack;
vm_stack->stack_vm_area = tsk->stack_vm_area;
call_rcu(&vm_stack->rcu, thread_stack_free_rcu);
}
static int free_vm_stack_cache(unsigned int cpu)
{
struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu);
int i;
for (i = 0; i < NR_CACHED_STACKS; i++) {
struct vm_struct *vm_stack = cached_vm_stacks[i];
if (!vm_stack)
continue;
vfree(vm_stack->addr);
cached_vm_stacks[i] = NULL;
}
return 0;
}
static int memcg_charge_kernel_stack(struct vm_struct *vm)
{
int i;
int ret;
int nr_charged = 0;
BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
if (ret)
goto err;
nr_charged++;
}
return 0;
err:
for (i = 0; i < nr_charged; i++)
memcg_kmem_uncharge_page(vm->pages[i], 0);
return ret;
}
static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
struct vm_struct *vm;
void *stack;
int i;
for (i = 0; i < NR_CACHED_STACKS; i++) {
struct vm_struct *s;
s = this_cpu_xchg(cached_stacks[i], NULL);
if (!s)
continue;
/* Reset stack metadata. */
kasan_unpoison_range(s->addr, THREAD_SIZE);
stack = kasan_reset_tag(s->addr);
/* Clear stale pointers from reused stack. */
memset(stack, 0, THREAD_SIZE);
if (memcg_charge_kernel_stack(s)) {
vfree(s->addr);
return -ENOMEM;
}
tsk->stack_vm_area = s;
tsk->stack = stack;
return 0;
}
/*
* Allocated stacks are cached and later reused by new threads,
* so memcg accounting is performed manually on assigning/releasing
* stacks to tasks. Drop __GFP_ACCOUNT.
*/
stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
VMALLOC_START, VMALLOC_END,
THREADINFO_GFP & ~__GFP_ACCOUNT,
PAGE_KERNEL,
0, node, __builtin_return_address(0));
if (!stack)
return -ENOMEM;
vm = find_vm_area(stack);
if (memcg_charge_kernel_stack(vm)) {
vfree(stack);
return -ENOMEM;
}
/*
* We can't call find_vm_area() in interrupt context, and
* free_thread_stack() can be called in interrupt context,
* so cache the vm_struct.
*/
tsk->stack_vm_area = vm;
stack = kasan_reset_tag(stack);
tsk->stack = stack;
return 0;
}
static void free_thread_stack(struct task_struct *tsk)
{
if (!try_release_thread_stack_to_cache(tsk->stack_vm_area))
thread_stack_delayed_free(tsk);
tsk->stack = NULL;
tsk->stack_vm_area = NULL;
}
# else /* !CONFIG_VMAP_STACK */
static void thread_stack_free_rcu(struct rcu_head *rh)
{
__free_pages(virt_to_page(rh), THREAD_SIZE_ORDER);
}
static void thread_stack_delayed_free(struct task_struct *tsk)
{
struct rcu_head *rh = tsk->stack;
call_rcu(rh, thread_stack_free_rcu);
}
static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
struct page *page = alloc_pages_node(node, THREADINFO_GFP,
THREAD_SIZE_ORDER);
if (likely(page)) {
tsk->stack = kasan_reset_tag(page_address(page));
return 0;
}
return -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
{
thread_stack_delayed_free(tsk);
tsk->stack = NULL;
}
# endif /* CONFIG_VMAP_STACK */
# else /* !(THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)) */
static struct kmem_cache *thread_stack_cache;
static void thread_stack_free_rcu(struct rcu_head *rh)
{
kmem_cache_free(thread_stack_cache, rh);
}
static void thread_stack_delayed_free(struct task_struct *tsk)
{
struct rcu_head *rh = tsk->stack;
call_rcu(rh, thread_stack_free_rcu);
}
static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
unsigned long *stack;
stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
stack = kasan_reset_tag(stack);
tsk->stack = stack;
return stack ? 0 : -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
{
thread_stack_delayed_free(tsk);
tsk->stack = NULL;
}
void thread_stack_cache_init(void)
{
thread_stack_cache = kmem_cache_create_usercopy("thread_stack",
THREAD_SIZE, THREAD_SIZE, 0, 0,
THREAD_SIZE, NULL);
BUG_ON(thread_stack_cache == NULL);
}
# endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */
#else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
unsigned long *stack;
stack = arch_alloc_thread_stack_node(tsk, node);
tsk->stack = stack;
return stack ? 0 : -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
{
arch_free_thread_stack(tsk);
tsk->stack = NULL;
}
#endif /* !CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
/* SLAB cache for signal_struct structures (tsk->signal) */
static struct kmem_cache *signal_cachep;
/* SLAB cache for sighand_struct structures (tsk->sighand) */
struct kmem_cache *sighand_cachep;
/* SLAB cache for files_struct structures (tsk->files) */
struct kmem_cache *files_cachep;
/* SLAB cache for fs_struct structures (tsk->fs) */
struct kmem_cache *fs_cachep;
/* SLAB cache for vm_area_struct structures */
static struct kmem_cache *vm_area_cachep;
/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;
#ifdef CONFIG_PER_VMA_LOCK
/* SLAB cache for vm_area_struct.lock */
static struct kmem_cache *vma_lock_cachep;
static bool vma_lock_alloc(struct vm_area_struct *vma)
{
vma->vm_lock = kmem_cache_alloc(vma_lock_cachep, GFP_KERNEL);
if (!vma->vm_lock)
return false;
init_rwsem(&vma->vm_lock->lock);
vma->vm_lock_seq = -1;
return true;
}
static inline void vma_lock_free(struct vm_area_struct *vma)
{
kmem_cache_free(vma_lock_cachep, vma->vm_lock);
}
#else /* CONFIG_PER_VMA_LOCK */
static inline bool vma_lock_alloc(struct vm_area_struct *vma) { return true; }
static inline void vma_lock_free(struct vm_area_struct *vma) {}
#endif /* CONFIG_PER_VMA_LOCK */
struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
{
struct vm_area_struct *vma;
vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (!vma)
return NULL;
vma_init(vma, mm);
if (!vma_lock_alloc(vma)) {
kmem_cache_free(vm_area_cachep, vma);
return NULL;
}
return vma;
}
struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
{
struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
if (!new)
return NULL;
ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
/*
* orig->shared.rb may be modified concurrently, but the clone
* will be reinitialized.
*/
data_race(memcpy(new, orig, sizeof(*new)));
if (!vma_lock_alloc(new)) {
kmem_cache_free(vm_area_cachep, new);
return NULL;
}
INIT_LIST_HEAD(&new->anon_vma_chain);
vma_numab_state_init(new);
dup_anon_vma_name(orig, new);
return new;
}
void __vm_area_free(struct vm_area_struct *vma)
{
vma_numab_state_free(vma);
free_anon_vma_name(vma);
vma_lock_free(vma);
kmem_cache_free(vm_area_cachep, vma);
}
#ifdef CONFIG_PER_VMA_LOCK
static void vm_area_free_rcu_cb(struct rcu_head *head)
{
struct vm_area_struct *vma = container_of(head, struct vm_area_struct,
vm_rcu);
/* The vma should not be locked while being destroyed. */
VM_BUG_ON_VMA(rwsem_is_locked(&vma->vm_lock->lock), vma);
__vm_area_free(vma);
}
#endif
void vm_area_free(struct vm_area_struct *vma)
{
#ifdef CONFIG_PER_VMA_LOCK
call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb);
#else
__vm_area_free(vma);
#endif
}
static void account_kernel_stack(struct task_struct *tsk, int account)
{
if (IS_ENABLED(CONFIG_VMAP_STACK)) {
struct vm_struct *vm = task_stack_vm_area(tsk);
int i;
for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
account * (PAGE_SIZE / 1024));
} else {
void *stack = task_stack_page(tsk);
/* All stack pages are in the same node. */
mod_lruvec_kmem_state(stack, NR_KERNEL_STACK_KB,
account * (THREAD_SIZE / 1024));
}
}
void exit_task_stack_account(struct task_struct *tsk)
{
account_kernel_stack(tsk, -1);
if (IS_ENABLED(CONFIG_VMAP_STACK)) {
struct vm_struct *vm;
int i;
vm = task_stack_vm_area(tsk);
for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
memcg_kmem_uncharge_page(vm->pages[i], 0);
}
}
static void release_task_stack(struct task_struct *tsk)
{
if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD))
return; /* Better to leak the stack than to free prematurely */
free_thread_stack(tsk);
}
#ifdef CONFIG_THREAD_INFO_IN_TASK
void put_task_stack(struct task_struct *tsk)
{
if (refcount_dec_and_test(&tsk->stack_refcount))
release_task_stack(tsk);
}
#endif
void free_task(struct task_struct *tsk)
{
#ifdef CONFIG_SECCOMP
WARN_ON_ONCE(tsk->seccomp.filter);
#endif
release_user_cpus_ptr(tsk);
scs_release(tsk);
#ifndef CONFIG_THREAD_INFO_IN_TASK
/*
* The task is finally done with both the stack and thread_info,
* so free both.
*/
release_task_stack(tsk);
#else
/*
* If the task had a separate stack allocation, it should be gone
* by now.
*/
WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
#endif
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
arch_release_task_struct(tsk);
if (tsk->flags & PF_KTHREAD)
free_kthread_struct(tsk);
bpf_task_storage_free(tsk);
free_task_struct(tsk);
}
EXPORT_SYMBOL(free_task);
static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
{
struct file *exe_file;
exe_file = get_mm_exe_file(oldmm);
RCU_INIT_POINTER(mm->exe_file, exe_file);
/*
* We depend on the oldmm having properly denied write access to the
* exe_file already.
*/
if (exe_file && deny_write_access(exe_file))
pr_warn_once("deny_write_access() failed in %s\n", __func__);
}
#ifdef CONFIG_MMU
static __latent_entropy int dup_mmap(struct mm_struct *mm,
struct mm_struct *oldmm)
{
struct vm_area_struct *mpnt, *tmp;
int retval;
unsigned long charge = 0;
LIST_HEAD(uf);
VMA_ITERATOR(old_vmi, oldmm, 0);
VMA_ITERATOR(vmi, mm, 0);
uprobe_start_dup_mmap();
if (mmap_write_lock_killable(oldmm)) {
retval = -EINTR;
goto fail_uprobe_end;
}
flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm);
/*
* Not linked in yet - no deadlock potential:
*/
mmap_write_lock_nested(mm, SINGLE_DEPTH_NESTING);
/* No ordering required: file already has been exposed. */
dup_mm_exe_file(mm, oldmm);
mm->total_vm = oldmm->total_vm;
mm->data_vm = oldmm->data_vm;
mm->exec_vm = oldmm->exec_vm;
mm->stack_vm = oldmm->stack_vm;
retval = ksm_fork(mm, oldmm);
if (retval)
goto out;
khugepaged_fork(mm, oldmm);
retval = vma_iter_bulk_alloc(&vmi, oldmm->map_count);
if (retval)
goto out;
mt_clear_in_rcu(vmi.mas.tree);
for_each_vma(old_vmi, mpnt) {
struct file *file;
vma_start_write(mpnt);
if (mpnt->vm_flags & VM_DONTCOPY) {
vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
continue;
}
charge = 0;
/*
* Don't duplicate many vmas if we've been oom-killed (for
* example)
*/
if (fatal_signal_pending(current)) {
retval = -EINTR;
goto loop_out;
}
if (mpnt->vm_flags & VM_ACCOUNT) {
unsigned long len = vma_pages(mpnt);
if (security_vm_enough_memory_mm(oldmm, len)) /* sic */
goto fail_nomem;
charge = len;
}
tmp = vm_area_dup(mpnt);
if (!tmp)
goto fail_nomem;
retval = vma_dup_policy(mpnt, tmp);
if (retval)
goto fail_nomem_policy;
tmp->vm_mm = mm;
retval = dup_userfaultfd(tmp, &uf);
if (retval)
goto fail_nomem_anon_vma_fork;
if (tmp->vm_flags & VM_WIPEONFORK) {
/*
* VM_WIPEONFORK gets a clean slate in the child.
* Don't prepare anon_vma until fault since we don't
* copy page for current vma.
*/
tmp->anon_vma = NULL;
} else if (anon_vma_fork(tmp, mpnt))
goto fail_nomem_anon_vma_fork;
vm_flags_clear(tmp, VM_LOCKED_MASK);
file = tmp->vm_file;
if (file) {
struct address_space *mapping = file->f_mapping;
get_file(file);
i_mmap_lock_write(mapping);
if (tmp->vm_flags & VM_SHARED)
mapping_allow_writable(mapping);
flush_dcache_mmap_lock(mapping);
/* insert tmp into the share list, just after mpnt */
vma_interval_tree_insert_after(tmp, mpnt,
&mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
/*
* Copy/update hugetlb private vma information.
*/
if (is_vm_hugetlb_page(tmp))
hugetlb_dup_vma_private(tmp);
/* Link the vma into the MT */
if (vma_iter_bulk_store(&vmi, tmp))
goto fail_nomem_vmi_store;
mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
retval = copy_page_range(tmp, mpnt);
if (tmp->vm_ops && tmp->vm_ops->open)
tmp->vm_ops->open(tmp);
if (retval)
goto loop_out;
}
/* a new mm has just been created */
retval = arch_dup_mmap(oldmm, mm);
loop_out:
vma_iter_free(&vmi);
if (!retval)
mt_set_in_rcu(vmi.mas.tree);
out:
mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
mmap_write_unlock(oldmm);
dup_userfaultfd_complete(&uf);
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
fail_nomem_vmi_store:
unlink_anon_vmas(tmp);
fail_nomem_anon_vma_fork:
mpol_put(vma_policy(tmp));
fail_nomem_policy:
vm_area_free(tmp);
fail_nomem:
retval = -ENOMEM;
vm_unacct_memory(charge);
goto loop_out;
}
static inline int mm_alloc_pgd(struct mm_struct *mm)
{
mm->pgd = pgd_alloc(mm);
if (unlikely(!mm->pgd))
return -ENOMEM;
return 0;
}
static inline void mm_free_pgd(struct mm_struct *mm)
{
pgd_free(mm, mm->pgd);
}
#else
static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
{
mmap_write_lock(oldmm);
dup_mm_exe_file(mm, oldmm);
mmap_write_unlock(oldmm);
return 0;
}
#define mm_alloc_pgd(mm) (0)
#define mm_free_pgd(mm)
#endif /* CONFIG_MMU */
static void check_mm(struct mm_struct *mm)
{
int i;
BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
"Please make sure 'struct resident_page_types[]' is updated as well");
for (i = 0; i < NR_MM_COUNTERS; i++) {
long x = percpu_counter_sum(&mm->rss_stat[i]);
if (unlikely(x))
pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
mm, resident_page_types[i], x);
}
if (mm_pgtables_bytes(mm))
pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
mm_pgtables_bytes(mm));
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
VM_BUG_ON_MM(mm->pmd_huge_pte, mm);
#endif
}
#define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL))
#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
static void do_check_lazy_tlb(void *arg)
{
struct mm_struct *mm = arg;
WARN_ON_ONCE(current->active_mm == mm);
}
static void do_shoot_lazy_tlb(void *arg)
{
struct mm_struct *mm = arg;
if (current->active_mm == mm) {
WARN_ON_ONCE(current->mm);
current->active_mm = &init_mm;
switch_mm(mm, &init_mm, current);
}
}
static void cleanup_lazy_tlbs(struct mm_struct *mm)
{
if (!IS_ENABLED(CONFIG_MMU_LAZY_TLB_SHOOTDOWN)) {
/*
* In this case, lazy tlb mms are refounted and would not reach
* __mmdrop until all CPUs have switched away and mmdrop()ed.
*/
return;
}
/*
* Lazy mm shootdown does not refcount "lazy tlb mm" usage, rather it
* requires lazy mm users to switch to another mm when the refcount
* drops to zero, before the mm is freed. This requires IPIs here to
* switch kernel threads to init_mm.
*
* archs that use IPIs to flush TLBs can piggy-back that lazy tlb mm
* switch with the final userspace teardown TLB flush which leaves the
* mm lazy on this CPU but no others, reducing the need for additional
* IPIs here. There are cases where a final IPI is still required here,
* such as the final mmdrop being performed on a different CPU than the
* one exiting, or kernel threads using the mm when userspace exits.
*
* IPI overheads have not found to be expensive, but they could be
* reduced in a number of possible ways, for example (roughly
* increasing order of complexity):
* - The last lazy reference created by exit_mm() could instead switch
* to init_mm, however it's probable this will run on the same CPU
* immediately afterwards, so this may not reduce IPIs much.
* - A batch of mms requiring IPIs could be gathered and freed at once.
* - CPUs store active_mm where it can be remotely checked without a
* lock, to filter out false-positives in the cpumask.
* - After mm_users or mm_count reaches zero, switching away from the
* mm could clear mm_cpumask to reduce some IPIs, perhaps together
* with some batching or delaying of the final IPIs.
* - A delayed freeing and RCU-like quiescing sequence based on mm
* switching to avoid IPIs completely.
*/
on_each_cpu_mask(mm_cpumask(mm), do_shoot_lazy_tlb, (void *)mm, 1);
if (IS_ENABLED(CONFIG_DEBUG_VM_SHOOT_LAZIES))
on_each_cpu(do_check_lazy_tlb, (void *)mm, 1);
}
/*
* Called when the last reference to the mm
* is dropped: either by a lazy thread or by
* mmput. Free the page directory and the mm.
*/
void __mmdrop(struct mm_struct *mm)
{
BUG_ON(mm == &init_mm);
WARN_ON_ONCE(mm == current->mm);
/* Ensure no CPUs are using this as their lazy tlb mm */
cleanup_lazy_tlbs(mm);
WARN_ON_ONCE(mm == current->active_mm);
mm_free_pgd(mm);
destroy_context(mm);
mmu_notifier_subscriptions_destroy(mm);
check_mm(mm);
put_user_ns(mm->user_ns);
mm_pasid_drop(mm);
mm_destroy_cid(mm);
percpu_counter_destroy_many(mm->rss_stat, NR_MM_COUNTERS);
free_mm(mm);
}
EXPORT_SYMBOL_GPL(__mmdrop);
static void mmdrop_async_fn(struct work_struct *work)
{
struct mm_struct *mm;
mm = container_of(work, struct mm_struct, async_put_work);
__mmdrop(mm);
}
static void mmdrop_async(struct mm_struct *mm)
{
if (unlikely(atomic_dec_and_test(&mm->mm_count))) {
INIT_WORK(&mm->async_put_work, mmdrop_async_fn);
schedule_work(&mm->async_put_work);
}
}
static inline void free_signal_struct(struct signal_struct *sig)
{
taskstats_tgid_free(sig);
sched_autogroup_exit(sig);
/*
* __mmdrop is not safe to call from softirq context on x86 due to
* pgd_dtor so postpone it to the async context
*/
if (sig->oom_mm)
mmdrop_async(sig->oom_mm);
kmem_cache_free(signal_cachep, sig);
}
static inline void put_signal_struct(struct signal_struct *sig)
{
if (refcount_dec_and_test(&sig->sigcnt))
free_signal_struct(sig);
}
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!tsk->exit_state);
WARN_ON(refcount_read(&tsk->usage));
WARN_ON(tsk == current);
io_uring_free(tsk);
cgroup_free(tsk);
task_numa_free(tsk, true);
security_task_free(tsk);
exit_creds(tsk);
delayacct_tsk_free(tsk);
put_signal_struct(tsk->signal);
sched_core_free(tsk);
free_task(tsk);
}
EXPORT_SYMBOL_GPL(__put_task_struct);
void __put_task_struct_rcu_cb(struct rcu_head *rhp)
{
struct task_struct *task = container_of(rhp, struct task_struct, rcu);
__put_task_struct(task);
}
EXPORT_SYMBOL_GPL(__put_task_struct_rcu_cb);
void __init __weak arch_task_cache_init(void) { }
/*
* set_max_threads
*/
static void set_max_threads(unsigned int max_threads_suggested)
{
u64 threads;
unsigned long nr_pages = totalram_pages();
/*
* The number of threads shall be limited such that the thread
* structures may only consume a small part of the available memory.
*/
if (fls64(nr_pages) + fls64(PAGE_SIZE) > 64)
threads = MAX_THREADS;
else
threads = div64_u64((u64) nr_pages * (u64) PAGE_SIZE,
(u64) THREAD_SIZE * 8UL);
if (threads > max_threads_suggested)
threads = max_threads_suggested;
max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
}
#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
/* Initialized by the architecture: */
int arch_task_struct_size __read_mostly;
#endif
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
static void task_struct_whitelist(unsigned long *offset, unsigned long *size)
{
/* Fetch thread_struct whitelist for the architecture. */
arch_thread_struct_whitelist(offset, size);
/*
* Handle zero-sized whitelist or empty thread_struct, otherwise
* adjust offset to position of thread_struct in task_struct.
*/
if (unlikely(*size == 0))
*offset = 0;
else
*offset += offsetof(struct task_struct, thread);
}
#endif /* CONFIG_ARCH_TASK_STRUCT_ALLOCATOR */
void __init fork_init(void)
{
int i;
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN 0
#endif
int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN);
unsigned long useroffset, usersize;
/* create a slab on which task_structs can be allocated */
task_struct_whitelist(&useroffset, &usersize);
task_struct_cachep = kmem_cache_create_usercopy("task_struct",
arch_task_struct_size, align,
SLAB_PANIC|SLAB_ACCOUNT,
useroffset, usersize, NULL);
#endif
/* do the arch specific task caches init */
arch_task_cache_init();
set_max_threads(MAX_THREADS);
init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
init_task.signal->rlim[RLIMIT_SIGPENDING] =
init_task.signal->rlim[RLIMIT_NPROC];
for (i = 0; i < UCOUNT_COUNTS; i++)
init_user_ns.ucount_max[i] = max_threads/2;
set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY);
set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY);
set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY);
set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY);
#ifdef CONFIG_VMAP_STACK
cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
NULL, free_vm_stack_cache);
#endif
scs_init();
lockdep_init_task(&init_task);
uprobes_init();
}
int __weak arch_dup_task_struct(struct task_struct *dst,
struct task_struct *src)
{
*dst = *src;
return 0;
}
void set_task_stack_end_magic(struct task_struct *tsk)
{
unsigned long *stackend;
stackend = end_of_stack(tsk);
*stackend = STACK_END_MAGIC; /* for overflow detection */
}
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
int err;
if (node == NUMA_NO_NODE)
node = tsk_fork_get_node(orig);
tsk = alloc_task_struct_node(node);
if (!tsk)
return NULL;
err = arch_dup_task_struct(tsk, orig);
if (err)
goto free_tsk;
err = alloc_thread_stack_node(tsk, node);
if (err)
goto free_tsk;
#ifdef CONFIG_THREAD_INFO_IN_TASK
refcount_set(&tsk->stack_refcount, 1);
#endif
account_kernel_stack(tsk, 1);
err = scs_prepare(tsk, node);
if (err)
goto free_stack;
#ifdef CONFIG_SECCOMP
/*
* We must handle setting up seccomp filters once we're under
* the sighand lock in case orig has changed between now and
* then. Until then, filter must be NULL to avoid messing up
* the usage counts on the error path calling free_task.
*/
tsk->seccomp.filter = NULL;
#endif
setup_thread_stack(tsk, orig);
clear_user_return_notifier(tsk);
clear_tsk_need_resched(tsk);
set_task_stack_end_magic(tsk);
clear_syscall_work_syscall_user_dispatch(tsk);
#ifdef CONFIG_STACKPROTECTOR
tsk->stack_canary = get_random_canary();
#endif
if (orig->cpus_ptr == &orig->cpus_mask)
tsk->cpus_ptr = &tsk->cpus_mask;
dup_user_cpus_ptr(tsk, orig, node);
/*
* One for the user space visible state that goes away when reaped.
* One for the scheduler.
*/
refcount_set(&tsk->rcu_users, 2);
/* One for the rcu users */
refcount_set(&tsk->usage, 1);
#ifdef CONFIG_BLK_DEV_IO_TRACE
tsk->btrace_seq = 0;
#endif
tsk->splice_pipe = NULL;
tsk->task_frag.page = NULL;
tsk->wake_q.next = NULL;
tsk->worker_private = NULL;
kcov_task_init(tsk);
kmsan_task_create(tsk);
kmap_local_fork(tsk);
#ifdef CONFIG_FAULT_INJECTION
tsk->fail_nth = 0;
#endif
#ifdef CONFIG_BLK_CGROUP
tsk->throttle_disk = NULL;
tsk->use_memdelay = 0;
#endif
#ifdef CONFIG_IOMMU_SVA
tsk->pasid_activated = 0;
#endif
#ifdef CONFIG_MEMCG
tsk->active_memcg = NULL;
#endif
#ifdef CONFIG_CPU_SUP_INTEL
tsk->reported_split_lock = 0;
#endif
#ifdef CONFIG_SCHED_MM_CID
tsk->mm_cid = -1;
tsk->last_mm_cid = -1;
tsk->mm_cid_active = 0;
tsk->migrate_from_cpu = -1;
#endif
return tsk;
free_stack:
exit_task_stack_account(tsk);
free_thread_stack(tsk);
free_tsk:
free_task_struct(tsk);
return NULL;
}
__cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);
static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;
static int __init coredump_filter_setup(char *s)
{
default_dump_filter =
(simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
MMF_DUMP_FILTER_MASK;
return 1;
}
__setup("coredump_filter=", coredump_filter_setup);
#include <linux/init_task.h>
static void mm_init_aio(struct mm_struct *mm)
{
#ifdef CONFIG_AIO
spin_lock_init(&mm->ioctx_lock);
mm->ioctx_table = NULL;
#endif
}
static __always_inline void mm_clear_owner(struct mm_struct *mm,
struct task_struct *p)
{
#ifdef CONFIG_MEMCG
if (mm->owner == p)
WRITE_ONCE(mm->owner, NULL);
#endif
}
static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
#ifdef CONFIG_MEMCG
mm->owner = p;
#endif
}
static void mm_init_uprobes_state(struct mm_struct *mm)
{
#ifdef CONFIG_UPROBES
mm->uprobes_state.xol_area = NULL;
#endif
}
static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
struct user_namespace *user_ns)
{
mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
seqcount_init(&mm->write_protect_seq);
mmap_init_lock(mm);
INIT_LIST_HEAD(&mm->mmlist);
#ifdef CONFIG_PER_VMA_LOCK
mm->mm_lock_seq = 0;
#endif
mm_pgtables_bytes_init(mm);
mm->map_count = 0;
mm->locked_vm = 0;
atomic64_set(&mm->pinned_vm, 0);
memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
spin_lock_init(&mm->page_table_lock);
spin_lock_init(&mm->arg_lock);
mm_init_cpumask(mm);
mm_init_aio(mm);
mm_init_owner(mm, p);
mm_pasid_init(mm);
RCU_INIT_POINTER(mm->exe_file, NULL);
mmu_notifier_subscriptions_init(mm);
init_tlb_flush_pending(mm);
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
hugetlb_count_init(mm);
if (current->mm) {
mm->flags = current->mm->flags & MMF_INIT_MASK;
mm->def_flags = current->mm->def_flags & VM_INIT_DEF_MASK;
} else {
mm->flags = default_dump_filter;
mm->def_flags = 0;
}
if (mm_alloc_pgd(mm))
goto fail_nopgd;
if (init_new_context(p, mm))
goto fail_nocontext;
if (mm_alloc_cid(mm))
goto fail_cid;
if (percpu_counter_init_many(mm->rss_stat, 0, GFP_KERNEL_ACCOUNT,
NR_MM_COUNTERS))
goto fail_pcpu;
mm->user_ns = get_user_ns(user_ns);
lru_gen_init_mm(mm);
return mm;
fail_pcpu:
mm_destroy_cid(mm);
fail_cid:
destroy_context(mm);
fail_nocontext:
mm_free_pgd(mm);
fail_nopgd:
free_mm(mm);
return NULL;
}
/*
* Allocate and initialize an mm_struct.
*/
struct mm_struct *mm_alloc(void)
{
struct mm_struct *mm;
mm = allocate_mm();
if (!mm)
return NULL;
memset(mm, 0, sizeof(*mm));
return mm_init(mm, current, current_user_ns());
}
static inline void __mmput(struct mm_struct *mm)
{
VM_BUG_ON(atomic_read(&mm->mm_users));
uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
exit_mmap(mm);
mm_put_huge_zero_page(mm);
set_mm_exe_file(mm, NULL);
if (!list_empty(&mm->mmlist)) {
spin_lock(&mmlist_lock);
list_del(&mm->mmlist);
spin_unlock(&mmlist_lock);
}
if (mm->binfmt)
module_put(mm->binfmt->module);
lru_gen_del_mm(mm);
mmdrop(mm);
}
/*
* Decrement the use count and release all resources for an mm.
*/
void mmput(struct mm_struct *mm)
{
might_sleep();
if (atomic_dec_and_test(&mm->mm_users))
__mmput(mm);
}
EXPORT_SYMBOL_GPL(mmput);
#ifdef CONFIG_MMU
static void mmput_async_fn(struct work_struct *work)
{
struct mm_struct *mm = container_of(work, struct mm_struct,
async_put_work);
__mmput(mm);
}
void mmput_async(struct mm_struct *mm)
{
if (atomic_dec_and_test(&mm->mm_users)) {
INIT_WORK(&mm->async_put_work, mmput_async_fn);
schedule_work(&mm->async_put_work);
}
}
EXPORT_SYMBOL_GPL(mmput_async);
#endif
/**
* set_mm_exe_file - change a reference to the mm's executable file
*
* This changes mm's executable file (shown as symlink /proc/[pid]/exe).
*
* Main users are mmput() and sys_execve(). Callers prevent concurrent
* invocations: in mmput() nobody alive left, in execve it happens before
* the new mm is made visible to anyone.
*
* Can only fail if new_exe_file != NULL.
*/
int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
{
struct file *old_exe_file;
/*
* It is safe to dereference the exe_file without RCU as
* this function is only called if nobody else can access
* this mm -- see comment above for justification.
*/
old_exe_file = rcu_dereference_raw(mm->exe_file);
if (new_exe_file) {
/*
* We expect the caller (i.e., sys_execve) to already denied
* write access, so this is unlikely to fail.
*/
if (unlikely(deny_write_access(new_exe_file)))
return -EACCES;
get_file(new_exe_file);
}
rcu_assign_pointer(mm->exe_file, new_exe_file);
if (old_exe_file) {
allow_write_access(old_exe_file);
fput(old_exe_file);
}
return 0;
}
/**
* replace_mm_exe_file - replace a reference to the mm's executable file
*
* This changes mm's executable file (shown as symlink /proc/[pid]/exe).
*
* Main user is sys_prctl(PR_SET_MM_MAP/EXE_FILE).
*/
int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
{
struct vm_area_struct *vma;
struct file *old_exe_file;
int ret = 0;
/* Forbid mm->exe_file change if old file still mapped. */
old_exe_file = get_mm_exe_file(mm);
if (old_exe_file) {
VMA_ITERATOR(vmi, mm, 0);
mmap_read_lock(mm);
for_each_vma(vmi, vma) {
if (!vma->vm_file)
continue;
if (path_equal(&vma->vm_file->f_path,
&old_exe_file->f_path)) {
ret = -EBUSY;
break;
}
}
mmap_read_unlock(mm);
fput(old_exe_file);
if (ret)
return ret;
}
ret = deny_write_access(new_exe_file);
if (ret)
return -EACCES;
get_file(new_exe_file);
/* set the new file */
mmap_write_lock(mm);
old_exe_file = rcu_dereference_raw(mm->exe_file);
rcu_assign_pointer(mm->exe_file, new_exe_file);
mmap_write_unlock(mm);
if (old_exe_file) {
allow_write_access(old_exe_file);
fput(old_exe_file);
}
return 0;
}
/**
* get_mm_exe_file - acquire a reference to the mm's executable file
*
* Returns %NULL if mm has no associated executable file.
* User must release file via fput().
*/
struct file *get_mm_exe_file(struct mm_struct *mm)
{
struct file *exe_file;
rcu_read_lock();
exe_file = rcu_dereference(mm->exe_file);
if (exe_file && !get_file_rcu(exe_file))
exe_file = NULL;
rcu_read_unlock();
return exe_file;
}
/**
* get_task_exe_file - acquire a reference to the task's executable file
*
* Returns %NULL if task's mm (if any) has no associated executable file or
* this is a kernel thread with borrowed mm (see the comment above get_task_mm).
* User must release file via fput().
*/
struct file *get_task_exe_file(struct task_struct *task)
{
struct file *exe_file = NULL;
struct mm_struct *mm;
task_lock(task);
mm = task->mm;
if (mm) {
if (!(task->flags & PF_KTHREAD))
exe_file = get_mm_exe_file(mm);
}
task_unlock(task);
return exe_file;
}
/**
* get_task_mm - acquire a reference to the task's mm
*
* Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
* this kernel workthread has transiently adopted a user mm with use_mm,
* to do its AIO) is not set and if so returns a reference to it, after
* bumping up the use count. User must release the mm via mmput()
* after use. Typically used by /proc and ptrace.
*/
struct mm_struct *get_task_mm(struct task_struct *task)
{
struct mm_struct *mm;
task_lock(task);
mm = task->mm;
if (mm) {
if (task->flags & PF_KTHREAD)
mm = NULL;
else
mmget(mm);
}
task_unlock(task);
return mm;
}
EXPORT_SYMBOL_GPL(get_task_mm);
struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
{
struct mm_struct *mm;
int err;
err = down_read_killable(&task->signal->exec_update_lock);
if (err)
return ERR_PTR(err);
mm = get_task_mm(task);
if (mm && mm != current->mm &&
!ptrace_may_access(task, mode)) {
mmput(mm);
mm = ERR_PTR(-EACCES);
}
up_read(&task->signal->exec_update_lock);
return mm;
}
static void complete_vfork_done(struct task_struct *tsk)
{
struct completion *vfork;
task_lock(tsk);
vfork = tsk->vfork_done;
if (likely(vfork)) {
tsk->vfork_done = NULL;
complete(vfork);
}
task_unlock(tsk);
}
static int wait_for_vfork_done(struct task_struct *child,
struct completion *vfork)
{
unsigned int state = TASK_UNINTERRUPTIBLE|TASK_KILLABLE|TASK_FREEZABLE;
int killed;
cgroup_enter_frozen();
killed = wait_for_completion_state(vfork, state);
cgroup_leave_frozen(false);
if (killed) {
task_lock(child);
child->vfork_done = NULL;
task_unlock(child);
}
put_task_struct(child);
return killed;
}
/* Please note the differences between mmput and mm_release.
* mmput is called whenever we stop holding onto a mm_struct,
* error success whatever.
*
* mm_release is called after a mm_struct has been removed
* from the current process.
*
* This difference is important for error handling, when we
* only half set up a mm_struct for a new process and need to restore
* the old one. Because we mmput the new mm_struct before
* restoring the old one. . .
* Eric Biederman 10 January 1998
*/
static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
uprobe_free_utask(tsk);
/* Get rid of any cached register state */
deactivate_mm(tsk, mm);
/*
* Signal userspace if we're not exiting with a core dump
* because we want to leave the value intact for debugging
* purposes.
*/
if (tsk->clear_child_tid) {
if (atomic_read(&mm->mm_users) > 1) {
/*
* We don't check the error code - if userspace has
* not set up a proper pointer then tough luck.
*/
put_user(0, tsk->clear_child_tid);
do_futex(tsk->clear_child_tid, FUTEX_WAKE,
1, NULL, NULL, 0, 0);
}
tsk->clear_child_tid = NULL;
}
/*
* All done, finally we can wake up parent and return this mm to him.
* Also kthread_stop() uses this completion for synchronization.
*/
if (tsk->vfork_done)
complete_vfork_done(tsk);
}
void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
futex_exit_release(tsk);
mm_release(tsk, mm);
}
void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
futex_exec_release(tsk);
mm_release(tsk, mm);
}
/**
* dup_mm() - duplicates an existing mm structure
* @tsk: the task_struct with which the new mm will be associated.
* @oldmm: the mm to duplicate.
*
* Allocates a new mm structure and duplicates the provided @oldmm structure
* content into it.
*
* Return: the duplicated mm or NULL on failure.
*/
static struct mm_struct *dup_mm(struct task_struct *tsk,
struct mm_struct *oldmm)
{
struct mm_struct *mm;
int err;
mm = allocate_mm();
if (!mm)
goto fail_nomem;
memcpy(mm, oldmm, sizeof(*mm));
if (!mm_init(mm, tsk, mm->user_ns))
goto fail_nomem;
err = dup_mmap(mm, oldmm);
if (err)
goto free_pt;
mm->hiwater_rss = get_mm_rss(mm);
mm->hiwater_vm = mm->total_vm;
if (mm->binfmt && !try_module_get(mm->binfmt->module))
goto free_pt;
return mm;
free_pt:
/* don't put binfmt in mmput, we haven't got module yet */
mm->binfmt = NULL;
mm_init_owner(mm, NULL);
mmput(mm);
fail_nomem:
return NULL;
}
static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
{
struct mm_struct *mm, *oldmm;
tsk->min_flt = tsk->maj_flt = 0;
tsk->nvcsw = tsk->nivcsw = 0;
#ifdef CONFIG_DETECT_HUNG_TASK
tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
tsk->last_switch_time = 0;
#endif
tsk->mm = NULL;
tsk->active_mm = NULL;
/*
* Are we cloning a kernel thread?
*
* We need to steal a active VM for that..
*/
oldmm = current->mm;
if (!oldmm)
return 0;
if (clone_flags & CLONE_VM) {
mmget(oldmm);
mm = oldmm;
} else {
mm = dup_mm(tsk, current->mm);
if (!mm)
return -ENOMEM;
}
tsk->mm = mm;
tsk->active_mm = mm;
sched_mm_cid_fork(tsk);
return 0;
}
static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
{
struct fs_struct *fs = current->fs;
if (clone_flags & CLONE_FS) {
/* tsk->fs is already what we want */
spin_lock(&fs->lock);
if (fs->in_exec) {
spin_unlock(&fs->lock);
return -EAGAIN;
}
fs->users++;
spin_unlock(&fs->lock);
return 0;
}
tsk->fs = copy_fs_struct(fs);
if (!tsk->fs)
return -ENOMEM;
return 0;
}
static int copy_files(unsigned long clone_flags, struct task_struct *tsk,
int no_files)
{
struct files_struct *oldf, *newf;
int error = 0;
/*
* A background process may not have any files ...
*/
oldf = current->files;
if (!oldf)
goto out;
if (no_files) {
tsk->files = NULL;
goto out;
}
if (clone_flags & CLONE_FILES) {
atomic_inc(&oldf->count);
goto out;
}
newf = dup_fd(oldf, NR_OPEN_MAX, &error);
if (!newf)
goto out;
tsk->files = newf;
error = 0;
out:
return error;
}
static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
{
struct sighand_struct *sig;
if (clone_flags & CLONE_SIGHAND) {
refcount_inc(¤t->sighand->count);
return 0;
}
sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
RCU_INIT_POINTER(tsk->sighand, sig);
if (!sig)
return -ENOMEM;
refcount_set(&sig->count, 1);
spin_lock_irq(¤t->sighand->siglock);
memcpy(sig->action, current->sighand->action, sizeof(sig->action));
spin_unlock_irq(¤t->sighand->siglock);
/* Reset all signal handler not set to SIG_IGN to SIG_DFL. */
if (clone_flags & CLONE_CLEAR_SIGHAND)
flush_signal_handlers(tsk, 0);
return 0;
}
void __cleanup_sighand(struct sighand_struct *sighand)
{
if (refcount_dec_and_test(&sighand->count)) {
signalfd_cleanup(sighand);
/*
* sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
* without an RCU grace period, see __lock_task_sighand().
*/
kmem_cache_free(sighand_cachep, sighand);
}
}
/*
* Initialize POSIX timer handling for a thread group.
*/
static void posix_cpu_timers_init_group(struct signal_struct *sig)
{
struct posix_cputimers *pct = &sig->posix_cputimers;
unsigned long cpu_limit;
cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
posix_cputimers_group_init(pct, cpu_limit);
}
static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
{
struct signal_struct *sig;
if (clone_flags & CLONE_THREAD)
return 0;
sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
tsk->signal = sig;
if (!sig)
return -ENOMEM;
sig->nr_threads = 1;
sig->quick_threads = 1;
atomic_set(&sig->live, 1);
refcount_set(&sig->sigcnt, 1);
/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
tsk->thread_node = (struct list_head)LIST_HEAD_INIT(sig->thread_head);
init_waitqueue_head(&sig->wait_chldexit);
sig->curr_target = tsk;
init_sigpending(&sig->shared_pending);
INIT_HLIST_HEAD(&sig->multiprocess);
seqlock_init(&sig->stats_lock);
prev_cputime_init(&sig->prev_cputime);
#ifdef CONFIG_POSIX_TIMERS
INIT_LIST_HEAD(&sig->posix_timers);
hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
sig->real_timer.function = it_real_fn;
#endif
task_lock(current->group_leader);
memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
task_unlock(current->group_leader);
posix_cpu_timers_init_group(sig);
tty_audit_fork(sig);
sched_autogroup_fork(sig);
sig->oom_score_adj = current->signal->oom_score_adj;
sig->oom_score_adj_min = current->signal->oom_score_adj_min;
mutex_init(&sig->cred_guard_mutex);
init_rwsem(&sig->exec_update_lock);
return 0;
}
static void copy_seccomp(struct task_struct *p)
{
#ifdef CONFIG_SECCOMP
/*
* Must be called with sighand->lock held, which is common to
* all threads in the group. Holding cred_guard_mutex is not
* needed because this new task is not yet running and cannot
* be racing exec.
*/
assert_spin_locked(¤t->sighand->siglock);
/* Ref-count the new filter user, and assign it. */
get_seccomp_filter(current);
p->seccomp = current->seccomp;
/*
* Explicitly enable no_new_privs here in case it got set
* between the task_struct being duplicated and holding the
* sighand lock. The seccomp state and nnp must be in sync.
*/
if (task_no_new_privs(current))
task_set_no_new_privs(p);
/*
* If the parent gained a seccomp mode after copying thread
* flags and between before we held the sighand lock, we have
* to manually enable the seccomp thread flag here.
*/
if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
set_task_syscall_work(p, SECCOMP);
#endif
}
SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
{
current->clear_child_tid = tidptr;
return task_pid_vnr(current);
}
static void rt_mutex_init_task(struct task_struct *p)
{
raw_spin_lock_init(&p->pi_lock);
#ifdef CONFIG_RT_MUTEXES
p->pi_waiters = RB_ROOT_CACHED;
p->pi_top_task = NULL;
p->pi_blocked_on = NULL;
#endif
}
static inline void init_task_pid_links(struct task_struct *task)
{
enum pid_type type;
for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type)
INIT_HLIST_NODE(&task->pid_links[type]);
}
static inline void
init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
{
if (type == PIDTYPE_PID)
task->thread_pid = pid;
else
task->signal->pids[type] = pid;
}
static inline void rcu_copy_process(struct task_struct *p)
{
#ifdef CONFIG_PREEMPT_RCU
p->rcu_read_lock_nesting = 0;
p->rcu_read_unlock_special.s = 0;
p->rcu_blocked_node = NULL;
INIT_LIST_HEAD(&p->rcu_node_entry);
#endif /* #ifdef CONFIG_PREEMPT_RCU */
#ifdef CONFIG_TASKS_RCU
p->rcu_tasks_holdout = false;
INIT_LIST_HEAD(&p->rcu_tasks_holdout_list);
p->rcu_tasks_idle_cpu = -1;
#endif /* #ifdef CONFIG_TASKS_RCU */
#ifdef CONFIG_TASKS_TRACE_RCU
p->trc_reader_nesting = 0;
p->trc_reader_special.s = 0;
INIT_LIST_HEAD(&p->trc_holdout_list);
INIT_LIST_HEAD(&p->trc_blkd_node);
#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
}
struct pid *pidfd_pid(const struct file *file)
{
if (file->f_op == &pidfd_fops)
return file->private_data;
return ERR_PTR(-EBADF);
}
static int pidfd_release(struct inode *inode, struct file *file)
{
struct pid *pid = file->private_data;
file->private_data = NULL;
put_pid(pid);
return 0;
}
#ifdef CONFIG_PROC_FS
/**
* pidfd_show_fdinfo - print information about a pidfd
* @m: proc fdinfo file
* @f: file referencing a pidfd
*
* Pid:
* This function will print the pid that a given pidfd refers to in the
* pid namespace of the procfs instance.
* If the pid namespace of the process is not a descendant of the pid
* namespace of the procfs instance 0 will be shown as its pid. This is
* similar to calling getppid() on a process whose parent is outside of
* its pid namespace.
*
* NSpid:
* If pid namespaces are supported then this function will also print
* the pid of a given pidfd refers to for all descendant pid namespaces
* starting from the current pid namespace of the instance, i.e. the
* Pid field and the first entry in the NSpid field will be identical.
* If the pid namespace of the process is not a descendant of the pid
* namespace of the procfs instance 0 will be shown as its first NSpid
* entry and no others will be shown.
* Note that this differs from the Pid and NSpid fields in
* /proc/<pid>/status where Pid and NSpid are always shown relative to
* the pid namespace of the procfs instance. The difference becomes
* obvious when sending around a pidfd between pid namespaces from a
* different branch of the tree, i.e. where no ancestral relation is
* present between the pid namespaces:
* - create two new pid namespaces ns1 and ns2 in the initial pid
* namespace (also take care to create new mount namespaces in the
* new pid namespace and mount procfs)
* - create a process with a pidfd in ns1
* - send pidfd from ns1 to ns2
* - read /proc/self/fdinfo/<pidfd> and observe that both Pid and NSpid
* have exactly one entry, which is 0
*/
static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
{
struct pid *pid = f->private_data;
struct pid_namespace *ns;
pid_t nr = -1;
if (likely(pid_has_task(pid, PIDTYPE_PID))) {
ns = proc_pid_ns(file_inode(m->file)->i_sb);
nr = pid_nr_ns(pid, ns);
}
seq_put_decimal_ll(m, "Pid:\t", nr);
#ifdef CONFIG_PID_NS
seq_put_decimal_ll(m, "\nNSpid:\t", nr);
if (nr > 0) {
int i;
/* If nr is non-zero it means that 'pid' is valid and that
* ns, i.e. the pid namespace associated with the procfs
* instance, is in the pid namespace hierarchy of pid.
* Start at one below the already printed level.
*/
for (i = ns->level + 1; i <= pid->level; i++)
seq_put_decimal_ll(m, "\t", pid->numbers[i].nr);
}
#endif
seq_putc(m, '\n');
}
#endif
/*
* Poll support for process exit notification.
*/
static __poll_t pidfd_poll(struct file *file, struct poll_table_struct *pts)
{
struct pid *pid = file->private_data;
__poll_t poll_flags = 0;
poll_wait(file, &pid->wait_pidfd, pts);
/*
* Inform pollers only when the whole thread group exits.
* If the thread group leader exits before all other threads in the
* group, then poll(2) should block, similar to the wait(2) family.
*/
if (thread_group_exited(pid))
poll_flags = EPOLLIN | EPOLLRDNORM;
return poll_flags;
}
const struct file_operations pidfd_fops = {
.release = pidfd_release,
.poll = pidfd_poll,
#ifdef CONFIG_PROC_FS
.show_fdinfo = pidfd_show_fdinfo,
#endif
};
/**
* __pidfd_prepare - allocate a new pidfd_file and reserve a pidfd
* @pid: the struct pid for which to create a pidfd
* @flags: flags of the new @pidfd
* @pidfd: the pidfd to return
*
* Allocate a new file that stashes @pid and reserve a new pidfd number in the
* caller's file descriptor table. The pidfd is reserved but not installed yet.
* The helper doesn't perform checks on @pid which makes it useful for pidfds
* created via CLONE_PIDFD where @pid has no task attached when the pidfd and
* pidfd file are prepared.
*
* If this function returns successfully the caller is responsible to either
* call fd_install() passing the returned pidfd and pidfd file as arguments in
* order to install the pidfd into its file descriptor table or they must use
* put_unused_fd() and fput() on the returned pidfd and pidfd file
* respectively.
*
* This function is useful when a pidfd must already be reserved but there
* might still be points of failure afterwards and the caller wants to ensure
* that no pidfd is leaked into its file descriptor table.
*
* Return: On success, a reserved pidfd is returned from the function and a new
* pidfd file is returned in the last argument to the function. On
* error, a negative error code is returned from the function and the
* last argument remains unchanged.
*/
static int __pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
{
int pidfd;
struct file *pidfd_file;
if (flags & ~(O_NONBLOCK | O_RDWR | O_CLOEXEC))
return -EINVAL;
pidfd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
if (pidfd < 0)
return pidfd;
pidfd_file = anon_inode_getfile("[pidfd]", &pidfd_fops, pid,
flags | O_RDWR | O_CLOEXEC);
if (IS_ERR(pidfd_file)) {
put_unused_fd(pidfd);
return PTR_ERR(pidfd_file);
}
get_pid(pid); /* held by pidfd_file now */
*ret = pidfd_file;
return pidfd;
}
/**
* pidfd_prepare - allocate a new pidfd_file and reserve a pidfd
* @pid: the struct pid for which to create a pidfd
* @flags: flags of the new @pidfd
* @pidfd: the pidfd to return
*
* Allocate a new file that stashes @pid and reserve a new pidfd number in the
* caller's file descriptor table. The pidfd is reserved but not installed yet.
*
* The helper verifies that @pid is used as a thread group leader.
*
* If this function returns successfully the caller is responsible to either
* call fd_install() passing the returned pidfd and pidfd file as arguments in
* order to install the pidfd into its file descriptor table or they must use
* put_unused_fd() and fput() on the returned pidfd and pidfd file
* respectively.
*
* This function is useful when a pidfd must already be reserved but there
* might still be points of failure afterwards and the caller wants to ensure
* that no pidfd is leaked into its file descriptor table.
*
* Return: On success, a reserved pidfd is returned from the function and a new
* pidfd file is returned in the last argument to the function. On
* error, a negative error code is returned from the function and the
* last argument remains unchanged.
*/
int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
{
if (!pid || !pid_has_task(pid, PIDTYPE_TGID))
return -EINVAL;
return __pidfd_prepare(pid, flags, ret);
}
static void __delayed_free_task(struct rcu_head *rhp)
{
struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
free_task(tsk);
}
static __always_inline void delayed_free_task(struct task_struct *tsk)
{
if (IS_ENABLED(CONFIG_MEMCG))
call_rcu(&tsk->rcu, __delayed_free_task);
else
free_task(tsk);
}
static void copy_oom_score_adj(u64 clone_flags, struct task_struct *tsk)
{
/* Skip if kernel thread */
if (!tsk->mm)
return;
/* Skip if spawning a thread or using vfork */
if ((clone_flags & (CLONE_VM | CLONE_THREAD | CLONE_VFORK)) != CLONE_VM)
return;
/* We need to synchronize with __set_oom_adj */
mutex_lock(&oom_adj_mutex);
set_bit(MMF_MULTIPROCESS, &tsk->mm->flags);
/* Update the values in case they were changed after copy_signal */
tsk->signal->oom_score_adj = current->signal->oom_score_adj;
tsk->signal->oom_score_adj_min = current->signal->oom_score_adj_min;
mutex_unlock(&oom_adj_mutex);
}
#ifdef CONFIG_RV
static void rv_task_fork(struct task_struct *p)
{
int i;
for (i = 0; i < RV_PER_TASK_MONITORS; i++)
p->rv[i].da_mon.monitoring = false;
}
#else
#define rv_task_fork(p) do {} while (0)
#endif
/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.
*
* It copies the registers, and all the appropriate
* parts of the process environment (as per the clone
* flags). The actual kick-off is left to the caller.
*/
__latent_entropy struct task_struct *copy_process(
struct pid *pid,
int trace,
int node,
struct kernel_clone_args *args)
{
int pidfd = -1, retval;
struct task_struct *p;
struct multiprocess_signals delayed;
struct file *pidfile = NULL;
const u64 clone_flags = args->flags;
struct nsproxy *nsp = current->nsproxy;
/*
* Don't allow sharing the root directory with processes in a different
* namespace
*/
if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return ERR_PTR(-EINVAL);
if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
return ERR_PTR(-EINVAL);
/*
* Thread groups must share signals as well, and detached threads
* can only be started up within the thread group.
*/
if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
return ERR_PTR(-EINVAL);
/*
* Shared signal handlers imply shared VM. By way of the above,
* thread groups also imply shared VM. Blocking this case allows
* for various simplifications in other code.
*/
if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
return ERR_PTR(-EINVAL);
/*
* Siblings of global init remain as zombies on exit since they are
* not reaped by their parent (swapper). To solve this and to avoid
* multi-rooted process trees, prevent global and container-inits
* from creating siblings.
*/
if ((clone_flags & CLONE_PARENT) &&
current->signal->flags & SIGNAL_UNKILLABLE)
return ERR_PTR(-EINVAL);
/*
* If the new process will be in a different pid or user namespace
* do not allow it to share a thread group with the forking task.
*/
if (clone_flags & CLONE_THREAD) {
if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
(task_active_pid_ns(current) != nsp->pid_ns_for_children))
return ERR_PTR(-EINVAL);
}
if (clone_flags & CLONE_PIDFD) {
/*
* - CLONE_DETACHED is blocked so that we can potentially
* reuse it later for CLONE_PIDFD.
* - CLONE_THREAD is blocked until someone really needs it.
*/
if (clone_flags & (CLONE_DETACHED | CLONE_THREAD))
return ERR_PTR(-EINVAL);
}
/*
* Force any signals received before this point to be delivered
* before the fork happens. Collect up signals sent to multiple
* processes that happen during the fork and delay them so that
* they appear to happen after the fork.
*/
sigemptyset(&delayed.signal);
INIT_HLIST_NODE(&delayed.node);
spin_lock_irq(¤t->sighand->siglock);
if (!(clone_flags & CLONE_THREAD))
hlist_add_head(&delayed.node, ¤t->signal->multiprocess);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
retval = -ERESTARTNOINTR;
if (task_sigpending(current))
goto fork_out;
retval = -ENOMEM;
p = dup_task_struct(current, node);
if (!p)
goto fork_out;
p->flags &= ~PF_KTHREAD;
if (args->kthread)
p->flags |= PF_KTHREAD;
if (args->user_worker) {
/*
* Mark us a user worker, and block any signal that isn't
* fatal or STOP
*/
p->flags |= PF_USER_WORKER;
siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
}
if (args->io_thread)
p->flags |= PF_IO_WORKER;
if (args->name)
strscpy_pad(p->comm, args->name, sizeof(p->comm));
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
/*
* Clear TID on mm_release()?
*/
p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? args->child_tid : NULL;
ftrace_graph_init_task(p);
rt_mutex_init_task(p);
lockdep_assert_irqs_enabled();
#ifdef CONFIG_PROVE_LOCKING
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
retval = copy_creds(p, clone_flags);
if (retval < 0)
goto bad_fork_free;
retval = -EAGAIN;
if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
if (p->real_cred->user != INIT_USER &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
goto bad_fork_cleanup_count;
}
current->flags &= ~PF_NPROC_EXCEEDED;
/*
* If multiple threads are within copy_process(), then this check
* triggers too late. This doesn't hurt, the check is only there
* to stop root fork bombs.
*/
retval = -EAGAIN;
if (data_race(nr_threads >= max_threads))
goto bad_fork_cleanup_count;
delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY);
p->flags |= PF_FORKNOEXEC;
INIT_LIST_HEAD(&p->children);
INIT_LIST_HEAD(&p->sibling);
rcu_copy_process(p);
p->vfork_done = NULL;
spin_lock_init(&p->alloc_lock);
init_sigpending(&p->pending);
p->utime = p->stime = p->gtime = 0;
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
p->utimescaled = p->stimescaled = 0;
#endif
prev_cputime_init(&p->prev_cputime);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
seqcount_init(&p->vtime.seqcount);
p->vtime.starttime = 0;
p->vtime.state = VTIME_INACTIVE;
#endif
#ifdef CONFIG_IO_URING
p->io_uring = NULL;
#endif
#if defined(SPLIT_RSS_COUNTING)
memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif
p->default_timer_slack_ns = current->timer_slack_ns;
#ifdef CONFIG_PSI
p->psi_flags = 0;
#endif
task_io_accounting_init(&p->ioac);
acct_clear_integrals(p);
posix_cputimers_init(&p->posix_cputimers);
p->io_context = NULL;
audit_set_context(p, NULL);
cgroup_fork(p);
if (args->kthread) {
if (!set_kthread_struct(p))
goto bad_fork_cleanup_delayacct;
}
#ifdef CONFIG_NUMA
p->mempolicy = mpol_dup(p->mempolicy);
if (IS_ERR(p->mempolicy)) {
retval = PTR_ERR(p->mempolicy);
p->mempolicy = NULL;
goto bad_fork_cleanup_delayacct;
}
#endif
#ifdef CONFIG_CPUSETS
p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
seqcount_spinlock_init(&p->mems_allowed_seq, &p->alloc_lock);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
memset(&p->irqtrace, 0, sizeof(p->irqtrace));
p->irqtrace.hardirq_disable_ip = _THIS_IP_;
p->irqtrace.softirq_enable_ip = _THIS_IP_;
p->softirqs_enabled = 1;
p->softirq_context = 0;
#endif
p->pagefault_disabled = 0;
#ifdef CONFIG_LOCKDEP
lockdep_init_task(p);
#endif
#ifdef CONFIG_DEBUG_MUTEXES
p->blocked_on = NULL; /* not blocked yet */
#endif
#ifdef CONFIG_BCACHE
p->sequential_io = 0;
p->sequential_io_avg = 0;
#endif
#ifdef CONFIG_BPF_SYSCALL
RCU_INIT_POINTER(p->bpf_storage, NULL);
p->bpf_ctx = NULL;
#endif
/* Perform scheduler related setup. Assign this task to a CPU. */
retval = sched_fork(clone_flags, p);
if (retval)
goto bad_fork_cleanup_policy;
retval = perf_event_init_task(p, clone_flags);
if (retval)
goto bad_fork_cleanup_policy;
retval = audit_alloc(p);
if (retval)
goto bad_fork_cleanup_perf;
/* copy all the process information */
shm_init_task(p);
retval = security_task_alloc(p, clone_flags);
if (retval)
goto bad_fork_cleanup_audit;
retval = copy_semundo(clone_flags, p);
if (retval)
goto bad_fork_cleanup_security;
retval = copy_files(clone_flags, p, args->no_files);
if (retval)
goto bad_fork_cleanup_semundo;
retval = copy_fs(clone_flags, p);
if (retval)
goto bad_fork_cleanup_files;
retval = copy_sighand(clone_flags, p);
if (retval)
goto bad_fork_cleanup_fs;
retval = copy_signal(clone_flags, p);
if (retval)
goto bad_fork_cleanup_sighand;
retval = copy_mm(clone_flags, p);
if (retval)
goto bad_fork_cleanup_signal;
retval = copy_namespaces(clone_flags, p);
if (retval)
goto bad_fork_cleanup_mm;
retval = copy_io(clone_flags, p);
if (retval)
goto bad_fork_cleanup_namespaces;
retval = copy_thread(p, args);
if (retval)
goto bad_fork_cleanup_io;
stackleak_task_init(p);
if (pid != &init_struct_pid) {
pid = alloc_pid(p->nsproxy->pid_ns_for_children, args->set_tid,
args->set_tid_size);
if (IS_ERR(pid)) {
retval = PTR_ERR(pid);
goto bad_fork_cleanup_thread;
}
}
/*
* This has to happen after we've potentially unshared the file
* descriptor table (so that the pidfd doesn't leak into the child
* if the fd table isn't shared).
*/
if (clone_flags & CLONE_PIDFD) {
/* Note that no task has been attached to @pid yet. */
retval = __pidfd_prepare(pid, O_RDWR | O_CLOEXEC, &pidfile);
if (retval < 0)
goto bad_fork_free_pid;
pidfd = retval;
retval = put_user(pidfd, args->pidfd);
if (retval)
goto bad_fork_put_pidfd;
}
#ifdef CONFIG_BLOCK
p->plug = NULL;
#endif
futex_init_task(p);
/*
* sigaltstack should be cleared when sharing the same VM
*/
if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
sas_ss_reset(p);
/*
* Syscall tracing and stepping should be turned off in the
* child regardless of CLONE_PTRACE.
*/
user_disable_single_step(p);
clear_task_syscall_work(p, SYSCALL_TRACE);
#if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
clear_task_syscall_work(p, SYSCALL_EMU);
#endif
clear_tsk_latency_tracing(p);
/* ok, now we should be set up.. */
p->pid = pid_nr(pid);
if (clone_flags & CLONE_THREAD) {
p->group_leader = current->group_leader;
p->tgid = current->tgid;
} else {
p->group_leader = p;
p->tgid = p->pid;
}
p->nr_dirtied = 0;
p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
p->dirty_paused_when = 0;
p->pdeath_signal = 0;
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
clear_posix_cputimers_work(p);
#ifdef CONFIG_KRETPROBES
p->kretprobe_instances.first = NULL;
#endif
#ifdef CONFIG_RETHOOK
p->rethooks.first = NULL;
#endif
/*
* Ensure that the cgroup subsystem policies allow the new process to be
* forked. It should be noted that the new process's css_set can be changed
* between here and cgroup_post_fork() if an organisation operation is in
* progress.
*/
retval = cgroup_can_fork(p, args);
if (retval)
goto bad_fork_put_pidfd;
/*
* Now that the cgroups are pinned, re-clone the parent cgroup and put
* the new task on the correct runqueue. All this *before* the task
* becomes visible.
*
* This isn't part of ->can_fork() because while the re-cloning is
* cgroup specific, it unconditionally needs to place the task on a
* runqueue.
*/
sched_cgroup_fork(p, args);
/*
* From this point on we must avoid any synchronous user-space
* communication until we take the tasklist-lock. In particular, we do
* not want user-space to be able to predict the process start-time by
* stalling fork(2) after we recorded the start_time but before it is
* visible to the system.
*/
p->start_time = ktime_get_ns();
p->start_boottime = ktime_get_boottime_ns();
/*
* Make it visible to the rest of the system, but dont wake it up yet.
* Need tasklist lock for parent etc handling!
*/
write_lock_irq(&tasklist_lock);
/* CLONE_PARENT re-uses the old parent */
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
p->parent_exec_id = current->parent_exec_id;
if (clone_flags & CLONE_THREAD)
p->exit_signal = -1;
else
p->exit_signal = current->group_leader->exit_signal;
} else {
p->real_parent = current;
p->parent_exec_id = current->self_exec_id;
p->exit_signal = args->exit_signal;
}
klp_copy_process(p);
sched_core_fork(p);
spin_lock(¤t->sighand->siglock);
rv_task_fork(p);
rseq_fork(p, clone_flags);
/* Don't start children in a dying pid namespace */
if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
retval = -ENOMEM;
goto bad_fork_cancel_cgroup;
}
/* Let kill terminate clone/fork in the middle */
if (fatal_signal_pending(current)) {
retval = -EINTR;
goto bad_fork_cancel_cgroup;
}
/* No more failure paths after this point. */
/*
* Copy seccomp details explicitly here, in case they were changed
* before holding sighand lock.
*/
copy_seccomp(p);
init_task_pid_links(p);
if (likely(p->pid)) {
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
init_task_pid(p, PIDTYPE_PID, pid);
if (thread_group_leader(p)) {
init_task_pid(p, PIDTYPE_TGID, pid);
init_task_pid(p, PIDTYPE_PGID, task_pgrp(current));
init_task_pid(p, PIDTYPE_SID, task_session(current));
if (is_child_reaper(pid)) {
ns_of_pid(pid)->child_reaper = p;
p->signal->flags |= SIGNAL_UNKILLABLE;
}
p->signal->shared_pending.signal = delayed.signal;
p->signal->tty = tty_kref_get(current->signal->tty);
/*
* Inherit has_child_subreaper flag under the same
* tasklist_lock with adding child to the process tree
* for propagate_has_child_subreaper optimization.
*/
p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
p->real_parent->signal->is_child_subreaper;
list_add_tail(&p->sibling, &p->real_parent->children);
list_add_tail_rcu(&p->tasks, &init_task.tasks);
attach_pid(p, PIDTYPE_TGID);
attach_pid(p, PIDTYPE_PGID);
attach_pid(p, PIDTYPE_SID);
__this_cpu_inc(process_counts);
} else {
current->signal->nr_threads++;
current->signal->quick_threads++;
atomic_inc(¤t->signal->live);
refcount_inc(¤t->signal->sigcnt);
task_join_group_stop(p);
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
list_add_tail_rcu(&p->thread_node,
&p->signal->thread_head);
}
attach_pid(p, PIDTYPE_PID);
nr_threads++;
}
total_forks++;
hlist_del_init(&delayed.node);
spin_unlock(¤t->sighand->siglock);
syscall_tracepoint_update(p);
write_unlock_irq(&tasklist_lock);
if (pidfile)
fd_install(pidfd, pidfile);
proc_fork_connector(p);
sched_post_fork(p);
cgroup_post_fork(p, args);
perf_event_fork(p);
trace_task_newtask(p, clone_flags);
uprobe_copy_process(p, clone_flags);
user_events_fork(p, clone_flags);
copy_oom_score_adj(clone_flags, p);
return p;
bad_fork_cancel_cgroup:
sched_core_free(p);
spin_unlock(¤t->sighand->siglock);
write_unlock_irq(&tasklist_lock);
cgroup_cancel_fork(p, args);
bad_fork_put_pidfd:
if (clone_flags & CLONE_PIDFD) {
fput(pidfile);
put_unused_fd(pidfd);
}
bad_fork_free_pid:
if (pid != &init_struct_pid)
free_pid(pid);
bad_fork_cleanup_thread:
exit_thread(p);
bad_fork_cleanup_io:
if (p->io_context)
exit_io_context(p);
bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
bad_fork_cleanup_mm:
if (p->mm) {
mm_clear_owner(p->mm, p);
mmput(p->mm);
}
bad_fork_cleanup_signal:
if (!(clone_flags & CLONE_THREAD))
free_signal_struct(p->signal);
bad_fork_cleanup_sighand:
__cleanup_sighand(p->sighand);
bad_fork_cleanup_fs:
exit_fs(p); /* blocking */
bad_fork_cleanup_files:
exit_files(p); /* blocking */
bad_fork_cleanup_semundo:
exit_sem(p);
bad_fork_cleanup_security:
security_task_free(p);
bad_fork_cleanup_audit:
audit_free(p);
bad_fork_cleanup_perf:
perf_event_free_task(p);
bad_fork_cleanup_policy:
lockdep_free_task(p);
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
#endif
bad_fork_cleanup_delayacct:
delayacct_tsk_free(p);
bad_fork_cleanup_count:
dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
exit_creds(p);
bad_fork_free:
WRITE_ONCE(p->__state, TASK_DEAD);
exit_task_stack_account(p);
put_task_stack(p);
delayed_free_task(p);
fork_out:
spin_lock_irq(¤t->sighand->siglock);
hlist_del_init(&delayed.node);
spin_unlock_irq(¤t->sighand->siglock);
return ERR_PTR(retval);
}
static inline void init_idle_pids(struct task_struct *idle)
{
enum pid_type type;
for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */
init_task_pid(idle, type, &init_struct_pid);
}
}
static int idle_dummy(void *dummy)
{
/* This function is never called */
return 0;
}
struct task_struct * __init fork_idle(int cpu)
{
struct task_struct *task;
struct kernel_clone_args args = {
.flags = CLONE_VM,
.fn = &idle_dummy,
.fn_arg = NULL,
.kthread = 1,
.idle = 1,
};
task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args);
if (!IS_ERR(task)) {
init_idle_pids(task);
init_idle(task, cpu);
}
return task;
}
/*
* This is like kernel_clone(), but shaved down and tailored to just
* creating io_uring workers. It returns a created task, or an error pointer.
* The returned task is inactive, and the caller must fire it up through
* wake_up_new_task(p). All signals are blocked in the created task.
*/
struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
{
unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
CLONE_IO;
struct kernel_clone_args args = {
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.fn = fn,
.fn_arg = arg,
.io_thread = 1,
.user_worker = 1,
};
return copy_process(NULL, 0, node, &args);
}
/*
* Ok, this is the main fork-routine.
*
* It copies the process, and if successful kick-starts
* it and waits for it to finish using the VM if required.
*
* args->exit_signal is expected to be checked for sanity by the caller.
*/
pid_t kernel_clone(struct kernel_clone_args *args)
{
u64 clone_flags = args->flags;
struct completion vfork;
struct pid *pid;
struct task_struct *p;
int trace = 0;
pid_t nr;
/*
* For legacy clone() calls, CLONE_PIDFD uses the parent_tid argument
* to return the pidfd. Hence, CLONE_PIDFD and CLONE_PARENT_SETTID are
* mutually exclusive. With clone3() CLONE_PIDFD has grown a separate
* field in struct clone_args and it still doesn't make sense to have
* them both point at the same memory location. Performing this check
* here has the advantage that we don't need to have a separate helper
* to check for legacy clone().
*/
if ((args->flags & CLONE_PIDFD) &&
(args->flags & CLONE_PARENT_SETTID) &&
(args->pidfd == args->parent_tid))
return -EINVAL;
/*
* Determine whether and which event to report to ptracer. When
* called from kernel_thread or CLONE_UNTRACED is explicitly
* requested, no event is reported; otherwise, report if the event
* for the type of forking is enabled.
*/
if (!(clone_flags & CLONE_UNTRACED)) {
if (clone_flags & CLONE_VFORK)
trace = PTRACE_EVENT_VFORK;
else if (args->exit_signal != SIGCHLD)
trace = PTRACE_EVENT_CLONE;
else
trace = PTRACE_EVENT_FORK;
if (likely(!ptrace_event_enabled(current, trace)))
trace = 0;
}
p = copy_process(NULL, trace, NUMA_NO_NODE, args);
add_latent_entropy();
if (IS_ERR(p))
return PTR_ERR(p);
/*
* Do this prior waking up the new thread - the thread pointer
* might get invalid after that point, if the thread exits quickly.
*/
trace_sched_process_fork(current, p);
pid = get_task_pid(p, PIDTYPE_PID);
nr = pid_vnr(pid);
if (clone_flags & CLONE_PARENT_SETTID)
put_user(nr, args->parent_tid);
if (clone_flags & CLONE_VFORK) {
p->vfork_done = &vfork;
init_completion(&vfork);
get_task_struct(p);
}
if (IS_ENABLED(CONFIG_LRU_GEN) && !(clone_flags & CLONE_VM)) {
/* lock the task to synchronize with memcg migration */
task_lock(p);
lru_gen_add_mm(p->mm);
task_unlock(p);
}
wake_up_new_task(p);
/* forking complete and child started to run, tell ptracer */
if (unlikely(trace))
ptrace_event_pid(trace, pid);
if (clone_flags & CLONE_VFORK) {
if (!wait_for_vfork_done(p, &vfork))
ptrace_event_pid(PTRACE_EVENT_VFORK_DONE, pid);
}
put_pid(pid);
return nr;
}
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name,
unsigned long flags)
{
struct kernel_clone_args args = {
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.fn = fn,
.fn_arg = arg,
.name = name,
.kthread = 1,
};
return kernel_clone(&args);
}
/*
* Create a user mode thread.
*/
pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct kernel_clone_args args = {
.flags = ((lower_32_bits(flags) | CLONE_VM |
CLONE_UNTRACED) & ~CSIGNAL),
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.fn = fn,
.fn_arg = arg,
};
return kernel_clone(&args);
}
#ifdef __ARCH_WANT_SYS_FORK
SYSCALL_DEFINE0(fork)
{
#ifdef CONFIG_MMU
struct kernel_clone_args args = {
.exit_signal = SIGCHLD,
};
return kernel_clone(&args);
#else
/* can not support in nommu mode */
return -EINVAL;
#endif
}
#endif
#ifdef __ARCH_WANT_SYS_VFORK
SYSCALL_DEFINE0(vfork)
{
struct kernel_clone_args args = {
.flags = CLONE_VFORK | CLONE_VM,
.exit_signal = SIGCHLD,
};
return kernel_clone(&args);
}
#endif
#ifdef __ARCH_WANT_SYS_CLONE
#ifdef CONFIG_CLONE_BACKWARDS
SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
int __user *, parent_tidptr,
unsigned long, tls,
int __user *, child_tidptr)
#elif defined(CONFIG_CLONE_BACKWARDS2)
SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags,
int __user *, parent_tidptr,
int __user *, child_tidptr,
unsigned long, tls)
#elif defined(CONFIG_CLONE_BACKWARDS3)
SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
int, stack_size,
int __user *, parent_tidptr,
int __user *, child_tidptr,
unsigned long, tls)
#else
SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
int __user *, parent_tidptr,
int __user *, child_tidptr,
unsigned long, tls)
#endif
{
struct kernel_clone_args args = {
.flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
.pidfd = parent_tidptr,
.child_tid = child_tidptr,
.parent_tid = parent_tidptr,
.exit_signal = (lower_32_bits(clone_flags) & CSIGNAL),
.stack = newsp,
.tls = tls,
};
return kernel_clone(&args);
}
#endif
#ifdef __ARCH_WANT_SYS_CLONE3
noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
struct clone_args __user *uargs,
size_t usize)
{
int err;
struct clone_args args;
pid_t *kset_tid = kargs->set_tid;
BUILD_BUG_ON(offsetofend(struct clone_args, tls) !=
CLONE_ARGS_SIZE_VER0);
BUILD_BUG_ON(offsetofend(struct clone_args, set_tid_size) !=
CLONE_ARGS_SIZE_VER1);
BUILD_BUG_ON(offsetofend(struct clone_args, cgroup) !=
CLONE_ARGS_SIZE_VER2);
BUILD_BUG_ON(sizeof(struct clone_args) != CLONE_ARGS_SIZE_VER2);
if (unlikely(usize > PAGE_SIZE))
return -E2BIG;
if (unlikely(usize < CLONE_ARGS_SIZE_VER0))
return -EINVAL;
err = copy_struct_from_user(&args, sizeof(args), uargs, usize);
if (err)
return err;
if (unlikely(args.set_tid_size > MAX_PID_NS_LEVEL))
return -EINVAL;
if (unlikely(!args.set_tid && args.set_tid_size > 0))
return -EINVAL;
if (unlikely(args.set_tid && args.set_tid_size == 0))
return -EINVAL;
/*
* Verify that higher 32bits of exit_signal are unset and that
* it is a valid signal
*/
if (unlikely((args.exit_signal & ~((u64)CSIGNAL)) ||
!valid_signal(args.exit_signal)))
return -EINVAL;
if ((args.flags & CLONE_INTO_CGROUP) &&
(args.cgroup > INT_MAX || usize < CLONE_ARGS_SIZE_VER2))
return -EINVAL;
*kargs = (struct kernel_clone_args){
.flags = args.flags,
.pidfd = u64_to_user_ptr(args.pidfd),
.child_tid = u64_to_user_ptr(args.child_tid),
.parent_tid = u64_to_user_ptr(args.parent_tid),
.exit_signal = args.exit_signal,
.stack = args.stack,
.stack_size = args.stack_size,
.tls = args.tls,
.set_tid_size = args.set_tid_size,
.cgroup = args.cgroup,
};
if (args.set_tid &&
copy_from_user(kset_tid, u64_to_user_ptr(args.set_tid),
(kargs->set_tid_size * sizeof(pid_t))))
return -EFAULT;
kargs->set_tid = kset_tid;
return 0;
}
/**
* clone3_stack_valid - check and prepare stack
* @kargs: kernel clone args
*
* Verify that the stack arguments userspace gave us are sane.
* In addition, set the stack direction for userspace since it's easy for us to
* determine.
*/
static inline bool clone3_stack_valid(struct kernel_clone_args *kargs)
{
if (kargs->stack == 0) {
if (kargs->stack_size > 0)
return false;
} else {
if (kargs->stack_size == 0)
return false;
if (!access_ok((void __user *)kargs->stack, kargs->stack_size))
return false;
#if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64)
kargs->stack += kargs->stack_size;
#endif
}
return true;
}
static bool clone3_args_valid(struct kernel_clone_args *kargs)
{
/* Verify that no unknown flags are passed along. */
if (kargs->flags &
~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP))
return false;
/*
* - make the CLONE_DETACHED bit reusable for clone3
* - make the CSIGNAL bits reusable for clone3
*/
if (kargs->flags & (CLONE_DETACHED | (CSIGNAL & (~CLONE_NEWTIME))))
return false;
if ((kargs->flags & (CLONE_SIGHAND | CLONE_CLEAR_SIGHAND)) ==
(CLONE_SIGHAND | CLONE_CLEAR_SIGHAND))
return false;
if ((kargs->flags & (CLONE_THREAD | CLONE_PARENT)) &&
kargs->exit_signal)
return false;
if (!clone3_stack_valid(kargs))
return false;
return true;
}
/**
* clone3 - create a new process with specific properties
* @uargs: argument structure
* @size: size of @uargs
*
* clone3() is the extensible successor to clone()/clone2().
* It takes a struct as argument that is versioned by its size.
*
* Return: On success, a positive PID for the child process.
* On error, a negative errno number.
*/
SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
{
int err;
struct kernel_clone_args kargs;
pid_t set_tid[MAX_PID_NS_LEVEL];
kargs.set_tid = set_tid;
err = copy_clone_args_from_user(&kargs, uargs, size);
if (err)
return err;
if (!clone3_args_valid(&kargs))
return -EINVAL;
return kernel_clone(&kargs);
}
#endif
void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
{
struct task_struct *leader, *parent, *child;
int res;
read_lock(&tasklist_lock);
leader = top = top->group_leader;
down:
for_each_thread(leader, parent) {
list_for_each_entry(child, &parent->children, sibling) {
res = visitor(child, data);
if (res) {
if (res < 0)
goto out;
leader = child;
goto down;
}
up:
;
}
}
if (leader != top) {
child = leader;
parent = child->real_parent;
leader = parent->group_leader;
goto up;
}
out:
read_unlock(&tasklist_lock);
}
#ifndef ARCH_MIN_MMSTRUCT_ALIGN
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif
static void sighand_ctor(void *data)
{
struct sighand_struct *sighand = data;
spin_lock_init(&sighand->siglock);
init_waitqueue_head(&sighand->signalfd_wqh);
}
void __init mm_cache_init(void)
{
unsigned int mm_size;
/*
* The mm_cpumask is located at the end of mm_struct, and is
* dynamically sized based on the maximum CPU number this system
* can have, taking hotplug into account (nr_cpu_ids).
*/
mm_size = sizeof(struct mm_struct) + cpumask_size() + mm_cid_size();
mm_cachep = kmem_cache_create_usercopy("mm_struct",
mm_size, ARCH_MIN_MMSTRUCT_ALIGN,
SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
offsetof(struct mm_struct, saved_auxv),
sizeof_field(struct mm_struct, saved_auxv),
NULL);
}
void __init proc_caches_init(void)
{
sighand_cachep = kmem_cache_create("sighand_cache",
sizeof(struct sighand_struct), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
SLAB_ACCOUNT, sighand_ctor);
signal_cachep = kmem_cache_create("signal_cache",
sizeof(struct signal_struct), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
NULL);
files_cachep = kmem_cache_create("files_cache",
sizeof(struct files_struct), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
NULL);
fs_cachep = kmem_cache_create("fs_cache",
sizeof(struct fs_struct), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT,
NULL);
vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC|SLAB_ACCOUNT);
#ifdef CONFIG_PER_VMA_LOCK
vma_lock_cachep = KMEM_CACHE(vma_lock, SLAB_PANIC|SLAB_ACCOUNT);
#endif
mmap_init();
nsproxy_cache_init();
}
/*
* Check constraints on flags passed to the unshare system call.
*/
static int check_unshare_flags(unsigned long unshare_flags)
{
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP|
CLONE_NEWTIME))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
* to unshare. Note that unsharing the address space or the
* signal handlers also need to unshare the signal queues (aka
* CLONE_THREAD).
*/
if (unshare_flags & (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)) {
if (!thread_group_empty(current))
return -EINVAL;
}
if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
if (refcount_read(¤t->sighand->count) > 1)
return -EINVAL;
}
if (unshare_flags & CLONE_VM) {
if (!current_is_single_threaded())
return -EINVAL;
}
return 0;
}
/*
* Unshare the filesystem structure if it is being shared
*/
static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
struct fs_struct *fs = current->fs;
if (!(unshare_flags & CLONE_FS) || !fs)
return 0;
/* don't need lock here; in the worst case we'll do useless copy */
if (fs->users == 1)
return 0;
*new_fsp = copy_fs_struct(fs);
if (!*new_fsp)
return -ENOMEM;
return 0;
}
/*
* Unshare file descriptor table if it is being shared
*/
int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
struct files_struct **new_fdp)
{
struct files_struct *fd = current->files;
int error = 0;
if ((unshare_flags & CLONE_FILES) &&
(fd && atomic_read(&fd->count) > 1)) {
*new_fdp = dup_fd(fd, max_fds, &error);
if (!*new_fdp)
return error;
}
return 0;
}
/*
* unshare allows a process to 'unshare' part of the process
* context which was originally shared using clone. copy_*
* functions used by kernel_clone() cannot be used here directly
* because they modify an inactive task_struct that is being
* constructed. Here we are modifying the current, active,
* task_struct.
*/
int ksys_unshare(unsigned long unshare_flags)
{
struct fs_struct *fs, *new_fs = NULL;
struct files_struct *new_fd = NULL;
struct cred *new_cred = NULL;
struct nsproxy *new_nsproxy = NULL;
int do_sysvsem = 0;
int err;
/*
* If unsharing a user namespace must also unshare the thread group
* and unshare the filesystem root and working directories.
*/
if (unshare_flags & CLONE_NEWUSER)
unshare_flags |= CLONE_THREAD | CLONE_FS;
/*
* If unsharing vm, must also unshare signal handlers.
*/
if (unshare_flags & CLONE_VM)
unshare_flags |= CLONE_SIGHAND;
/*
* If unsharing a signal handlers, must also unshare the signal queues.
*/
if (unshare_flags & CLONE_SIGHAND)
unshare_flags |= CLONE_THREAD;
/*
* If unsharing namespace, must also unshare filesystem information.
*/
if (unshare_flags & CLONE_NEWNS)
unshare_flags |= CLONE_FS;
err = check_unshare_flags(unshare_flags);
if (err)
goto bad_unshare_out;
/*
* CLONE_NEWIPC must also detach from the undolist: after switching
* to a new ipc namespace, the semaphore arrays from the old
* namespace are unreachable.
*/
if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
do_sysvsem = 1;
err = unshare_fs(unshare_flags, &new_fs);
if (err)
goto bad_unshare_out;
err = unshare_fd(unshare_flags, NR_OPEN_MAX, &new_fd);
if (err)
goto bad_unshare_cleanup_fs;
err = unshare_userns(unshare_flags, &new_cred);
if (err)
goto bad_unshare_cleanup_fd;
err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
new_cred, new_fs);
if (err)
goto bad_unshare_cleanup_cred;
if (new_cred) {
err = set_cred_ucounts(new_cred);
if (err)
goto bad_unshare_cleanup_cred;
}
if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
if (do_sysvsem) {
/*
* CLONE_SYSVSEM is equivalent to sys_exit().
*/
exit_sem(current);
}
if (unshare_flags & CLONE_NEWIPC) {
/* Orphan segments in old ns (see sem above). */
exit_shm(current);
shm_init_task(current);
}
if (new_nsproxy)
switch_task_namespaces(current, new_nsproxy);
task_lock(current);
if (new_fs) {
fs = current->fs;
spin_lock(&fs->lock);
current->fs = new_fs;
if (--fs->users)
new_fs = NULL;
else
new_fs = fs;
spin_unlock(&fs->lock);
}
if (new_fd)
swap(current->files, new_fd);
task_unlock(current);
if (new_cred) {
/* Install the new user namespace */
commit_creds(new_cred);
new_cred = NULL;
}
}
perf_event_namespaces(current);
bad_unshare_cleanup_cred:
if (new_cred)
put_cred(new_cred);
bad_unshare_cleanup_fd:
if (new_fd)
put_files_struct(new_fd);
bad_unshare_cleanup_fs:
if (new_fs)
free_fs_struct(new_fs);
bad_unshare_out:
return err;
}
SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
{
return ksys_unshare(unshare_flags);
}
/*
* Helper to unshare the files of the current task.
* We don't want to expose copy_files internals to
* the exec layer of the kernel.
*/
int unshare_files(void)
{
struct task_struct *task = current;
struct files_struct *old, *copy = NULL;
int error;
error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©);
if (error || !copy)
return error;
old = task->files;
task_lock(task);
task->files = copy;
task_unlock(task);
put_files_struct(old);
return 0;
}
int sysctl_max_threads(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
int ret;
int threads = max_threads;
int min = 1;
int max = MAX_THREADS;
t = *table;
t.data = &threads;
t.extra1 = &min;
t.extra2 = &max;
ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
if (ret || !write)
return ret;
max_threads = threads;
return 0;
}
| linux-master | kernel/fork.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Simple stack backtrace regression test module
*
* (C) Copyright 2008 Intel Corporation
* Author: Arjan van de Ven <[email protected]>
*/
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
static void backtrace_test_normal(void)
{
pr_info("Testing a backtrace from process context.\n");
pr_info("The following trace is a kernel self test and not a bug!\n");
dump_stack();
}
static DECLARE_COMPLETION(backtrace_work);
static void backtrace_test_irq_callback(unsigned long data)
{
dump_stack();
complete(&backtrace_work);
}
static DECLARE_TASKLET_OLD(backtrace_tasklet, &backtrace_test_irq_callback);
static void backtrace_test_irq(void)
{
pr_info("Testing a backtrace from irq context.\n");
pr_info("The following trace is a kernel self test and not a bug!\n");
init_completion(&backtrace_work);
tasklet_schedule(&backtrace_tasklet);
wait_for_completion(&backtrace_work);
}
#ifdef CONFIG_STACKTRACE
static void backtrace_test_saved(void)
{
unsigned long entries[8];
unsigned int nr_entries;
pr_info("Testing a saved backtrace.\n");
pr_info("The following trace is a kernel self test and not a bug!\n");
nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
stack_trace_print(entries, nr_entries, 0);
}
#else
static void backtrace_test_saved(void)
{
pr_info("Saved backtrace test skipped.\n");
}
#endif
static int backtrace_regression_test(void)
{
pr_info("====[ backtrace testing ]===========\n");
backtrace_test_normal();
backtrace_test_irq();
backtrace_test_saved();
pr_info("====[ end of backtrace testing ]====\n");
return 0;
}
static void exitf(void)
{
}
module_init(backtrace_regression_test);
module_exit(exitf);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arjan van de Ven <[email protected]>");
| linux-master | kernel/backtracetest.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>
#include <linux/highuid.h>
#include <linux/cred.h>
#include <linux/securebits.h>
#include <linux/security.h>
#include <linux/keyctl.h>
#include <linux/key-type.h>
#include <keys/user-type.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/ctype.h>
#include <linux/projid.h>
#include <linux/fs_struct.h>
#include <linux/bsearch.h>
#include <linux/sort.h>
static struct kmem_cache *user_ns_cachep __read_mostly;
static DEFINE_MUTEX(userns_state_mutex);
static bool new_idmap_permitted(const struct file *file,
struct user_namespace *ns, int cap_setid,
struct uid_gid_map *map);
static void free_user_ns(struct work_struct *work);
static struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
{
return inc_ucount(ns, uid, UCOUNT_USER_NAMESPACES);
}
static void dec_user_namespaces(struct ucounts *ucounts)
{
return dec_ucount(ucounts, UCOUNT_USER_NAMESPACES);
}
static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
{
/* Start with the same capabilities as init but useless for doing
* anything as the capabilities are bound to the new user namespace.
*/
cred->securebits = SECUREBITS_DEFAULT;
cred->cap_inheritable = CAP_EMPTY_SET;
cred->cap_permitted = CAP_FULL_SET;
cred->cap_effective = CAP_FULL_SET;
cred->cap_ambient = CAP_EMPTY_SET;
cred->cap_bset = CAP_FULL_SET;
#ifdef CONFIG_KEYS
key_put(cred->request_key_auth);
cred->request_key_auth = NULL;
#endif
/* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
cred->user_ns = user_ns;
}
static unsigned long enforced_nproc_rlimit(void)
{
unsigned long limit = RLIM_INFINITY;
/* Is RLIMIT_NPROC currently enforced? */
if (!uid_eq(current_uid(), GLOBAL_ROOT_UID) ||
(current_user_ns() != &init_user_ns))
limit = rlimit(RLIMIT_NPROC);
return limit;
}
/*
* Create a new user namespace, deriving the creator from the user in the
* passed credentials, and replacing that user with the new root user for the
* new namespace.
*
* This is called by copy_creds(), which will finish setting the target task's
* credentials.
*/
int create_user_ns(struct cred *new)
{
struct user_namespace *ns, *parent_ns = new->user_ns;
kuid_t owner = new->euid;
kgid_t group = new->egid;
struct ucounts *ucounts;
int ret, i;
ret = -ENOSPC;
if (parent_ns->level > 32)
goto fail;
ucounts = inc_user_namespaces(parent_ns, owner);
if (!ucounts)
goto fail;
/*
* Verify that we can not violate the policy of which files
* may be accessed that is specified by the root directory,
* by verifying that the root directory is at the root of the
* mount namespace which allows all files to be accessed.
*/
ret = -EPERM;
if (current_chrooted())
goto fail_dec;
/* The creator needs a mapping in the parent user namespace
* or else we won't be able to reasonably tell userspace who
* created a user_namespace.
*/
ret = -EPERM;
if (!kuid_has_mapping(parent_ns, owner) ||
!kgid_has_mapping(parent_ns, group))
goto fail_dec;
ret = security_create_user_ns(new);
if (ret < 0)
goto fail_dec;
ret = -ENOMEM;
ns = kmem_cache_zalloc(user_ns_cachep, GFP_KERNEL);
if (!ns)
goto fail_dec;
ns->parent_could_setfcap = cap_raised(new->cap_effective, CAP_SETFCAP);
ret = ns_alloc_inum(&ns->ns);
if (ret)
goto fail_free;
ns->ns.ops = &userns_operations;
refcount_set(&ns->ns.count, 1);
/* Leave the new->user_ns reference with the new user namespace. */
ns->parent = parent_ns;
ns->level = parent_ns->level + 1;
ns->owner = owner;
ns->group = group;
INIT_WORK(&ns->work, free_user_ns);
for (i = 0; i < UCOUNT_COUNTS; i++) {
ns->ucount_max[i] = INT_MAX;
}
set_userns_rlimit_max(ns, UCOUNT_RLIMIT_NPROC, enforced_nproc_rlimit());
set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE));
set_userns_rlimit_max(ns, UCOUNT_RLIMIT_SIGPENDING, rlimit(RLIMIT_SIGPENDING));
set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MEMLOCK, rlimit(RLIMIT_MEMLOCK));
ns->ucounts = ucounts;
/* Inherit USERNS_SETGROUPS_ALLOWED from our parent */
mutex_lock(&userns_state_mutex);
ns->flags = parent_ns->flags;
mutex_unlock(&userns_state_mutex);
#ifdef CONFIG_KEYS
INIT_LIST_HEAD(&ns->keyring_name_list);
init_rwsem(&ns->keyring_sem);
#endif
ret = -ENOMEM;
if (!setup_userns_sysctls(ns))
goto fail_keyring;
set_cred_user_ns(new, ns);
return 0;
fail_keyring:
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
#endif
ns_free_inum(&ns->ns);
fail_free:
kmem_cache_free(user_ns_cachep, ns);
fail_dec:
dec_user_namespaces(ucounts);
fail:
return ret;
}
int unshare_userns(unsigned long unshare_flags, struct cred **new_cred)
{
struct cred *cred;
int err = -ENOMEM;
if (!(unshare_flags & CLONE_NEWUSER))
return 0;
cred = prepare_creds();
if (cred) {
err = create_user_ns(cred);
if (err)
put_cred(cred);
else
*new_cred = cred;
}
return err;
}
static void free_user_ns(struct work_struct *work)
{
struct user_namespace *parent, *ns =
container_of(work, struct user_namespace, work);
do {
struct ucounts *ucounts = ns->ucounts;
parent = ns->parent;
if (ns->gid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
kfree(ns->gid_map.forward);
kfree(ns->gid_map.reverse);
}
if (ns->uid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
kfree(ns->uid_map.forward);
kfree(ns->uid_map.reverse);
}
if (ns->projid_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
kfree(ns->projid_map.forward);
kfree(ns->projid_map.reverse);
}
retire_userns_sysctls(ns);
key_free_user_ns(ns);
ns_free_inum(&ns->ns);
kmem_cache_free(user_ns_cachep, ns);
dec_user_namespaces(ucounts);
ns = parent;
} while (refcount_dec_and_test(&parent->ns.count));
}
void __put_user_ns(struct user_namespace *ns)
{
schedule_work(&ns->work);
}
EXPORT_SYMBOL(__put_user_ns);
/**
* struct idmap_key - holds the information necessary to find an idmapping in a
* sorted idmap array. It is passed to cmp_map_id() as first argument.
*/
struct idmap_key {
bool map_up; /* true -> id from kid; false -> kid from id */
u32 id; /* id to find */
u32 count; /* == 0 unless used with map_id_range_down() */
};
/**
* cmp_map_id - Function to be passed to bsearch() to find the requested
* idmapping. Expects struct idmap_key to be passed via @k.
*/
static int cmp_map_id(const void *k, const void *e)
{
u32 first, last, id2;
const struct idmap_key *key = k;
const struct uid_gid_extent *el = e;
id2 = key->id + key->count - 1;
/* handle map_id_{down,up}() */
if (key->map_up)
first = el->lower_first;
else
first = el->first;
last = first + el->count - 1;
if (key->id >= first && key->id <= last &&
(id2 >= first && id2 <= last))
return 0;
if (key->id < first || id2 < first)
return -1;
return 1;
}
/**
* map_id_range_down_max - Find idmap via binary search in ordered idmap array.
* Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static struct uid_gid_extent *
map_id_range_down_max(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
{
struct idmap_key key;
key.map_up = false;
key.count = count;
key.id = id;
return bsearch(&key, map->forward, extents,
sizeof(struct uid_gid_extent), cmp_map_id);
}
/**
* map_id_range_down_base - Find idmap via binary search in static extent array.
* Can only be called if number of mappings is equal or less than
* UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static struct uid_gid_extent *
map_id_range_down_base(unsigned extents, struct uid_gid_map *map, u32 id, u32 count)
{
unsigned idx;
u32 first, last, id2;
id2 = id + count - 1;
/* Find the matching extent */
for (idx = 0; idx < extents; idx++) {
first = map->extent[idx].first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last &&
(id2 >= first && id2 <= last))
return &map->extent[idx];
}
return NULL;
}
static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
{
struct uid_gid_extent *extent;
unsigned extents = map->nr_extents;
smp_rmb();
if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
extent = map_id_range_down_base(extents, map, id, count);
else
extent = map_id_range_down_max(extents, map, id, count);
/* Map the id or note failure */
if (extent)
id = (id - extent->first) + extent->lower_first;
else
id = (u32) -1;
return id;
}
static u32 map_id_down(struct uid_gid_map *map, u32 id)
{
return map_id_range_down(map, id, 1);
}
/**
* map_id_up_base - Find idmap via binary search in static extent array.
* Can only be called if number of mappings is equal or less than
* UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static struct uid_gid_extent *
map_id_up_base(unsigned extents, struct uid_gid_map *map, u32 id)
{
unsigned idx;
u32 first, last;
/* Find the matching extent */
for (idx = 0; idx < extents; idx++) {
first = map->extent[idx].lower_first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last)
return &map->extent[idx];
}
return NULL;
}
/**
* map_id_up_max - Find idmap via binary search in ordered idmap array.
* Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static struct uid_gid_extent *
map_id_up_max(unsigned extents, struct uid_gid_map *map, u32 id)
{
struct idmap_key key;
key.map_up = true;
key.count = 1;
key.id = id;
return bsearch(&key, map->reverse, extents,
sizeof(struct uid_gid_extent), cmp_map_id);
}
static u32 map_id_up(struct uid_gid_map *map, u32 id)
{
struct uid_gid_extent *extent;
unsigned extents = map->nr_extents;
smp_rmb();
if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
extent = map_id_up_base(extents, map, id);
else
extent = map_id_up_max(extents, map, id);
/* Map the id or note failure */
if (extent)
id = (id - extent->lower_first) + extent->first;
else
id = (u32) -1;
return id;
}
/**
* make_kuid - Map a user-namespace uid pair into a kuid.
* @ns: User namespace that the uid is in
* @uid: User identifier
*
* Maps a user-namespace uid pair into a kernel internal kuid,
* and returns that kuid.
*
* When there is no mapping defined for the user-namespace uid
* pair INVALID_UID is returned. Callers are expected to test
* for and handle INVALID_UID being returned. INVALID_UID
* may be tested for using uid_valid().
*/
kuid_t make_kuid(struct user_namespace *ns, uid_t uid)
{
/* Map the uid to a global kernel uid */
return KUIDT_INIT(map_id_down(&ns->uid_map, uid));
}
EXPORT_SYMBOL(make_kuid);
/**
* from_kuid - Create a uid from a kuid user-namespace pair.
* @targ: The user namespace we want a uid in.
* @kuid: The kernel internal uid to start with.
*
* Map @kuid into the user-namespace specified by @targ and
* return the resulting uid.
*
* There is always a mapping into the initial user_namespace.
*
* If @kuid has no mapping in @targ (uid_t)-1 is returned.
*/
uid_t from_kuid(struct user_namespace *targ, kuid_t kuid)
{
/* Map the uid from a global kernel uid */
return map_id_up(&targ->uid_map, __kuid_val(kuid));
}
EXPORT_SYMBOL(from_kuid);
/**
* from_kuid_munged - Create a uid from a kuid user-namespace pair.
* @targ: The user namespace we want a uid in.
* @kuid: The kernel internal uid to start with.
*
* Map @kuid into the user-namespace specified by @targ and
* return the resulting uid.
*
* There is always a mapping into the initial user_namespace.
*
* Unlike from_kuid from_kuid_munged never fails and always
* returns a valid uid. This makes from_kuid_munged appropriate
* for use in syscalls like stat and getuid where failing the
* system call and failing to provide a valid uid are not an
* options.
*
* If @kuid has no mapping in @targ overflowuid is returned.
*/
uid_t from_kuid_munged(struct user_namespace *targ, kuid_t kuid)
{
uid_t uid;
uid = from_kuid(targ, kuid);
if (uid == (uid_t) -1)
uid = overflowuid;
return uid;
}
EXPORT_SYMBOL(from_kuid_munged);
/**
* make_kgid - Map a user-namespace gid pair into a kgid.
* @ns: User namespace that the gid is in
* @gid: group identifier
*
* Maps a user-namespace gid pair into a kernel internal kgid,
* and returns that kgid.
*
* When there is no mapping defined for the user-namespace gid
* pair INVALID_GID is returned. Callers are expected to test
* for and handle INVALID_GID being returned. INVALID_GID may be
* tested for using gid_valid().
*/
kgid_t make_kgid(struct user_namespace *ns, gid_t gid)
{
/* Map the gid to a global kernel gid */
return KGIDT_INIT(map_id_down(&ns->gid_map, gid));
}
EXPORT_SYMBOL(make_kgid);
/**
* from_kgid - Create a gid from a kgid user-namespace pair.
* @targ: The user namespace we want a gid in.
* @kgid: The kernel internal gid to start with.
*
* Map @kgid into the user-namespace specified by @targ and
* return the resulting gid.
*
* There is always a mapping into the initial user_namespace.
*
* If @kgid has no mapping in @targ (gid_t)-1 is returned.
*/
gid_t from_kgid(struct user_namespace *targ, kgid_t kgid)
{
/* Map the gid from a global kernel gid */
return map_id_up(&targ->gid_map, __kgid_val(kgid));
}
EXPORT_SYMBOL(from_kgid);
/**
* from_kgid_munged - Create a gid from a kgid user-namespace pair.
* @targ: The user namespace we want a gid in.
* @kgid: The kernel internal gid to start with.
*
* Map @kgid into the user-namespace specified by @targ and
* return the resulting gid.
*
* There is always a mapping into the initial user_namespace.
*
* Unlike from_kgid from_kgid_munged never fails and always
* returns a valid gid. This makes from_kgid_munged appropriate
* for use in syscalls like stat and getgid where failing the
* system call and failing to provide a valid gid are not options.
*
* If @kgid has no mapping in @targ overflowgid is returned.
*/
gid_t from_kgid_munged(struct user_namespace *targ, kgid_t kgid)
{
gid_t gid;
gid = from_kgid(targ, kgid);
if (gid == (gid_t) -1)
gid = overflowgid;
return gid;
}
EXPORT_SYMBOL(from_kgid_munged);
/**
* make_kprojid - Map a user-namespace projid pair into a kprojid.
* @ns: User namespace that the projid is in
* @projid: Project identifier
*
* Maps a user-namespace uid pair into a kernel internal kuid,
* and returns that kuid.
*
* When there is no mapping defined for the user-namespace projid
* pair INVALID_PROJID is returned. Callers are expected to test
* for and handle INVALID_PROJID being returned. INVALID_PROJID
* may be tested for using projid_valid().
*/
kprojid_t make_kprojid(struct user_namespace *ns, projid_t projid)
{
/* Map the uid to a global kernel uid */
return KPROJIDT_INIT(map_id_down(&ns->projid_map, projid));
}
EXPORT_SYMBOL(make_kprojid);
/**
* from_kprojid - Create a projid from a kprojid user-namespace pair.
* @targ: The user namespace we want a projid in.
* @kprojid: The kernel internal project identifier to start with.
*
* Map @kprojid into the user-namespace specified by @targ and
* return the resulting projid.
*
* There is always a mapping into the initial user_namespace.
*
* If @kprojid has no mapping in @targ (projid_t)-1 is returned.
*/
projid_t from_kprojid(struct user_namespace *targ, kprojid_t kprojid)
{
/* Map the uid from a global kernel uid */
return map_id_up(&targ->projid_map, __kprojid_val(kprojid));
}
EXPORT_SYMBOL(from_kprojid);
/**
* from_kprojid_munged - Create a projiid from a kprojid user-namespace pair.
* @targ: The user namespace we want a projid in.
* @kprojid: The kernel internal projid to start with.
*
* Map @kprojid into the user-namespace specified by @targ and
* return the resulting projid.
*
* There is always a mapping into the initial user_namespace.
*
* Unlike from_kprojid from_kprojid_munged never fails and always
* returns a valid projid. This makes from_kprojid_munged
* appropriate for use in syscalls like stat and where
* failing the system call and failing to provide a valid projid are
* not an options.
*
* If @kprojid has no mapping in @targ OVERFLOW_PROJID is returned.
*/
projid_t from_kprojid_munged(struct user_namespace *targ, kprojid_t kprojid)
{
projid_t projid;
projid = from_kprojid(targ, kprojid);
if (projid == (projid_t) -1)
projid = OVERFLOW_PROJID;
return projid;
}
EXPORT_SYMBOL(from_kprojid_munged);
static int uid_m_show(struct seq_file *seq, void *v)
{
struct user_namespace *ns = seq->private;
struct uid_gid_extent *extent = v;
struct user_namespace *lower_ns;
uid_t lower;
lower_ns = seq_user_ns(seq);
if ((lower_ns == ns) && lower_ns->parent)
lower_ns = lower_ns->parent;
lower = from_kuid(lower_ns, KUIDT_INIT(extent->lower_first));
seq_printf(seq, "%10u %10u %10u\n",
extent->first,
lower,
extent->count);
return 0;
}
static int gid_m_show(struct seq_file *seq, void *v)
{
struct user_namespace *ns = seq->private;
struct uid_gid_extent *extent = v;
struct user_namespace *lower_ns;
gid_t lower;
lower_ns = seq_user_ns(seq);
if ((lower_ns == ns) && lower_ns->parent)
lower_ns = lower_ns->parent;
lower = from_kgid(lower_ns, KGIDT_INIT(extent->lower_first));
seq_printf(seq, "%10u %10u %10u\n",
extent->first,
lower,
extent->count);
return 0;
}
static int projid_m_show(struct seq_file *seq, void *v)
{
struct user_namespace *ns = seq->private;
struct uid_gid_extent *extent = v;
struct user_namespace *lower_ns;
projid_t lower;
lower_ns = seq_user_ns(seq);
if ((lower_ns == ns) && lower_ns->parent)
lower_ns = lower_ns->parent;
lower = from_kprojid(lower_ns, KPROJIDT_INIT(extent->lower_first));
seq_printf(seq, "%10u %10u %10u\n",
extent->first,
lower,
extent->count);
return 0;
}
static void *m_start(struct seq_file *seq, loff_t *ppos,
struct uid_gid_map *map)
{
loff_t pos = *ppos;
unsigned extents = map->nr_extents;
smp_rmb();
if (pos >= extents)
return NULL;
if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
return &map->extent[pos];
return &map->forward[pos];
}
static void *uid_m_start(struct seq_file *seq, loff_t *ppos)
{
struct user_namespace *ns = seq->private;
return m_start(seq, ppos, &ns->uid_map);
}
static void *gid_m_start(struct seq_file *seq, loff_t *ppos)
{
struct user_namespace *ns = seq->private;
return m_start(seq, ppos, &ns->gid_map);
}
static void *projid_m_start(struct seq_file *seq, loff_t *ppos)
{
struct user_namespace *ns = seq->private;
return m_start(seq, ppos, &ns->projid_map);
}
static void *m_next(struct seq_file *seq, void *v, loff_t *pos)
{
(*pos)++;
return seq->op->start(seq, pos);
}
static void m_stop(struct seq_file *seq, void *v)
{
return;
}
const struct seq_operations proc_uid_seq_operations = {
.start = uid_m_start,
.stop = m_stop,
.next = m_next,
.show = uid_m_show,
};
const struct seq_operations proc_gid_seq_operations = {
.start = gid_m_start,
.stop = m_stop,
.next = m_next,
.show = gid_m_show,
};
const struct seq_operations proc_projid_seq_operations = {
.start = projid_m_start,
.stop = m_stop,
.next = m_next,
.show = projid_m_show,
};
static bool mappings_overlap(struct uid_gid_map *new_map,
struct uid_gid_extent *extent)
{
u32 upper_first, lower_first, upper_last, lower_last;
unsigned idx;
upper_first = extent->first;
lower_first = extent->lower_first;
upper_last = upper_first + extent->count - 1;
lower_last = lower_first + extent->count - 1;
for (idx = 0; idx < new_map->nr_extents; idx++) {
u32 prev_upper_first, prev_lower_first;
u32 prev_upper_last, prev_lower_last;
struct uid_gid_extent *prev;
if (new_map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
prev = &new_map->extent[idx];
else
prev = &new_map->forward[idx];
prev_upper_first = prev->first;
prev_lower_first = prev->lower_first;
prev_upper_last = prev_upper_first + prev->count - 1;
prev_lower_last = prev_lower_first + prev->count - 1;
/* Does the upper range intersect a previous extent? */
if ((prev_upper_first <= upper_last) &&
(prev_upper_last >= upper_first))
return true;
/* Does the lower range intersect a previous extent? */
if ((prev_lower_first <= lower_last) &&
(prev_lower_last >= lower_first))
return true;
}
return false;
}
/**
* insert_extent - Safely insert a new idmap extent into struct uid_gid_map.
* Takes care to allocate a 4K block of memory if the number of mappings exceeds
* UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static int insert_extent(struct uid_gid_map *map, struct uid_gid_extent *extent)
{
struct uid_gid_extent *dest;
if (map->nr_extents == UID_GID_MAP_MAX_BASE_EXTENTS) {
struct uid_gid_extent *forward;
/* Allocate memory for 340 mappings. */
forward = kmalloc_array(UID_GID_MAP_MAX_EXTENTS,
sizeof(struct uid_gid_extent),
GFP_KERNEL);
if (!forward)
return -ENOMEM;
/* Copy over memory. Only set up memory for the forward pointer.
* Defer the memory setup for the reverse pointer.
*/
memcpy(forward, map->extent,
map->nr_extents * sizeof(map->extent[0]));
map->forward = forward;
map->reverse = NULL;
}
if (map->nr_extents < UID_GID_MAP_MAX_BASE_EXTENTS)
dest = &map->extent[map->nr_extents];
else
dest = &map->forward[map->nr_extents];
*dest = *extent;
map->nr_extents++;
return 0;
}
/* cmp function to sort() forward mappings */
static int cmp_extents_forward(const void *a, const void *b)
{
const struct uid_gid_extent *e1 = a;
const struct uid_gid_extent *e2 = b;
if (e1->first < e2->first)
return -1;
if (e1->first > e2->first)
return 1;
return 0;
}
/* cmp function to sort() reverse mappings */
static int cmp_extents_reverse(const void *a, const void *b)
{
const struct uid_gid_extent *e1 = a;
const struct uid_gid_extent *e2 = b;
if (e1->lower_first < e2->lower_first)
return -1;
if (e1->lower_first > e2->lower_first)
return 1;
return 0;
}
/**
* sort_idmaps - Sorts an array of idmap entries.
* Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS.
*/
static int sort_idmaps(struct uid_gid_map *map)
{
if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
return 0;
/* Sort forward array. */
sort(map->forward, map->nr_extents, sizeof(struct uid_gid_extent),
cmp_extents_forward, NULL);
/* Only copy the memory from forward we actually need. */
map->reverse = kmemdup(map->forward,
map->nr_extents * sizeof(struct uid_gid_extent),
GFP_KERNEL);
if (!map->reverse)
return -ENOMEM;
/* Sort reverse array. */
sort(map->reverse, map->nr_extents, sizeof(struct uid_gid_extent),
cmp_extents_reverse, NULL);
return 0;
}
/**
* verify_root_map() - check the uid 0 mapping
* @file: idmapping file
* @map_ns: user namespace of the target process
* @new_map: requested idmap
*
* If a process requests mapping parent uid 0 into the new ns, verify that the
* process writing the map had the CAP_SETFCAP capability as the target process
* will be able to write fscaps that are valid in ancestor user namespaces.
*
* Return: true if the mapping is allowed, false if not.
*/
static bool verify_root_map(const struct file *file,
struct user_namespace *map_ns,
struct uid_gid_map *new_map)
{
int idx;
const struct user_namespace *file_ns = file->f_cred->user_ns;
struct uid_gid_extent *extent0 = NULL;
for (idx = 0; idx < new_map->nr_extents; idx++) {
if (new_map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
extent0 = &new_map->extent[idx];
else
extent0 = &new_map->forward[idx];
if (extent0->lower_first == 0)
break;
extent0 = NULL;
}
if (!extent0)
return true;
if (map_ns == file_ns) {
/* The process unshared its ns and is writing to its own
* /proc/self/uid_map. User already has full capabilites in
* the new namespace. Verify that the parent had CAP_SETFCAP
* when it unshared.
* */
if (!file_ns->parent_could_setfcap)
return false;
} else {
/* Process p1 is writing to uid_map of p2, who is in a child
* user namespace to p1's. Verify that the opener of the map
* file has CAP_SETFCAP against the parent of the new map
* namespace */
if (!file_ns_capable(file, map_ns->parent, CAP_SETFCAP))
return false;
}
return true;
}
static ssize_t map_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos,
int cap_setid,
struct uid_gid_map *map,
struct uid_gid_map *parent_map)
{
struct seq_file *seq = file->private_data;
struct user_namespace *map_ns = seq->private;
struct uid_gid_map new_map;
unsigned idx;
struct uid_gid_extent extent;
char *kbuf = NULL, *pos, *next_line;
ssize_t ret;
/* Only allow < page size writes at the beginning of the file */
if ((*ppos != 0) || (count >= PAGE_SIZE))
return -EINVAL;
/* Slurp in the user data */
kbuf = memdup_user_nul(buf, count);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
/*
* The userns_state_mutex serializes all writes to any given map.
*
* Any map is only ever written once.
*
* An id map fits within 1 cache line on most architectures.
*
* On read nothing needs to be done unless you are on an
* architecture with a crazy cache coherency model like alpha.
*
* There is a one time data dependency between reading the
* count of the extents and the values of the extents. The
* desired behavior is to see the values of the extents that
* were written before the count of the extents.
*
* To achieve this smp_wmb() is used on guarantee the write
* order and smp_rmb() is guaranteed that we don't have crazy
* architectures returning stale data.
*/
mutex_lock(&userns_state_mutex);
memset(&new_map, 0, sizeof(struct uid_gid_map));
ret = -EPERM;
/* Only allow one successful write to the map */
if (map->nr_extents != 0)
goto out;
/*
* Adjusting namespace settings requires capabilities on the target.
*/
if (cap_valid(cap_setid) && !file_ns_capable(file, map_ns, CAP_SYS_ADMIN))
goto out;
/* Parse the user data */
ret = -EINVAL;
pos = kbuf;
for (; pos; pos = next_line) {
/* Find the end of line and ensure I don't look past it */
next_line = strchr(pos, '\n');
if (next_line) {
*next_line = '\0';
next_line++;
if (*next_line == '\0')
next_line = NULL;
}
pos = skip_spaces(pos);
extent.first = simple_strtoul(pos, &pos, 10);
if (!isspace(*pos))
goto out;
pos = skip_spaces(pos);
extent.lower_first = simple_strtoul(pos, &pos, 10);
if (!isspace(*pos))
goto out;
pos = skip_spaces(pos);
extent.count = simple_strtoul(pos, &pos, 10);
if (*pos && !isspace(*pos))
goto out;
/* Verify there is not trailing junk on the line */
pos = skip_spaces(pos);
if (*pos != '\0')
goto out;
/* Verify we have been given valid starting values */
if ((extent.first == (u32) -1) ||
(extent.lower_first == (u32) -1))
goto out;
/* Verify count is not zero and does not cause the
* extent to wrap
*/
if ((extent.first + extent.count) <= extent.first)
goto out;
if ((extent.lower_first + extent.count) <=
extent.lower_first)
goto out;
/* Do the ranges in extent overlap any previous extents? */
if (mappings_overlap(&new_map, &extent))
goto out;
if ((new_map.nr_extents + 1) == UID_GID_MAP_MAX_EXTENTS &&
(next_line != NULL))
goto out;
ret = insert_extent(&new_map, &extent);
if (ret < 0)
goto out;
ret = -EINVAL;
}
/* Be very certain the new map actually exists */
if (new_map.nr_extents == 0)
goto out;
ret = -EPERM;
/* Validate the user is allowed to use user id's mapped to. */
if (!new_idmap_permitted(file, map_ns, cap_setid, &new_map))
goto out;
ret = -EPERM;
/* Map the lower ids from the parent user namespace to the
* kernel global id space.
*/
for (idx = 0; idx < new_map.nr_extents; idx++) {
struct uid_gid_extent *e;
u32 lower_first;
if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS)
e = &new_map.extent[idx];
else
e = &new_map.forward[idx];
lower_first = map_id_range_down(parent_map,
e->lower_first,
e->count);
/* Fail if we can not map the specified extent to
* the kernel global id space.
*/
if (lower_first == (u32) -1)
goto out;
e->lower_first = lower_first;
}
/*
* If we want to use binary search for lookup, this clones the extent
* array and sorts both copies.
*/
ret = sort_idmaps(&new_map);
if (ret < 0)
goto out;
/* Install the map */
if (new_map.nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS) {
memcpy(map->extent, new_map.extent,
new_map.nr_extents * sizeof(new_map.extent[0]));
} else {
map->forward = new_map.forward;
map->reverse = new_map.reverse;
}
smp_wmb();
map->nr_extents = new_map.nr_extents;
*ppos = count;
ret = count;
out:
if (ret < 0 && new_map.nr_extents > UID_GID_MAP_MAX_BASE_EXTENTS) {
kfree(new_map.forward);
kfree(new_map.reverse);
map->forward = NULL;
map->reverse = NULL;
map->nr_extents = 0;
}
mutex_unlock(&userns_state_mutex);
kfree(kbuf);
return ret;
}
ssize_t proc_uid_map_write(struct file *file, const char __user *buf,
size_t size, loff_t *ppos)
{
struct seq_file *seq = file->private_data;
struct user_namespace *ns = seq->private;
struct user_namespace *seq_ns = seq_user_ns(seq);
if (!ns->parent)
return -EPERM;
if ((seq_ns != ns) && (seq_ns != ns->parent))
return -EPERM;
return map_write(file, buf, size, ppos, CAP_SETUID,
&ns->uid_map, &ns->parent->uid_map);
}
ssize_t proc_gid_map_write(struct file *file, const char __user *buf,
size_t size, loff_t *ppos)
{
struct seq_file *seq = file->private_data;
struct user_namespace *ns = seq->private;
struct user_namespace *seq_ns = seq_user_ns(seq);
if (!ns->parent)
return -EPERM;
if ((seq_ns != ns) && (seq_ns != ns->parent))
return -EPERM;
return map_write(file, buf, size, ppos, CAP_SETGID,
&ns->gid_map, &ns->parent->gid_map);
}
ssize_t proc_projid_map_write(struct file *file, const char __user *buf,
size_t size, loff_t *ppos)
{
struct seq_file *seq = file->private_data;
struct user_namespace *ns = seq->private;
struct user_namespace *seq_ns = seq_user_ns(seq);
if (!ns->parent)
return -EPERM;
if ((seq_ns != ns) && (seq_ns != ns->parent))
return -EPERM;
/* Anyone can set any valid project id no capability needed */
return map_write(file, buf, size, ppos, -1,
&ns->projid_map, &ns->parent->projid_map);
}
static bool new_idmap_permitted(const struct file *file,
struct user_namespace *ns, int cap_setid,
struct uid_gid_map *new_map)
{
const struct cred *cred = file->f_cred;
if (cap_setid == CAP_SETUID && !verify_root_map(file, ns, new_map))
return false;
/* Don't allow mappings that would allow anything that wouldn't
* be allowed without the establishment of unprivileged mappings.
*/
if ((new_map->nr_extents == 1) && (new_map->extent[0].count == 1) &&
uid_eq(ns->owner, cred->euid)) {
u32 id = new_map->extent[0].lower_first;
if (cap_setid == CAP_SETUID) {
kuid_t uid = make_kuid(ns->parent, id);
if (uid_eq(uid, cred->euid))
return true;
} else if (cap_setid == CAP_SETGID) {
kgid_t gid = make_kgid(ns->parent, id);
if (!(ns->flags & USERNS_SETGROUPS_ALLOWED) &&
gid_eq(gid, cred->egid))
return true;
}
}
/* Allow anyone to set a mapping that doesn't require privilege */
if (!cap_valid(cap_setid))
return true;
/* Allow the specified ids if we have the appropriate capability
* (CAP_SETUID or CAP_SETGID) over the parent user namespace.
* And the opener of the id file also has the appropriate capability.
*/
if (ns_capable(ns->parent, cap_setid) &&
file_ns_capable(file, ns->parent, cap_setid))
return true;
return false;
}
int proc_setgroups_show(struct seq_file *seq, void *v)
{
struct user_namespace *ns = seq->private;
unsigned long userns_flags = READ_ONCE(ns->flags);
seq_printf(seq, "%s\n",
(userns_flags & USERNS_SETGROUPS_ALLOWED) ?
"allow" : "deny");
return 0;
}
ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct seq_file *seq = file->private_data;
struct user_namespace *ns = seq->private;
char kbuf[8], *pos;
bool setgroups_allowed;
ssize_t ret;
/* Only allow a very narrow range of strings to be written */
ret = -EINVAL;
if ((*ppos != 0) || (count >= sizeof(kbuf)))
goto out;
/* What was written? */
ret = -EFAULT;
if (copy_from_user(kbuf, buf, count))
goto out;
kbuf[count] = '\0';
pos = kbuf;
/* What is being requested? */
ret = -EINVAL;
if (strncmp(pos, "allow", 5) == 0) {
pos += 5;
setgroups_allowed = true;
}
else if (strncmp(pos, "deny", 4) == 0) {
pos += 4;
setgroups_allowed = false;
}
else
goto out;
/* Verify there is not trailing junk on the line */
pos = skip_spaces(pos);
if (*pos != '\0')
goto out;
ret = -EPERM;
mutex_lock(&userns_state_mutex);
if (setgroups_allowed) {
/* Enabling setgroups after setgroups has been disabled
* is not allowed.
*/
if (!(ns->flags & USERNS_SETGROUPS_ALLOWED))
goto out_unlock;
} else {
/* Permanently disabling setgroups after setgroups has
* been enabled by writing the gid_map is not allowed.
*/
if (ns->gid_map.nr_extents != 0)
goto out_unlock;
ns->flags &= ~USERNS_SETGROUPS_ALLOWED;
}
mutex_unlock(&userns_state_mutex);
/* Report a successful write */
*ppos = count;
ret = count;
out:
return ret;
out_unlock:
mutex_unlock(&userns_state_mutex);
goto out;
}
bool userns_may_setgroups(const struct user_namespace *ns)
{
bool allowed;
mutex_lock(&userns_state_mutex);
/* It is not safe to use setgroups until a gid mapping in
* the user namespace has been established.
*/
allowed = ns->gid_map.nr_extents != 0;
/* Is setgroups allowed? */
allowed = allowed && (ns->flags & USERNS_SETGROUPS_ALLOWED);
mutex_unlock(&userns_state_mutex);
return allowed;
}
/*
* Returns true if @child is the same namespace or a descendant of
* @ancestor.
*/
bool in_userns(const struct user_namespace *ancestor,
const struct user_namespace *child)
{
const struct user_namespace *ns;
for (ns = child; ns->level > ancestor->level; ns = ns->parent)
;
return (ns == ancestor);
}
bool current_in_userns(const struct user_namespace *target_ns)
{
return in_userns(target_ns, current_user_ns());
}
EXPORT_SYMBOL(current_in_userns);
static inline struct user_namespace *to_user_ns(struct ns_common *ns)
{
return container_of(ns, struct user_namespace, ns);
}
static struct ns_common *userns_get(struct task_struct *task)
{
struct user_namespace *user_ns;
rcu_read_lock();
user_ns = get_user_ns(__task_cred(task)->user_ns);
rcu_read_unlock();
return user_ns ? &user_ns->ns : NULL;
}
static void userns_put(struct ns_common *ns)
{
put_user_ns(to_user_ns(ns));
}
static int userns_install(struct nsset *nsset, struct ns_common *ns)
{
struct user_namespace *user_ns = to_user_ns(ns);
struct cred *cred;
/* Don't allow gaining capabilities by reentering
* the same user namespace.
*/
if (user_ns == current_user_ns())
return -EINVAL;
/* Tasks that share a thread group must share a user namespace */
if (!thread_group_empty(current))
return -EINVAL;
if (current->fs->users != 1)
return -EINVAL;
if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
cred = nsset_cred(nsset);
if (!cred)
return -EINVAL;
put_user_ns(cred->user_ns);
set_cred_user_ns(cred, get_user_ns(user_ns));
if (set_cred_ucounts(cred) < 0)
return -EINVAL;
return 0;
}
struct ns_common *ns_get_owner(struct ns_common *ns)
{
struct user_namespace *my_user_ns = current_user_ns();
struct user_namespace *owner, *p;
/* See if the owner is in the current user namespace */
owner = p = ns->ops->owner(ns);
for (;;) {
if (!p)
return ERR_PTR(-EPERM);
if (p == my_user_ns)
break;
p = p->parent;
}
return &get_user_ns(owner)->ns;
}
static struct user_namespace *userns_owner(struct ns_common *ns)
{
return to_user_ns(ns)->parent;
}
const struct proc_ns_operations userns_operations = {
.name = "user",
.type = CLONE_NEWUSER,
.get = userns_get,
.put = userns_put,
.install = userns_install,
.owner = userns_owner,
.get_parent = ns_get_owner,
};
static __init int user_namespaces_init(void)
{
user_ns_cachep = KMEM_CACHE(user_namespace, SLAB_PANIC | SLAB_ACCOUNT);
return 0;
}
subsys_initcall(user_namespaces_init);
| linux-master | kernel/user_namespace.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kexec.c - kexec_load system call
* Copyright (C) 2002-2004 Eric Biederman <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/security.h>
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include "kexec_internal.h"
static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
unsigned long nr_segments,
struct kexec_segment *segments,
unsigned long flags)
{
int ret;
struct kimage *image;
bool kexec_on_panic = flags & KEXEC_ON_CRASH;
if (kexec_on_panic) {
/* Verify we have a valid entry point */
if ((entry < phys_to_boot_phys(crashk_res.start)) ||
(entry > phys_to_boot_phys(crashk_res.end)))
return -EADDRNOTAVAIL;
}
/* Allocate and initialize a controlling structure */
image = do_kimage_alloc_init();
if (!image)
return -ENOMEM;
image->start = entry;
image->nr_segments = nr_segments;
memcpy(image->segment, segments, nr_segments * sizeof(*segments));
if (kexec_on_panic) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
}
ret = sanity_check_segment_list(image);
if (ret)
goto out_free_image;
/*
* Find a location for the control code buffer, and add it
* the vector of segments so that it's pages will also be
* counted as destination pages.
*/
ret = -ENOMEM;
image->control_code_page = kimage_alloc_control_pages(image,
get_order(KEXEC_CONTROL_PAGE_SIZE));
if (!image->control_code_page) {
pr_err("Could not allocate control_code_buffer\n");
goto out_free_image;
}
if (!kexec_on_panic) {
image->swap_page = kimage_alloc_control_pages(image, 0);
if (!image->swap_page) {
pr_err("Could not allocate swap buffer\n");
goto out_free_control_pages;
}
}
*rimage = image;
return 0;
out_free_control_pages:
kimage_free_page_list(&image->control_pages);
out_free_image:
kfree(image);
return ret;
}
static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
struct kexec_segment *segments, unsigned long flags)
{
struct kimage **dest_image, *image;
unsigned long i;
int ret;
/*
* Because we write directly to the reserved memory region when loading
* crash kernels we need a serialization here to prevent multiple crash
* kernels from attempting to load simultaneously.
*/
if (!kexec_trylock())
return -EBUSY;
if (flags & KEXEC_ON_CRASH) {
dest_image = &kexec_crash_image;
if (kexec_crash_image)
arch_kexec_unprotect_crashkres();
} else {
dest_image = &kexec_image;
}
if (nr_segments == 0) {
/* Uninstall image */
kimage_free(xchg(dest_image, NULL));
ret = 0;
goto out_unlock;
}
if (flags & KEXEC_ON_CRASH) {
/*
* Loading another kernel to switch to if this one
* crashes. Free any current crash dump kernel before
* we corrupt it.
*/
kimage_free(xchg(&kexec_crash_image, NULL));
}
ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
if (ret)
goto out_unlock;
if (flags & KEXEC_PRESERVE_CONTEXT)
image->preserve_context = 1;
#ifdef CONFIG_CRASH_HOTPLUG
if (flags & KEXEC_UPDATE_ELFCOREHDR)
image->update_elfcorehdr = 1;
#endif
ret = machine_kexec_prepare(image);
if (ret)
goto out;
/*
* Some architecture(like S390) may touch the crash memory before
* machine_kexec_prepare(), we must copy vmcoreinfo data after it.
*/
ret = kimage_crash_copy_vmcoreinfo(image);
if (ret)
goto out;
for (i = 0; i < nr_segments; i++) {
ret = kimage_load_segment(image, &image->segment[i]);
if (ret)
goto out;
}
kimage_terminate(image);
ret = machine_kexec_post_load(image);
if (ret)
goto out;
/* Install the new kernel and uninstall the old */
image = xchg(dest_image, image);
out:
if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
arch_kexec_protect_crashkres();
kimage_free(image);
out_unlock:
kexec_unlock();
return ret;
}
/*
* Exec Kernel system call: for obvious reasons only root may call it.
*
* This call breaks up into three pieces.
* - A generic part which loads the new kernel from the current
* address space, and very carefully places the data in the
* allocated pages.
*
* - A generic part that interacts with the kernel and tells all of
* the devices to shut down. Preventing on-going dmas, and placing
* the devices in a consistent state so a later kernel can
* reinitialize them.
*
* - A machine specific part that includes the syscall number
* and then copies the image to it's final destination. And
* jumps into the image at entry.
*
* kexec does not sync, or unmount filesystems so if you need
* that to happen you need to do that yourself.
*/
static inline int kexec_load_check(unsigned long nr_segments,
unsigned long flags)
{
int image_type = (flags & KEXEC_ON_CRASH) ?
KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
int result;
/* We only trust the superuser with rebooting the system. */
if (!kexec_load_permitted(image_type))
return -EPERM;
/* Permit LSMs and IMA to fail the kexec */
result = security_kernel_load_data(LOADING_KEXEC_IMAGE, false);
if (result < 0)
return result;
/*
* kexec can be used to circumvent module loading restrictions, so
* prevent loading in that case
*/
result = security_locked_down(LOCKDOWN_KEXEC);
if (result)
return result;
/*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
*/
if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
return -EINVAL;
/* Put an artificial cap on the number
* of segments passed to kexec_load.
*/
if (nr_segments > KEXEC_SEGMENT_MAX)
return -EINVAL;
return 0;
}
SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
struct kexec_segment __user *, segments, unsigned long, flags)
{
struct kexec_segment *ksegments;
unsigned long result;
result = kexec_load_check(nr_segments, flags);
if (result)
return result;
/* Verify we are on the appropriate architecture */
if (((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH) &&
((flags & KEXEC_ARCH_MASK) != KEXEC_ARCH_DEFAULT))
return -EINVAL;
ksegments = memdup_user(segments, nr_segments * sizeof(ksegments[0]));
if (IS_ERR(ksegments))
return PTR_ERR(ksegments);
result = do_kexec_load(entry, nr_segments, ksegments, flags);
kfree(ksegments);
return result;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry,
compat_ulong_t, nr_segments,
struct compat_kexec_segment __user *, segments,
compat_ulong_t, flags)
{
struct compat_kexec_segment in;
struct kexec_segment *ksegments;
unsigned long i, result;
result = kexec_load_check(nr_segments, flags);
if (result)
return result;
/* Don't allow clients that don't understand the native
* architecture to do anything.
*/
if ((flags & KEXEC_ARCH_MASK) == KEXEC_ARCH_DEFAULT)
return -EINVAL;
ksegments = kmalloc_array(nr_segments, sizeof(ksegments[0]),
GFP_KERNEL);
if (!ksegments)
return -ENOMEM;
for (i = 0; i < nr_segments; i++) {
result = copy_from_user(&in, &segments[i], sizeof(in));
if (result)
goto fail;
ksegments[i].buf = compat_ptr(in.buf);
ksegments[i].bufsz = in.bufsz;
ksegments[i].mem = in.mem;
ksegments[i].memsz = in.memsz;
}
result = do_kexec_load(entry, nr_segments, ksegments, flags);
fail:
kfree(ksegments);
return result;
}
#endif
| linux-master | kernel/kexec.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/regset.h>
static int __regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
void *p = *data, *to_free = NULL;
int res;
if (!regset->regset_get)
return -EOPNOTSUPP;
if (size > regset->n * regset->size)
size = regset->n * regset->size;
if (!p) {
to_free = p = kzalloc(size, GFP_KERNEL);
if (!p)
return -ENOMEM;
}
res = regset->regset_get(target, regset,
(struct membuf){.p = p, .left = size});
if (res < 0) {
kfree(to_free);
return res;
}
*data = p;
return size - res;
}
int regset_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void *data)
{
return __regset_get(target, regset, size, &data);
}
EXPORT_SYMBOL(regset_get);
int regset_get_alloc(struct task_struct *target,
const struct user_regset *regset,
unsigned int size,
void **data)
{
*data = NULL;
return __regset_get(target, regset, size, data);
}
EXPORT_SYMBOL(regset_get_alloc);
/**
* copy_regset_to_user - fetch a thread's user_regset data into user memory
* @target: thread to be examined
* @view: &struct user_regset_view describing user thread machine state
* @setno: index in @view->regsets
* @offset: offset into the regset data, in bytes
* @size: amount of data to copy, in bytes
* @data: user-mode pointer to copy into
*/
int copy_regset_to_user(struct task_struct *target,
const struct user_regset_view *view,
unsigned int setno,
unsigned int offset, unsigned int size,
void __user *data)
{
const struct user_regset *regset = &view->regsets[setno];
void *buf;
int ret;
ret = regset_get_alloc(target, regset, size, &buf);
if (ret > 0)
ret = copy_to_user(data, buf, ret) ? -EFAULT : 0;
kfree(buf);
return ret;
}
| linux-master | kernel/regset.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* Rewritten by Rusty Russell, on the backs of many others...
Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
*/
#include <linux/elf.h>
#include <linux/ftrace.h>
#include <linux/memory.h>
#include <linux/extable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/filter.h>
#include <asm/sections.h>
#include <linux/uaccess.h>
/*
* mutex protecting text section modification (dynamic code patching).
* some users need to sleep (allocating memory...) while they hold this lock.
*
* Note: Also protects SMP-alternatives modification on x86.
*
* NOT exported to modules - patching kernel text is a really delicate matter.
*/
DEFINE_MUTEX(text_mutex);
extern struct exception_table_entry __start___ex_table[];
extern struct exception_table_entry __stop___ex_table[];
/* Cleared by build time tools if the table is already sorted. */
u32 __initdata __visible main_extable_sort_needed = 1;
/* Sort the kernel's built-in exception table */
void __init sort_main_extable(void)
{
if (main_extable_sort_needed &&
&__stop___ex_table > &__start___ex_table) {
pr_notice("Sorting __ex_table...\n");
sort_extable(__start___ex_table, __stop___ex_table);
}
}
/* Given an address, look for it in the kernel exception table */
const
struct exception_table_entry *search_kernel_exception_table(unsigned long addr)
{
return search_extable(__start___ex_table,
__stop___ex_table - __start___ex_table, addr);
}
/* Given an address, look for it in the exception tables. */
const struct exception_table_entry *search_exception_tables(unsigned long addr)
{
const struct exception_table_entry *e;
e = search_kernel_exception_table(addr);
if (!e)
e = search_module_extables(addr);
if (!e)
e = search_bpf_extables(addr);
return e;
}
int notrace core_kernel_text(unsigned long addr)
{
if (is_kernel_text(addr))
return 1;
if (system_state < SYSTEM_FREEING_INITMEM &&
is_kernel_inittext(addr))
return 1;
return 0;
}
int __kernel_text_address(unsigned long addr)
{
if (kernel_text_address(addr))
return 1;
/*
* There might be init symbols in saved stacktraces.
* Give those symbols a chance to be printed in
* backtraces (such as lockdep traces).
*
* Since we are after the module-symbols check, there's
* no danger of address overlap:
*/
if (is_kernel_inittext(addr))
return 1;
return 0;
}
int kernel_text_address(unsigned long addr)
{
bool no_rcu;
int ret = 1;
if (core_kernel_text(addr))
return 1;
/*
* If a stack dump happens while RCU is not watching, then
* RCU needs to be notified that it requires to start
* watching again. This can happen either by tracing that
* triggers a stack trace, or a WARN() that happens during
* coming back from idle, or cpu on or offlining.
*
* is_module_text_address() as well as the kprobe slots,
* is_bpf_text_address() and is_bpf_image_address require
* RCU to be watching.
*/
no_rcu = !rcu_is_watching();
/* Treat this like an NMI as it can happen anywhere */
if (no_rcu)
ct_nmi_enter();
if (is_module_text_address(addr))
goto out;
if (is_ftrace_trampoline(addr))
goto out;
if (is_kprobe_optinsn_slot(addr) || is_kprobe_insn_slot(addr))
goto out;
if (is_bpf_text_address(addr))
goto out;
ret = 0;
out:
if (no_rcu)
ct_nmi_exit();
return ret;
}
/*
* On some architectures (PPC64, IA64, PARISC) function pointers
* are actually only tokens to some data that then holds the
* real function address. As a result, to find if a function
* pointer is part of the kernel text, we need to do some
* special dereferencing first.
*/
#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
void *dereference_function_descriptor(void *ptr)
{
func_desc_t *desc = ptr;
void *p;
if (!get_kernel_nofault(p, (void *)&desc->addr))
ptr = p;
return ptr;
}
EXPORT_SYMBOL_GPL(dereference_function_descriptor);
void *dereference_kernel_function_descriptor(void *ptr)
{
if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
return ptr;
return dereference_function_descriptor(ptr);
}
#endif
int func_ptr_is_kernel_text(void *ptr)
{
unsigned long addr;
addr = (unsigned long) dereference_function_descriptor(ptr);
if (core_kernel_text(addr))
return 1;
return is_module_text_address(addr);
}
| linux-master | kernel/extable.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic pidhash and scalable, time-bounded PID allocator
*
* (C) 2002-2003 Nadia Yvette Chambers, IBM
* (C) 2004 Nadia Yvette Chambers, Oracle
* (C) 2002-2004 Ingo Molnar, Red Hat
*
* pid-structures are backing objects for tasks sharing a given ID to chain
* against. There is very little to them aside from hashing them and
* parking tasks using given ID's on a list.
*
* The hash is always changed with the tasklist_lock write-acquired,
* and the hash is only accessed with the tasklist_lock at least
* read-acquired, so there's no additional SMP locking needed here.
*
* We have a list of bitmap pages, which bitmaps represent the PID space.
* Allocating and freeing PIDs is completely lockless. The worst-case
* allocation scenario when all but one out of 1 million PIDs possible are
* allocated already: the scanning of 32 list entries and at most PAGE_SIZE
* bytes. The typical fastpath is a single successful setbit. Freeing is O(1).
*
* Pid namespaces:
* (C) 2007 Pavel Emelyanov <[email protected]>, OpenVZ, SWsoft Inc.
* (C) 2007 Sukadev Bhattiprolu <[email protected]>, IBM
* Many thanks to Oleg Nesterov for comments and help
*
*/
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/memblock.h>
#include <linux/pid_namespace.h>
#include <linux/init_task.h>
#include <linux/syscalls.h>
#include <linux/proc_ns.h>
#include <linux/refcount.h>
#include <linux/anon_inodes.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/idr.h>
#include <net/sock.h>
#include <uapi/linux/pidfd.h>
struct pid init_struct_pid = {
.count = REFCOUNT_INIT(1),
.tasks = {
{ .first = NULL },
{ .first = NULL },
{ .first = NULL },
},
.level = 0,
.numbers = { {
.nr = 0,
.ns = &init_pid_ns,
}, }
};
int pid_max = PID_MAX_DEFAULT;
#define RESERVED_PIDS 300
int pid_max_min = RESERVED_PIDS + 1;
int pid_max_max = PID_MAX_LIMIT;
/*
* PID-map pages start out as NULL, they get allocated upon
* first use and are never deallocated. This way a low pid_max
* value does not cause lots of bitmaps to be allocated, but
* the scheme scales to up to 4 million PIDs, runtime.
*/
struct pid_namespace init_pid_ns = {
.ns.count = REFCOUNT_INIT(2),
.idr = IDR_INIT(init_pid_ns.idr),
.pid_allocated = PIDNS_ADDING,
.level = 0,
.child_reaper = &init_task,
.user_ns = &init_user_ns,
.ns.inum = PROC_PID_INIT_INO,
#ifdef CONFIG_PID_NS
.ns.ops = &pidns_operations,
#endif
#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
.memfd_noexec_scope = MEMFD_NOEXEC_SCOPE_EXEC,
#endif
};
EXPORT_SYMBOL_GPL(init_pid_ns);
/*
* Note: disable interrupts while the pidmap_lock is held as an
* interrupt might come in and do read_lock(&tasklist_lock).
*
* If we don't disable interrupts there is a nasty deadlock between
* detach_pid()->free_pid() and another cpu that does
* spin_lock(&pidmap_lock) followed by an interrupt routine that does
* read_lock(&tasklist_lock);
*
* After we clean up the tasklist_lock and know there are no
* irq handlers that take it we can leave the interrupts enabled.
* For now it is easier to be safe than to prove it can't happen.
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);
void put_pid(struct pid *pid)
{
struct pid_namespace *ns;
if (!pid)
return;
ns = pid->numbers[pid->level].ns;
if (refcount_dec_and_test(&pid->count)) {
kmem_cache_free(ns->pid_cachep, pid);
put_pid_ns(ns);
}
}
EXPORT_SYMBOL_GPL(put_pid);
static void delayed_put_pid(struct rcu_head *rhp)
{
struct pid *pid = container_of(rhp, struct pid, rcu);
put_pid(pid);
}
void free_pid(struct pid *pid)
{
/* We can be called with write_lock_irq(&tasklist_lock) held */
int i;
unsigned long flags;
spin_lock_irqsave(&pidmap_lock, flags);
for (i = 0; i <= pid->level; i++) {
struct upid *upid = pid->numbers + i;
struct pid_namespace *ns = upid->ns;
switch (--ns->pid_allocated) {
case 2:
case 1:
/* When all that is left in the pid namespace
* is the reaper wake up the reaper. The reaper
* may be sleeping in zap_pid_ns_processes().
*/
wake_up_process(ns->child_reaper);
break;
case PIDNS_ADDING:
/* Handle a fork failure of the first process */
WARN_ON(ns->child_reaper);
ns->pid_allocated = 0;
break;
}
idr_remove(&ns->idr, upid->nr);
}
spin_unlock_irqrestore(&pidmap_lock, flags);
call_rcu(&pid->rcu, delayed_put_pid);
}
struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
size_t set_tid_size)
{
struct pid *pid;
enum pid_type type;
int i, nr;
struct pid_namespace *tmp;
struct upid *upid;
int retval = -ENOMEM;
/*
* set_tid_size contains the size of the set_tid array. Starting at
* the most nested currently active PID namespace it tells alloc_pid()
* which PID to set for a process in that most nested PID namespace
* up to set_tid_size PID namespaces. It does not have to set the PID
* for a process in all nested PID namespaces but set_tid_size must
* never be greater than the current ns->level + 1.
*/
if (set_tid_size > ns->level + 1)
return ERR_PTR(-EINVAL);
pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
if (!pid)
return ERR_PTR(retval);
tmp = ns;
pid->level = ns->level;
for (i = ns->level; i >= 0; i--) {
int tid = 0;
if (set_tid_size) {
tid = set_tid[ns->level - i];
retval = -EINVAL;
if (tid < 1 || tid >= pid_max)
goto out_free;
/*
* Also fail if a PID != 1 is requested and
* no PID 1 exists.
*/
if (tid != 1 && !tmp->child_reaper)
goto out_free;
retval = -EPERM;
if (!checkpoint_restore_ns_capable(tmp->user_ns))
goto out_free;
set_tid_size--;
}
idr_preload(GFP_KERNEL);
spin_lock_irq(&pidmap_lock);
if (tid) {
nr = idr_alloc(&tmp->idr, NULL, tid,
tid + 1, GFP_ATOMIC);
/*
* If ENOSPC is returned it means that the PID is
* alreay in use. Return EEXIST in that case.
*/
if (nr == -ENOSPC)
nr = -EEXIST;
} else {
int pid_min = 1;
/*
* init really needs pid 1, but after reaching the
* maximum wrap back to RESERVED_PIDS
*/
if (idr_get_cursor(&tmp->idr) > RESERVED_PIDS)
pid_min = RESERVED_PIDS;
/*
* Store a null pointer so find_pid_ns does not find
* a partially initialized PID (see below).
*/
nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
pid_max, GFP_ATOMIC);
}
spin_unlock_irq(&pidmap_lock);
idr_preload_end();
if (nr < 0) {
retval = (nr == -ENOSPC) ? -EAGAIN : nr;
goto out_free;
}
pid->numbers[i].nr = nr;
pid->numbers[i].ns = tmp;
tmp = tmp->parent;
}
/*
* ENOMEM is not the most obvious choice especially for the case
* where the child subreaper has already exited and the pid
* namespace denies the creation of any new processes. But ENOMEM
* is what we have exposed to userspace for a long time and it is
* documented behavior for pid namespaces. So we can't easily
* change it even if there were an error code better suited.
*/
retval = -ENOMEM;
get_pid_ns(ns);
refcount_set(&pid->count, 1);
spin_lock_init(&pid->lock);
for (type = 0; type < PIDTYPE_MAX; ++type)
INIT_HLIST_HEAD(&pid->tasks[type]);
init_waitqueue_head(&pid->wait_pidfd);
INIT_HLIST_HEAD(&pid->inodes);
upid = pid->numbers + ns->level;
spin_lock_irq(&pidmap_lock);
if (!(ns->pid_allocated & PIDNS_ADDING))
goto out_unlock;
for ( ; upid >= pid->numbers; --upid) {
/* Make the PID visible to find_pid_ns. */
idr_replace(&upid->ns->idr, pid, upid->nr);
upid->ns->pid_allocated++;
}
spin_unlock_irq(&pidmap_lock);
return pid;
out_unlock:
spin_unlock_irq(&pidmap_lock);
put_pid_ns(ns);
out_free:
spin_lock_irq(&pidmap_lock);
while (++i <= ns->level) {
upid = pid->numbers + i;
idr_remove(&upid->ns->idr, upid->nr);
}
/* On failure to allocate the first pid, reset the state */
if (ns->pid_allocated == PIDNS_ADDING)
idr_set_cursor(&ns->idr, 0);
spin_unlock_irq(&pidmap_lock);
kmem_cache_free(ns->pid_cachep, pid);
return ERR_PTR(retval);
}
void disable_pid_allocation(struct pid_namespace *ns)
{
spin_lock_irq(&pidmap_lock);
ns->pid_allocated &= ~PIDNS_ADDING;
spin_unlock_irq(&pidmap_lock);
}
struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
{
return idr_find(&ns->idr, nr);
}
EXPORT_SYMBOL_GPL(find_pid_ns);
struct pid *find_vpid(int nr)
{
return find_pid_ns(nr, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(find_vpid);
static struct pid **task_pid_ptr(struct task_struct *task, enum pid_type type)
{
return (type == PIDTYPE_PID) ?
&task->thread_pid :
&task->signal->pids[type];
}
/*
* attach_pid() must be called with the tasklist_lock write-held.
*/
void attach_pid(struct task_struct *task, enum pid_type type)
{
struct pid *pid = *task_pid_ptr(task, type);
hlist_add_head_rcu(&task->pid_links[type], &pid->tasks[type]);
}
static void __change_pid(struct task_struct *task, enum pid_type type,
struct pid *new)
{
struct pid **pid_ptr = task_pid_ptr(task, type);
struct pid *pid;
int tmp;
pid = *pid_ptr;
hlist_del_rcu(&task->pid_links[type]);
*pid_ptr = new;
for (tmp = PIDTYPE_MAX; --tmp >= 0; )
if (pid_has_task(pid, tmp))
return;
free_pid(pid);
}
void detach_pid(struct task_struct *task, enum pid_type type)
{
__change_pid(task, type, NULL);
}
void change_pid(struct task_struct *task, enum pid_type type,
struct pid *pid)
{
__change_pid(task, type, pid);
attach_pid(task, type);
}
void exchange_tids(struct task_struct *left, struct task_struct *right)
{
struct pid *pid1 = left->thread_pid;
struct pid *pid2 = right->thread_pid;
struct hlist_head *head1 = &pid1->tasks[PIDTYPE_PID];
struct hlist_head *head2 = &pid2->tasks[PIDTYPE_PID];
/* Swap the single entry tid lists */
hlists_swap_heads_rcu(head1, head2);
/* Swap the per task_struct pid */
rcu_assign_pointer(left->thread_pid, pid2);
rcu_assign_pointer(right->thread_pid, pid1);
/* Swap the cached value */
WRITE_ONCE(left->pid, pid_nr(pid2));
WRITE_ONCE(right->pid, pid_nr(pid1));
}
/* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */
void transfer_pid(struct task_struct *old, struct task_struct *new,
enum pid_type type)
{
if (type == PIDTYPE_PID)
new->thread_pid = old->thread_pid;
hlist_replace_rcu(&old->pid_links[type], &new->pid_links[type]);
}
struct task_struct *pid_task(struct pid *pid, enum pid_type type)
{
struct task_struct *result = NULL;
if (pid) {
struct hlist_node *first;
first = rcu_dereference_check(hlist_first_rcu(&pid->tasks[type]),
lockdep_tasklist_lock_is_held());
if (first)
result = hlist_entry(first, struct task_struct, pid_links[(type)]);
}
return result;
}
EXPORT_SYMBOL(pid_task);
/*
* Must be called under rcu_read_lock().
*/
struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
{
RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
"find_task_by_pid_ns() needs rcu_read_lock() protection");
return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID);
}
struct task_struct *find_task_by_vpid(pid_t vnr)
{
return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
}
struct task_struct *find_get_task_by_vpid(pid_t nr)
{
struct task_struct *task;
rcu_read_lock();
task = find_task_by_vpid(nr);
if (task)
get_task_struct(task);
rcu_read_unlock();
return task;
}
struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
{
struct pid *pid;
rcu_read_lock();
pid = get_pid(rcu_dereference(*task_pid_ptr(task, type)));
rcu_read_unlock();
return pid;
}
EXPORT_SYMBOL_GPL(get_task_pid);
struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)
{
struct task_struct *result;
rcu_read_lock();
result = pid_task(pid, type);
if (result)
get_task_struct(result);
rcu_read_unlock();
return result;
}
EXPORT_SYMBOL_GPL(get_pid_task);
struct pid *find_get_pid(pid_t nr)
{
struct pid *pid;
rcu_read_lock();
pid = get_pid(find_vpid(nr));
rcu_read_unlock();
return pid;
}
EXPORT_SYMBOL_GPL(find_get_pid);
pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
{
struct upid *upid;
pid_t nr = 0;
if (pid && ns->level <= pid->level) {
upid = &pid->numbers[ns->level];
if (upid->ns == ns)
nr = upid->nr;
}
return nr;
}
EXPORT_SYMBOL_GPL(pid_nr_ns);
pid_t pid_vnr(struct pid *pid)
{
return pid_nr_ns(pid, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(pid_vnr);
pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
struct pid_namespace *ns)
{
pid_t nr = 0;
rcu_read_lock();
if (!ns)
ns = task_active_pid_ns(current);
nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
rcu_read_unlock();
return nr;
}
EXPORT_SYMBOL(__task_pid_nr_ns);
struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
{
return ns_of_pid(task_pid(tsk));
}
EXPORT_SYMBOL_GPL(task_active_pid_ns);
/*
* Used by proc to find the first pid that is greater than or equal to nr.
*
* If there is a pid at nr this function is exactly the same as find_pid_ns.
*/
struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
{
return idr_get_next(&ns->idr, &nr);
}
EXPORT_SYMBOL_GPL(find_ge_pid);
struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags)
{
struct fd f;
struct pid *pid;
f = fdget(fd);
if (!f.file)
return ERR_PTR(-EBADF);
pid = pidfd_pid(f.file);
if (!IS_ERR(pid)) {
get_pid(pid);
*flags = f.file->f_flags;
}
fdput(f);
return pid;
}
/**
* pidfd_get_task() - Get the task associated with a pidfd
*
* @pidfd: pidfd for which to get the task
* @flags: flags associated with this pidfd
*
* Return the task associated with @pidfd. The function takes a reference on
* the returned task. The caller is responsible for releasing that reference.
*
* Currently, the process identified by @pidfd is always a thread-group leader.
* This restriction currently exists for all aspects of pidfds including pidfd
* creation (CLONE_PIDFD cannot be used with CLONE_THREAD) and pidfd polling
* (only supports thread group leaders).
*
* Return: On success, the task_struct associated with the pidfd.
* On error, a negative errno number will be returned.
*/
struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags)
{
unsigned int f_flags;
struct pid *pid;
struct task_struct *task;
pid = pidfd_get_pid(pidfd, &f_flags);
if (IS_ERR(pid))
return ERR_CAST(pid);
task = get_pid_task(pid, PIDTYPE_TGID);
put_pid(pid);
if (!task)
return ERR_PTR(-ESRCH);
*flags = f_flags;
return task;
}
/**
* pidfd_create() - Create a new pid file descriptor.
*
* @pid: struct pid that the pidfd will reference
* @flags: flags to pass
*
* This creates a new pid file descriptor with the O_CLOEXEC flag set.
*
* Note, that this function can only be called after the fd table has
* been unshared to avoid leaking the pidfd to the new process.
*
* This symbol should not be explicitly exported to loadable modules.
*
* Return: On success, a cloexec pidfd is returned.
* On error, a negative errno number will be returned.
*/
int pidfd_create(struct pid *pid, unsigned int flags)
{
int pidfd;
struct file *pidfd_file;
pidfd = pidfd_prepare(pid, flags, &pidfd_file);
if (pidfd < 0)
return pidfd;
fd_install(pidfd, pidfd_file);
return pidfd;
}
/**
* sys_pidfd_open() - Open new pid file descriptor.
*
* @pid: pid for which to retrieve a pidfd
* @flags: flags to pass
*
* This creates a new pid file descriptor with the O_CLOEXEC flag set for
* the process identified by @pid. Currently, the process identified by
* @pid must be a thread-group leader. This restriction currently exists
* for all aspects of pidfds including pidfd creation (CLONE_PIDFD cannot
* be used with CLONE_THREAD) and pidfd polling (only supports thread group
* leaders).
*
* Return: On success, a cloexec pidfd is returned.
* On error, a negative errno number will be returned.
*/
SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags)
{
int fd;
struct pid *p;
if (flags & ~PIDFD_NONBLOCK)
return -EINVAL;
if (pid <= 0)
return -EINVAL;
p = find_get_pid(pid);
if (!p)
return -ESRCH;
fd = pidfd_create(p, flags);
put_pid(p);
return fd;
}
void __init pid_idr_init(void)
{
/* Verify no one has done anything silly: */
BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_ADDING);
/* bump default and minimum pid_max based on number of cpus */
pid_max = min(pid_max_max, max_t(int, pid_max,
PIDS_PER_CPU_DEFAULT * num_possible_cpus()));
pid_max_min = max_t(int, pid_max_min,
PIDS_PER_CPU_MIN * num_possible_cpus());
pr_info("pid_max: default: %u minimum: %u\n", pid_max, pid_max_min);
idr_init(&init_pid_ns.idr);
init_pid_ns.pid_cachep = kmem_cache_create("pid",
struct_size_t(struct pid, numbers, 1),
__alignof__(struct pid),
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,
NULL);
}
static struct file *__pidfd_fget(struct task_struct *task, int fd)
{
struct file *file;
int ret;
ret = down_read_killable(&task->signal->exec_update_lock);
if (ret)
return ERR_PTR(ret);
if (ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS))
file = fget_task(task, fd);
else
file = ERR_PTR(-EPERM);
up_read(&task->signal->exec_update_lock);
return file ?: ERR_PTR(-EBADF);
}
static int pidfd_getfd(struct pid *pid, int fd)
{
struct task_struct *task;
struct file *file;
int ret;
task = get_pid_task(pid, PIDTYPE_PID);
if (!task)
return -ESRCH;
file = __pidfd_fget(task, fd);
put_task_struct(task);
if (IS_ERR(file))
return PTR_ERR(file);
ret = receive_fd(file, O_CLOEXEC);
fput(file);
return ret;
}
/**
* sys_pidfd_getfd() - Get a file descriptor from another process
*
* @pidfd: the pidfd file descriptor of the process
* @fd: the file descriptor number to get
* @flags: flags on how to get the fd (reserved)
*
* This syscall gets a copy of a file descriptor from another process
* based on the pidfd, and file descriptor number. It requires that
* the calling process has the ability to ptrace the process represented
* by the pidfd. The process which is having its file descriptor copied
* is otherwise unaffected.
*
* Return: On success, a cloexec file descriptor is returned.
* On error, a negative errno number will be returned.
*/
SYSCALL_DEFINE3(pidfd_getfd, int, pidfd, int, fd,
unsigned int, flags)
{
struct pid *pid;
struct fd f;
int ret;
/* flags is currently unused - make sure it's unset */
if (flags)
return -EINVAL;
f = fdget(pidfd);
if (!f.file)
return -EBADF;
pid = pidfd_pid(f.file);
if (IS_ERR(pid))
ret = PTR_ERR(pid);
else
ret = pidfd_getfd(pid, fd);
fdput(f);
return ret;
}
| linux-master | kernel/pid.c |
// SPDX-License-Identifier: GPL-2.0
/*
* padata.c - generic interface to process data streams in parallel
*
* See Documentation/core-api/padata.rst for more information.
*
* Copyright (C) 2008, 2009 secunet Security Networks AG
* Copyright (C) 2008, 2009 Steffen Klassert <[email protected]>
*
* Copyright (c) 2020 Oracle and/or its affiliates.
* Author: Daniel Jordan <[email protected]>
*/
#include <linux/completion.h>
#include <linux/export.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/cpu.h>
#include <linux/padata.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/rcupdate.h>
#define PADATA_WORK_ONSTACK 1 /* Work's memory is on stack */
struct padata_work {
struct work_struct pw_work;
struct list_head pw_list; /* padata_free_works linkage */
void *pw_data;
};
static DEFINE_SPINLOCK(padata_works_lock);
static struct padata_work *padata_works;
static LIST_HEAD(padata_free_works);
struct padata_mt_job_state {
spinlock_t lock;
struct completion completion;
struct padata_mt_job *job;
int nworks;
int nworks_fini;
unsigned long chunk_size;
};
static void padata_free_pd(struct parallel_data *pd);
static void __init padata_mt_helper(struct work_struct *work);
static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
{
int cpu, target_cpu;
target_cpu = cpumask_first(pd->cpumask.pcpu);
for (cpu = 0; cpu < cpu_index; cpu++)
target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
return target_cpu;
}
static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
{
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
return padata_index_to_cpu(pd, cpu_index);
}
static struct padata_work *padata_work_alloc(void)
{
struct padata_work *pw;
lockdep_assert_held(&padata_works_lock);
if (list_empty(&padata_free_works))
return NULL; /* No more work items allowed to be queued. */
pw = list_first_entry(&padata_free_works, struct padata_work, pw_list);
list_del(&pw->pw_list);
return pw;
}
/*
* This function is marked __ref because this function may be optimized in such
* a way that it directly refers to work_fn's address, which causes modpost to
* complain when work_fn is marked __init. This scenario was observed with clang
* LTO, where padata_work_init() was optimized to refer directly to
* padata_mt_helper() because the calls to padata_work_init() with other work_fn
* values were eliminated or inlined.
*/
static void __ref padata_work_init(struct padata_work *pw, work_func_t work_fn,
void *data, int flags)
{
if (flags & PADATA_WORK_ONSTACK)
INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
else
INIT_WORK(&pw->pw_work, work_fn);
pw->pw_data = data;
}
static int __init padata_work_alloc_mt(int nworks, void *data,
struct list_head *head)
{
int i;
spin_lock(&padata_works_lock);
/* Start at 1 because the current task participates in the job. */
for (i = 1; i < nworks; ++i) {
struct padata_work *pw = padata_work_alloc();
if (!pw)
break;
padata_work_init(pw, padata_mt_helper, data, 0);
list_add(&pw->pw_list, head);
}
spin_unlock(&padata_works_lock);
return i;
}
static void padata_work_free(struct padata_work *pw)
{
lockdep_assert_held(&padata_works_lock);
list_add(&pw->pw_list, &padata_free_works);
}
static void __init padata_works_free(struct list_head *works)
{
struct padata_work *cur, *next;
if (list_empty(works))
return;
spin_lock(&padata_works_lock);
list_for_each_entry_safe(cur, next, works, pw_list) {
list_del(&cur->pw_list);
padata_work_free(cur);
}
spin_unlock(&padata_works_lock);
}
static void padata_parallel_worker(struct work_struct *parallel_work)
{
struct padata_work *pw = container_of(parallel_work, struct padata_work,
pw_work);
struct padata_priv *padata = pw->pw_data;
local_bh_disable();
padata->parallel(padata);
spin_lock(&padata_works_lock);
padata_work_free(pw);
spin_unlock(&padata_works_lock);
local_bh_enable();
}
/**
* padata_do_parallel - padata parallelization function
*
* @ps: padatashell
* @padata: object to be parallelized
* @cb_cpu: pointer to the CPU that the serialization callback function should
* run on. If it's not in the serial cpumask of @pinst
* (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
* none found, returns -EINVAL.
*
* The parallelization callback function will run with BHs off.
* Note: Every object which is parallelized by padata_do_parallel
* must be seen by padata_do_serial.
*
* Return: 0 on success or else negative error code.
*/
int padata_do_parallel(struct padata_shell *ps,
struct padata_priv *padata, int *cb_cpu)
{
struct padata_instance *pinst = ps->pinst;
int i, cpu, cpu_index, err;
struct parallel_data *pd;
struct padata_work *pw;
rcu_read_lock_bh();
pd = rcu_dereference_bh(ps->pd);
err = -EINVAL;
if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
goto out;
if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
if (cpumask_empty(pd->cpumask.cbcpu))
goto out;
/* Select an alternate fallback CPU and notify the caller. */
cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
cpu = cpumask_first(pd->cpumask.cbcpu);
for (i = 0; i < cpu_index; i++)
cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
*cb_cpu = cpu;
}
err = -EBUSY;
if ((pinst->flags & PADATA_RESET))
goto out;
refcount_inc(&pd->refcnt);
padata->pd = pd;
padata->cb_cpu = *cb_cpu;
spin_lock(&padata_works_lock);
padata->seq_nr = ++pd->seq_nr;
pw = padata_work_alloc();
spin_unlock(&padata_works_lock);
if (!pw) {
/* Maximum works limit exceeded, run in the current task. */
padata->parallel(padata);
}
rcu_read_unlock_bh();
if (pw) {
padata_work_init(pw, padata_parallel_worker, padata, 0);
queue_work(pinst->parallel_wq, &pw->pw_work);
}
return 0;
out:
rcu_read_unlock_bh();
return err;
}
EXPORT_SYMBOL(padata_do_parallel);
/*
* padata_find_next - Find the next object that needs serialization.
*
* Return:
* * A pointer to the control struct of the next object that needs
* serialization, if present in one of the percpu reorder queues.
* * NULL, if the next object that needs serialization will
* be parallel processed by another cpu and is not yet present in
* the cpu's reorder queue.
*/
static struct padata_priv *padata_find_next(struct parallel_data *pd,
bool remove_object)
{
struct padata_priv *padata;
struct padata_list *reorder;
int cpu = pd->cpu;
reorder = per_cpu_ptr(pd->reorder_list, cpu);
spin_lock(&reorder->lock);
if (list_empty(&reorder->list)) {
spin_unlock(&reorder->lock);
return NULL;
}
padata = list_entry(reorder->list.next, struct padata_priv, list);
/*
* Checks the rare case where two or more parallel jobs have hashed to
* the same CPU and one of the later ones finishes first.
*/
if (padata->seq_nr != pd->processed) {
spin_unlock(&reorder->lock);
return NULL;
}
if (remove_object) {
list_del_init(&padata->list);
++pd->processed;
pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
}
spin_unlock(&reorder->lock);
return padata;
}
static void padata_reorder(struct parallel_data *pd)
{
struct padata_instance *pinst = pd->ps->pinst;
int cb_cpu;
struct padata_priv *padata;
struct padata_serial_queue *squeue;
struct padata_list *reorder;
/*
* We need to ensure that only one cpu can work on dequeueing of
* the reorder queue the time. Calculating in which percpu reorder
* queue the next object will arrive takes some time. A spinlock
* would be highly contended. Also it is not clear in which order
* the objects arrive to the reorder queues. So a cpu could wait to
* get the lock just to notice that there is nothing to do at the
* moment. Therefore we use a trylock and let the holder of the lock
* care for all the objects enqueued during the holdtime of the lock.
*/
if (!spin_trylock_bh(&pd->lock))
return;
while (1) {
padata = padata_find_next(pd, true);
/*
* If the next object that needs serialization is parallel
* processed by another cpu and is still on it's way to the
* cpu's reorder queue, nothing to do for now.
*/
if (!padata)
break;
cb_cpu = padata->cb_cpu;
squeue = per_cpu_ptr(pd->squeue, cb_cpu);
spin_lock(&squeue->serial.lock);
list_add_tail(&padata->list, &squeue->serial.list);
spin_unlock(&squeue->serial.lock);
queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
}
spin_unlock_bh(&pd->lock);
/*
* The next object that needs serialization might have arrived to
* the reorder queues in the meantime.
*
* Ensure reorder queue is read after pd->lock is dropped so we see
* new objects from another task in padata_do_serial. Pairs with
* smp_mb in padata_do_serial.
*/
smp_mb();
reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
if (!list_empty(&reorder->list) && padata_find_next(pd, false))
queue_work(pinst->serial_wq, &pd->reorder_work);
}
static void invoke_padata_reorder(struct work_struct *work)
{
struct parallel_data *pd;
local_bh_disable();
pd = container_of(work, struct parallel_data, reorder_work);
padata_reorder(pd);
local_bh_enable();
}
static void padata_serial_worker(struct work_struct *serial_work)
{
struct padata_serial_queue *squeue;
struct parallel_data *pd;
LIST_HEAD(local_list);
int cnt;
local_bh_disable();
squeue = container_of(serial_work, struct padata_serial_queue, work);
pd = squeue->pd;
spin_lock(&squeue->serial.lock);
list_replace_init(&squeue->serial.list, &local_list);
spin_unlock(&squeue->serial.lock);
cnt = 0;
while (!list_empty(&local_list)) {
struct padata_priv *padata;
padata = list_entry(local_list.next,
struct padata_priv, list);
list_del_init(&padata->list);
padata->serial(padata);
cnt++;
}
local_bh_enable();
if (refcount_sub_and_test(cnt, &pd->refcnt))
padata_free_pd(pd);
}
/**
* padata_do_serial - padata serialization function
*
* @padata: object to be serialized.
*
* padata_do_serial must be called for every parallelized object.
* The serialization callback function will run with BHs off.
*/
void padata_do_serial(struct padata_priv *padata)
{
struct parallel_data *pd = padata->pd;
int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
struct padata_priv *cur;
struct list_head *pos;
spin_lock(&reorder->lock);
/* Sort in ascending order of sequence number. */
list_for_each_prev(pos, &reorder->list) {
cur = list_entry(pos, struct padata_priv, list);
if (cur->seq_nr < padata->seq_nr)
break;
}
list_add(&padata->list, pos);
spin_unlock(&reorder->lock);
/*
* Ensure the addition to the reorder list is ordered correctly
* with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
* in padata_reorder.
*/
smp_mb();
padata_reorder(pd);
}
EXPORT_SYMBOL(padata_do_serial);
static int padata_setup_cpumasks(struct padata_instance *pinst)
{
struct workqueue_attrs *attrs;
int err;
attrs = alloc_workqueue_attrs();
if (!attrs)
return -ENOMEM;
/* Restrict parallel_wq workers to pd->cpumask.pcpu. */
cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
free_workqueue_attrs(attrs);
return err;
}
static void __init padata_mt_helper(struct work_struct *w)
{
struct padata_work *pw = container_of(w, struct padata_work, pw_work);
struct padata_mt_job_state *ps = pw->pw_data;
struct padata_mt_job *job = ps->job;
bool done;
spin_lock(&ps->lock);
while (job->size > 0) {
unsigned long start, size, end;
start = job->start;
/* So end is chunk size aligned if enough work remains. */
size = roundup(start + 1, ps->chunk_size) - start;
size = min(size, job->size);
end = start + size;
job->start = end;
job->size -= size;
spin_unlock(&ps->lock);
job->thread_fn(start, end, job->fn_arg);
spin_lock(&ps->lock);
}
++ps->nworks_fini;
done = (ps->nworks_fini == ps->nworks);
spin_unlock(&ps->lock);
if (done)
complete(&ps->completion);
}
/**
* padata_do_multithreaded - run a multithreaded job
* @job: Description of the job.
*
* See the definition of struct padata_mt_job for more details.
*/
void __init padata_do_multithreaded(struct padata_mt_job *job)
{
/* In case threads finish at different times. */
static const unsigned long load_balance_factor = 4;
struct padata_work my_work, *pw;
struct padata_mt_job_state ps;
LIST_HEAD(works);
int nworks;
if (job->size == 0)
return;
/* Ensure at least one thread when size < min_chunk. */
nworks = max(job->size / max(job->min_chunk, job->align), 1ul);
nworks = min(nworks, job->max_threads);
if (nworks == 1) {
/* Single thread, no coordination needed, cut to the chase. */
job->thread_fn(job->start, job->start + job->size, job->fn_arg);
return;
}
spin_lock_init(&ps.lock);
init_completion(&ps.completion);
ps.job = job;
ps.nworks = padata_work_alloc_mt(nworks, &ps, &works);
ps.nworks_fini = 0;
/*
* Chunk size is the amount of work a helper does per call to the
* thread function. Load balance large jobs between threads by
* increasing the number of chunks, guarantee at least the minimum
* chunk size from the caller, and honor the caller's alignment.
*/
ps.chunk_size = job->size / (ps.nworks * load_balance_factor);
ps.chunk_size = max(ps.chunk_size, job->min_chunk);
ps.chunk_size = roundup(ps.chunk_size, job->align);
list_for_each_entry(pw, &works, pw_list)
queue_work(system_unbound_wq, &pw->pw_work);
/* Use the current thread, which saves starting a workqueue worker. */
padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
padata_mt_helper(&my_work.pw_work);
/* Wait for all the helpers to finish. */
wait_for_completion(&ps.completion);
destroy_work_on_stack(&my_work.pw_work);
padata_works_free(&works);
}
static void __padata_list_init(struct padata_list *pd_list)
{
INIT_LIST_HEAD(&pd_list->list);
spin_lock_init(&pd_list->lock);
}
/* Initialize all percpu queues used by serial workers */
static void padata_init_squeues(struct parallel_data *pd)
{
int cpu;
struct padata_serial_queue *squeue;
for_each_cpu(cpu, pd->cpumask.cbcpu) {
squeue = per_cpu_ptr(pd->squeue, cpu);
squeue->pd = pd;
__padata_list_init(&squeue->serial);
INIT_WORK(&squeue->work, padata_serial_worker);
}
}
/* Initialize per-CPU reorder lists */
static void padata_init_reorder_list(struct parallel_data *pd)
{
int cpu;
struct padata_list *list;
for_each_cpu(cpu, pd->cpumask.pcpu) {
list = per_cpu_ptr(pd->reorder_list, cpu);
__padata_list_init(list);
}
}
/* Allocate and initialize the internal cpumask dependend resources. */
static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
{
struct padata_instance *pinst = ps->pinst;
struct parallel_data *pd;
pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
if (!pd)
goto err;
pd->reorder_list = alloc_percpu(struct padata_list);
if (!pd->reorder_list)
goto err_free_pd;
pd->squeue = alloc_percpu(struct padata_serial_queue);
if (!pd->squeue)
goto err_free_reorder_list;
pd->ps = ps;
if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
goto err_free_squeue;
if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
goto err_free_pcpu;
cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask);
cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask);
padata_init_reorder_list(pd);
padata_init_squeues(pd);
pd->seq_nr = -1;
refcount_set(&pd->refcnt, 1);
spin_lock_init(&pd->lock);
pd->cpu = cpumask_first(pd->cpumask.pcpu);
INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
return pd;
err_free_pcpu:
free_cpumask_var(pd->cpumask.pcpu);
err_free_squeue:
free_percpu(pd->squeue);
err_free_reorder_list:
free_percpu(pd->reorder_list);
err_free_pd:
kfree(pd);
err:
return NULL;
}
static void padata_free_pd(struct parallel_data *pd)
{
free_cpumask_var(pd->cpumask.pcpu);
free_cpumask_var(pd->cpumask.cbcpu);
free_percpu(pd->reorder_list);
free_percpu(pd->squeue);
kfree(pd);
}
static void __padata_start(struct padata_instance *pinst)
{
pinst->flags |= PADATA_INIT;
}
static void __padata_stop(struct padata_instance *pinst)
{
if (!(pinst->flags & PADATA_INIT))
return;
pinst->flags &= ~PADATA_INIT;
synchronize_rcu();
}
/* Replace the internal control structure with a new one. */
static int padata_replace_one(struct padata_shell *ps)
{
struct parallel_data *pd_new;
pd_new = padata_alloc_pd(ps);
if (!pd_new)
return -ENOMEM;
ps->opd = rcu_dereference_protected(ps->pd, 1);
rcu_assign_pointer(ps->pd, pd_new);
return 0;
}
static int padata_replace(struct padata_instance *pinst)
{
struct padata_shell *ps;
int err = 0;
pinst->flags |= PADATA_RESET;
list_for_each_entry(ps, &pinst->pslist, list) {
err = padata_replace_one(ps);
if (err)
break;
}
synchronize_rcu();
list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
if (refcount_dec_and_test(&ps->opd->refcnt))
padata_free_pd(ps->opd);
pinst->flags &= ~PADATA_RESET;
return err;
}
/* If cpumask contains no active cpu, we mark the instance as invalid. */
static bool padata_validate_cpumask(struct padata_instance *pinst,
const struct cpumask *cpumask)
{
if (!cpumask_intersects(cpumask, cpu_online_mask)) {
pinst->flags |= PADATA_INVALID;
return false;
}
pinst->flags &= ~PADATA_INVALID;
return true;
}
static int __padata_set_cpumasks(struct padata_instance *pinst,
cpumask_var_t pcpumask,
cpumask_var_t cbcpumask)
{
int valid;
int err;
valid = padata_validate_cpumask(pinst, pcpumask);
if (!valid) {
__padata_stop(pinst);
goto out_replace;
}
valid = padata_validate_cpumask(pinst, cbcpumask);
if (!valid)
__padata_stop(pinst);
out_replace:
cpumask_copy(pinst->cpumask.pcpu, pcpumask);
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
if (valid)
__padata_start(pinst);
return err;
}
/**
* padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
* equivalent to @cpumask.
* @pinst: padata instance
* @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
* to parallel and serial cpumasks respectively.
* @cpumask: the cpumask to use
*
* Return: 0 on success or negative error code
*/
int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
cpumask_var_t cpumask)
{
struct cpumask *serial_mask, *parallel_mask;
int err = -EINVAL;
cpus_read_lock();
mutex_lock(&pinst->lock);
switch (cpumask_type) {
case PADATA_CPU_PARALLEL:
serial_mask = pinst->cpumask.cbcpu;
parallel_mask = cpumask;
break;
case PADATA_CPU_SERIAL:
parallel_mask = pinst->cpumask.pcpu;
serial_mask = cpumask;
break;
default:
goto out;
}
err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
out:
mutex_unlock(&pinst->lock);
cpus_read_unlock();
return err;
}
EXPORT_SYMBOL(padata_set_cpumask);
#ifdef CONFIG_HOTPLUG_CPU
static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
{
int err = 0;
if (cpumask_test_cpu(cpu, cpu_online_mask)) {
err = padata_replace(pinst);
if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
__padata_start(pinst);
}
return err;
}
static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
{
int err = 0;
if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
!padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
__padata_stop(pinst);
err = padata_replace(pinst);
}
return err;
}
static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
{
return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
}
static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
{
struct padata_instance *pinst;
int ret;
pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node);
if (!pinst_has_cpu(pinst, cpu))
return 0;
mutex_lock(&pinst->lock);
ret = __padata_add_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
return ret;
}
static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
{
struct padata_instance *pinst;
int ret;
pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node);
if (!pinst_has_cpu(pinst, cpu))
return 0;
mutex_lock(&pinst->lock);
ret = __padata_remove_cpu(pinst, cpu);
mutex_unlock(&pinst->lock);
return ret;
}
static enum cpuhp_state hp_online;
#endif
static void __padata_free(struct padata_instance *pinst)
{
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD,
&pinst->cpu_dead_node);
cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node);
#endif
WARN_ON(!list_empty(&pinst->pslist));
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
destroy_workqueue(pinst->serial_wq);
destroy_workqueue(pinst->parallel_wq);
kfree(pinst);
}
#define kobj2pinst(_kobj) \
container_of(_kobj, struct padata_instance, kobj)
#define attr2pentry(_attr) \
container_of(_attr, struct padata_sysfs_entry, attr)
static void padata_sysfs_release(struct kobject *kobj)
{
struct padata_instance *pinst = kobj2pinst(kobj);
__padata_free(pinst);
}
struct padata_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
ssize_t (*store)(struct padata_instance *, struct attribute *,
const char *, size_t);
};
static ssize_t show_cpumask(struct padata_instance *pinst,
struct attribute *attr, char *buf)
{
struct cpumask *cpumask;
ssize_t len;
mutex_lock(&pinst->lock);
if (!strcmp(attr->name, "serial_cpumask"))
cpumask = pinst->cpumask.cbcpu;
else
cpumask = pinst->cpumask.pcpu;
len = snprintf(buf, PAGE_SIZE, "%*pb\n",
nr_cpu_ids, cpumask_bits(cpumask));
mutex_unlock(&pinst->lock);
return len < PAGE_SIZE ? len : -EINVAL;
}
static ssize_t store_cpumask(struct padata_instance *pinst,
struct attribute *attr,
const char *buf, size_t count)
{
cpumask_var_t new_cpumask;
ssize_t ret;
int mask_type;
if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
return -ENOMEM;
ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
nr_cpumask_bits);
if (ret < 0)
goto out;
mask_type = !strcmp(attr->name, "serial_cpumask") ?
PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
if (!ret)
ret = count;
out:
free_cpumask_var(new_cpumask);
return ret;
}
#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
static struct padata_sysfs_entry _name##_attr = \
__ATTR(_name, 0644, _show_name, _store_name)
#define PADATA_ATTR_RO(_name, _show_name) \
static struct padata_sysfs_entry _name##_attr = \
__ATTR(_name, 0400, _show_name, NULL)
PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
/*
* Padata sysfs provides the following objects:
* serial_cpumask [RW] - cpumask for serial workers
* parallel_cpumask [RW] - cpumask for parallel workers
*/
static struct attribute *padata_default_attrs[] = {
&serial_cpumask_attr.attr,
¶llel_cpumask_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(padata_default);
static ssize_t padata_sysfs_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
struct padata_instance *pinst;
struct padata_sysfs_entry *pentry;
ssize_t ret = -EIO;
pinst = kobj2pinst(kobj);
pentry = attr2pentry(attr);
if (pentry->show)
ret = pentry->show(pinst, attr, buf);
return ret;
}
static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct padata_instance *pinst;
struct padata_sysfs_entry *pentry;
ssize_t ret = -EIO;
pinst = kobj2pinst(kobj);
pentry = attr2pentry(attr);
if (pentry->show)
ret = pentry->store(pinst, attr, buf, count);
return ret;
}
static const struct sysfs_ops padata_sysfs_ops = {
.show = padata_sysfs_show,
.store = padata_sysfs_store,
};
static const struct kobj_type padata_attr_type = {
.sysfs_ops = &padata_sysfs_ops,
.default_groups = padata_default_groups,
.release = padata_sysfs_release,
};
/**
* padata_alloc - allocate and initialize a padata instance
* @name: used to identify the instance
*
* Return: new instance on success, NULL on error
*/
struct padata_instance *padata_alloc(const char *name)
{
struct padata_instance *pinst;
pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
if (!pinst)
goto err;
pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
name);
if (!pinst->parallel_wq)
goto err_free_inst;
cpus_read_lock();
pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
WQ_CPU_INTENSIVE, 1, name);
if (!pinst->serial_wq)
goto err_put_cpus;
if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
goto err_free_serial_wq;
if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
free_cpumask_var(pinst->cpumask.pcpu);
goto err_free_serial_wq;
}
INIT_LIST_HEAD(&pinst->pslist);
cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask);
cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask);
if (padata_setup_cpumasks(pinst))
goto err_free_masks;
__padata_start(pinst);
kobject_init(&pinst->kobj, &padata_attr_type);
mutex_init(&pinst->lock);
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_state_add_instance_nocalls_cpuslocked(hp_online,
&pinst->cpu_online_node);
cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
&pinst->cpu_dead_node);
#endif
cpus_read_unlock();
return pinst;
err_free_masks:
free_cpumask_var(pinst->cpumask.pcpu);
free_cpumask_var(pinst->cpumask.cbcpu);
err_free_serial_wq:
destroy_workqueue(pinst->serial_wq);
err_put_cpus:
cpus_read_unlock();
destroy_workqueue(pinst->parallel_wq);
err_free_inst:
kfree(pinst);
err:
return NULL;
}
EXPORT_SYMBOL(padata_alloc);
/**
* padata_free - free a padata instance
*
* @pinst: padata instance to free
*/
void padata_free(struct padata_instance *pinst)
{
kobject_put(&pinst->kobj);
}
EXPORT_SYMBOL(padata_free);
/**
* padata_alloc_shell - Allocate and initialize padata shell.
*
* @pinst: Parent padata_instance object.
*
* Return: new shell on success, NULL on error
*/
struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
{
struct parallel_data *pd;
struct padata_shell *ps;
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
if (!ps)
goto out;
ps->pinst = pinst;
cpus_read_lock();
pd = padata_alloc_pd(ps);
cpus_read_unlock();
if (!pd)
goto out_free_ps;
mutex_lock(&pinst->lock);
RCU_INIT_POINTER(ps->pd, pd);
list_add(&ps->list, &pinst->pslist);
mutex_unlock(&pinst->lock);
return ps;
out_free_ps:
kfree(ps);
out:
return NULL;
}
EXPORT_SYMBOL(padata_alloc_shell);
/**
* padata_free_shell - free a padata shell
*
* @ps: padata shell to free
*/
void padata_free_shell(struct padata_shell *ps)
{
if (!ps)
return;
mutex_lock(&ps->pinst->lock);
list_del(&ps->list);
padata_free_pd(rcu_dereference_protected(ps->pd, 1));
mutex_unlock(&ps->pinst->lock);
kfree(ps);
}
EXPORT_SYMBOL(padata_free_shell);
void __init padata_init(void)
{
unsigned int i, possible_cpus;
#ifdef CONFIG_HOTPLUG_CPU
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
padata_cpu_online, NULL);
if (ret < 0)
goto err;
hp_online = ret;
ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
NULL, padata_cpu_dead);
if (ret < 0)
goto remove_online_state;
#endif
possible_cpus = num_possible_cpus();
padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work),
GFP_KERNEL);
if (!padata_works)
goto remove_dead_state;
for (i = 0; i < possible_cpus; ++i)
list_add(&padata_works[i].pw_list, &padata_free_works);
return;
remove_dead_state:
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
remove_online_state:
cpuhp_remove_multi_state(hp_online);
err:
#endif
pr_warn("padata: initialization failed\n");
}
| linux-master | kernel/padata.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Load ELF vmlinux file for the kexec_file_load syscall.
*
* Copyright (C) 2004 Adam Litke ([email protected])
* Copyright (C) 2004 IBM Corp.
* Copyright (C) 2005 R Sharada ([email protected])
* Copyright (C) 2006 Mohan Kumar M ([email protected])
* Copyright (C) 2016 IBM Corporation
*
* Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
* Heavily modified for the kernel by
* Thiago Jung Bauermann <[email protected]>.
*/
#define pr_fmt(fmt) "kexec_elf: " fmt
#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
{
return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
}
static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
{
if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
value = le64_to_cpu(value);
else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
value = be64_to_cpu(value);
return value;
}
static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value)
{
if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
value = le32_to_cpu(value);
else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
value = be32_to_cpu(value);
return value;
}
static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value)
{
if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
value = le16_to_cpu(value);
else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
value = be16_to_cpu(value);
return value;
}
/**
* elf_is_ehdr_sane - check that it is safe to use the ELF header
* @buf_len: size of the buffer in which the ELF file is loaded.
*/
static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len)
{
if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) {
pr_debug("Bad program header size.\n");
return false;
} else if (ehdr->e_shnum > 0 &&
ehdr->e_shentsize != sizeof(struct elf_shdr)) {
pr_debug("Bad section header size.\n");
return false;
} else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
ehdr->e_version != EV_CURRENT) {
pr_debug("Unknown ELF version.\n");
return false;
}
if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
size_t phdr_size;
/*
* e_phnum is at most 65535 so calculating the size of the
* program header cannot overflow.
*/
phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
/* Sanity check the program header table location. */
if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) {
pr_debug("Program headers at invalid location.\n");
return false;
} else if (ehdr->e_phoff + phdr_size > buf_len) {
pr_debug("Program headers truncated.\n");
return false;
}
}
if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
size_t shdr_size;
/*
* e_shnum is at most 65536 so calculating
* the size of the section header cannot overflow.
*/
shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum;
/* Sanity check the section header table location. */
if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) {
pr_debug("Section headers at invalid location.\n");
return false;
} else if (ehdr->e_shoff + shdr_size > buf_len) {
pr_debug("Section headers truncated.\n");
return false;
}
}
return true;
}
static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
{
struct elfhdr *buf_ehdr;
if (len < sizeof(*buf_ehdr)) {
pr_debug("Buffer is too small to hold ELF header.\n");
return -ENOEXEC;
}
memset(ehdr, 0, sizeof(*ehdr));
memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident));
if (!elf_is_elf_file(ehdr)) {
pr_debug("No ELF header magic.\n");
return -ENOEXEC;
}
if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) {
pr_debug("Not a supported ELF class.\n");
return -ENOEXEC;
} else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
pr_debug("Not a supported ELF data format.\n");
return -ENOEXEC;
}
buf_ehdr = (struct elfhdr *) buf;
if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) {
pr_debug("Bad ELF header size.\n");
return -ENOEXEC;
}
ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type);
ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version);
ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize);
ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
switch (ehdr->e_ident[EI_CLASS]) {
case ELFCLASS64:
ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry);
ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff);
ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff);
break;
case ELFCLASS32:
ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry);
ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff);
ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff);
break;
default:
pr_debug("Unknown ELF class.\n");
return -EINVAL;
}
return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
}
/**
* elf_is_phdr_sane - check that it is safe to use the program header
* @buf_len: size of the buffer in which the ELF file is loaded.
*/
static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
{
if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) {
pr_debug("ELF segment location wraps around.\n");
return false;
} else if (phdr->p_offset + phdr->p_filesz > buf_len) {
pr_debug("ELF segment not in file.\n");
return false;
} else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) {
pr_debug("ELF segment address wraps around.\n");
return false;
}
return true;
}
static int elf_read_phdr(const char *buf, size_t len,
struct kexec_elf_info *elf_info,
int idx)
{
/* Override the const in proghdrs, we are the ones doing the loading. */
struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
const struct elfhdr *ehdr = elf_info->ehdr;
const char *pbuf;
struct elf_phdr *buf_phdr;
pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr));
buf_phdr = (struct elf_phdr *) pbuf;
phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
switch (ehdr->e_ident[EI_CLASS]) {
case ELFCLASS64:
phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset);
phdr->p_paddr = elf64_to_cpu(ehdr, buf_phdr->p_paddr);
phdr->p_vaddr = elf64_to_cpu(ehdr, buf_phdr->p_vaddr);
phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz);
phdr->p_memsz = elf64_to_cpu(ehdr, buf_phdr->p_memsz);
phdr->p_align = elf64_to_cpu(ehdr, buf_phdr->p_align);
break;
case ELFCLASS32:
phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset);
phdr->p_paddr = elf32_to_cpu(ehdr, buf_phdr->p_paddr);
phdr->p_vaddr = elf32_to_cpu(ehdr, buf_phdr->p_vaddr);
phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz);
phdr->p_memsz = elf32_to_cpu(ehdr, buf_phdr->p_memsz);
phdr->p_align = elf32_to_cpu(ehdr, buf_phdr->p_align);
break;
default:
pr_debug("Unknown ELF class.\n");
return -EINVAL;
}
return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
}
/**
* elf_read_phdrs - read the program headers from the buffer
*
* This function assumes that the program header table was checked for sanity.
* Use elf_is_ehdr_sane() if it wasn't.
*/
static int elf_read_phdrs(const char *buf, size_t len,
struct kexec_elf_info *elf_info)
{
size_t phdr_size, i;
const struct elfhdr *ehdr = elf_info->ehdr;
/*
* e_phnum is at most 65535 so calculating the size of the
* program header cannot overflow.
*/
phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL);
if (!elf_info->proghdrs)
return -ENOMEM;
for (i = 0; i < ehdr->e_phnum; i++) {
int ret;
ret = elf_read_phdr(buf, len, elf_info, i);
if (ret) {
kfree(elf_info->proghdrs);
elf_info->proghdrs = NULL;
return ret;
}
}
return 0;
}
/**
* elf_read_from_buffer - read ELF file and sets up ELF header and ELF info
* @buf: Buffer to read ELF file from.
* @len: Size of @buf.
* @ehdr: Pointer to existing struct which will be populated.
* @elf_info: Pointer to existing struct which will be populated.
*
* This function allows reading ELF files with different byte order than
* the kernel, byte-swapping the fields as needed.
*
* Return:
* On success returns 0, and the caller should call
* kexec_free_elf_info(elf_info) to free the memory allocated for the section
* and program headers.
*/
static int elf_read_from_buffer(const char *buf, size_t len,
struct elfhdr *ehdr,
struct kexec_elf_info *elf_info)
{
int ret;
ret = elf_read_ehdr(buf, len, ehdr);
if (ret)
return ret;
elf_info->buffer = buf;
elf_info->ehdr = ehdr;
if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
ret = elf_read_phdrs(buf, len, elf_info);
if (ret)
return ret;
}
return 0;
}
/**
* kexec_free_elf_info - free memory allocated by elf_read_from_buffer
*/
void kexec_free_elf_info(struct kexec_elf_info *elf_info)
{
kfree(elf_info->proghdrs);
memset(elf_info, 0, sizeof(*elf_info));
}
/**
* kexec_build_elf_info - read ELF executable and check that we can use it
*/
int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr,
struct kexec_elf_info *elf_info)
{
int i;
int ret;
ret = elf_read_from_buffer(buf, len, ehdr, elf_info);
if (ret)
return ret;
/* Big endian vmlinux has type ET_DYN. */
if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
pr_err("Not an ELF executable.\n");
goto error;
} else if (!elf_info->proghdrs) {
pr_err("No ELF program header.\n");
goto error;
}
for (i = 0; i < ehdr->e_phnum; i++) {
/*
* Kexec does not support loading interpreters.
* In addition this check keeps us from attempting
* to kexec ordinay executables.
*/
if (elf_info->proghdrs[i].p_type == PT_INTERP) {
pr_err("Requires an ELF interpreter.\n");
goto error;
}
}
return 0;
error:
kexec_free_elf_info(elf_info);
return -ENOEXEC;
}
int kexec_elf_probe(const char *buf, unsigned long len)
{
struct elfhdr ehdr;
struct kexec_elf_info elf_info;
int ret;
ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info);
if (ret)
return ret;
kexec_free_elf_info(&elf_info);
return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
}
/**
* kexec_elf_load - load ELF executable image
* @lowest_load_addr: On return, will be the address where the first PT_LOAD
* section will be loaded in memory.
*
* Return:
* 0 on success, negative value on failure.
*/
int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
struct kexec_elf_info *elf_info,
struct kexec_buf *kbuf,
unsigned long *lowest_load_addr)
{
unsigned long lowest_addr = UINT_MAX;
int ret;
size_t i;
/* Read in the PT_LOAD segments. */
for (i = 0; i < ehdr->e_phnum; i++) {
unsigned long load_addr;
size_t size;
const struct elf_phdr *phdr;
phdr = &elf_info->proghdrs[i];
if (phdr->p_type != PT_LOAD)
continue;
size = phdr->p_filesz;
if (size > phdr->p_memsz)
size = phdr->p_memsz;
kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset;
kbuf->bufsz = size;
kbuf->memsz = phdr->p_memsz;
kbuf->buf_align = phdr->p_align;
kbuf->buf_min = phdr->p_paddr;
kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(kbuf);
if (ret)
goto out;
load_addr = kbuf->mem;
if (load_addr < lowest_addr)
lowest_addr = load_addr;
}
*lowest_load_addr = lowest_addr;
ret = 0;
out:
return ret;
}
| linux-master | kernel/kexec_elf.c |
// SPDX-License-Identifier: GPL-2.0
/*
* fail_function.c: Function-based error injection
*/
#include <linux/error-injection.h>
#include <linux/debugfs.h>
#include <linux/fault-inject.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
static void fei_post_handler(struct kprobe *kp, struct pt_regs *regs,
unsigned long flags)
{
/*
* A dummy post handler is required to prohibit optimizing, because
* jump optimization does not support execution path overriding.
*/
}
struct fei_attr {
struct list_head list;
struct kprobe kp;
unsigned long retval;
};
static DEFINE_MUTEX(fei_lock);
static LIST_HEAD(fei_attr_list);
static DECLARE_FAULT_ATTR(fei_fault_attr);
static struct dentry *fei_debugfs_dir;
static unsigned long adjust_error_retval(unsigned long addr, unsigned long retv)
{
switch (get_injectable_error_type(addr)) {
case EI_ETYPE_NULL:
return 0;
case EI_ETYPE_ERRNO:
if (retv < (unsigned long)-MAX_ERRNO)
return (unsigned long)-EINVAL;
break;
case EI_ETYPE_ERRNO_NULL:
if (retv != 0 && retv < (unsigned long)-MAX_ERRNO)
return (unsigned long)-EINVAL;
break;
case EI_ETYPE_TRUE:
return 1;
}
return retv;
}
static struct fei_attr *fei_attr_new(const char *sym, unsigned long addr)
{
struct fei_attr *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (attr) {
attr->kp.symbol_name = kstrdup(sym, GFP_KERNEL);
if (!attr->kp.symbol_name) {
kfree(attr);
return NULL;
}
attr->kp.pre_handler = fei_kprobe_handler;
attr->kp.post_handler = fei_post_handler;
attr->retval = adjust_error_retval(addr, 0);
INIT_LIST_HEAD(&attr->list);
}
return attr;
}
static void fei_attr_free(struct fei_attr *attr)
{
if (attr) {
kfree(attr->kp.symbol_name);
kfree(attr);
}
}
static struct fei_attr *fei_attr_lookup(const char *sym)
{
struct fei_attr *attr;
list_for_each_entry(attr, &fei_attr_list, list) {
if (!strcmp(attr->kp.symbol_name, sym))
return attr;
}
return NULL;
}
static bool fei_attr_is_valid(struct fei_attr *_attr)
{
struct fei_attr *attr;
list_for_each_entry(attr, &fei_attr_list, list) {
if (attr == _attr)
return true;
}
return false;
}
static int fei_retval_set(void *data, u64 val)
{
struct fei_attr *attr = data;
unsigned long retv = (unsigned long)val;
int err = 0;
mutex_lock(&fei_lock);
/*
* Since this operation can be done after retval file is removed,
* It is safer to check the attr is still valid before accessing
* its member.
*/
if (!fei_attr_is_valid(attr)) {
err = -ENOENT;
goto out;
}
if (attr->kp.addr) {
if (adjust_error_retval((unsigned long)attr->kp.addr,
val) != retv)
err = -EINVAL;
}
if (!err)
attr->retval = val;
out:
mutex_unlock(&fei_lock);
return err;
}
static int fei_retval_get(void *data, u64 *val)
{
struct fei_attr *attr = data;
int err = 0;
mutex_lock(&fei_lock);
/* Here we also validate @attr to ensure it still exists. */
if (!fei_attr_is_valid(attr))
err = -ENOENT;
else
*val = attr->retval;
mutex_unlock(&fei_lock);
return err;
}
DEFINE_DEBUGFS_ATTRIBUTE(fei_retval_ops, fei_retval_get, fei_retval_set,
"%llx\n");
static void fei_debugfs_add_attr(struct fei_attr *attr)
{
struct dentry *dir;
dir = debugfs_create_dir(attr->kp.symbol_name, fei_debugfs_dir);
debugfs_create_file("retval", 0600, dir, attr, &fei_retval_ops);
}
static void fei_debugfs_remove_attr(struct fei_attr *attr)
{
debugfs_lookup_and_remove(attr->kp.symbol_name, fei_debugfs_dir);
}
static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
{
struct fei_attr *attr = container_of(kp, struct fei_attr, kp);
if (should_fail(&fei_fault_attr, 1)) {
regs_set_return_value(regs, attr->retval);
override_function_with_return(regs);
return 1;
}
return 0;
}
NOKPROBE_SYMBOL(fei_kprobe_handler)
static void *fei_seq_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&fei_lock);
return seq_list_start(&fei_attr_list, *pos);
}
static void fei_seq_stop(struct seq_file *m, void *v)
{
mutex_unlock(&fei_lock);
}
static void *fei_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
return seq_list_next(v, &fei_attr_list, pos);
}
static int fei_seq_show(struct seq_file *m, void *v)
{
struct fei_attr *attr = list_entry(v, struct fei_attr, list);
seq_printf(m, "%ps\n", attr->kp.addr);
return 0;
}
static const struct seq_operations fei_seq_ops = {
.start = fei_seq_start,
.next = fei_seq_next,
.stop = fei_seq_stop,
.show = fei_seq_show,
};
static int fei_open(struct inode *inode, struct file *file)
{
return seq_open(file, &fei_seq_ops);
}
static void fei_attr_remove(struct fei_attr *attr)
{
fei_debugfs_remove_attr(attr);
unregister_kprobe(&attr->kp);
list_del(&attr->list);
fei_attr_free(attr);
}
static void fei_attr_remove_all(void)
{
struct fei_attr *attr, *n;
list_for_each_entry_safe(attr, n, &fei_attr_list, list) {
fei_attr_remove(attr);
}
}
static ssize_t fei_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
struct fei_attr *attr;
unsigned long addr;
char *buf, *sym;
int ret;
/* cut off if it is too long */
if (count > KSYM_NAME_LEN)
count = KSYM_NAME_LEN;
buf = memdup_user_nul(buffer, count);
if (IS_ERR(buf))
return PTR_ERR(buf);
sym = strstrip(buf);
mutex_lock(&fei_lock);
/* Writing just spaces will remove all injection points */
if (sym[0] == '\0') {
fei_attr_remove_all();
ret = count;
goto out;
}
/* Writing !function will remove one injection point */
if (sym[0] == '!') {
attr = fei_attr_lookup(sym + 1);
if (!attr) {
ret = -ENOENT;
goto out;
}
fei_attr_remove(attr);
ret = count;
goto out;
}
addr = kallsyms_lookup_name(sym);
if (!addr) {
ret = -EINVAL;
goto out;
}
if (!within_error_injection_list(addr)) {
ret = -ERANGE;
goto out;
}
if (fei_attr_lookup(sym)) {
ret = -EBUSY;
goto out;
}
attr = fei_attr_new(sym, addr);
if (!attr) {
ret = -ENOMEM;
goto out;
}
ret = register_kprobe(&attr->kp);
if (ret) {
fei_attr_free(attr);
goto out;
}
fei_debugfs_add_attr(attr);
list_add_tail(&attr->list, &fei_attr_list);
ret = count;
out:
mutex_unlock(&fei_lock);
kfree(buf);
return ret;
}
static const struct file_operations fei_ops = {
.open = fei_open,
.read = seq_read,
.write = fei_write,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init fei_debugfs_init(void)
{
struct dentry *dir;
dir = fault_create_debugfs_attr("fail_function", NULL,
&fei_fault_attr);
if (IS_ERR(dir))
return PTR_ERR(dir);
/* injectable attribute is just a symlink of error_inject/list */
debugfs_create_symlink("injectable", dir, "../error_injection/list");
debugfs_create_file("inject", 0600, dir, NULL, &fei_ops);
fei_debugfs_dir = dir;
return 0;
}
late_initcall(fei_debugfs_init);
| linux-master | kernel/fail_function.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Clang Control Flow Integrity (CFI) error handling.
*
* Copyright (C) 2022 Google LLC
*/
#include <linux/cfi.h>
enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
unsigned long *target, u32 type)
{
if (target)
pr_err("CFI failure at %pS (target: %pS; expected type: 0x%08x)\n",
(void *)addr, (void *)*target, type);
else
pr_err("CFI failure at %pS (no target information)\n",
(void *)addr);
if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) {
__warn(NULL, 0, (void *)addr, 0, regs, NULL);
return BUG_TRAP_TYPE_WARN;
}
return BUG_TRAP_TYPE_BUG;
}
#ifdef CONFIG_ARCH_USES_CFI_TRAPS
static inline unsigned long trap_address(s32 *p)
{
return (unsigned long)((long)p + (long)*p);
}
static bool is_trap(unsigned long addr, s32 *start, s32 *end)
{
s32 *p;
for (p = start; p < end; ++p) {
if (trap_address(p) == addr)
return true;
}
return false;
}
#ifdef CONFIG_MODULES
/* Populates `kcfi_trap(_end)?` fields in `struct module`. */
void module_cfi_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
struct module *mod)
{
char *secstrings;
unsigned int i;
mod->kcfi_traps = NULL;
mod->kcfi_traps_end = NULL;
secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (i = 1; i < hdr->e_shnum; i++) {
if (strcmp(secstrings + sechdrs[i].sh_name, "__kcfi_traps"))
continue;
mod->kcfi_traps = (s32 *)sechdrs[i].sh_addr;
mod->kcfi_traps_end = (s32 *)(sechdrs[i].sh_addr + sechdrs[i].sh_size);
break;
}
}
static bool is_module_cfi_trap(unsigned long addr)
{
struct module *mod;
bool found = false;
rcu_read_lock_sched_notrace();
mod = __module_address(addr);
if (mod)
found = is_trap(addr, mod->kcfi_traps, mod->kcfi_traps_end);
rcu_read_unlock_sched_notrace();
return found;
}
#else /* CONFIG_MODULES */
static inline bool is_module_cfi_trap(unsigned long addr)
{
return false;
}
#endif /* CONFIG_MODULES */
extern s32 __start___kcfi_traps[];
extern s32 __stop___kcfi_traps[];
bool is_cfi_trap(unsigned long addr)
{
if (is_trap(addr, __start___kcfi_traps, __stop___kcfi_traps))
return true;
return is_module_cfi_trap(addr);
}
#endif /* CONFIG_ARCH_USES_CFI_TRAPS */
| linux-master | kernel/cfi.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/exit.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/sched/autogroup.h>
#include <linux/sched/mm.h>
#include <linux/sched/stat.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/iocontext.h>
#include <linux/key.h>
#include <linux/cpu.h>
#include <linux/acct.h>
#include <linux/tsacct_kern.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/freezer.h>
#include <linux/binfmts.h>
#include <linux/nsproxy.h>
#include <linux/pid_namespace.h>
#include <linux/ptrace.h>
#include <linux/profile.h>
#include <linux/mount.h>
#include <linux/proc_fs.h>
#include <linux/kthread.h>
#include <linux/mempolicy.h>
#include <linux/taskstats_kern.h>
#include <linux/delayacct.h>
#include <linux/cgroup.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/posix-timers.h>
#include <linux/cn_proc.h>
#include <linux/mutex.h>
#include <linux/futex.h>
#include <linux/pipe_fs_i.h>
#include <linux/audit.h> /* for audit_free() */
#include <linux/resource.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/blkdev.h>
#include <linux/task_work.h>
#include <linux/fs_struct.h>
#include <linux/init_task.h>
#include <linux/perf_event.h>
#include <trace/events/sched.h>
#include <linux/hw_breakpoint.h>
#include <linux/oom.h>
#include <linux/writeback.h>
#include <linux/shm.h>
#include <linux/kcov.h>
#include <linux/kmsan.h>
#include <linux/random.h>
#include <linux/rcuwait.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
#include <linux/kprobes.h>
#include <linux/rethook.h>
#include <linux/sysfs.h>
#include <linux/user_events.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/mmu_context.h>
/*
* The default value should be high enough to not crash a system that randomly
* crashes its kernel from time to time, but low enough to at least not permit
* overflowing 32-bit refcounts or the ldsem writer count.
*/
static unsigned int oops_limit = 10000;
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_exit_table[] = {
{
.procname = "oops_limit",
.data = &oops_limit,
.maxlen = sizeof(oops_limit),
.mode = 0644,
.proc_handler = proc_douintvec,
},
{ }
};
static __init int kernel_exit_sysctls_init(void)
{
register_sysctl_init("kernel", kern_exit_table);
return 0;
}
late_initcall(kernel_exit_sysctls_init);
#endif
static atomic_t oops_count = ATOMIC_INIT(0);
#ifdef CONFIG_SYSFS
static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr,
char *page)
{
return sysfs_emit(page, "%d\n", atomic_read(&oops_count));
}
static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count);
static __init int kernel_exit_sysfs_init(void)
{
sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL);
return 0;
}
late_initcall(kernel_exit_sysfs_init);
#endif
static void __unhash_process(struct task_struct *p, bool group_dead)
{
nr_threads--;
detach_pid(p, PIDTYPE_PID);
if (group_dead) {
detach_pid(p, PIDTYPE_TGID);
detach_pid(p, PIDTYPE_PGID);
detach_pid(p, PIDTYPE_SID);
list_del_rcu(&p->tasks);
list_del_init(&p->sibling);
__this_cpu_dec(process_counts);
}
list_del_rcu(&p->thread_group);
list_del_rcu(&p->thread_node);
}
/*
* This function expects the tasklist_lock write-locked.
*/
static void __exit_signal(struct task_struct *tsk)
{
struct signal_struct *sig = tsk->signal;
bool group_dead = thread_group_leader(tsk);
struct sighand_struct *sighand;
struct tty_struct *tty;
u64 utime, stime;
sighand = rcu_dereference_check(tsk->sighand,
lockdep_tasklist_lock_is_held());
spin_lock(&sighand->siglock);
#ifdef CONFIG_POSIX_TIMERS
posix_cpu_timers_exit(tsk);
if (group_dead)
posix_cpu_timers_exit_group(tsk);
#endif
if (group_dead) {
tty = sig->tty;
sig->tty = NULL;
} else {
/*
* If there is any task waiting for the group exit
* then notify it:
*/
if (sig->notify_count > 0 && !--sig->notify_count)
wake_up_process(sig->group_exec_task);
if (tsk == sig->curr_target)
sig->curr_target = next_thread(tsk);
}
add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
sizeof(unsigned long long));
/*
* Accumulate here the counters for all threads as they die. We could
* skip the group leader because it is the last user of signal_struct,
* but we want to avoid the race with thread_group_cputime() which can
* see the empty ->thread_head list.
*/
task_cputime(tsk, &utime, &stime);
write_seqlock(&sig->stats_lock);
sig->utime += utime;
sig->stime += stime;
sig->gtime += task_gtime(tsk);
sig->min_flt += tsk->min_flt;
sig->maj_flt += tsk->maj_flt;
sig->nvcsw += tsk->nvcsw;
sig->nivcsw += tsk->nivcsw;
sig->inblock += task_io_get_inblock(tsk);
sig->oublock += task_io_get_oublock(tsk);
task_io_accounting_add(&sig->ioac, &tsk->ioac);
sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
sig->nr_threads--;
__unhash_process(tsk, group_dead);
write_sequnlock(&sig->stats_lock);
/*
* Do this under ->siglock, we can race with another thread
* doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
*/
flush_sigqueue(&tsk->pending);
tsk->sighand = NULL;
spin_unlock(&sighand->siglock);
__cleanup_sighand(sighand);
clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
if (group_dead) {
flush_sigqueue(&sig->shared_pending);
tty_kref_put(tty);
}
}
static void delayed_put_task_struct(struct rcu_head *rhp)
{
struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
kprobe_flush_task(tsk);
rethook_flush_task(tsk);
perf_event_delayed_put(tsk);
trace_sched_process_free(tsk);
put_task_struct(tsk);
}
void put_task_struct_rcu_user(struct task_struct *task)
{
if (refcount_dec_and_test(&task->rcu_users))
call_rcu(&task->rcu, delayed_put_task_struct);
}
void __weak release_thread(struct task_struct *dead_task)
{
}
void release_task(struct task_struct *p)
{
struct task_struct *leader;
struct pid *thread_pid;
int zap_leader;
repeat:
/* don't need to get the RCU readlock here - the process is dead and
* can't be modifying its own credentials. But shut RCU-lockdep up */
rcu_read_lock();
dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
rcu_read_unlock();
cgroup_release(p);
write_lock_irq(&tasklist_lock);
ptrace_release_task(p);
thread_pid = get_pid(p->thread_pid);
__exit_signal(p);
/*
* If we are the last non-leader member of the thread
* group, and the leader is zombie, then notify the
* group leader's parent process. (if it wants notification.)
*/
zap_leader = 0;
leader = p->group_leader;
if (leader != p && thread_group_empty(leader)
&& leader->exit_state == EXIT_ZOMBIE) {
/*
* If we were the last child thread and the leader has
* exited already, and the leader's parent ignores SIGCHLD,
* then we are the one who should release the leader.
*/
zap_leader = do_notify_parent(leader, leader->exit_signal);
if (zap_leader)
leader->exit_state = EXIT_DEAD;
}
write_unlock_irq(&tasklist_lock);
seccomp_filter_release(p);
proc_flush_pid(thread_pid);
put_pid(thread_pid);
release_thread(p);
put_task_struct_rcu_user(p);
p = leader;
if (unlikely(zap_leader))
goto repeat;
}
int rcuwait_wake_up(struct rcuwait *w)
{
int ret = 0;
struct task_struct *task;
rcu_read_lock();
/*
* Order condition vs @task, such that everything prior to the load
* of @task is visible. This is the condition as to why the user called
* rcuwait_wake() in the first place. Pairs with set_current_state()
* barrier (A) in rcuwait_wait_event().
*
* WAIT WAKE
* [S] tsk = current [S] cond = true
* MB (A) MB (B)
* [L] cond [L] tsk
*/
smp_mb(); /* (B) */
task = rcu_dereference(w->task);
if (task)
ret = wake_up_process(task);
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(rcuwait_wake_up);
/*
* Determine if a process group is "orphaned", according to the POSIX
* definition in 2.2.2.52. Orphaned process groups are not to be affected
* by terminal-generated stop signals. Newly orphaned process groups are
* to receive a SIGHUP and a SIGCONT.
*
* "I ask you, have you ever known what it is to be an orphan?"
*/
static int will_become_orphaned_pgrp(struct pid *pgrp,
struct task_struct *ignored_task)
{
struct task_struct *p;
do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
if ((p == ignored_task) ||
(p->exit_state && thread_group_empty(p)) ||
is_global_init(p->real_parent))
continue;
if (task_pgrp(p->real_parent) != pgrp &&
task_session(p->real_parent) == task_session(p))
return 0;
} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
return 1;
}
int is_current_pgrp_orphaned(void)
{
int retval;
read_lock(&tasklist_lock);
retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
read_unlock(&tasklist_lock);
return retval;
}
static bool has_stopped_jobs(struct pid *pgrp)
{
struct task_struct *p;
do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
if (p->signal->flags & SIGNAL_STOP_STOPPED)
return true;
} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
return false;
}
/*
* Check to see if any process groups have become orphaned as
* a result of our exiting, and if they have any stopped jobs,
* send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
*/
static void
kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
{
struct pid *pgrp = task_pgrp(tsk);
struct task_struct *ignored_task = tsk;
if (!parent)
/* exit: our father is in a different pgrp than
* we are and we were the only connection outside.
*/
parent = tsk->real_parent;
else
/* reparent: our child is in a different pgrp than
* we are, and it was the only connection outside.
*/
ignored_task = NULL;
if (task_pgrp(parent) != pgrp &&
task_session(parent) == task_session(tsk) &&
will_become_orphaned_pgrp(pgrp, ignored_task) &&
has_stopped_jobs(pgrp)) {
__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
}
}
static void coredump_task_exit(struct task_struct *tsk)
{
struct core_state *core_state;
/*
* Serialize with any possible pending coredump.
* We must hold siglock around checking core_state
* and setting PF_POSTCOREDUMP. The core-inducing thread
* will increment ->nr_threads for each thread in the
* group without PF_POSTCOREDUMP set.
*/
spin_lock_irq(&tsk->sighand->siglock);
tsk->flags |= PF_POSTCOREDUMP;
core_state = tsk->signal->core_state;
spin_unlock_irq(&tsk->sighand->siglock);
/* The vhost_worker does not particpate in coredumps */
if (core_state &&
((tsk->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)) {
struct core_thread self;
self.task = current;
if (self.task->flags & PF_SIGNALED)
self.next = xchg(&core_state->dumper.next, &self);
else
self.task = NULL;
/*
* Implies mb(), the result of xchg() must be visible
* to core_state->dumper.
*/
if (atomic_dec_and_test(&core_state->nr_threads))
complete(&core_state->startup);
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
if (!self.task) /* see coredump_finish() */
break;
schedule();
}
__set_current_state(TASK_RUNNING);
}
}
#ifdef CONFIG_MEMCG
/*
* A task is exiting. If it owned this mm, find a new owner for the mm.
*/
void mm_update_next_owner(struct mm_struct *mm)
{
struct task_struct *c, *g, *p = current;
retry:
/*
* If the exiting or execing task is not the owner, it's
* someone else's problem.
*/
if (mm->owner != p)
return;
/*
* The current owner is exiting/execing and there are no other
* candidates. Do not leave the mm pointing to a possibly
* freed task structure.
*/
if (atomic_read(&mm->mm_users) <= 1) {
WRITE_ONCE(mm->owner, NULL);
return;
}
read_lock(&tasklist_lock);
/*
* Search in the children
*/
list_for_each_entry(c, &p->children, sibling) {
if (c->mm == mm)
goto assign_new_owner;
}
/*
* Search in the siblings
*/
list_for_each_entry(c, &p->real_parent->children, sibling) {
if (c->mm == mm)
goto assign_new_owner;
}
/*
* Search through everything else, we should not get here often.
*/
for_each_process(g) {
if (g->flags & PF_KTHREAD)
continue;
for_each_thread(g, c) {
if (c->mm == mm)
goto assign_new_owner;
if (c->mm)
break;
}
}
read_unlock(&tasklist_lock);
/*
* We found no owner yet mm_users > 1: this implies that we are
* most likely racing with swapoff (try_to_unuse()) or /proc or
* ptrace or page migration (get_task_mm()). Mark owner as NULL.
*/
WRITE_ONCE(mm->owner, NULL);
return;
assign_new_owner:
BUG_ON(c == p);
get_task_struct(c);
/*
* The task_lock protects c->mm from changing.
* We always want mm->owner->mm == mm
*/
task_lock(c);
/*
* Delay read_unlock() till we have the task_lock()
* to ensure that c does not slip away underneath us
*/
read_unlock(&tasklist_lock);
if (c->mm != mm) {
task_unlock(c);
put_task_struct(c);
goto retry;
}
WRITE_ONCE(mm->owner, c);
lru_gen_migrate_mm(mm);
task_unlock(c);
put_task_struct(c);
}
#endif /* CONFIG_MEMCG */
/*
* Turn us into a lazy TLB process if we
* aren't already..
*/
static void exit_mm(void)
{
struct mm_struct *mm = current->mm;
exit_mm_release(current, mm);
if (!mm)
return;
sync_mm_rss(mm);
mmap_read_lock(mm);
mmgrab_lazy_tlb(mm);
BUG_ON(mm != current->active_mm);
/* more a memory barrier than a real lock */
task_lock(current);
/*
* When a thread stops operating on an address space, the loop
* in membarrier_private_expedited() may not observe that
* tsk->mm, and the loop in membarrier_global_expedited() may
* not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
* rq->membarrier_state, so those would not issue an IPI.
* Membarrier requires a memory barrier after accessing
* user-space memory, before clearing tsk->mm or the
* rq->membarrier_state.
*/
smp_mb__after_spinlock();
local_irq_disable();
current->mm = NULL;
membarrier_update_current_mm(NULL);
enter_lazy_tlb(mm, current);
local_irq_enable();
task_unlock(current);
mmap_read_unlock(mm);
mm_update_next_owner(mm);
mmput(mm);
if (test_thread_flag(TIF_MEMDIE))
exit_oom_victim();
}
static struct task_struct *find_alive_thread(struct task_struct *p)
{
struct task_struct *t;
for_each_thread(p, t) {
if (!(t->flags & PF_EXITING))
return t;
}
return NULL;
}
static struct task_struct *find_child_reaper(struct task_struct *father,
struct list_head *dead)
__releases(&tasklist_lock)
__acquires(&tasklist_lock)
{
struct pid_namespace *pid_ns = task_active_pid_ns(father);
struct task_struct *reaper = pid_ns->child_reaper;
struct task_struct *p, *n;
if (likely(reaper != father))
return reaper;
reaper = find_alive_thread(father);
if (reaper) {
pid_ns->child_reaper = reaper;
return reaper;
}
write_unlock_irq(&tasklist_lock);
list_for_each_entry_safe(p, n, dead, ptrace_entry) {
list_del_init(&p->ptrace_entry);
release_task(p);
}
zap_pid_ns_processes(pid_ns);
write_lock_irq(&tasklist_lock);
return father;
}
/*
* When we die, we re-parent all our children, and try to:
* 1. give them to another thread in our thread group, if such a member exists
* 2. give it to the first ancestor process which prctl'd itself as a
* child_subreaper for its children (like a service manager)
* 3. give it to the init process (PID 1) in our pid namespace
*/
static struct task_struct *find_new_reaper(struct task_struct *father,
struct task_struct *child_reaper)
{
struct task_struct *thread, *reaper;
thread = find_alive_thread(father);
if (thread)
return thread;
if (father->signal->has_child_subreaper) {
unsigned int ns_level = task_pid(father)->level;
/*
* Find the first ->is_child_subreaper ancestor in our pid_ns.
* We can't check reaper != child_reaper to ensure we do not
* cross the namespaces, the exiting parent could be injected
* by setns() + fork().
* We check pid->level, this is slightly more efficient than
* task_active_pid_ns(reaper) != task_active_pid_ns(father).
*/
for (reaper = father->real_parent;
task_pid(reaper)->level == ns_level;
reaper = reaper->real_parent) {
if (reaper == &init_task)
break;
if (!reaper->signal->is_child_subreaper)
continue;
thread = find_alive_thread(reaper);
if (thread)
return thread;
}
}
return child_reaper;
}
/*
* Any that need to be release_task'd are put on the @dead list.
*/
static void reparent_leader(struct task_struct *father, struct task_struct *p,
struct list_head *dead)
{
if (unlikely(p->exit_state == EXIT_DEAD))
return;
/* We don't want people slaying init. */
p->exit_signal = SIGCHLD;
/* If it has exited notify the new parent about this child's death. */
if (!p->ptrace &&
p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
if (do_notify_parent(p, p->exit_signal)) {
p->exit_state = EXIT_DEAD;
list_add(&p->ptrace_entry, dead);
}
}
kill_orphaned_pgrp(p, father);
}
/*
* This does two things:
*
* A. Make init inherit all the child processes
* B. Check to see if any process groups have become orphaned
* as a result of our exiting, and if they have any stopped
* jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
*/
static void forget_original_parent(struct task_struct *father,
struct list_head *dead)
{
struct task_struct *p, *t, *reaper;
if (unlikely(!list_empty(&father->ptraced)))
exit_ptrace(father, dead);
/* Can drop and reacquire tasklist_lock */
reaper = find_child_reaper(father, dead);
if (list_empty(&father->children))
return;
reaper = find_new_reaper(father, reaper);
list_for_each_entry(p, &father->children, sibling) {
for_each_thread(p, t) {
RCU_INIT_POINTER(t->real_parent, reaper);
BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
if (likely(!t->ptrace))
t->parent = t->real_parent;
if (t->pdeath_signal)
group_send_sig_info(t->pdeath_signal,
SEND_SIG_NOINFO, t,
PIDTYPE_TGID);
}
/*
* If this is a threaded reparent there is no need to
* notify anyone anything has happened.
*/
if (!same_thread_group(reaper, father))
reparent_leader(father, p, dead);
}
list_splice_tail_init(&father->children, &reaper->children);
}
/*
* Send signals to all our closest relatives so that they know
* to properly mourn us..
*/
static void exit_notify(struct task_struct *tsk, int group_dead)
{
bool autoreap;
struct task_struct *p, *n;
LIST_HEAD(dead);
write_lock_irq(&tasklist_lock);
forget_original_parent(tsk, &dead);
if (group_dead)
kill_orphaned_pgrp(tsk->group_leader, NULL);
tsk->exit_state = EXIT_ZOMBIE;
if (unlikely(tsk->ptrace)) {
int sig = thread_group_leader(tsk) &&
thread_group_empty(tsk) &&
!ptrace_reparented(tsk) ?
tsk->exit_signal : SIGCHLD;
autoreap = do_notify_parent(tsk, sig);
} else if (thread_group_leader(tsk)) {
autoreap = thread_group_empty(tsk) &&
do_notify_parent(tsk, tsk->exit_signal);
} else {
autoreap = true;
}
if (autoreap) {
tsk->exit_state = EXIT_DEAD;
list_add(&tsk->ptrace_entry, &dead);
}
/* mt-exec, de_thread() is waiting for group leader */
if (unlikely(tsk->signal->notify_count < 0))
wake_up_process(tsk->signal->group_exec_task);
write_unlock_irq(&tasklist_lock);
list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
list_del_init(&p->ptrace_entry);
release_task(p);
}
}
#ifdef CONFIG_DEBUG_STACK_USAGE
static void check_stack_usage(void)
{
static DEFINE_SPINLOCK(low_water_lock);
static int lowest_to_date = THREAD_SIZE;
unsigned long free;
free = stack_not_used(current);
if (free >= lowest_to_date)
return;
spin_lock(&low_water_lock);
if (free < lowest_to_date) {
pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
current->comm, task_pid_nr(current), free);
lowest_to_date = free;
}
spin_unlock(&low_water_lock);
}
#else
static inline void check_stack_usage(void) {}
#endif
static void synchronize_group_exit(struct task_struct *tsk, long code)
{
struct sighand_struct *sighand = tsk->sighand;
struct signal_struct *signal = tsk->signal;
spin_lock_irq(&sighand->siglock);
signal->quick_threads--;
if ((signal->quick_threads == 0) &&
!(signal->flags & SIGNAL_GROUP_EXIT)) {
signal->flags = SIGNAL_GROUP_EXIT;
signal->group_exit_code = code;
signal->group_stop_count = 0;
}
spin_unlock_irq(&sighand->siglock);
}
void __noreturn do_exit(long code)
{
struct task_struct *tsk = current;
int group_dead;
WARN_ON(irqs_disabled());
synchronize_group_exit(tsk, code);
WARN_ON(tsk->plug);
kcov_task_exit(tsk);
kmsan_task_exit(tsk);
coredump_task_exit(tsk);
ptrace_event(PTRACE_EVENT_EXIT, code);
user_events_exit(tsk);
validate_creds_for_do_exit(tsk);
io_uring_files_cancel();
exit_signals(tsk); /* sets PF_EXITING */
/* sync mm's RSS info before statistics gathering */
if (tsk->mm)
sync_mm_rss(tsk->mm);
acct_update_integrals(tsk);
group_dead = atomic_dec_and_test(&tsk->signal->live);
if (group_dead) {
/*
* If the last thread of global init has exited, panic
* immediately to get a useable coredump.
*/
if (unlikely(is_global_init(tsk)))
panic("Attempted to kill init! exitcode=0x%08x\n",
tsk->signal->group_exit_code ?: (int)code);
#ifdef CONFIG_POSIX_TIMERS
hrtimer_cancel(&tsk->signal->real_timer);
exit_itimers(tsk);
#endif
if (tsk->mm)
setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
}
acct_collect(code, group_dead);
if (group_dead)
tty_audit_exit();
audit_free(tsk);
tsk->exit_code = code;
taskstats_exit(tsk, group_dead);
exit_mm();
if (group_dead)
acct_process();
trace_sched_process_exit(tsk);
exit_sem(tsk);
exit_shm(tsk);
exit_files(tsk);
exit_fs(tsk);
if (group_dead)
disassociate_ctty(1);
exit_task_namespaces(tsk);
exit_task_work(tsk);
exit_thread(tsk);
/*
* Flush inherited counters to the parent - before the parent
* gets woken up by child-exit notifications.
*
* because of cgroup mode, must be called before cgroup_exit()
*/
perf_event_exit_task(tsk);
sched_autogroup_exit_task(tsk);
cgroup_exit(tsk);
/*
* FIXME: do that only when needed, using sched_exit tracepoint
*/
flush_ptrace_hw_breakpoint(tsk);
exit_tasks_rcu_start();
exit_notify(tsk, group_dead);
proc_exit_connector(tsk);
mpol_put_task_policy(tsk);
#ifdef CONFIG_FUTEX
if (unlikely(current->pi_state_cache))
kfree(current->pi_state_cache);
#endif
/*
* Make sure we are holding no locks:
*/
debug_check_no_locks_held();
if (tsk->io_context)
exit_io_context(tsk);
if (tsk->splice_pipe)
free_pipe_info(tsk->splice_pipe);
if (tsk->task_frag.page)
put_page(tsk->task_frag.page);
validate_creds_for_do_exit(tsk);
exit_task_stack_account(tsk);
check_stack_usage();
preempt_disable();
if (tsk->nr_dirtied)
__this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
exit_rcu();
exit_tasks_rcu_finish();
lockdep_free_task(tsk);
do_task_dead();
}
void __noreturn make_task_dead(int signr)
{
/*
* Take the task off the cpu after something catastrophic has
* happened.
*
* We can get here from a kernel oops, sometimes with preemption off.
* Start by checking for critical errors.
* Then fix up important state like USER_DS and preemption.
* Then do everything else.
*/
struct task_struct *tsk = current;
unsigned int limit;
if (unlikely(in_interrupt()))
panic("Aiee, killing interrupt handler!");
if (unlikely(!tsk->pid))
panic("Attempted to kill the idle task!");
if (unlikely(irqs_disabled())) {
pr_info("note: %s[%d] exited with irqs disabled\n",
current->comm, task_pid_nr(current));
local_irq_enable();
}
if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
preempt_count());
preempt_count_set(PREEMPT_ENABLED);
}
/*
* Every time the system oopses, if the oops happens while a reference
* to an object was held, the reference leaks.
* If the oops doesn't also leak memory, repeated oopsing can cause
* reference counters to wrap around (if they're not using refcount_t).
* This means that repeated oopsing can make unexploitable-looking bugs
* exploitable through repeated oopsing.
* To make sure this can't happen, place an upper bound on how often the
* kernel may oops without panic().
*/
limit = READ_ONCE(oops_limit);
if (atomic_inc_return(&oops_count) >= limit && limit)
panic("Oopsed too often (kernel.oops_limit is %d)", limit);
/*
* We're taking recursive faults here in make_task_dead. Safest is to just
* leave this task alone and wait for reboot.
*/
if (unlikely(tsk->flags & PF_EXITING)) {
pr_alert("Fixing recursive fault but reboot is needed!\n");
futex_exit_recursive(tsk);
tsk->exit_state = EXIT_DEAD;
refcount_inc(&tsk->rcu_users);
do_task_dead();
}
do_exit(signr);
}
SYSCALL_DEFINE1(exit, int, error_code)
{
do_exit((error_code&0xff)<<8);
}
/*
* Take down every thread in the group. This is called by fatal signals
* as well as by sys_exit_group (below).
*/
void __noreturn
do_group_exit(int exit_code)
{
struct signal_struct *sig = current->signal;
if (sig->flags & SIGNAL_GROUP_EXIT)
exit_code = sig->group_exit_code;
else if (sig->group_exec_task)
exit_code = 0;
else {
struct sighand_struct *const sighand = current->sighand;
spin_lock_irq(&sighand->siglock);
if (sig->flags & SIGNAL_GROUP_EXIT)
/* Another thread got here before we took the lock. */
exit_code = sig->group_exit_code;
else if (sig->group_exec_task)
exit_code = 0;
else {
sig->group_exit_code = exit_code;
sig->flags = SIGNAL_GROUP_EXIT;
zap_other_threads(current);
}
spin_unlock_irq(&sighand->siglock);
}
do_exit(exit_code);
/* NOTREACHED */
}
/*
* this kills every thread in the thread group. Note that any externally
* wait4()-ing process will get the correct exit code - even if this
* thread is not the thread group leader.
*/
SYSCALL_DEFINE1(exit_group, int, error_code)
{
do_group_exit((error_code & 0xff) << 8);
/* NOTREACHED */
return 0;
}
struct waitid_info {
pid_t pid;
uid_t uid;
int status;
int cause;
};
struct wait_opts {
enum pid_type wo_type;
int wo_flags;
struct pid *wo_pid;
struct waitid_info *wo_info;
int wo_stat;
struct rusage *wo_rusage;
wait_queue_entry_t child_wait;
int notask_error;
};
static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
{
return wo->wo_type == PIDTYPE_MAX ||
task_pid_type(p, wo->wo_type) == wo->wo_pid;
}
static int
eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p)
{
if (!eligible_pid(wo, p))
return 0;
/*
* Wait for all children (clone and not) if __WALL is set or
* if it is traced by us.
*/
if (ptrace || (wo->wo_flags & __WALL))
return 1;
/*
* Otherwise, wait for clone children *only* if __WCLONE is set;
* otherwise, wait for non-clone children *only*.
*
* Note: a "clone" child here is one that reports to its parent
* using a signal other than SIGCHLD, or a non-leader thread which
* we can only see if it is traced by us.
*/
if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
return 0;
return 1;
}
/*
* Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
* read_lock(&tasklist_lock) on entry. If we return zero, we still hold
* the lock and this task is uninteresting. If we return nonzero, we have
* released the lock and the system call should return.
*/
static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
{
int state, status;
pid_t pid = task_pid_vnr(p);
uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
struct waitid_info *infop;
if (!likely(wo->wo_flags & WEXITED))
return 0;
if (unlikely(wo->wo_flags & WNOWAIT)) {
status = (p->signal->flags & SIGNAL_GROUP_EXIT)
? p->signal->group_exit_code : p->exit_code;
get_task_struct(p);
read_unlock(&tasklist_lock);
sched_annotate_sleep();
if (wo->wo_rusage)
getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
put_task_struct(p);
goto out_info;
}
/*
* Move the task's state to DEAD/TRACE, only one thread can do this.
*/
state = (ptrace_reparented(p) && thread_group_leader(p)) ?
EXIT_TRACE : EXIT_DEAD;
if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
return 0;
/*
* We own this thread, nobody else can reap it.
*/
read_unlock(&tasklist_lock);
sched_annotate_sleep();
/*
* Check thread_group_leader() to exclude the traced sub-threads.
*/
if (state == EXIT_DEAD && thread_group_leader(p)) {
struct signal_struct *sig = p->signal;
struct signal_struct *psig = current->signal;
unsigned long maxrss;
u64 tgutime, tgstime;
/*
* The resource counters for the group leader are in its
* own task_struct. Those for dead threads in the group
* are in its signal_struct, as are those for the child
* processes it has previously reaped. All these
* accumulate in the parent's signal_struct c* fields.
*
* We don't bother to take a lock here to protect these
* p->signal fields because the whole thread group is dead
* and nobody can change them.
*
* psig->stats_lock also protects us from our sub-threads
* which can reap other children at the same time. Until
* we change k_getrusage()-like users to rely on this lock
* we have to take ->siglock as well.
*
* We use thread_group_cputime_adjusted() to get times for
* the thread group, which consolidates times for all threads
* in the group including the group leader.
*/
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
spin_lock_irq(¤t->sighand->siglock);
write_seqlock(&psig->stats_lock);
psig->cutime += tgutime + sig->cutime;
psig->cstime += tgstime + sig->cstime;
psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
psig->cmin_flt +=
p->min_flt + sig->min_flt + sig->cmin_flt;
psig->cmaj_flt +=
p->maj_flt + sig->maj_flt + sig->cmaj_flt;
psig->cnvcsw +=
p->nvcsw + sig->nvcsw + sig->cnvcsw;
psig->cnivcsw +=
p->nivcsw + sig->nivcsw + sig->cnivcsw;
psig->cinblock +=
task_io_get_inblock(p) +
sig->inblock + sig->cinblock;
psig->coublock +=
task_io_get_oublock(p) +
sig->oublock + sig->coublock;
maxrss = max(sig->maxrss, sig->cmaxrss);
if (psig->cmaxrss < maxrss)
psig->cmaxrss = maxrss;
task_io_accounting_add(&psig->ioac, &p->ioac);
task_io_accounting_add(&psig->ioac, &sig->ioac);
write_sequnlock(&psig->stats_lock);
spin_unlock_irq(¤t->sighand->siglock);
}
if (wo->wo_rusage)
getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
status = (p->signal->flags & SIGNAL_GROUP_EXIT)
? p->signal->group_exit_code : p->exit_code;
wo->wo_stat = status;
if (state == EXIT_TRACE) {
write_lock_irq(&tasklist_lock);
/* We dropped tasklist, ptracer could die and untrace */
ptrace_unlink(p);
/* If parent wants a zombie, don't release it now */
state = EXIT_ZOMBIE;
if (do_notify_parent(p, p->exit_signal))
state = EXIT_DEAD;
p->exit_state = state;
write_unlock_irq(&tasklist_lock);
}
if (state == EXIT_DEAD)
release_task(p);
out_info:
infop = wo->wo_info;
if (infop) {
if ((status & 0x7f) == 0) {
infop->cause = CLD_EXITED;
infop->status = status >> 8;
} else {
infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
infop->status = status & 0x7f;
}
infop->pid = pid;
infop->uid = uid;
}
return pid;
}
static int *task_stopped_code(struct task_struct *p, bool ptrace)
{
if (ptrace) {
if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING))
return &p->exit_code;
} else {
if (p->signal->flags & SIGNAL_STOP_STOPPED)
return &p->signal->group_exit_code;
}
return NULL;
}
/**
* wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
* @wo: wait options
* @ptrace: is the wait for ptrace
* @p: task to wait for
*
* Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
*
* CONTEXT:
* read_lock(&tasklist_lock), which is released if return value is
* non-zero. Also, grabs and releases @p->sighand->siglock.
*
* RETURNS:
* 0 if wait condition didn't exist and search for other wait conditions
* should continue. Non-zero return, -errno on failure and @p's pid on
* success, implies that tasklist_lock is released and wait condition
* search should terminate.
*/
static int wait_task_stopped(struct wait_opts *wo,
int ptrace, struct task_struct *p)
{
struct waitid_info *infop;
int exit_code, *p_code, why;
uid_t uid = 0; /* unneeded, required by compiler */
pid_t pid;
/*
* Traditionally we see ptrace'd stopped tasks regardless of options.
*/
if (!ptrace && !(wo->wo_flags & WUNTRACED))
return 0;
if (!task_stopped_code(p, ptrace))
return 0;
exit_code = 0;
spin_lock_irq(&p->sighand->siglock);
p_code = task_stopped_code(p, ptrace);
if (unlikely(!p_code))
goto unlock_sig;
exit_code = *p_code;
if (!exit_code)
goto unlock_sig;
if (!unlikely(wo->wo_flags & WNOWAIT))
*p_code = 0;
uid = from_kuid_munged(current_user_ns(), task_uid(p));
unlock_sig:
spin_unlock_irq(&p->sighand->siglock);
if (!exit_code)
return 0;
/*
* Now we are pretty sure this task is interesting.
* Make sure it doesn't get reaped out from under us while we
* give up the lock and then examine it below. We don't want to
* keep holding onto the tasklist_lock while we call getrusage and
* possibly take page faults for user memory.
*/
get_task_struct(p);
pid = task_pid_vnr(p);
why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
read_unlock(&tasklist_lock);
sched_annotate_sleep();
if (wo->wo_rusage)
getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
put_task_struct(p);
if (likely(!(wo->wo_flags & WNOWAIT)))
wo->wo_stat = (exit_code << 8) | 0x7f;
infop = wo->wo_info;
if (infop) {
infop->cause = why;
infop->status = exit_code;
infop->pid = pid;
infop->uid = uid;
}
return pid;
}
/*
* Handle do_wait work for one task in a live, non-stopped state.
* read_lock(&tasklist_lock) on entry. If we return zero, we still hold
* the lock and this task is uninteresting. If we return nonzero, we have
* released the lock and the system call should return.
*/
static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
{
struct waitid_info *infop;
pid_t pid;
uid_t uid;
if (!unlikely(wo->wo_flags & WCONTINUED))
return 0;
if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
return 0;
spin_lock_irq(&p->sighand->siglock);
/* Re-check with the lock held. */
if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
spin_unlock_irq(&p->sighand->siglock);
return 0;
}
if (!unlikely(wo->wo_flags & WNOWAIT))
p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
uid = from_kuid_munged(current_user_ns(), task_uid(p));
spin_unlock_irq(&p->sighand->siglock);
pid = task_pid_vnr(p);
get_task_struct(p);
read_unlock(&tasklist_lock);
sched_annotate_sleep();
if (wo->wo_rusage)
getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
put_task_struct(p);
infop = wo->wo_info;
if (!infop) {
wo->wo_stat = 0xffff;
} else {
infop->cause = CLD_CONTINUED;
infop->pid = pid;
infop->uid = uid;
infop->status = SIGCONT;
}
return pid;
}
/*
* Consider @p for a wait by @parent.
*
* -ECHILD should be in ->notask_error before the first call.
* Returns nonzero for a final return, when we have unlocked tasklist_lock.
* Returns zero if the search for a child should continue;
* then ->notask_error is 0 if @p is an eligible child,
* or still -ECHILD.
*/
static int wait_consider_task(struct wait_opts *wo, int ptrace,
struct task_struct *p)
{
/*
* We can race with wait_task_zombie() from another thread.
* Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
* can't confuse the checks below.
*/
int exit_state = READ_ONCE(p->exit_state);
int ret;
if (unlikely(exit_state == EXIT_DEAD))
return 0;
ret = eligible_child(wo, ptrace, p);
if (!ret)
return ret;
if (unlikely(exit_state == EXIT_TRACE)) {
/*
* ptrace == 0 means we are the natural parent. In this case
* we should clear notask_error, debugger will notify us.
*/
if (likely(!ptrace))
wo->notask_error = 0;
return 0;
}
if (likely(!ptrace) && unlikely(p->ptrace)) {
/*
* If it is traced by its real parent's group, just pretend
* the caller is ptrace_do_wait() and reap this child if it
* is zombie.
*
* This also hides group stop state from real parent; otherwise
* a single stop can be reported twice as group and ptrace stop.
* If a ptracer wants to distinguish these two events for its
* own children it should create a separate process which takes
* the role of real parent.
*/
if (!ptrace_reparented(p))
ptrace = 1;
}
/* slay zombie? */
if (exit_state == EXIT_ZOMBIE) {
/* we don't reap group leaders with subthreads */
if (!delay_group_leader(p)) {
/*
* A zombie ptracee is only visible to its ptracer.
* Notification and reaping will be cascaded to the
* real parent when the ptracer detaches.
*/
if (unlikely(ptrace) || likely(!p->ptrace))
return wait_task_zombie(wo, p);
}
/*
* Allow access to stopped/continued state via zombie by
* falling through. Clearing of notask_error is complex.
*
* When !@ptrace:
*
* If WEXITED is set, notask_error should naturally be
* cleared. If not, subset of WSTOPPED|WCONTINUED is set,
* so, if there are live subthreads, there are events to
* wait for. If all subthreads are dead, it's still safe
* to clear - this function will be called again in finite
* amount time once all the subthreads are released and
* will then return without clearing.
*
* When @ptrace:
*
* Stopped state is per-task and thus can't change once the
* target task dies. Only continued and exited can happen.
* Clear notask_error if WCONTINUED | WEXITED.
*/
if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
wo->notask_error = 0;
} else {
/*
* @p is alive and it's gonna stop, continue or exit, so
* there always is something to wait for.
*/
wo->notask_error = 0;
}
/*
* Wait for stopped. Depending on @ptrace, different stopped state
* is used and the two don't interact with each other.
*/
ret = wait_task_stopped(wo, ptrace, p);
if (ret)
return ret;
/*
* Wait for continued. There's only one continued state and the
* ptracer can consume it which can confuse the real parent. Don't
* use WCONTINUED from ptracer. You don't need or want it.
*/
return wait_task_continued(wo, p);
}
/*
* Do the work of do_wait() for one thread in the group, @tsk.
*
* -ECHILD should be in ->notask_error before the first call.
* Returns nonzero for a final return, when we have unlocked tasklist_lock.
* Returns zero if the search for a child should continue; then
* ->notask_error is 0 if there were any eligible children,
* or still -ECHILD.
*/
static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
{
struct task_struct *p;
list_for_each_entry(p, &tsk->children, sibling) {
int ret = wait_consider_task(wo, 0, p);
if (ret)
return ret;
}
return 0;
}
static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
{
struct task_struct *p;
list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
int ret = wait_consider_task(wo, 1, p);
if (ret)
return ret;
}
return 0;
}
static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
int sync, void *key)
{
struct wait_opts *wo = container_of(wait, struct wait_opts,
child_wait);
struct task_struct *p = key;
if (!eligible_pid(wo, p))
return 0;
if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
return 0;
return default_wake_function(wait, mode, sync, key);
}
void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
{
__wake_up_sync_key(&parent->signal->wait_chldexit,
TASK_INTERRUPTIBLE, p);
}
static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
struct task_struct *target)
{
struct task_struct *parent =
!ptrace ? target->real_parent : target->parent;
return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
same_thread_group(current, parent));
}
/*
* Optimization for waiting on PIDTYPE_PID. No need to iterate through child
* and tracee lists to find the target task.
*/
static int do_wait_pid(struct wait_opts *wo)
{
bool ptrace;
struct task_struct *target;
int retval;
ptrace = false;
target = pid_task(wo->wo_pid, PIDTYPE_TGID);
if (target && is_effectively_child(wo, ptrace, target)) {
retval = wait_consider_task(wo, ptrace, target);
if (retval)
return retval;
}
ptrace = true;
target = pid_task(wo->wo_pid, PIDTYPE_PID);
if (target && target->ptrace &&
is_effectively_child(wo, ptrace, target)) {
retval = wait_consider_task(wo, ptrace, target);
if (retval)
return retval;
}
return 0;
}
static long do_wait(struct wait_opts *wo)
{
int retval;
trace_sched_process_wait(wo->wo_pid);
init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
wo->child_wait.private = current;
add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
repeat:
/*
* If there is nothing that can match our criteria, just get out.
* We will clear ->notask_error to zero if we see any child that
* might later match our criteria, even if we are not able to reap
* it yet.
*/
wo->notask_error = -ECHILD;
if ((wo->wo_type < PIDTYPE_MAX) &&
(!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
goto notask;
set_current_state(TASK_INTERRUPTIBLE);
read_lock(&tasklist_lock);
if (wo->wo_type == PIDTYPE_PID) {
retval = do_wait_pid(wo);
if (retval)
goto end;
} else {
struct task_struct *tsk = current;
do {
retval = do_wait_thread(wo, tsk);
if (retval)
goto end;
retval = ptrace_do_wait(wo, tsk);
if (retval)
goto end;
if (wo->wo_flags & __WNOTHREAD)
break;
} while_each_thread(current, tsk);
}
read_unlock(&tasklist_lock);
notask:
retval = wo->notask_error;
if (!retval && !(wo->wo_flags & WNOHANG)) {
retval = -ERESTARTSYS;
if (!signal_pending(current)) {
schedule();
goto repeat;
}
}
end:
__set_current_state(TASK_RUNNING);
remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
return retval;
}
static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
int options, struct rusage *ru)
{
struct wait_opts wo;
struct pid *pid = NULL;
enum pid_type type;
long ret;
unsigned int f_flags = 0;
if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
__WNOTHREAD|__WCLONE|__WALL))
return -EINVAL;
if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
return -EINVAL;
switch (which) {
case P_ALL:
type = PIDTYPE_MAX;
break;
case P_PID:
type = PIDTYPE_PID;
if (upid <= 0)
return -EINVAL;
pid = find_get_pid(upid);
break;
case P_PGID:
type = PIDTYPE_PGID;
if (upid < 0)
return -EINVAL;
if (upid)
pid = find_get_pid(upid);
else
pid = get_task_pid(current, PIDTYPE_PGID);
break;
case P_PIDFD:
type = PIDTYPE_PID;
if (upid < 0)
return -EINVAL;
pid = pidfd_get_pid(upid, &f_flags);
if (IS_ERR(pid))
return PTR_ERR(pid);
break;
default:
return -EINVAL;
}
wo.wo_type = type;
wo.wo_pid = pid;
wo.wo_flags = options;
wo.wo_info = infop;
wo.wo_rusage = ru;
if (f_flags & O_NONBLOCK)
wo.wo_flags |= WNOHANG;
ret = do_wait(&wo);
if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK))
ret = -EAGAIN;
put_pid(pid);
return ret;
}
SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
infop, int, options, struct rusage __user *, ru)
{
struct rusage r;
struct waitid_info info = {.status = 0};
long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
int signo = 0;
if (err > 0) {
signo = SIGCHLD;
err = 0;
if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
return -EFAULT;
}
if (!infop)
return err;
if (!user_write_access_begin(infop, sizeof(*infop)))
return -EFAULT;
unsafe_put_user(signo, &infop->si_signo, Efault);
unsafe_put_user(0, &infop->si_errno, Efault);
unsafe_put_user(info.cause, &infop->si_code, Efault);
unsafe_put_user(info.pid, &infop->si_pid, Efault);
unsafe_put_user(info.uid, &infop->si_uid, Efault);
unsafe_put_user(info.status, &infop->si_status, Efault);
user_write_access_end();
return err;
Efault:
user_write_access_end();
return -EFAULT;
}
long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
struct rusage *ru)
{
struct wait_opts wo;
struct pid *pid = NULL;
enum pid_type type;
long ret;
if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
__WNOTHREAD|__WCLONE|__WALL))
return -EINVAL;
/* -INT_MIN is not defined */
if (upid == INT_MIN)
return -ESRCH;
if (upid == -1)
type = PIDTYPE_MAX;
else if (upid < 0) {
type = PIDTYPE_PGID;
pid = find_get_pid(-upid);
} else if (upid == 0) {
type = PIDTYPE_PGID;
pid = get_task_pid(current, PIDTYPE_PGID);
} else /* upid > 0 */ {
type = PIDTYPE_PID;
pid = find_get_pid(upid);
}
wo.wo_type = type;
wo.wo_pid = pid;
wo.wo_flags = options | WEXITED;
wo.wo_info = NULL;
wo.wo_stat = 0;
wo.wo_rusage = ru;
ret = do_wait(&wo);
put_pid(pid);
if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr))
ret = -EFAULT;
return ret;
}
int kernel_wait(pid_t pid, int *stat)
{
struct wait_opts wo = {
.wo_type = PIDTYPE_PID,
.wo_pid = find_get_pid(pid),
.wo_flags = WEXITED,
};
int ret;
ret = do_wait(&wo);
if (ret > 0 && wo.wo_stat)
*stat = wo.wo_stat;
put_pid(wo.wo_pid);
return ret;
}
SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
int, options, struct rusage __user *, ru)
{
struct rusage r;
long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);
if (err > 0) {
if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
return -EFAULT;
}
return err;
}
#ifdef __ARCH_WANT_SYS_WAITPID
/*
* sys_waitpid() remains for compatibility. waitpid() should be
* implemented by calling sys_wait4() from libc.a.
*/
SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
{
return kernel_wait4(pid, stat_addr, options, NULL);
}
#endif
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(wait4,
compat_pid_t, pid,
compat_uint_t __user *, stat_addr,
int, options,
struct compat_rusage __user *, ru)
{
struct rusage r;
long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);
if (err > 0) {
if (ru && put_compat_rusage(&r, ru))
return -EFAULT;
}
return err;
}
COMPAT_SYSCALL_DEFINE5(waitid,
int, which, compat_pid_t, pid,
struct compat_siginfo __user *, infop, int, options,
struct compat_rusage __user *, uru)
{
struct rusage ru;
struct waitid_info info = {.status = 0};
long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);
int signo = 0;
if (err > 0) {
signo = SIGCHLD;
err = 0;
if (uru) {
/* kernel_waitid() overwrites everything in ru */
if (COMPAT_USE_64BIT_TIME)
err = copy_to_user(uru, &ru, sizeof(ru));
else
err = put_compat_rusage(&ru, uru);
if (err)
return -EFAULT;
}
}
if (!infop)
return err;
if (!user_write_access_begin(infop, sizeof(*infop)))
return -EFAULT;
unsafe_put_user(signo, &infop->si_signo, Efault);
unsafe_put_user(0, &infop->si_errno, Efault);
unsafe_put_user(info.cause, &infop->si_code, Efault);
unsafe_put_user(info.pid, &infop->si_pid, Efault);
unsafe_put_user(info.uid, &infop->si_uid, Efault);
unsafe_put_user(info.status, &infop->si_status, Efault);
user_write_access_end();
return err;
Efault:
user_write_access_end();
return -EFAULT;
}
#endif
/**
* thread_group_exited - check that a thread group has exited
* @pid: tgid of thread group to be checked.
*
* Test if the thread group represented by tgid has exited (all
* threads are zombies, dead or completely gone).
*
* Return: true if the thread group has exited. false otherwise.
*/
bool thread_group_exited(struct pid *pid)
{
struct task_struct *task;
bool exited;
rcu_read_lock();
task = pid_task(pid, PIDTYPE_PID);
exited = !task ||
(READ_ONCE(task->exit_state) && thread_group_empty(task));
rcu_read_unlock();
return exited;
}
EXPORT_SYMBOL(thread_group_exited);
/*
* This needs to be __function_aligned as GCC implicitly makes any
* implementation of abort() cold and drops alignment specified by
* -falign-functions=N.
*
* See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11
*/
__weak __function_aligned void abort(void)
{
BUG();
/* if that doesn't kill us, halt */
panic("Oops failed to kill thread");
}
EXPORT_SYMBOL(abort);
| linux-master | kernel/exit.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/panic.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* This function is used through-out the kernel (including mm and fs)
* to indicate a major problem.
*/
#include <linux/debug_locks.h>
#include <linux/sched/debug.h>
#include <linux/interrupt.h>
#include <linux/kgdb.h>
#include <linux/kmsg_dump.h>
#include <linux/kallsyms.h>
#include <linux/notifier.h>
#include <linux/vt_kern.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/ftrace.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/kexec.h>
#include <linux/panic_notifier.h>
#include <linux/sched.h>
#include <linux/string_helpers.h>
#include <linux/sysrq.h>
#include <linux/init.h>
#include <linux/nmi.h>
#include <linux/console.h>
#include <linux/bug.h>
#include <linux/ratelimit.h>
#include <linux/debugfs.h>
#include <linux/sysfs.h>
#include <linux/context_tracking.h>
#include <trace/events/error_report.h>
#include <asm/sections.h>
#define PANIC_TIMER_STEP 100
#define PANIC_BLINK_SPD 18
#ifdef CONFIG_SMP
/*
* Should we dump all CPUs backtraces in an oops event?
* Defaults to 0, can be changed via sysctl.
*/
static unsigned int __read_mostly sysctl_oops_all_cpu_backtrace;
#else
#define sysctl_oops_all_cpu_backtrace 0
#endif /* CONFIG_SMP */
int panic_on_oops = CONFIG_PANIC_ON_OOPS_VALUE;
static unsigned long tainted_mask =
IS_ENABLED(CONFIG_RANDSTRUCT) ? (1 << TAINT_RANDSTRUCT) : 0;
static int pause_on_oops;
static int pause_on_oops_flag;
static DEFINE_SPINLOCK(pause_on_oops_lock);
bool crash_kexec_post_notifiers;
int panic_on_warn __read_mostly;
unsigned long panic_on_taint;
bool panic_on_taint_nousertaint = false;
static unsigned int warn_limit __read_mostly;
int panic_timeout = CONFIG_PANIC_TIMEOUT;
EXPORT_SYMBOL_GPL(panic_timeout);
#define PANIC_PRINT_TASK_INFO 0x00000001
#define PANIC_PRINT_MEM_INFO 0x00000002
#define PANIC_PRINT_TIMER_INFO 0x00000004
#define PANIC_PRINT_LOCK_INFO 0x00000008
#define PANIC_PRINT_FTRACE_INFO 0x00000010
#define PANIC_PRINT_ALL_PRINTK_MSG 0x00000020
#define PANIC_PRINT_ALL_CPU_BT 0x00000040
unsigned long panic_print;
ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
EXPORT_SYMBOL(panic_notifier_list);
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_panic_table[] = {
#ifdef CONFIG_SMP
{
.procname = "oops_all_cpu_backtrace",
.data = &sysctl_oops_all_cpu_backtrace,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif
{
.procname = "warn_limit",
.data = &warn_limit,
.maxlen = sizeof(warn_limit),
.mode = 0644,
.proc_handler = proc_douintvec,
},
{ }
};
static __init int kernel_panic_sysctls_init(void)
{
register_sysctl_init("kernel", kern_panic_table);
return 0;
}
late_initcall(kernel_panic_sysctls_init);
#endif
static atomic_t warn_count = ATOMIC_INIT(0);
#ifdef CONFIG_SYSFS
static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr,
char *page)
{
return sysfs_emit(page, "%d\n", atomic_read(&warn_count));
}
static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count);
static __init int kernel_panic_sysfs_init(void)
{
sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL);
return 0;
}
late_initcall(kernel_panic_sysfs_init);
#endif
static long no_blink(int state)
{
return 0;
}
/* Returns how long it waited in ms */
long (*panic_blink)(int state);
EXPORT_SYMBOL(panic_blink);
/*
* Stop ourself in panic -- architecture code may override this
*/
void __weak __noreturn panic_smp_self_stop(void)
{
while (1)
cpu_relax();
}
/*
* Stop ourselves in NMI context if another CPU has already panicked. Arch code
* may override this to prepare for crash dumping, e.g. save regs info.
*/
void __weak __noreturn nmi_panic_self_stop(struct pt_regs *regs)
{
panic_smp_self_stop();
}
/*
* Stop other CPUs in panic. Architecture dependent code may override this
* with more suitable version. For example, if the architecture supports
* crash dump, it should save registers of each stopped CPU and disable
* per-CPU features such as virtualization extensions.
*/
void __weak crash_smp_send_stop(void)
{
static int cpus_stopped;
/*
* This function can be called twice in panic path, but obviously
* we execute this only once.
*/
if (cpus_stopped)
return;
/*
* Note smp_send_stop is the usual smp shutdown function, which
* unfortunately means it may not be hardened to work in a panic
* situation.
*/
smp_send_stop();
cpus_stopped = 1;
}
atomic_t panic_cpu = ATOMIC_INIT(PANIC_CPU_INVALID);
/*
* A variant of panic() called from NMI context. We return if we've already
* panicked on this CPU. If another CPU already panicked, loop in
* nmi_panic_self_stop() which can provide architecture dependent code such
* as saving register state for crash dump.
*/
void nmi_panic(struct pt_regs *regs, const char *msg)
{
int old_cpu, cpu;
cpu = raw_smp_processor_id();
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu);
if (old_cpu == PANIC_CPU_INVALID)
panic("%s", msg);
else if (old_cpu != cpu)
nmi_panic_self_stop(regs);
}
EXPORT_SYMBOL(nmi_panic);
static void panic_print_sys_info(bool console_flush)
{
if (console_flush) {
if (panic_print & PANIC_PRINT_ALL_PRINTK_MSG)
console_flush_on_panic(CONSOLE_REPLAY_ALL);
return;
}
if (panic_print & PANIC_PRINT_TASK_INFO)
show_state();
if (panic_print & PANIC_PRINT_MEM_INFO)
show_mem();
if (panic_print & PANIC_PRINT_TIMER_INFO)
sysrq_timer_list_show();
if (panic_print & PANIC_PRINT_LOCK_INFO)
debug_show_all_locks();
if (panic_print & PANIC_PRINT_FTRACE_INFO)
ftrace_dump(DUMP_ALL);
}
void check_panic_on_warn(const char *origin)
{
unsigned int limit;
if (panic_on_warn)
panic("%s: panic_on_warn set ...\n", origin);
limit = READ_ONCE(warn_limit);
if (atomic_inc_return(&warn_count) >= limit && limit)
panic("%s: system warned too often (kernel.warn_limit is %d)",
origin, limit);
}
/*
* Helper that triggers the NMI backtrace (if set in panic_print)
* and then performs the secondary CPUs shutdown - we cannot have
* the NMI backtrace after the CPUs are off!
*/
static void panic_other_cpus_shutdown(bool crash_kexec)
{
if (panic_print & PANIC_PRINT_ALL_CPU_BT)
trigger_all_cpu_backtrace();
/*
* Note that smp_send_stop() is the usual SMP shutdown function,
* which unfortunately may not be hardened to work in a panic
* situation. If we want to do crash dump after notifier calls
* and kmsg_dump, we will need architecture dependent extra
* bits in addition to stopping other CPUs, hence we rely on
* crash_smp_send_stop() for that.
*/
if (!crash_kexec)
smp_send_stop();
else
crash_smp_send_stop();
}
/**
* panic - halt the system
* @fmt: The text string to print
*
* Display a message, then perform cleanups.
*
* This function never returns.
*/
void panic(const char *fmt, ...)
{
static char buf[1024];
va_list args;
long i, i_next = 0, len;
int state = 0;
int old_cpu, this_cpu;
bool _crash_kexec_post_notifiers = crash_kexec_post_notifiers;
if (panic_on_warn) {
/*
* This thread may hit another WARN() in the panic path.
* Resetting this prevents additional WARN() from panicking the
* system on this thread. Other threads are blocked by the
* panic_mutex in panic().
*/
panic_on_warn = 0;
}
/*
* Disable local interrupts. This will prevent panic_smp_self_stop
* from deadlocking the first cpu that invokes the panic, since
* there is nothing to prevent an interrupt handler (that runs
* after setting panic_cpu) from invoking panic() again.
*/
local_irq_disable();
preempt_disable_notrace();
/*
* It's possible to come here directly from a panic-assertion and
* not have preempt disabled. Some functions called from here want
* preempt to be disabled. No point enabling it later though...
*
* Only one CPU is allowed to execute the panic code from here. For
* multiple parallel invocations of panic, all other CPUs either
* stop themself or will wait until they are stopped by the 1st CPU
* with smp_send_stop().
*
* `old_cpu == PANIC_CPU_INVALID' means this is the 1st CPU which
* comes here, so go ahead.
* `old_cpu == this_cpu' means we came from nmi_panic() which sets
* panic_cpu to this CPU. In this case, this is also the 1st CPU.
*/
this_cpu = raw_smp_processor_id();
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
panic_smp_self_stop();
console_verbose();
bust_spinlocks(1);
va_start(args, fmt);
len = vscnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
if (len && buf[len - 1] == '\n')
buf[len - 1] = '\0';
pr_emerg("Kernel panic - not syncing: %s\n", buf);
#ifdef CONFIG_DEBUG_BUGVERBOSE
/*
* Avoid nested stack-dumping if a panic occurs during oops processing
*/
if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
dump_stack();
#endif
/*
* If kgdb is enabled, give it a chance to run before we stop all
* the other CPUs or else we won't be able to debug processes left
* running on them.
*/
kgdb_panic(buf);
/*
* If we have crashed and we have a crash kernel loaded let it handle
* everything else.
* If we want to run this after calling panic_notifiers, pass
* the "crash_kexec_post_notifiers" option to the kernel.
*
* Bypass the panic_cpu check and call __crash_kexec directly.
*/
if (!_crash_kexec_post_notifiers)
__crash_kexec(NULL);
panic_other_cpus_shutdown(_crash_kexec_post_notifiers);
/*
* Run any panic handlers, including those that might need to
* add information to the kmsg dump output.
*/
atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
panic_print_sys_info(false);
kmsg_dump(KMSG_DUMP_PANIC);
/*
* If you doubt kdump always works fine in any situation,
* "crash_kexec_post_notifiers" offers you a chance to run
* panic_notifiers and dumping kmsg before kdump.
* Note: since some panic_notifiers can make crashed kernel
* more unstable, it can increase risks of the kdump failure too.
*
* Bypass the panic_cpu check and call __crash_kexec directly.
*/
if (_crash_kexec_post_notifiers)
__crash_kexec(NULL);
console_unblank();
/*
* We may have ended up stopping the CPU holding the lock (in
* smp_send_stop()) while still having some valuable data in the console
* buffer. Try to acquire the lock then release it regardless of the
* result. The release will also print the buffers out. Locks debug
* should be disabled to avoid reporting bad unlock balance when
* panic() is not being callled from OOPS.
*/
debug_locks_off();
console_flush_on_panic(CONSOLE_FLUSH_PENDING);
panic_print_sys_info(true);
if (!panic_blink)
panic_blink = no_blink;
if (panic_timeout > 0) {
/*
* Delay timeout seconds before rebooting the machine.
* We can't use the "normal" timers since we just panicked.
*/
pr_emerg("Rebooting in %d seconds..\n", panic_timeout);
for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
touch_nmi_watchdog();
if (i >= i_next) {
i += panic_blink(state ^= 1);
i_next = i + 3600 / PANIC_BLINK_SPD;
}
mdelay(PANIC_TIMER_STEP);
}
}
if (panic_timeout != 0) {
/*
* This will not be a clean reboot, with everything
* shutting down. But if there is a chance of
* rebooting the system it will be rebooted.
*/
if (panic_reboot_mode != REBOOT_UNDEFINED)
reboot_mode = panic_reboot_mode;
emergency_restart();
}
#ifdef __sparc__
{
extern int stop_a_enabled;
/* Make sure the user can actually press Stop-A (L1-A) */
stop_a_enabled = 1;
pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
"twice on console to return to the boot prom\n");
}
#endif
#if defined(CONFIG_S390)
disabled_wait();
#endif
pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf);
/* Do not scroll important messages printed above */
suppress_printk = 1;
local_irq_enable();
for (i = 0; ; i += PANIC_TIMER_STEP) {
touch_softlockup_watchdog();
if (i >= i_next) {
i += panic_blink(state ^= 1);
i_next = i + 3600 / PANIC_BLINK_SPD;
}
mdelay(PANIC_TIMER_STEP);
}
}
EXPORT_SYMBOL(panic);
/*
* TAINT_FORCED_RMMOD could be a per-module flag but the module
* is being removed anyway.
*/
const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
[ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
[ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
[ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
[ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
[ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
[ TAINT_BAD_PAGE ] = { 'B', ' ', false },
[ TAINT_USER ] = { 'U', ' ', false },
[ TAINT_DIE ] = { 'D', ' ', false },
[ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
[ TAINT_WARN ] = { 'W', ' ', false },
[ TAINT_CRAP ] = { 'C', ' ', true },
[ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
[ TAINT_OOT_MODULE ] = { 'O', ' ', true },
[ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
[ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
[ TAINT_LIVEPATCH ] = { 'K', ' ', true },
[ TAINT_AUX ] = { 'X', ' ', true },
[ TAINT_RANDSTRUCT ] = { 'T', ' ', true },
[ TAINT_TEST ] = { 'N', ' ', true },
};
/**
* print_tainted - return a string to represent the kernel taint state.
*
* For individual taint flag meanings, see Documentation/admin-guide/sysctl/kernel.rst
*
* The string is overwritten by the next call to print_tainted(),
* but is always NULL terminated.
*/
const char *print_tainted(void)
{
static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
if (tainted_mask) {
char *s;
int i;
s = buf + sprintf(buf, "Tainted: ");
for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
const struct taint_flag *t = &taint_flags[i];
*s++ = test_bit(i, &tainted_mask) ?
t->c_true : t->c_false;
}
*s = 0;
} else
snprintf(buf, sizeof(buf), "Not tainted");
return buf;
}
int test_taint(unsigned flag)
{
return test_bit(flag, &tainted_mask);
}
EXPORT_SYMBOL(test_taint);
unsigned long get_taint(void)
{
return tainted_mask;
}
/**
* add_taint: add a taint flag if not already set.
* @flag: one of the TAINT_* constants.
* @lockdep_ok: whether lock debugging is still OK.
*
* If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
* some notewortht-but-not-corrupting cases, it can be set to true.
*/
void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
{
if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
pr_warn("Disabling lock debugging due to kernel taint\n");
set_bit(flag, &tainted_mask);
if (tainted_mask & panic_on_taint) {
panic_on_taint = 0;
panic("panic_on_taint set ...");
}
}
EXPORT_SYMBOL(add_taint);
static void spin_msec(int msecs)
{
int i;
for (i = 0; i < msecs; i++) {
touch_nmi_watchdog();
mdelay(1);
}
}
/*
* It just happens that oops_enter() and oops_exit() are identically
* implemented...
*/
static void do_oops_enter_exit(void)
{
unsigned long flags;
static int spin_counter;
if (!pause_on_oops)
return;
spin_lock_irqsave(&pause_on_oops_lock, flags);
if (pause_on_oops_flag == 0) {
/* This CPU may now print the oops message */
pause_on_oops_flag = 1;
} else {
/* We need to stall this CPU */
if (!spin_counter) {
/* This CPU gets to do the counting */
spin_counter = pause_on_oops;
do {
spin_unlock(&pause_on_oops_lock);
spin_msec(MSEC_PER_SEC);
spin_lock(&pause_on_oops_lock);
} while (--spin_counter);
pause_on_oops_flag = 0;
} else {
/* This CPU waits for a different one */
while (spin_counter) {
spin_unlock(&pause_on_oops_lock);
spin_msec(1);
spin_lock(&pause_on_oops_lock);
}
}
}
spin_unlock_irqrestore(&pause_on_oops_lock, flags);
}
/*
* Return true if the calling CPU is allowed to print oops-related info.
* This is a bit racy..
*/
bool oops_may_print(void)
{
return pause_on_oops_flag == 0;
}
/*
* Called when the architecture enters its oops handler, before it prints
* anything. If this is the first CPU to oops, and it's oopsing the first
* time then let it proceed.
*
* This is all enabled by the pause_on_oops kernel boot option. We do all
* this to ensure that oopses don't scroll off the screen. It has the
* side-effect of preventing later-oopsing CPUs from mucking up the display,
* too.
*
* It turns out that the CPU which is allowed to print ends up pausing for
* the right duration, whereas all the other CPUs pause for twice as long:
* once in oops_enter(), once in oops_exit().
*/
void oops_enter(void)
{
tracing_off();
/* can't trust the integrity of the kernel anymore: */
debug_locks_off();
do_oops_enter_exit();
if (sysctl_oops_all_cpu_backtrace)
trigger_all_cpu_backtrace();
}
static void print_oops_end_marker(void)
{
pr_warn("---[ end trace %016llx ]---\n", 0ULL);
}
/*
* Called when the architecture exits its oops handler, after printing
* everything.
*/
void oops_exit(void)
{
do_oops_enter_exit();
print_oops_end_marker();
kmsg_dump(KMSG_DUMP_OOPS);
}
struct warn_args {
const char *fmt;
va_list args;
};
void __warn(const char *file, int line, void *caller, unsigned taint,
struct pt_regs *regs, struct warn_args *args)
{
disable_trace_on_warning();
if (file)
pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
raw_smp_processor_id(), current->pid, file, line,
caller);
else
pr_warn("WARNING: CPU: %d PID: %d at %pS\n",
raw_smp_processor_id(), current->pid, caller);
if (args)
vprintk(args->fmt, args->args);
print_modules();
if (regs)
show_regs(regs);
check_panic_on_warn("kernel");
if (!regs)
dump_stack();
print_irqtrace_events(current);
print_oops_end_marker();
trace_error_report_end(ERROR_DETECTOR_WARN, (unsigned long)caller);
/* Just a warning, don't kill lockdep. */
add_taint(taint, LOCKDEP_STILL_OK);
}
#ifdef CONFIG_BUG
#ifndef __WARN_FLAGS
void warn_slowpath_fmt(const char *file, int line, unsigned taint,
const char *fmt, ...)
{
bool rcu = warn_rcu_enter();
struct warn_args args;
pr_warn(CUT_HERE);
if (!fmt) {
__warn(file, line, __builtin_return_address(0), taint,
NULL, NULL);
warn_rcu_exit(rcu);
return;
}
args.fmt = fmt;
va_start(args.args, fmt);
__warn(file, line, __builtin_return_address(0), taint, NULL, &args);
va_end(args.args);
warn_rcu_exit(rcu);
}
EXPORT_SYMBOL(warn_slowpath_fmt);
#else
void __warn_printk(const char *fmt, ...)
{
bool rcu = warn_rcu_enter();
va_list args;
pr_warn(CUT_HERE);
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
warn_rcu_exit(rcu);
}
EXPORT_SYMBOL(__warn_printk);
#endif
/* Support resetting WARN*_ONCE state */
static int clear_warn_once_set(void *data, u64 val)
{
generic_bug_clear_once();
memset(__start_once, 0, __end_once - __start_once);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set,
"%lld\n");
static __init int register_warn_debugfs(void)
{
/* Don't care about failure */
debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL,
&clear_warn_once_fops);
return 0;
}
device_initcall(register_warn_debugfs);
#endif
#ifdef CONFIG_STACKPROTECTOR
/*
* Called when gcc's -fstack-protector feature is used, and
* gcc detects corruption of the on-stack canary value
*/
__visible noinstr void __stack_chk_fail(void)
{
instrumentation_begin();
panic("stack-protector: Kernel stack is corrupted in: %pB",
__builtin_return_address(0));
instrumentation_end();
}
EXPORT_SYMBOL(__stack_chk_fail);
#endif
core_param(panic, panic_timeout, int, 0644);
core_param(panic_print, panic_print, ulong, 0644);
core_param(pause_on_oops, pause_on_oops, int, 0644);
core_param(panic_on_warn, panic_on_warn, int, 0644);
core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, 0644);
static int __init oops_setup(char *s)
{
if (!s)
return -EINVAL;
if (!strcmp(s, "panic"))
panic_on_oops = 1;
return 0;
}
early_param("oops", oops_setup);
static int __init panic_on_taint_setup(char *s)
{
char *taint_str;
if (!s)
return -EINVAL;
taint_str = strsep(&s, ",");
if (kstrtoul(taint_str, 16, &panic_on_taint))
return -EINVAL;
/* make sure panic_on_taint doesn't hold out-of-range TAINT flags */
panic_on_taint &= TAINT_FLAGS_MAX;
if (!panic_on_taint)
return -EINVAL;
if (s && !strcmp(s, "nousertaint"))
panic_on_taint_nousertaint = true;
pr_info("panic_on_taint: bitmask=0x%lx nousertaint_mode=%s\n",
panic_on_taint, str_enabled_disabled(panic_on_taint_nousertaint));
return 0;
}
early_param("panic_on_taint", panic_on_taint_setup);
| linux-master | kernel/panic.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Module signature checker
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#include <linux/errno.h>
#include <linux/printk.h>
#include <linux/module_signature.h>
#include <asm/byteorder.h>
/**
* mod_check_sig - check that the given signature is sane
*
* @ms: Signature to check.
* @file_len: Size of the file to which @ms is appended.
* @name: What is being checked. Used for error messages.
*/
int mod_check_sig(const struct module_signature *ms, size_t file_len,
const char *name)
{
if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms))
return -EBADMSG;
if (ms->id_type != PKEY_ID_PKCS7) {
pr_err("%s: not signed with expected PKCS#7 message\n",
name);
return -ENOPKG;
}
if (ms->algo != 0 ||
ms->hash != 0 ||
ms->signer_len != 0 ||
ms->key_id_len != 0 ||
ms->__pad[0] != 0 ||
ms->__pad[1] != 0 ||
ms->__pad[2] != 0) {
pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
name);
return -EBADMSG;
}
return 0;
}
| linux-master | kernel/module_signature.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kexec: kexec_file_load system call
*
* Copyright (C) 2014 Red Hat Inc.
* Authors:
* Vivek Goyal <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/kexec.h>
#include <linux/memblock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/ima.h>
#include <crypto/hash.h>
#include <crypto/sha2.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#include "kexec_internal.h"
#ifdef CONFIG_KEXEC_SIG
static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE);
void set_kexec_sig_enforced(void)
{
sig_enforce = true;
}
#endif
static int kexec_calculate_store_digests(struct kimage *image);
/* Maximum size in bytes for kernel/initrd files. */
#define KEXEC_FILE_SIZE_MAX min_t(s64, 4LL << 30, SSIZE_MAX)
/*
* Currently this is the only default function that is exported as some
* architectures need it to do additional handlings.
* In the future, other default functions may be exported too if required.
*/
int kexec_image_probe_default(struct kimage *image, void *buf,
unsigned long buf_len)
{
const struct kexec_file_ops * const *fops;
int ret = -ENOEXEC;
for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) {
ret = (*fops)->probe(buf, buf_len);
if (!ret) {
image->fops = *fops;
return ret;
}
}
return ret;
}
static void *kexec_image_load_default(struct kimage *image)
{
if (!image->fops || !image->fops->load)
return ERR_PTR(-ENOEXEC);
return image->fops->load(image, image->kernel_buf,
image->kernel_buf_len, image->initrd_buf,
image->initrd_buf_len, image->cmdline_buf,
image->cmdline_buf_len);
}
int kexec_image_post_load_cleanup_default(struct kimage *image)
{
if (!image->fops || !image->fops->cleanup)
return 0;
return image->fops->cleanup(image->image_loader_data);
}
/*
* Free up memory used by kernel, initrd, and command line. This is temporary
* memory allocation which is not needed any more after these buffers have
* been loaded into separate segments and have been copied elsewhere.
*/
void kimage_file_post_load_cleanup(struct kimage *image)
{
struct purgatory_info *pi = &image->purgatory_info;
vfree(image->kernel_buf);
image->kernel_buf = NULL;
vfree(image->initrd_buf);
image->initrd_buf = NULL;
kfree(image->cmdline_buf);
image->cmdline_buf = NULL;
vfree(pi->purgatory_buf);
pi->purgatory_buf = NULL;
vfree(pi->sechdrs);
pi->sechdrs = NULL;
#ifdef CONFIG_IMA_KEXEC
vfree(image->ima_buffer);
image->ima_buffer = NULL;
#endif /* CONFIG_IMA_KEXEC */
/* See if architecture has anything to cleanup post load */
arch_kimage_file_post_load_cleanup(image);
/*
* Above call should have called into bootloader to free up
* any data stored in kimage->image_loader_data. It should
* be ok now to free it up.
*/
kfree(image->image_loader_data);
image->image_loader_data = NULL;
}
#ifdef CONFIG_KEXEC_SIG
#ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len)
{
int ret;
ret = verify_pefile_signature(kernel, kernel_len,
VERIFY_USE_SECONDARY_KEYRING,
VERIFYING_KEXEC_PE_SIGNATURE);
if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
ret = verify_pefile_signature(kernel, kernel_len,
VERIFY_USE_PLATFORM_KEYRING,
VERIFYING_KEXEC_PE_SIGNATURE);
}
return ret;
}
#endif
static int kexec_image_verify_sig(struct kimage *image, void *buf,
unsigned long buf_len)
{
if (!image->fops || !image->fops->verify_sig) {
pr_debug("kernel loader does not support signature verification.\n");
return -EKEYREJECTED;
}
return image->fops->verify_sig(buf, buf_len);
}
static int
kimage_validate_signature(struct kimage *image)
{
int ret;
ret = kexec_image_verify_sig(image, image->kernel_buf,
image->kernel_buf_len);
if (ret) {
if (sig_enforce) {
pr_notice("Enforced kernel signature verification failed (%d).\n", ret);
return ret;
}
/*
* If IMA is guaranteed to appraise a signature on the kexec
* image, permit it even if the kernel is otherwise locked
* down.
*/
if (!ima_appraise_signature(READING_KEXEC_IMAGE) &&
security_locked_down(LOCKDOWN_KEXEC))
return -EPERM;
pr_debug("kernel signature verification failed (%d).\n", ret);
}
return 0;
}
#endif
/*
* In file mode list of segments is prepared by kernel. Copy relevant
* data from user space, do error checking, prepare segment list
*/
static int
kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
const char __user *cmdline_ptr,
unsigned long cmdline_len, unsigned flags)
{
ssize_t ret;
void *ldata;
ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
KEXEC_FILE_SIZE_MAX, NULL,
READING_KEXEC_IMAGE);
if (ret < 0)
return ret;
image->kernel_buf_len = ret;
/* Call arch image probe handlers */
ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
image->kernel_buf_len);
if (ret)
goto out;
#ifdef CONFIG_KEXEC_SIG
ret = kimage_validate_signature(image);
if (ret)
goto out;
#endif
/* It is possible that there no initramfs is being loaded */
if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
KEXEC_FILE_SIZE_MAX, NULL,
READING_KEXEC_INITRAMFS);
if (ret < 0)
goto out;
image->initrd_buf_len = ret;
ret = 0;
}
if (cmdline_len) {
image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len);
if (IS_ERR(image->cmdline_buf)) {
ret = PTR_ERR(image->cmdline_buf);
image->cmdline_buf = NULL;
goto out;
}
image->cmdline_buf_len = cmdline_len;
/* command line should be a string with last byte null */
if (image->cmdline_buf[cmdline_len - 1] != '\0') {
ret = -EINVAL;
goto out;
}
ima_kexec_cmdline(kernel_fd, image->cmdline_buf,
image->cmdline_buf_len - 1);
}
/* IMA needs to pass the measurement list to the next kernel. */
ima_add_kexec_buffer(image);
/* Call image load handler */
ldata = kexec_image_load_default(image);
if (IS_ERR(ldata)) {
ret = PTR_ERR(ldata);
goto out;
}
image->image_loader_data = ldata;
out:
/* In case of error, free up all allocated memory in this function */
if (ret)
kimage_file_post_load_cleanup(image);
return ret;
}
static int
kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
int initrd_fd, const char __user *cmdline_ptr,
unsigned long cmdline_len, unsigned long flags)
{
int ret;
struct kimage *image;
bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
image = do_kimage_alloc_init();
if (!image)
return -ENOMEM;
image->file_mode = 1;
if (kexec_on_panic) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
}
ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
cmdline_ptr, cmdline_len, flags);
if (ret)
goto out_free_image;
ret = sanity_check_segment_list(image);
if (ret)
goto out_free_post_load_bufs;
ret = -ENOMEM;
image->control_code_page = kimage_alloc_control_pages(image,
get_order(KEXEC_CONTROL_PAGE_SIZE));
if (!image->control_code_page) {
pr_err("Could not allocate control_code_buffer\n");
goto out_free_post_load_bufs;
}
if (!kexec_on_panic) {
image->swap_page = kimage_alloc_control_pages(image, 0);
if (!image->swap_page) {
pr_err("Could not allocate swap buffer\n");
goto out_free_control_pages;
}
}
*rimage = image;
return 0;
out_free_control_pages:
kimage_free_page_list(&image->control_pages);
out_free_post_load_bufs:
kimage_file_post_load_cleanup(image);
out_free_image:
kfree(image);
return ret;
}
SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
unsigned long, cmdline_len, const char __user *, cmdline_ptr,
unsigned long, flags)
{
int image_type = (flags & KEXEC_FILE_ON_CRASH) ?
KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT;
struct kimage **dest_image, *image;
int ret = 0, i;
/* We only trust the superuser with rebooting the system. */
if (!kexec_load_permitted(image_type))
return -EPERM;
/* Make sure we have a legal set of flags */
if (flags != (flags & KEXEC_FILE_FLAGS))
return -EINVAL;
image = NULL;
if (!kexec_trylock())
return -EBUSY;
if (image_type == KEXEC_TYPE_CRASH) {
dest_image = &kexec_crash_image;
if (kexec_crash_image)
arch_kexec_unprotect_crashkres();
} else {
dest_image = &kexec_image;
}
if (flags & KEXEC_FILE_UNLOAD)
goto exchange;
/*
* In case of crash, new kernel gets loaded in reserved region. It is
* same memory where old crash kernel might be loaded. Free any
* current crash dump kernel before we corrupt it.
*/
if (flags & KEXEC_FILE_ON_CRASH)
kimage_free(xchg(&kexec_crash_image, NULL));
ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
cmdline_len, flags);
if (ret)
goto out;
ret = machine_kexec_prepare(image);
if (ret)
goto out;
/*
* Some architecture(like S390) may touch the crash memory before
* machine_kexec_prepare(), we must copy vmcoreinfo data after it.
*/
ret = kimage_crash_copy_vmcoreinfo(image);
if (ret)
goto out;
ret = kexec_calculate_store_digests(image);
if (ret)
goto out;
for (i = 0; i < image->nr_segments; i++) {
struct kexec_segment *ksegment;
ksegment = &image->segment[i];
pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
i, ksegment->buf, ksegment->bufsz, ksegment->mem,
ksegment->memsz);
ret = kimage_load_segment(image, &image->segment[i]);
if (ret)
goto out;
}
kimage_terminate(image);
ret = machine_kexec_post_load(image);
if (ret)
goto out;
/*
* Free up any temporary buffers allocated which are not needed
* after image has been loaded
*/
kimage_file_post_load_cleanup(image);
exchange:
image = xchg(dest_image, image);
out:
if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
arch_kexec_protect_crashkres();
kexec_unlock();
kimage_free(image);
return ret;
}
static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
struct kexec_buf *kbuf)
{
struct kimage *image = kbuf->image;
unsigned long temp_start, temp_end;
temp_end = min(end, kbuf->buf_max);
temp_start = temp_end - kbuf->memsz;
do {
/* align down start */
temp_start = temp_start & (~(kbuf->buf_align - 1));
if (temp_start < start || temp_start < kbuf->buf_min)
return 0;
temp_end = temp_start + kbuf->memsz - 1;
/*
* Make sure this does not conflict with any of existing
* segments
*/
if (kimage_is_destination_range(image, temp_start, temp_end)) {
temp_start = temp_start - PAGE_SIZE;
continue;
}
/* We found a suitable memory range */
break;
} while (1);
/* If we are here, we found a suitable memory range */
kbuf->mem = temp_start;
/* Success, stop navigating through remaining System RAM ranges */
return 1;
}
static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
struct kexec_buf *kbuf)
{
struct kimage *image = kbuf->image;
unsigned long temp_start, temp_end;
temp_start = max(start, kbuf->buf_min);
do {
temp_start = ALIGN(temp_start, kbuf->buf_align);
temp_end = temp_start + kbuf->memsz - 1;
if (temp_end > end || temp_end > kbuf->buf_max)
return 0;
/*
* Make sure this does not conflict with any of existing
* segments
*/
if (kimage_is_destination_range(image, temp_start, temp_end)) {
temp_start = temp_start + PAGE_SIZE;
continue;
}
/* We found a suitable memory range */
break;
} while (1);
/* If we are here, we found a suitable memory range */
kbuf->mem = temp_start;
/* Success, stop navigating through remaining System RAM ranges */
return 1;
}
static int locate_mem_hole_callback(struct resource *res, void *arg)
{
struct kexec_buf *kbuf = (struct kexec_buf *)arg;
u64 start = res->start, end = res->end;
unsigned long sz = end - start + 1;
/* Returning 0 will take to next memory range */
/* Don't use memory that will be detected and handled by a driver. */
if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
return 0;
if (sz < kbuf->memsz)
return 0;
if (end < kbuf->buf_min || start > kbuf->buf_max)
return 0;
/*
* Allocate memory top down with-in ram range. Otherwise bottom up
* allocation.
*/
if (kbuf->top_down)
return locate_mem_hole_top_down(start, end, kbuf);
return locate_mem_hole_bottom_up(start, end, kbuf);
}
#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
static int kexec_walk_memblock(struct kexec_buf *kbuf,
int (*func)(struct resource *, void *))
{
int ret = 0;
u64 i;
phys_addr_t mstart, mend;
struct resource res = { };
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return func(&crashk_res, kbuf);
/*
* Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
* IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
* locate_mem_hole_callback().
*/
if (kbuf->top_down) {
for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&mstart, &mend, NULL) {
/*
* In memblock, end points to the first byte after the
* range while in kexec, end points to the last byte
* in the range.
*/
res.start = mstart;
res.end = mend - 1;
ret = func(&res, kbuf);
if (ret)
break;
}
} else {
for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&mstart, &mend, NULL) {
/*
* In memblock, end points to the first byte after the
* range while in kexec, end points to the last byte
* in the range.
*/
res.start = mstart;
res.end = mend - 1;
ret = func(&res, kbuf);
if (ret)
break;
}
}
return ret;
}
#else
static int kexec_walk_memblock(struct kexec_buf *kbuf,
int (*func)(struct resource *, void *))
{
return 0;
}
#endif
/**
* kexec_walk_resources - call func(data) on free memory regions
* @kbuf: Context info for the search. Also passed to @func.
* @func: Function to call for each memory region.
*
* Return: The memory walk will stop when func returns a non-zero value
* and that value will be returned. If all free regions are visited without
* func returning non-zero, then zero will be returned.
*/
static int kexec_walk_resources(struct kexec_buf *kbuf,
int (*func)(struct resource *, void *))
{
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return walk_iomem_res_desc(crashk_res.desc,
IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY,
crashk_res.start, crashk_res.end,
kbuf, func);
else
return walk_system_ram_res(0, ULONG_MAX, kbuf, func);
}
/**
* kexec_locate_mem_hole - find free memory for the purgatory or the next kernel
* @kbuf: Parameters for the memory search.
*
* On success, kbuf->mem will have the start address of the memory region found.
*
* Return: 0 on success, negative errno on error.
*/
int kexec_locate_mem_hole(struct kexec_buf *kbuf)
{
int ret;
/* Arch knows where to place */
if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN)
return 0;
if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
ret = kexec_walk_resources(kbuf, locate_mem_hole_callback);
else
ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
return ret == 1 ? 0 : -EADDRNOTAVAIL;
}
/**
* kexec_add_buffer - place a buffer in a kexec segment
* @kbuf: Buffer contents and memory parameters.
*
* This function assumes that kexec_lock is held.
* On successful return, @kbuf->mem will have the physical address of
* the buffer in memory.
*
* Return: 0 on success, negative errno on error.
*/
int kexec_add_buffer(struct kexec_buf *kbuf)
{
struct kexec_segment *ksegment;
int ret;
/* Currently adding segment this way is allowed only in file mode */
if (!kbuf->image->file_mode)
return -EINVAL;
if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX)
return -EINVAL;
/*
* Make sure we are not trying to add buffer after allocating
* control pages. All segments need to be placed first before
* any control pages are allocated. As control page allocation
* logic goes through list of segments to make sure there are
* no destination overlaps.
*/
if (!list_empty(&kbuf->image->control_pages)) {
WARN_ON(1);
return -EINVAL;
}
/* Ensure minimum alignment needed for segments. */
kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);
/* Walk the RAM ranges and allocate a suitable range for the buffer */
ret = arch_kexec_locate_mem_hole(kbuf);
if (ret)
return ret;
/* Found a suitable memory range */
ksegment = &kbuf->image->segment[kbuf->image->nr_segments];
ksegment->kbuf = kbuf->buffer;
ksegment->bufsz = kbuf->bufsz;
ksegment->mem = kbuf->mem;
ksegment->memsz = kbuf->memsz;
kbuf->image->nr_segments++;
return 0;
}
/* Calculate and store the digest of segments */
static int kexec_calculate_store_digests(struct kimage *image)
{
struct crypto_shash *tfm;
struct shash_desc *desc;
int ret = 0, i, j, zero_buf_sz, sha_region_sz;
size_t desc_size, nullsz;
char *digest;
void *zero_buf;
struct kexec_sha_region *sha_regions;
struct purgatory_info *pi = &image->purgatory_info;
if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY))
return 0;
zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
zero_buf_sz = PAGE_SIZE;
tfm = crypto_alloc_shash("sha256", 0, 0);
if (IS_ERR(tfm)) {
ret = PTR_ERR(tfm);
goto out;
}
desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
desc = kzalloc(desc_size, GFP_KERNEL);
if (!desc) {
ret = -ENOMEM;
goto out_free_tfm;
}
sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
sha_regions = vzalloc(sha_region_sz);
if (!sha_regions) {
ret = -ENOMEM;
goto out_free_desc;
}
desc->tfm = tfm;
ret = crypto_shash_init(desc);
if (ret < 0)
goto out_free_sha_regions;
digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
if (!digest) {
ret = -ENOMEM;
goto out_free_sha_regions;
}
for (j = i = 0; i < image->nr_segments; i++) {
struct kexec_segment *ksegment;
#ifdef CONFIG_CRASH_HOTPLUG
/* Exclude elfcorehdr segment to allow future changes via hotplug */
if (j == image->elfcorehdr_index)
continue;
#endif
ksegment = &image->segment[i];
/*
* Skip purgatory as it will be modified once we put digest
* info in purgatory.
*/
if (ksegment->kbuf == pi->purgatory_buf)
continue;
ret = crypto_shash_update(desc, ksegment->kbuf,
ksegment->bufsz);
if (ret)
break;
/*
* Assume rest of the buffer is filled with zero and
* update digest accordingly.
*/
nullsz = ksegment->memsz - ksegment->bufsz;
while (nullsz) {
unsigned long bytes = nullsz;
if (bytes > zero_buf_sz)
bytes = zero_buf_sz;
ret = crypto_shash_update(desc, zero_buf, bytes);
if (ret)
break;
nullsz -= bytes;
}
if (ret)
break;
sha_regions[j].start = ksegment->mem;
sha_regions[j].len = ksegment->memsz;
j++;
}
if (!ret) {
ret = crypto_shash_final(desc, digest);
if (ret)
goto out_free_digest;
ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions",
sha_regions, sha_region_sz, 0);
if (ret)
goto out_free_digest;
ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest",
digest, SHA256_DIGEST_SIZE, 0);
if (ret)
goto out_free_digest;
}
out_free_digest:
kfree(digest);
out_free_sha_regions:
vfree(sha_regions);
out_free_desc:
kfree(desc);
out_free_tfm:
kfree(tfm);
out:
return ret;
}
#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY
/*
* kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
* @pi: Purgatory to be loaded.
* @kbuf: Buffer to setup.
*
* Allocates the memory needed for the buffer. Caller is responsible to free
* the memory after use.
*
* Return: 0 on success, negative errno on error.
*/
static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
struct kexec_buf *kbuf)
{
const Elf_Shdr *sechdrs;
unsigned long bss_align;
unsigned long bss_sz;
unsigned long align;
int i, ret;
sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
kbuf->buf_align = bss_align = 1;
kbuf->bufsz = bss_sz = 0;
for (i = 0; i < pi->ehdr->e_shnum; i++) {
if (!(sechdrs[i].sh_flags & SHF_ALLOC))
continue;
align = sechdrs[i].sh_addralign;
if (sechdrs[i].sh_type != SHT_NOBITS) {
if (kbuf->buf_align < align)
kbuf->buf_align = align;
kbuf->bufsz = ALIGN(kbuf->bufsz, align);
kbuf->bufsz += sechdrs[i].sh_size;
} else {
if (bss_align < align)
bss_align = align;
bss_sz = ALIGN(bss_sz, align);
bss_sz += sechdrs[i].sh_size;
}
}
kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
kbuf->memsz = kbuf->bufsz + bss_sz;
if (kbuf->buf_align < bss_align)
kbuf->buf_align = bss_align;
kbuf->buffer = vzalloc(kbuf->bufsz);
if (!kbuf->buffer)
return -ENOMEM;
pi->purgatory_buf = kbuf->buffer;
ret = kexec_add_buffer(kbuf);
if (ret)
goto out;
return 0;
out:
vfree(pi->purgatory_buf);
pi->purgatory_buf = NULL;
return ret;
}
/*
* kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
* @pi: Purgatory to be loaded.
* @kbuf: Buffer prepared to store purgatory.
*
* Allocates the memory needed for the buffer. Caller is responsible to free
* the memory after use.
*
* Return: 0 on success, negative errno on error.
*/
static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
struct kexec_buf *kbuf)
{
unsigned long bss_addr;
unsigned long offset;
size_t sechdrs_size;
Elf_Shdr *sechdrs;
int i;
/*
* The section headers in kexec_purgatory are read-only. In order to
* have them modifiable make a temporary copy.
*/
sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum);
sechdrs = vzalloc(sechdrs_size);
if (!sechdrs)
return -ENOMEM;
memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size);
pi->sechdrs = sechdrs;
offset = 0;
bss_addr = kbuf->mem + kbuf->bufsz;
kbuf->image->start = pi->ehdr->e_entry;
for (i = 0; i < pi->ehdr->e_shnum; i++) {
unsigned long align;
void *src, *dst;
if (!(sechdrs[i].sh_flags & SHF_ALLOC))
continue;
align = sechdrs[i].sh_addralign;
if (sechdrs[i].sh_type == SHT_NOBITS) {
bss_addr = ALIGN(bss_addr, align);
sechdrs[i].sh_addr = bss_addr;
bss_addr += sechdrs[i].sh_size;
continue;
}
offset = ALIGN(offset, align);
/*
* Check if the segment contains the entry point, if so,
* calculate the value of image->start based on it.
* If the compiler has produced more than one .text section
* (Eg: .text.hot), they are generally after the main .text
* section, and they shall not be used to calculate
* image->start. So do not re-calculate image->start if it
* is not set to the initial value, and warn the user so they
* have a chance to fix their purgatory's linker script.
*/
if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
pi->ehdr->e_entry < (sechdrs[i].sh_addr
+ sechdrs[i].sh_size) &&
!WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) {
kbuf->image->start -= sechdrs[i].sh_addr;
kbuf->image->start += kbuf->mem + offset;
}
src = (void *)pi->ehdr + sechdrs[i].sh_offset;
dst = pi->purgatory_buf + offset;
memcpy(dst, src, sechdrs[i].sh_size);
sechdrs[i].sh_addr = kbuf->mem + offset;
sechdrs[i].sh_offset = offset;
offset += sechdrs[i].sh_size;
}
return 0;
}
static int kexec_apply_relocations(struct kimage *image)
{
int i, ret;
struct purgatory_info *pi = &image->purgatory_info;
const Elf_Shdr *sechdrs;
sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
for (i = 0; i < pi->ehdr->e_shnum; i++) {
const Elf_Shdr *relsec;
const Elf_Shdr *symtab;
Elf_Shdr *section;
relsec = sechdrs + i;
if (relsec->sh_type != SHT_RELA &&
relsec->sh_type != SHT_REL)
continue;
/*
* For section of type SHT_RELA/SHT_REL,
* ->sh_link contains section header index of associated
* symbol table. And ->sh_info contains section header
* index of section to which relocations apply.
*/
if (relsec->sh_info >= pi->ehdr->e_shnum ||
relsec->sh_link >= pi->ehdr->e_shnum)
return -ENOEXEC;
section = pi->sechdrs + relsec->sh_info;
symtab = sechdrs + relsec->sh_link;
if (!(section->sh_flags & SHF_ALLOC))
continue;
/*
* symtab->sh_link contain section header index of associated
* string table.
*/
if (symtab->sh_link >= pi->ehdr->e_shnum)
/* Invalid section number? */
continue;
/*
* Respective architecture needs to provide support for applying
* relocations of type SHT_RELA/SHT_REL.
*/
if (relsec->sh_type == SHT_RELA)
ret = arch_kexec_apply_relocations_add(pi, section,
relsec, symtab);
else if (relsec->sh_type == SHT_REL)
ret = arch_kexec_apply_relocations(pi, section,
relsec, symtab);
if (ret)
return ret;
}
return 0;
}
/*
* kexec_load_purgatory - Load and relocate the purgatory object.
* @image: Image to add the purgatory to.
* @kbuf: Memory parameters to use.
*
* Allocates the memory needed for image->purgatory_info.sechdrs and
* image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible
* to free the memory after use.
*
* Return: 0 on success, negative errno on error.
*/
int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf)
{
struct purgatory_info *pi = &image->purgatory_info;
int ret;
if (kexec_purgatory_size <= 0)
return -EINVAL;
pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
ret = kexec_purgatory_setup_kbuf(pi, kbuf);
if (ret)
return ret;
ret = kexec_purgatory_setup_sechdrs(pi, kbuf);
if (ret)
goto out_free_kbuf;
ret = kexec_apply_relocations(image);
if (ret)
goto out;
return 0;
out:
vfree(pi->sechdrs);
pi->sechdrs = NULL;
out_free_kbuf:
vfree(pi->purgatory_buf);
pi->purgatory_buf = NULL;
return ret;
}
/*
* kexec_purgatory_find_symbol - find a symbol in the purgatory
* @pi: Purgatory to search in.
* @name: Name of the symbol.
*
* Return: pointer to symbol in read-only symtab on success, NULL on error.
*/
static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
const char *name)
{
const Elf_Shdr *sechdrs;
const Elf_Ehdr *ehdr;
const Elf_Sym *syms;
const char *strtab;
int i, k;
if (!pi->ehdr)
return NULL;
ehdr = pi->ehdr;
sechdrs = (void *)ehdr + ehdr->e_shoff;
for (i = 0; i < ehdr->e_shnum; i++) {
if (sechdrs[i].sh_type != SHT_SYMTAB)
continue;
if (sechdrs[i].sh_link >= ehdr->e_shnum)
/* Invalid strtab section number */
continue;
strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;
syms = (void *)ehdr + sechdrs[i].sh_offset;
/* Go through symbols for a match */
for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
continue;
if (strcmp(strtab + syms[k].st_name, name) != 0)
continue;
if (syms[k].st_shndx == SHN_UNDEF ||
syms[k].st_shndx >= ehdr->e_shnum) {
pr_debug("Symbol: %s has bad section index %d.\n",
name, syms[k].st_shndx);
return NULL;
}
/* Found the symbol we are looking for */
return &syms[k];
}
}
return NULL;
}
void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
{
struct purgatory_info *pi = &image->purgatory_info;
const Elf_Sym *sym;
Elf_Shdr *sechdr;
sym = kexec_purgatory_find_symbol(pi, name);
if (!sym)
return ERR_PTR(-EINVAL);
sechdr = &pi->sechdrs[sym->st_shndx];
/*
* Returns the address where symbol will finally be loaded after
* kexec_load_segment()
*/
return (void *)(sechdr->sh_addr + sym->st_value);
}
/*
* Get or set value of a symbol. If "get_value" is true, symbol value is
* returned in buf otherwise symbol value is set based on value in buf.
*/
int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
void *buf, unsigned int size, bool get_value)
{
struct purgatory_info *pi = &image->purgatory_info;
const Elf_Sym *sym;
Elf_Shdr *sec;
char *sym_buf;
sym = kexec_purgatory_find_symbol(pi, name);
if (!sym)
return -EINVAL;
if (sym->st_size != size) {
pr_err("symbol %s size mismatch: expected %lu actual %u\n",
name, (unsigned long)sym->st_size, size);
return -EINVAL;
}
sec = pi->sechdrs + sym->st_shndx;
if (sec->sh_type == SHT_NOBITS) {
pr_err("symbol %s is in a bss section. Cannot %s\n", name,
get_value ? "get" : "set");
return -EINVAL;
}
sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value;
if (get_value)
memcpy((void *)buf, sym_buf, size);
else
memcpy((void *)sym_buf, buf, size);
return 0;
}
#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */
| linux-master | kernel/kexec_file.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Uniprocessor-only support functions. The counterpart to kernel/smp.c
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/smp.h>
#include <linux/hypervisor.h>
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int wait)
{
unsigned long flags;
if (cpu != 0)
return -ENXIO;
local_irq_save(flags);
func(info);
local_irq_restore(flags);
return 0;
}
EXPORT_SYMBOL(smp_call_function_single);
int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
{
unsigned long flags;
local_irq_save(flags);
csd->func(csd->info);
local_irq_restore(flags);
return 0;
}
EXPORT_SYMBOL(smp_call_function_single_async);
/*
* Preemption is disabled here to make sure the cond_func is called under the
* same conditions in UP and SMP.
*/
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask)
{
unsigned long flags;
preempt_disable();
if ((!cond_func || cond_func(0, info)) && cpumask_test_cpu(0, mask)) {
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
{
int ret;
if (cpu != 0)
return -ENXIO;
if (phys)
hypervisor_pin_vcpu(0);
ret = func(par);
if (phys)
hypervisor_pin_vcpu(-1);
return ret;
}
EXPORT_SYMBOL_GPL(smp_call_on_cpu);
| linux-master | kernel/up.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Test cases for API provided by resource.c and ioport.h
*/
#include <kunit/test.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/string.h>
#define R0_START 0x0000
#define R0_END 0xffff
#define R1_START 0x1234
#define R1_END 0x2345
#define R2_START 0x4567
#define R2_END 0x5678
#define R3_START 0x6789
#define R3_END 0x789a
#define R4_START 0x2000
#define R4_END 0x7000
static struct resource r0 = { .start = R0_START, .end = R0_END };
static struct resource r1 = { .start = R1_START, .end = R1_END };
static struct resource r2 = { .start = R2_START, .end = R2_END };
static struct resource r3 = { .start = R3_START, .end = R3_END };
static struct resource r4 = { .start = R4_START, .end = R4_END };
struct result {
struct resource *r1;
struct resource *r2;
struct resource r;
bool ret;
};
static struct result results_for_union[] = {
{
.r1 = &r1, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
}, {
.r1 = &r3, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
}, {
.r1 = &r4, .r2 = &r0, .r.start = R0_START, .r.end = R0_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r1, .ret = false,
}, {
.r1 = &r3, .r2 = &r1, .ret = false,
}, {
.r1 = &r4, .r2 = &r1, .r.start = R1_START, .r.end = R4_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r3, .ret = false,
}, {
.r1 = &r2, .r2 = &r4, .r.start = R4_START, .r.end = R4_END, .ret = true,
}, {
.r1 = &r3, .r2 = &r4, .r.start = R4_START, .r.end = R3_END, .ret = true,
},
};
static struct result results_for_intersection[] = {
{
.r1 = &r1, .r2 = &r0, .r.start = R1_START, .r.end = R1_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r0, .r.start = R2_START, .r.end = R2_END, .ret = true,
}, {
.r1 = &r3, .r2 = &r0, .r.start = R3_START, .r.end = R3_END, .ret = true,
}, {
.r1 = &r4, .r2 = &r0, .r.start = R4_START, .r.end = R4_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r1, .ret = false,
}, {
.r1 = &r3, .r2 = &r1, .ret = false,
}, {
.r1 = &r4, .r2 = &r1, .r.start = R4_START, .r.end = R1_END, .ret = true,
}, {
.r1 = &r2, .r2 = &r3, .ret = false,
}, {
.r1 = &r2, .r2 = &r4, .r.start = R2_START, .r.end = R2_END, .ret = true,
}, {
.r1 = &r3, .r2 = &r4, .r.start = R3_START, .r.end = R4_END, .ret = true,
},
};
static void resource_do_test(struct kunit *test, bool ret, struct resource *r,
bool exp_ret, struct resource *exp_r,
struct resource *r1, struct resource *r2)
{
KUNIT_EXPECT_EQ_MSG(test, ret, exp_ret, "Resources %pR %pR", r1, r2);
KUNIT_EXPECT_EQ_MSG(test, r->start, exp_r->start, "Start elements are not equal");
KUNIT_EXPECT_EQ_MSG(test, r->end, exp_r->end, "End elements are not equal");
}
static void resource_do_union_test(struct kunit *test, struct result *r)
{
struct resource result;
bool ret;
memset(&result, 0, sizeof(result));
ret = resource_union(r->r1, r->r2, &result);
resource_do_test(test, ret, &result, r->ret, &r->r, r->r1, r->r2);
memset(&result, 0, sizeof(result));
ret = resource_union(r->r2, r->r1, &result);
resource_do_test(test, ret, &result, r->ret, &r->r, r->r2, r->r1);
}
static void resource_test_union(struct kunit *test)
{
struct result *r = results_for_union;
unsigned int i = 0;
do {
resource_do_union_test(test, &r[i]);
} while (++i < ARRAY_SIZE(results_for_union));
}
static void resource_do_intersection_test(struct kunit *test, struct result *r)
{
struct resource result;
bool ret;
memset(&result, 0, sizeof(result));
ret = resource_intersection(r->r1, r->r2, &result);
resource_do_test(test, ret, &result, r->ret, &r->r, r->r1, r->r2);
memset(&result, 0, sizeof(result));
ret = resource_intersection(r->r2, r->r1, &result);
resource_do_test(test, ret, &result, r->ret, &r->r, r->r2, r->r1);
}
static void resource_test_intersection(struct kunit *test)
{
struct result *r = results_for_intersection;
unsigned int i = 0;
do {
resource_do_intersection_test(test, &r[i]);
} while (++i < ARRAY_SIZE(results_for_intersection));
}
static struct kunit_case resource_test_cases[] = {
KUNIT_CASE(resource_test_union),
KUNIT_CASE(resource_test_intersection),
{}
};
static struct kunit_suite resource_test_suite = {
.name = "resource",
.test_cases = resource_test_cases,
};
kunit_test_suite(resource_test_suite);
MODULE_LICENSE("GPL");
| linux-master | kernel/resource_kunit.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Supplementary group IDs
*/
#include <linux/cred.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/sort.h>
#include <linux/syscalls.h>
#include <linux/user_namespace.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
struct group_info *groups_alloc(int gidsetsize)
{
struct group_info *gi;
gi = kvmalloc(struct_size(gi, gid, gidsetsize), GFP_KERNEL_ACCOUNT);
if (!gi)
return NULL;
atomic_set(&gi->usage, 1);
gi->ngroups = gidsetsize;
return gi;
}
EXPORT_SYMBOL(groups_alloc);
void groups_free(struct group_info *group_info)
{
kvfree(group_info);
}
EXPORT_SYMBOL(groups_free);
/* export the group_info to a user-space array */
static int groups_to_user(gid_t __user *grouplist,
const struct group_info *group_info)
{
struct user_namespace *user_ns = current_user_ns();
int i;
unsigned int count = group_info->ngroups;
for (i = 0; i < count; i++) {
gid_t gid;
gid = from_kgid_munged(user_ns, group_info->gid[i]);
if (put_user(gid, grouplist+i))
return -EFAULT;
}
return 0;
}
/* fill a group_info from a user-space array - it must be allocated already */
static int groups_from_user(struct group_info *group_info,
gid_t __user *grouplist)
{
struct user_namespace *user_ns = current_user_ns();
int i;
unsigned int count = group_info->ngroups;
for (i = 0; i < count; i++) {
gid_t gid;
kgid_t kgid;
if (get_user(gid, grouplist+i))
return -EFAULT;
kgid = make_kgid(user_ns, gid);
if (!gid_valid(kgid))
return -EINVAL;
group_info->gid[i] = kgid;
}
return 0;
}
static int gid_cmp(const void *_a, const void *_b)
{
kgid_t a = *(kgid_t *)_a;
kgid_t b = *(kgid_t *)_b;
return gid_gt(a, b) - gid_lt(a, b);
}
void groups_sort(struct group_info *group_info)
{
sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid),
gid_cmp, NULL);
}
EXPORT_SYMBOL(groups_sort);
/* a simple bsearch */
int groups_search(const struct group_info *group_info, kgid_t grp)
{
unsigned int left, right;
if (!group_info)
return 0;
left = 0;
right = group_info->ngroups;
while (left < right) {
unsigned int mid = (left+right)/2;
if (gid_gt(grp, group_info->gid[mid]))
left = mid + 1;
else if (gid_lt(grp, group_info->gid[mid]))
right = mid;
else
return 1;
}
return 0;
}
/**
* set_groups - Change a group subscription in a set of credentials
* @new: The newly prepared set of credentials to alter
* @group_info: The group list to install
*/
void set_groups(struct cred *new, struct group_info *group_info)
{
put_group_info(new->group_info);
get_group_info(group_info);
new->group_info = group_info;
}
EXPORT_SYMBOL(set_groups);
/**
* set_current_groups - Change current's group subscription
* @group_info: The group list to impose
*
* Validate a group subscription and, if valid, impose it upon current's task
* security record.
*/
int set_current_groups(struct group_info *group_info)
{
struct cred *new;
const struct cred *old;
int retval;
new = prepare_creds();
if (!new)
return -ENOMEM;
old = current_cred();
set_groups(new, group_info);
retval = security_task_fix_setgroups(new, old);
if (retval < 0)
goto error;
return commit_creds(new);
error:
abort_creds(new);
return retval;
}
EXPORT_SYMBOL(set_current_groups);
SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
{
const struct cred *cred = current_cred();
int i;
if (gidsetsize < 0)
return -EINVAL;
/* no need to grab task_lock here; it cannot change */
i = cred->group_info->ngroups;
if (gidsetsize) {
if (i > gidsetsize) {
i = -EINVAL;
goto out;
}
if (groups_to_user(grouplist, cred->group_info)) {
i = -EFAULT;
goto out;
}
}
out:
return i;
}
bool may_setgroups(void)
{
struct user_namespace *user_ns = current_user_ns();
return ns_capable_setid(user_ns, CAP_SETGID) &&
userns_may_setgroups(user_ns);
}
/*
* SMP: Our groups are copy-on-write. We can set them safely
* without another task interfering.
*/
SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
{
struct group_info *group_info;
int retval;
if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
group_info = groups_alloc(gidsetsize);
if (!group_info)
return -ENOMEM;
retval = groups_from_user(group_info, grouplist);
if (retval) {
put_group_info(group_info);
return retval;
}
groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);
return retval;
}
/*
* Check whether we're fsgid/egid or in the supplemental group..
*/
int in_group_p(kgid_t grp)
{
const struct cred *cred = current_cred();
int retval = 1;
if (!gid_eq(grp, cred->fsgid))
retval = groups_search(cred->group_info, grp);
return retval;
}
EXPORT_SYMBOL(in_group_p);
int in_egroup_p(kgid_t grp)
{
const struct cred *cred = current_cred();
int retval = 1;
if (!gid_eq(grp, cred->egid))
retval = groups_search(cred->group_info, grp);
return retval;
}
EXPORT_SYMBOL(in_egroup_p);
| linux-master | kernel/groups.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* auditsc.c -- System-call auditing support
* Handles all system-call specific auditing features.
*
* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright (C) 2005, 2006 IBM Corporation
* All Rights Reserved.
*
* Written by Rickard E. (Rik) Faith <[email protected]>
*
* Many of the ideas implemented here are from Stephen C. Tweedie,
* especially the idea of avoiding a copy by using getname.
*
* The method for actual interception of syscall entry and exit (not in
* this file -- see entry.S) is based on a GPL'd patch written by
* [email protected] and Copyright 2003 SuSE Linux AG.
*
* POSIX message queue support added by George Wilson <[email protected]>,
* 2006.
*
* The support of additional filter rules compares (>, <, >=, <=) was
* added by Dustin Kirkland <[email protected]>, 2005.
*
* Modified by Amy Griffis <[email protected]> to collect additional
* filesystem information.
*
* Subject and object context labeling support added by <[email protected]>
* and <[email protected]> for LSPP certification compliance.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <asm/types.h>
#include <linux/atomic.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/socket.h>
#include <linux/mqueue.h>
#include <linux/audit.h>
#include <linux/personality.h>
#include <linux/time.h>
#include <linux/netlink.h>
#include <linux/compiler.h>
#include <asm/unistd.h>
#include <linux/security.h>
#include <linux/list.h>
#include <linux/binfmts.h>
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <asm/syscall.h>
#include <linux/capability.h>
#include <linux/fs_struct.h>
#include <linux/compat.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/fsnotify_backend.h>
#include <uapi/linux/limits.h>
#include <uapi/linux/netfilter/nf_tables.h>
#include <uapi/linux/openat2.h> // struct open_how
#include <uapi/linux/fanotify.h>
#include "audit.h"
/* flags stating the success for a syscall */
#define AUDITSC_INVALID 0
#define AUDITSC_SUCCESS 1
#define AUDITSC_FAILURE 2
/* no execve audit message should be longer than this (userspace limits),
* see the note near the top of audit_log_execve_info() about this value */
#define MAX_EXECVE_AUDIT_LEN 7500
/* max length to print of cmdline/proctitle value during audit */
#define MAX_PROCTITLE_AUDIT_LEN 128
/* number of audit rules */
int audit_n_rules;
/* determines whether we collect data for signals sent */
int audit_signals;
struct audit_aux_data {
struct audit_aux_data *next;
int type;
};
/* Number of target pids per aux struct. */
#define AUDIT_AUX_PIDS 16
struct audit_aux_data_pids {
struct audit_aux_data d;
pid_t target_pid[AUDIT_AUX_PIDS];
kuid_t target_auid[AUDIT_AUX_PIDS];
kuid_t target_uid[AUDIT_AUX_PIDS];
unsigned int target_sessionid[AUDIT_AUX_PIDS];
u32 target_sid[AUDIT_AUX_PIDS];
char target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
int pid_count;
};
struct audit_aux_data_bprm_fcaps {
struct audit_aux_data d;
struct audit_cap_data fcap;
unsigned int fcap_ver;
struct audit_cap_data old_pcap;
struct audit_cap_data new_pcap;
};
struct audit_tree_refs {
struct audit_tree_refs *next;
struct audit_chunk *c[31];
};
struct audit_nfcfgop_tab {
enum audit_nfcfgop op;
const char *s;
};
static const struct audit_nfcfgop_tab audit_nfcfgs[] = {
{ AUDIT_XT_OP_REGISTER, "xt_register" },
{ AUDIT_XT_OP_REPLACE, "xt_replace" },
{ AUDIT_XT_OP_UNREGISTER, "xt_unregister" },
{ AUDIT_NFT_OP_TABLE_REGISTER, "nft_register_table" },
{ AUDIT_NFT_OP_TABLE_UNREGISTER, "nft_unregister_table" },
{ AUDIT_NFT_OP_CHAIN_REGISTER, "nft_register_chain" },
{ AUDIT_NFT_OP_CHAIN_UNREGISTER, "nft_unregister_chain" },
{ AUDIT_NFT_OP_RULE_REGISTER, "nft_register_rule" },
{ AUDIT_NFT_OP_RULE_UNREGISTER, "nft_unregister_rule" },
{ AUDIT_NFT_OP_SET_REGISTER, "nft_register_set" },
{ AUDIT_NFT_OP_SET_UNREGISTER, "nft_unregister_set" },
{ AUDIT_NFT_OP_SETELEM_REGISTER, "nft_register_setelem" },
{ AUDIT_NFT_OP_SETELEM_UNREGISTER, "nft_unregister_setelem" },
{ AUDIT_NFT_OP_GEN_REGISTER, "nft_register_gen" },
{ AUDIT_NFT_OP_OBJ_REGISTER, "nft_register_obj" },
{ AUDIT_NFT_OP_OBJ_UNREGISTER, "nft_unregister_obj" },
{ AUDIT_NFT_OP_OBJ_RESET, "nft_reset_obj" },
{ AUDIT_NFT_OP_FLOWTABLE_REGISTER, "nft_register_flowtable" },
{ AUDIT_NFT_OP_FLOWTABLE_UNREGISTER, "nft_unregister_flowtable" },
{ AUDIT_NFT_OP_SETELEM_RESET, "nft_reset_setelem" },
{ AUDIT_NFT_OP_RULE_RESET, "nft_reset_rule" },
{ AUDIT_NFT_OP_INVALID, "nft_invalid" },
};
static int audit_match_perm(struct audit_context *ctx, int mask)
{
unsigned n;
if (unlikely(!ctx))
return 0;
n = ctx->major;
switch (audit_classify_syscall(ctx->arch, n)) {
case AUDITSC_NATIVE:
if ((mask & AUDIT_PERM_WRITE) &&
audit_match_class(AUDIT_CLASS_WRITE, n))
return 1;
if ((mask & AUDIT_PERM_READ) &&
audit_match_class(AUDIT_CLASS_READ, n))
return 1;
if ((mask & AUDIT_PERM_ATTR) &&
audit_match_class(AUDIT_CLASS_CHATTR, n))
return 1;
return 0;
case AUDITSC_COMPAT: /* 32bit on biarch */
if ((mask & AUDIT_PERM_WRITE) &&
audit_match_class(AUDIT_CLASS_WRITE_32, n))
return 1;
if ((mask & AUDIT_PERM_READ) &&
audit_match_class(AUDIT_CLASS_READ_32, n))
return 1;
if ((mask & AUDIT_PERM_ATTR) &&
audit_match_class(AUDIT_CLASS_CHATTR_32, n))
return 1;
return 0;
case AUDITSC_OPEN:
return mask & ACC_MODE(ctx->argv[1]);
case AUDITSC_OPENAT:
return mask & ACC_MODE(ctx->argv[2]);
case AUDITSC_SOCKETCALL:
return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND);
case AUDITSC_EXECVE:
return mask & AUDIT_PERM_EXEC;
case AUDITSC_OPENAT2:
return mask & ACC_MODE((u32)ctx->openat2.flags);
default:
return 0;
}
}
static int audit_match_filetype(struct audit_context *ctx, int val)
{
struct audit_names *n;
umode_t mode = (umode_t)val;
if (unlikely(!ctx))
return 0;
list_for_each_entry(n, &ctx->names_list, list) {
if ((n->ino != AUDIT_INO_UNSET) &&
((n->mode & S_IFMT) == mode))
return 1;
}
return 0;
}
/*
* We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
* ->first_trees points to its beginning, ->trees - to the current end of data.
* ->tree_count is the number of free entries in array pointed to by ->trees.
* Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
* "empty" becomes (p, p, 31) afterwards. We don't shrink the list (and seriously,
* it's going to remain 1-element for almost any setup) until we free context itself.
* References in it _are_ dropped - at the same time we free/drop aux stuff.
*/
static void audit_set_auditable(struct audit_context *ctx)
{
if (!ctx->prio) {
ctx->prio = 1;
ctx->current_state = AUDIT_STATE_RECORD;
}
}
static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
{
struct audit_tree_refs *p = ctx->trees;
int left = ctx->tree_count;
if (likely(left)) {
p->c[--left] = chunk;
ctx->tree_count = left;
return 1;
}
if (!p)
return 0;
p = p->next;
if (p) {
p->c[30] = chunk;
ctx->trees = p;
ctx->tree_count = 30;
return 1;
}
return 0;
}
static int grow_tree_refs(struct audit_context *ctx)
{
struct audit_tree_refs *p = ctx->trees;
ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
if (!ctx->trees) {
ctx->trees = p;
return 0;
}
if (p)
p->next = ctx->trees;
else
ctx->first_trees = ctx->trees;
ctx->tree_count = 31;
return 1;
}
static void unroll_tree_refs(struct audit_context *ctx,
struct audit_tree_refs *p, int count)
{
struct audit_tree_refs *q;
int n;
if (!p) {
/* we started with empty chain */
p = ctx->first_trees;
count = 31;
/* if the very first allocation has failed, nothing to do */
if (!p)
return;
}
n = count;
for (q = p; q != ctx->trees; q = q->next, n = 31) {
while (n--) {
audit_put_chunk(q->c[n]);
q->c[n] = NULL;
}
}
while (n-- > ctx->tree_count) {
audit_put_chunk(q->c[n]);
q->c[n] = NULL;
}
ctx->trees = p;
ctx->tree_count = count;
}
static void free_tree_refs(struct audit_context *ctx)
{
struct audit_tree_refs *p, *q;
for (p = ctx->first_trees; p; p = q) {
q = p->next;
kfree(p);
}
}
static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
{
struct audit_tree_refs *p;
int n;
if (!tree)
return 0;
/* full ones */
for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
for (n = 0; n < 31; n++)
if (audit_tree_match(p->c[n], tree))
return 1;
}
/* partial */
if (p) {
for (n = ctx->tree_count; n < 31; n++)
if (audit_tree_match(p->c[n], tree))
return 1;
}
return 0;
}
static int audit_compare_uid(kuid_t uid,
struct audit_names *name,
struct audit_field *f,
struct audit_context *ctx)
{
struct audit_names *n;
int rc;
if (name) {
rc = audit_uid_comparator(uid, f->op, name->uid);
if (rc)
return rc;
}
if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
rc = audit_uid_comparator(uid, f->op, n->uid);
if (rc)
return rc;
}
}
return 0;
}
static int audit_compare_gid(kgid_t gid,
struct audit_names *name,
struct audit_field *f,
struct audit_context *ctx)
{
struct audit_names *n;
int rc;
if (name) {
rc = audit_gid_comparator(gid, f->op, name->gid);
if (rc)
return rc;
}
if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
rc = audit_gid_comparator(gid, f->op, n->gid);
if (rc)
return rc;
}
}
return 0;
}
static int audit_field_compare(struct task_struct *tsk,
const struct cred *cred,
struct audit_field *f,
struct audit_context *ctx,
struct audit_names *name)
{
switch (f->val) {
/* process to file object comparisons */
case AUDIT_COMPARE_UID_TO_OBJ_UID:
return audit_compare_uid(cred->uid, name, f, ctx);
case AUDIT_COMPARE_GID_TO_OBJ_GID:
return audit_compare_gid(cred->gid, name, f, ctx);
case AUDIT_COMPARE_EUID_TO_OBJ_UID:
return audit_compare_uid(cred->euid, name, f, ctx);
case AUDIT_COMPARE_EGID_TO_OBJ_GID:
return audit_compare_gid(cred->egid, name, f, ctx);
case AUDIT_COMPARE_AUID_TO_OBJ_UID:
return audit_compare_uid(audit_get_loginuid(tsk), name, f, ctx);
case AUDIT_COMPARE_SUID_TO_OBJ_UID:
return audit_compare_uid(cred->suid, name, f, ctx);
case AUDIT_COMPARE_SGID_TO_OBJ_GID:
return audit_compare_gid(cred->sgid, name, f, ctx);
case AUDIT_COMPARE_FSUID_TO_OBJ_UID:
return audit_compare_uid(cred->fsuid, name, f, ctx);
case AUDIT_COMPARE_FSGID_TO_OBJ_GID:
return audit_compare_gid(cred->fsgid, name, f, ctx);
/* uid comparisons */
case AUDIT_COMPARE_UID_TO_AUID:
return audit_uid_comparator(cred->uid, f->op,
audit_get_loginuid(tsk));
case AUDIT_COMPARE_UID_TO_EUID:
return audit_uid_comparator(cred->uid, f->op, cred->euid);
case AUDIT_COMPARE_UID_TO_SUID:
return audit_uid_comparator(cred->uid, f->op, cred->suid);
case AUDIT_COMPARE_UID_TO_FSUID:
return audit_uid_comparator(cred->uid, f->op, cred->fsuid);
/* auid comparisons */
case AUDIT_COMPARE_AUID_TO_EUID:
return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
cred->euid);
case AUDIT_COMPARE_AUID_TO_SUID:
return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
cred->suid);
case AUDIT_COMPARE_AUID_TO_FSUID:
return audit_uid_comparator(audit_get_loginuid(tsk), f->op,
cred->fsuid);
/* euid comparisons */
case AUDIT_COMPARE_EUID_TO_SUID:
return audit_uid_comparator(cred->euid, f->op, cred->suid);
case AUDIT_COMPARE_EUID_TO_FSUID:
return audit_uid_comparator(cred->euid, f->op, cred->fsuid);
/* suid comparisons */
case AUDIT_COMPARE_SUID_TO_FSUID:
return audit_uid_comparator(cred->suid, f->op, cred->fsuid);
/* gid comparisons */
case AUDIT_COMPARE_GID_TO_EGID:
return audit_gid_comparator(cred->gid, f->op, cred->egid);
case AUDIT_COMPARE_GID_TO_SGID:
return audit_gid_comparator(cred->gid, f->op, cred->sgid);
case AUDIT_COMPARE_GID_TO_FSGID:
return audit_gid_comparator(cred->gid, f->op, cred->fsgid);
/* egid comparisons */
case AUDIT_COMPARE_EGID_TO_SGID:
return audit_gid_comparator(cred->egid, f->op, cred->sgid);
case AUDIT_COMPARE_EGID_TO_FSGID:
return audit_gid_comparator(cred->egid, f->op, cred->fsgid);
/* sgid comparison */
case AUDIT_COMPARE_SGID_TO_FSGID:
return audit_gid_comparator(cred->sgid, f->op, cred->fsgid);
default:
WARN(1, "Missing AUDIT_COMPARE define. Report as a bug\n");
return 0;
}
return 0;
}
/* Determine if any context name data matches a rule's watch data */
/* Compare a task_struct with an audit_rule. Return 1 on match, 0
* otherwise.
*
* If task_creation is true, this is an explicit indication that we are
* filtering a task rule at task creation time. This and tsk == current are
* the only situations where tsk->cred may be accessed without an rcu read lock.
*/
static int audit_filter_rules(struct task_struct *tsk,
struct audit_krule *rule,
struct audit_context *ctx,
struct audit_names *name,
enum audit_state *state,
bool task_creation)
{
const struct cred *cred;
int i, need_sid = 1;
u32 sid;
unsigned int sessionid;
if (ctx && rule->prio <= ctx->prio)
return 0;
cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
for (i = 0; i < rule->field_count; i++) {
struct audit_field *f = &rule->fields[i];
struct audit_names *n;
int result = 0;
pid_t pid;
switch (f->type) {
case AUDIT_PID:
pid = task_tgid_nr(tsk);
result = audit_comparator(pid, f->op, f->val);
break;
case AUDIT_PPID:
if (ctx) {
if (!ctx->ppid)
ctx->ppid = task_ppid_nr(tsk);
result = audit_comparator(ctx->ppid, f->op, f->val);
}
break;
case AUDIT_EXE:
result = audit_exe_compare(tsk, rule->exe);
if (f->op == Audit_not_equal)
result = !result;
break;
case AUDIT_UID:
result = audit_uid_comparator(cred->uid, f->op, f->uid);
break;
case AUDIT_EUID:
result = audit_uid_comparator(cred->euid, f->op, f->uid);
break;
case AUDIT_SUID:
result = audit_uid_comparator(cred->suid, f->op, f->uid);
break;
case AUDIT_FSUID:
result = audit_uid_comparator(cred->fsuid, f->op, f->uid);
break;
case AUDIT_GID:
result = audit_gid_comparator(cred->gid, f->op, f->gid);
if (f->op == Audit_equal) {
if (!result)
result = groups_search(cred->group_info, f->gid);
} else if (f->op == Audit_not_equal) {
if (result)
result = !groups_search(cred->group_info, f->gid);
}
break;
case AUDIT_EGID:
result = audit_gid_comparator(cred->egid, f->op, f->gid);
if (f->op == Audit_equal) {
if (!result)
result = groups_search(cred->group_info, f->gid);
} else if (f->op == Audit_not_equal) {
if (result)
result = !groups_search(cred->group_info, f->gid);
}
break;
case AUDIT_SGID:
result = audit_gid_comparator(cred->sgid, f->op, f->gid);
break;
case AUDIT_FSGID:
result = audit_gid_comparator(cred->fsgid, f->op, f->gid);
break;
case AUDIT_SESSIONID:
sessionid = audit_get_sessionid(tsk);
result = audit_comparator(sessionid, f->op, f->val);
break;
case AUDIT_PERS:
result = audit_comparator(tsk->personality, f->op, f->val);
break;
case AUDIT_ARCH:
if (ctx)
result = audit_comparator(ctx->arch, f->op, f->val);
break;
case AUDIT_EXIT:
if (ctx && ctx->return_valid != AUDITSC_INVALID)
result = audit_comparator(ctx->return_code, f->op, f->val);
break;
case AUDIT_SUCCESS:
if (ctx && ctx->return_valid != AUDITSC_INVALID) {
if (f->val)
result = audit_comparator(ctx->return_valid, f->op, AUDITSC_SUCCESS);
else
result = audit_comparator(ctx->return_valid, f->op, AUDITSC_FAILURE);
}
break;
case AUDIT_DEVMAJOR:
if (name) {
if (audit_comparator(MAJOR(name->dev), f->op, f->val) ||
audit_comparator(MAJOR(name->rdev), f->op, f->val))
++result;
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_comparator(MAJOR(n->dev), f->op, f->val) ||
audit_comparator(MAJOR(n->rdev), f->op, f->val)) {
++result;
break;
}
}
}
break;
case AUDIT_DEVMINOR:
if (name) {
if (audit_comparator(MINOR(name->dev), f->op, f->val) ||
audit_comparator(MINOR(name->rdev), f->op, f->val))
++result;
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_comparator(MINOR(n->dev), f->op, f->val) ||
audit_comparator(MINOR(n->rdev), f->op, f->val)) {
++result;
break;
}
}
}
break;
case AUDIT_INODE:
if (name)
result = audit_comparator(name->ino, f->op, f->val);
else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_comparator(n->ino, f->op, f->val)) {
++result;
break;
}
}
}
break;
case AUDIT_OBJ_UID:
if (name) {
result = audit_uid_comparator(name->uid, f->op, f->uid);
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_uid_comparator(n->uid, f->op, f->uid)) {
++result;
break;
}
}
}
break;
case AUDIT_OBJ_GID:
if (name) {
result = audit_gid_comparator(name->gid, f->op, f->gid);
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_gid_comparator(n->gid, f->op, f->gid)) {
++result;
break;
}
}
}
break;
case AUDIT_WATCH:
if (name) {
result = audit_watch_compare(rule->watch,
name->ino,
name->dev);
if (f->op == Audit_not_equal)
result = !result;
}
break;
case AUDIT_DIR:
if (ctx) {
result = match_tree_refs(ctx, rule->tree);
if (f->op == Audit_not_equal)
result = !result;
}
break;
case AUDIT_LOGINUID:
result = audit_uid_comparator(audit_get_loginuid(tsk),
f->op, f->uid);
break;
case AUDIT_LOGINUID_SET:
result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
break;
case AUDIT_SADDR_FAM:
if (ctx && ctx->sockaddr)
result = audit_comparator(ctx->sockaddr->ss_family,
f->op, f->val);
break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
/* NOTE: this may return negative values indicating
a temporary error. We simply treat this as a
match for now to avoid losing information that
may be wanted. An error message will also be
logged upon error */
if (f->lsm_rule) {
if (need_sid) {
/* @tsk should always be equal to
* @current with the exception of
* fork()/copy_process() in which case
* the new @tsk creds are still a dup
* of @current's creds so we can still
* use security_current_getsecid_subj()
* here even though it always refs
* @current's creds
*/
security_current_getsecid_subj(&sid);
need_sid = 0;
}
result = security_audit_rule_match(sid, f->type,
f->op,
f->lsm_rule);
}
break;
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
/* The above note for AUDIT_SUBJ_USER...AUDIT_SUBJ_CLR
also applies here */
if (f->lsm_rule) {
/* Find files that match */
if (name) {
result = security_audit_rule_match(
name->osid,
f->type,
f->op,
f->lsm_rule);
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
if (security_audit_rule_match(
n->osid,
f->type,
f->op,
f->lsm_rule)) {
++result;
break;
}
}
}
/* Find ipc objects that match */
if (!ctx || ctx->type != AUDIT_IPC)
break;
if (security_audit_rule_match(ctx->ipc.osid,
f->type, f->op,
f->lsm_rule))
++result;
}
break;
case AUDIT_ARG0:
case AUDIT_ARG1:
case AUDIT_ARG2:
case AUDIT_ARG3:
if (ctx)
result = audit_comparator(ctx->argv[f->type-AUDIT_ARG0], f->op, f->val);
break;
case AUDIT_FILTERKEY:
/* ignore this field for filtering */
result = 1;
break;
case AUDIT_PERM:
result = audit_match_perm(ctx, f->val);
if (f->op == Audit_not_equal)
result = !result;
break;
case AUDIT_FILETYPE:
result = audit_match_filetype(ctx, f->val);
if (f->op == Audit_not_equal)
result = !result;
break;
case AUDIT_FIELD_COMPARE:
result = audit_field_compare(tsk, cred, f, ctx, name);
break;
}
if (!result)
return 0;
}
if (ctx) {
if (rule->filterkey) {
kfree(ctx->filterkey);
ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
}
ctx->prio = rule->prio;
}
switch (rule->action) {
case AUDIT_NEVER:
*state = AUDIT_STATE_DISABLED;
break;
case AUDIT_ALWAYS:
*state = AUDIT_STATE_RECORD;
break;
}
return 1;
}
/* At process creation time, we can determine if system-call auditing is
* completely disabled for this task. Since we only have the task
* structure at this point, we can only check uid and gid.
*/
static enum audit_state audit_filter_task(struct task_struct *tsk, char **key)
{
struct audit_entry *e;
enum audit_state state;
rcu_read_lock();
list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) {
if (audit_filter_rules(tsk, &e->rule, NULL, NULL,
&state, true)) {
if (state == AUDIT_STATE_RECORD)
*key = kstrdup(e->rule.filterkey, GFP_ATOMIC);
rcu_read_unlock();
return state;
}
}
rcu_read_unlock();
return AUDIT_STATE_BUILD;
}
static int audit_in_mask(const struct audit_krule *rule, unsigned long val)
{
int word, bit;
if (val > 0xffffffff)
return false;
word = AUDIT_WORD(val);
if (word >= AUDIT_BITMASK_SIZE)
return false;
bit = AUDIT_BIT(val);
return rule->mask[word] & bit;
}
/**
* __audit_filter_op - common filter helper for operations (syscall/uring/etc)
* @tsk: associated task
* @ctx: audit context
* @list: audit filter list
* @name: audit_name (can be NULL)
* @op: current syscall/uring_op
*
* Run the udit filters specified in @list against @tsk using @ctx,
* @name, and @op, as necessary; the caller is responsible for ensuring
* that the call is made while the RCU read lock is held. The @name
* parameter can be NULL, but all others must be specified.
* Returns 1/true if the filter finds a match, 0/false if none are found.
*/
static int __audit_filter_op(struct task_struct *tsk,
struct audit_context *ctx,
struct list_head *list,
struct audit_names *name,
unsigned long op)
{
struct audit_entry *e;
enum audit_state state;
list_for_each_entry_rcu(e, list, list) {
if (audit_in_mask(&e->rule, op) &&
audit_filter_rules(tsk, &e->rule, ctx, name,
&state, false)) {
ctx->current_state = state;
return 1;
}
}
return 0;
}
/**
* audit_filter_uring - apply filters to an io_uring operation
* @tsk: associated task
* @ctx: audit context
*/
static void audit_filter_uring(struct task_struct *tsk,
struct audit_context *ctx)
{
if (auditd_test_task(tsk))
return;
rcu_read_lock();
__audit_filter_op(tsk, ctx, &audit_filter_list[AUDIT_FILTER_URING_EXIT],
NULL, ctx->uring_op);
rcu_read_unlock();
}
/* At syscall exit time, this filter is called if the audit_state is
* not low enough that auditing cannot take place, but is also not
* high enough that we already know we have to write an audit record
* (i.e., the state is AUDIT_STATE_BUILD).
*/
static void audit_filter_syscall(struct task_struct *tsk,
struct audit_context *ctx)
{
if (auditd_test_task(tsk))
return;
rcu_read_lock();
__audit_filter_op(tsk, ctx, &audit_filter_list[AUDIT_FILTER_EXIT],
NULL, ctx->major);
rcu_read_unlock();
}
/*
* Given an audit_name check the inode hash table to see if they match.
* Called holding the rcu read lock to protect the use of audit_inode_hash
*/
static int audit_filter_inode_name(struct task_struct *tsk,
struct audit_names *n,
struct audit_context *ctx)
{
int h = audit_hash_ino((u32)n->ino);
struct list_head *list = &audit_inode_hash[h];
return __audit_filter_op(tsk, ctx, list, n, ctx->major);
}
/* At syscall exit time, this filter is called if any audit_names have been
* collected during syscall processing. We only check rules in sublists at hash
* buckets applicable to the inode numbers in audit_names.
* Regarding audit_state, same rules apply as for audit_filter_syscall().
*/
void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx)
{
struct audit_names *n;
if (auditd_test_task(tsk))
return;
rcu_read_lock();
list_for_each_entry(n, &ctx->names_list, list) {
if (audit_filter_inode_name(tsk, n, ctx))
break;
}
rcu_read_unlock();
}
static inline void audit_proctitle_free(struct audit_context *context)
{
kfree(context->proctitle.value);
context->proctitle.value = NULL;
context->proctitle.len = 0;
}
static inline void audit_free_module(struct audit_context *context)
{
if (context->type == AUDIT_KERN_MODULE) {
kfree(context->module.name);
context->module.name = NULL;
}
}
static inline void audit_free_names(struct audit_context *context)
{
struct audit_names *n, *next;
list_for_each_entry_safe(n, next, &context->names_list, list) {
list_del(&n->list);
if (n->name)
putname(n->name);
if (n->should_free)
kfree(n);
}
context->name_count = 0;
path_put(&context->pwd);
context->pwd.dentry = NULL;
context->pwd.mnt = NULL;
}
static inline void audit_free_aux(struct audit_context *context)
{
struct audit_aux_data *aux;
while ((aux = context->aux)) {
context->aux = aux->next;
kfree(aux);
}
context->aux = NULL;
while ((aux = context->aux_pids)) {
context->aux_pids = aux->next;
kfree(aux);
}
context->aux_pids = NULL;
}
/**
* audit_reset_context - reset a audit_context structure
* @ctx: the audit_context to reset
*
* All fields in the audit_context will be reset to an initial state, all
* references held by fields will be dropped, and private memory will be
* released. When this function returns the audit_context will be suitable
* for reuse, so long as the passed context is not NULL or a dummy context.
*/
static void audit_reset_context(struct audit_context *ctx)
{
if (!ctx)
return;
/* if ctx is non-null, reset the "ctx->context" regardless */
ctx->context = AUDIT_CTX_UNUSED;
if (ctx->dummy)
return;
/*
* NOTE: It shouldn't matter in what order we release the fields, so
* release them in the order in which they appear in the struct;
* this gives us some hope of quickly making sure we are
* resetting the audit_context properly.
*
* Other things worth mentioning:
* - we don't reset "dummy"
* - we don't reset "state", we do reset "current_state"
* - we preserve "filterkey" if "state" is AUDIT_STATE_RECORD
* - much of this is likely overkill, but play it safe for now
* - we really need to work on improving the audit_context struct
*/
ctx->current_state = ctx->state;
ctx->serial = 0;
ctx->major = 0;
ctx->uring_op = 0;
ctx->ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 };
memset(ctx->argv, 0, sizeof(ctx->argv));
ctx->return_code = 0;
ctx->prio = (ctx->state == AUDIT_STATE_RECORD ? ~0ULL : 0);
ctx->return_valid = AUDITSC_INVALID;
audit_free_names(ctx);
if (ctx->state != AUDIT_STATE_RECORD) {
kfree(ctx->filterkey);
ctx->filterkey = NULL;
}
audit_free_aux(ctx);
kfree(ctx->sockaddr);
ctx->sockaddr = NULL;
ctx->sockaddr_len = 0;
ctx->ppid = 0;
ctx->uid = ctx->euid = ctx->suid = ctx->fsuid = KUIDT_INIT(0);
ctx->gid = ctx->egid = ctx->sgid = ctx->fsgid = KGIDT_INIT(0);
ctx->personality = 0;
ctx->arch = 0;
ctx->target_pid = 0;
ctx->target_auid = ctx->target_uid = KUIDT_INIT(0);
ctx->target_sessionid = 0;
ctx->target_sid = 0;
ctx->target_comm[0] = '\0';
unroll_tree_refs(ctx, NULL, 0);
WARN_ON(!list_empty(&ctx->killed_trees));
audit_free_module(ctx);
ctx->fds[0] = -1;
ctx->type = 0; /* reset last for audit_free_*() */
}
static inline struct audit_context *audit_alloc_context(enum audit_state state)
{
struct audit_context *context;
context = kzalloc(sizeof(*context), GFP_KERNEL);
if (!context)
return NULL;
context->context = AUDIT_CTX_UNUSED;
context->state = state;
context->prio = state == AUDIT_STATE_RECORD ? ~0ULL : 0;
INIT_LIST_HEAD(&context->killed_trees);
INIT_LIST_HEAD(&context->names_list);
context->fds[0] = -1;
context->return_valid = AUDITSC_INVALID;
return context;
}
/**
* audit_alloc - allocate an audit context block for a task
* @tsk: task
*
* Filter on the task information and allocate a per-task audit context
* if necessary. Doing so turns on system call auditing for the
* specified task. This is called from copy_process, so no lock is
* needed.
*/
int audit_alloc(struct task_struct *tsk)
{
struct audit_context *context;
enum audit_state state;
char *key = NULL;
if (likely(!audit_ever_enabled))
return 0;
state = audit_filter_task(tsk, &key);
if (state == AUDIT_STATE_DISABLED) {
clear_task_syscall_work(tsk, SYSCALL_AUDIT);
return 0;
}
context = audit_alloc_context(state);
if (!context) {
kfree(key);
audit_log_lost("out of memory in audit_alloc");
return -ENOMEM;
}
context->filterkey = key;
audit_set_context(tsk, context);
set_task_syscall_work(tsk, SYSCALL_AUDIT);
return 0;
}
static inline void audit_free_context(struct audit_context *context)
{
/* resetting is extra work, but it is likely just noise */
audit_reset_context(context);
audit_proctitle_free(context);
free_tree_refs(context);
kfree(context->filterkey);
kfree(context);
}
static int audit_log_pid_context(struct audit_context *context, pid_t pid,
kuid_t auid, kuid_t uid, unsigned int sessionid,
u32 sid, char *comm)
{
struct audit_buffer *ab;
char *ctx = NULL;
u32 len;
int rc = 0;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
if (!ab)
return rc;
audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
from_kuid(&init_user_ns, auid),
from_kuid(&init_user_ns, uid), sessionid);
if (sid) {
if (security_secid_to_secctx(sid, &ctx, &len)) {
audit_log_format(ab, " obj=(none)");
rc = 1;
} else {
audit_log_format(ab, " obj=%s", ctx);
security_release_secctx(ctx, len);
}
}
audit_log_format(ab, " ocomm=");
audit_log_untrustedstring(ab, comm);
audit_log_end(ab);
return rc;
}
static void audit_log_execve_info(struct audit_context *context,
struct audit_buffer **ab)
{
long len_max;
long len_rem;
long len_full;
long len_buf;
long len_abuf = 0;
long len_tmp;
bool require_data;
bool encode;
unsigned int iter;
unsigned int arg;
char *buf_head;
char *buf;
const char __user *p = (const char __user *)current->mm->arg_start;
/* NOTE: this buffer needs to be large enough to hold all the non-arg
* data we put in the audit record for this argument (see the
* code below) ... at this point in time 96 is plenty */
char abuf[96];
/* NOTE: we set MAX_EXECVE_AUDIT_LEN to a rather arbitrary limit, the
* current value of 7500 is not as important as the fact that it
* is less than 8k, a setting of 7500 gives us plenty of wiggle
* room if we go over a little bit in the logging below */
WARN_ON_ONCE(MAX_EXECVE_AUDIT_LEN > 7500);
len_max = MAX_EXECVE_AUDIT_LEN;
/* scratch buffer to hold the userspace args */
buf_head = kmalloc(MAX_EXECVE_AUDIT_LEN + 1, GFP_KERNEL);
if (!buf_head) {
audit_panic("out of memory for argv string");
return;
}
buf = buf_head;
audit_log_format(*ab, "argc=%d", context->execve.argc);
len_rem = len_max;
len_buf = 0;
len_full = 0;
require_data = true;
encode = false;
iter = 0;
arg = 0;
do {
/* NOTE: we don't ever want to trust this value for anything
* serious, but the audit record format insists we
* provide an argument length for really long arguments,
* e.g. > MAX_EXECVE_AUDIT_LEN, so we have no choice but
* to use strncpy_from_user() to obtain this value for
* recording in the log, although we don't use it
* anywhere here to avoid a double-fetch problem */
if (len_full == 0)
len_full = strnlen_user(p, MAX_ARG_STRLEN) - 1;
/* read more data from userspace */
if (require_data) {
/* can we make more room in the buffer? */
if (buf != buf_head) {
memmove(buf_head, buf, len_buf);
buf = buf_head;
}
/* fetch as much as we can of the argument */
len_tmp = strncpy_from_user(&buf_head[len_buf], p,
len_max - len_buf);
if (len_tmp == -EFAULT) {
/* unable to copy from userspace */
send_sig(SIGKILL, current, 0);
goto out;
} else if (len_tmp == (len_max - len_buf)) {
/* buffer is not large enough */
require_data = true;
/* NOTE: if we are going to span multiple
* buffers force the encoding so we stand
* a chance at a sane len_full value and
* consistent record encoding */
encode = true;
len_full = len_full * 2;
p += len_tmp;
} else {
require_data = false;
if (!encode)
encode = audit_string_contains_control(
buf, len_tmp);
/* try to use a trusted value for len_full */
if (len_full < len_max)
len_full = (encode ?
len_tmp * 2 : len_tmp);
p += len_tmp + 1;
}
len_buf += len_tmp;
buf_head[len_buf] = '\0';
/* length of the buffer in the audit record? */
len_abuf = (encode ? len_buf * 2 : len_buf + 2);
}
/* write as much as we can to the audit log */
if (len_buf >= 0) {
/* NOTE: some magic numbers here - basically if we
* can't fit a reasonable amount of data into the
* existing audit buffer, flush it and start with
* a new buffer */
if ((sizeof(abuf) + 8) > len_rem) {
len_rem = len_max;
audit_log_end(*ab);
*ab = audit_log_start(context,
GFP_KERNEL, AUDIT_EXECVE);
if (!*ab)
goto out;
}
/* create the non-arg portion of the arg record */
len_tmp = 0;
if (require_data || (iter > 0) ||
((len_abuf + sizeof(abuf)) > len_rem)) {
if (iter == 0) {
len_tmp += snprintf(&abuf[len_tmp],
sizeof(abuf) - len_tmp,
" a%d_len=%lu",
arg, len_full);
}
len_tmp += snprintf(&abuf[len_tmp],
sizeof(abuf) - len_tmp,
" a%d[%d]=", arg, iter++);
} else
len_tmp += snprintf(&abuf[len_tmp],
sizeof(abuf) - len_tmp,
" a%d=", arg);
WARN_ON(len_tmp >= sizeof(abuf));
abuf[sizeof(abuf) - 1] = '\0';
/* log the arg in the audit record */
audit_log_format(*ab, "%s", abuf);
len_rem -= len_tmp;
len_tmp = len_buf;
if (encode) {
if (len_abuf > len_rem)
len_tmp = len_rem / 2; /* encoding */
audit_log_n_hex(*ab, buf, len_tmp);
len_rem -= len_tmp * 2;
len_abuf -= len_tmp * 2;
} else {
if (len_abuf > len_rem)
len_tmp = len_rem - 2; /* quotes */
audit_log_n_string(*ab, buf, len_tmp);
len_rem -= len_tmp + 2;
/* don't subtract the "2" because we still need
* to add quotes to the remaining string */
len_abuf -= len_tmp;
}
len_buf -= len_tmp;
buf += len_tmp;
}
/* ready to move to the next argument? */
if ((len_buf == 0) && !require_data) {
arg++;
iter = 0;
len_full = 0;
require_data = true;
encode = false;
}
} while (arg < context->execve.argc);
/* NOTE: the caller handles the final audit_log_end() call */
out:
kfree(buf_head);
}
static void audit_log_cap(struct audit_buffer *ab, char *prefix,
kernel_cap_t *cap)
{
if (cap_isclear(*cap)) {
audit_log_format(ab, " %s=0", prefix);
return;
}
audit_log_format(ab, " %s=%016llx", prefix, cap->val);
}
static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
{
if (name->fcap_ver == -1) {
audit_log_format(ab, " cap_fe=? cap_fver=? cap_fp=? cap_fi=?");
return;
}
audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
audit_log_format(ab, " cap_fe=%d cap_fver=%x cap_frootid=%d",
name->fcap.fE, name->fcap_ver,
from_kuid(&init_user_ns, name->fcap.rootid));
}
static void audit_log_time(struct audit_context *context, struct audit_buffer **ab)
{
const struct audit_ntp_data *ntp = &context->time.ntp_data;
const struct timespec64 *tk = &context->time.tk_injoffset;
static const char * const ntp_name[] = {
"offset",
"freq",
"status",
"tai",
"tick",
"adjust",
};
int type;
if (context->type == AUDIT_TIME_ADJNTPVAL) {
for (type = 0; type < AUDIT_NTP_NVALS; type++) {
if (ntp->vals[type].newval != ntp->vals[type].oldval) {
if (!*ab) {
*ab = audit_log_start(context,
GFP_KERNEL,
AUDIT_TIME_ADJNTPVAL);
if (!*ab)
return;
}
audit_log_format(*ab, "op=%s old=%lli new=%lli",
ntp_name[type],
ntp->vals[type].oldval,
ntp->vals[type].newval);
audit_log_end(*ab);
*ab = NULL;
}
}
}
if (tk->tv_sec != 0 || tk->tv_nsec != 0) {
if (!*ab) {
*ab = audit_log_start(context, GFP_KERNEL,
AUDIT_TIME_INJOFFSET);
if (!*ab)
return;
}
audit_log_format(*ab, "sec=%lli nsec=%li",
(long long)tk->tv_sec, tk->tv_nsec);
audit_log_end(*ab);
*ab = NULL;
}
}
static void show_special(struct audit_context *context, int *call_panic)
{
struct audit_buffer *ab;
int i;
ab = audit_log_start(context, GFP_KERNEL, context->type);
if (!ab)
return;
switch (context->type) {
case AUDIT_SOCKETCALL: {
int nargs = context->socketcall.nargs;
audit_log_format(ab, "nargs=%d", nargs);
for (i = 0; i < nargs; i++)
audit_log_format(ab, " a%d=%lx", i,
context->socketcall.args[i]);
break; }
case AUDIT_IPC: {
u32 osid = context->ipc.osid;
audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
from_kuid(&init_user_ns, context->ipc.uid),
from_kgid(&init_user_ns, context->ipc.gid),
context->ipc.mode);
if (osid) {
char *ctx = NULL;
u32 len;
if (security_secid_to_secctx(osid, &ctx, &len)) {
audit_log_format(ab, " osid=%u", osid);
*call_panic = 1;
} else {
audit_log_format(ab, " obj=%s", ctx);
security_release_secctx(ctx, len);
}
}
if (context->ipc.has_perm) {
audit_log_end(ab);
ab = audit_log_start(context, GFP_KERNEL,
AUDIT_IPC_SET_PERM);
if (unlikely(!ab))
return;
audit_log_format(ab,
"qbytes=%lx ouid=%u ogid=%u mode=%#ho",
context->ipc.qbytes,
context->ipc.perm_uid,
context->ipc.perm_gid,
context->ipc.perm_mode);
}
break; }
case AUDIT_MQ_OPEN:
audit_log_format(ab,
"oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
"mq_msgsize=%ld mq_curmsgs=%ld",
context->mq_open.oflag, context->mq_open.mode,
context->mq_open.attr.mq_flags,
context->mq_open.attr.mq_maxmsg,
context->mq_open.attr.mq_msgsize,
context->mq_open.attr.mq_curmsgs);
break;
case AUDIT_MQ_SENDRECV:
audit_log_format(ab,
"mqdes=%d msg_len=%zd msg_prio=%u "
"abs_timeout_sec=%lld abs_timeout_nsec=%ld",
context->mq_sendrecv.mqdes,
context->mq_sendrecv.msg_len,
context->mq_sendrecv.msg_prio,
(long long) context->mq_sendrecv.abs_timeout.tv_sec,
context->mq_sendrecv.abs_timeout.tv_nsec);
break;
case AUDIT_MQ_NOTIFY:
audit_log_format(ab, "mqdes=%d sigev_signo=%d",
context->mq_notify.mqdes,
context->mq_notify.sigev_signo);
break;
case AUDIT_MQ_GETSETATTR: {
struct mq_attr *attr = &context->mq_getsetattr.mqstat;
audit_log_format(ab,
"mqdes=%d mq_flags=0x%lx mq_maxmsg=%ld mq_msgsize=%ld "
"mq_curmsgs=%ld ",
context->mq_getsetattr.mqdes,
attr->mq_flags, attr->mq_maxmsg,
attr->mq_msgsize, attr->mq_curmsgs);
break; }
case AUDIT_CAPSET:
audit_log_format(ab, "pid=%d", context->capset.pid);
audit_log_cap(ab, "cap_pi", &context->capset.cap.inheritable);
audit_log_cap(ab, "cap_pp", &context->capset.cap.permitted);
audit_log_cap(ab, "cap_pe", &context->capset.cap.effective);
audit_log_cap(ab, "cap_pa", &context->capset.cap.ambient);
break;
case AUDIT_MMAP:
audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
context->mmap.flags);
break;
case AUDIT_OPENAT2:
audit_log_format(ab, "oflag=0%llo mode=0%llo resolve=0x%llx",
context->openat2.flags,
context->openat2.mode,
context->openat2.resolve);
break;
case AUDIT_EXECVE:
audit_log_execve_info(context, &ab);
break;
case AUDIT_KERN_MODULE:
audit_log_format(ab, "name=");
if (context->module.name) {
audit_log_untrustedstring(ab, context->module.name);
} else
audit_log_format(ab, "(null)");
break;
case AUDIT_TIME_ADJNTPVAL:
case AUDIT_TIME_INJOFFSET:
/* this call deviates from the rest, eating the buffer */
audit_log_time(context, &ab);
break;
}
audit_log_end(ab);
}
static inline int audit_proctitle_rtrim(char *proctitle, int len)
{
char *end = proctitle + len - 1;
while (end > proctitle && !isprint(*end))
end--;
/* catch the case where proctitle is only 1 non-print character */
len = end - proctitle + 1;
len -= isprint(proctitle[len-1]) == 0;
return len;
}
/*
* audit_log_name - produce AUDIT_PATH record from struct audit_names
* @context: audit_context for the task
* @n: audit_names structure with reportable details
* @path: optional path to report instead of audit_names->name
* @record_num: record number to report when handling a list of names
* @call_panic: optional pointer to int that will be updated if secid fails
*/
static void audit_log_name(struct audit_context *context, struct audit_names *n,
const struct path *path, int record_num, int *call_panic)
{
struct audit_buffer *ab;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
if (!ab)
return;
audit_log_format(ab, "item=%d", record_num);
if (path)
audit_log_d_path(ab, " name=", path);
else if (n->name) {
switch (n->name_len) {
case AUDIT_NAME_FULL:
/* log the full path */
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab, n->name->name);
break;
case 0:
/* name was specified as a relative path and the
* directory component is the cwd
*/
if (context->pwd.dentry && context->pwd.mnt)
audit_log_d_path(ab, " name=", &context->pwd);
else
audit_log_format(ab, " name=(null)");
break;
default:
/* log the name's directory component */
audit_log_format(ab, " name=");
audit_log_n_untrustedstring(ab, n->name->name,
n->name_len);
}
} else
audit_log_format(ab, " name=(null)");
if (n->ino != AUDIT_INO_UNSET)
audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#ho ouid=%u ogid=%u rdev=%02x:%02x",
n->ino,
MAJOR(n->dev),
MINOR(n->dev),
n->mode,
from_kuid(&init_user_ns, n->uid),
from_kgid(&init_user_ns, n->gid),
MAJOR(n->rdev),
MINOR(n->rdev));
if (n->osid != 0) {
char *ctx = NULL;
u32 len;
if (security_secid_to_secctx(
n->osid, &ctx, &len)) {
audit_log_format(ab, " osid=%u", n->osid);
if (call_panic)
*call_panic = 2;
} else {
audit_log_format(ab, " obj=%s", ctx);
security_release_secctx(ctx, len);
}
}
/* log the audit_names record type */
switch (n->type) {
case AUDIT_TYPE_NORMAL:
audit_log_format(ab, " nametype=NORMAL");
break;
case AUDIT_TYPE_PARENT:
audit_log_format(ab, " nametype=PARENT");
break;
case AUDIT_TYPE_CHILD_DELETE:
audit_log_format(ab, " nametype=DELETE");
break;
case AUDIT_TYPE_CHILD_CREATE:
audit_log_format(ab, " nametype=CREATE");
break;
default:
audit_log_format(ab, " nametype=UNKNOWN");
break;
}
audit_log_fcaps(ab, n);
audit_log_end(ab);
}
static void audit_log_proctitle(void)
{
int res;
char *buf;
char *msg = "(null)";
int len = strlen(msg);
struct audit_context *context = audit_context();
struct audit_buffer *ab;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_PROCTITLE);
if (!ab)
return; /* audit_panic or being filtered */
audit_log_format(ab, "proctitle=");
/* Not cached */
if (!context->proctitle.value) {
buf = kmalloc(MAX_PROCTITLE_AUDIT_LEN, GFP_KERNEL);
if (!buf)
goto out;
/* Historically called this from procfs naming */
res = get_cmdline(current, buf, MAX_PROCTITLE_AUDIT_LEN);
if (res == 0) {
kfree(buf);
goto out;
}
res = audit_proctitle_rtrim(buf, res);
if (res == 0) {
kfree(buf);
goto out;
}
context->proctitle.value = buf;
context->proctitle.len = res;
}
msg = context->proctitle.value;
len = context->proctitle.len;
out:
audit_log_n_untrustedstring(ab, msg, len);
audit_log_end(ab);
}
/**
* audit_log_uring - generate a AUDIT_URINGOP record
* @ctx: the audit context
*/
static void audit_log_uring(struct audit_context *ctx)
{
struct audit_buffer *ab;
const struct cred *cred;
ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_URINGOP);
if (!ab)
return;
cred = current_cred();
audit_log_format(ab, "uring_op=%d", ctx->uring_op);
if (ctx->return_valid != AUDITSC_INVALID)
audit_log_format(ab, " success=%s exit=%ld",
(ctx->return_valid == AUDITSC_SUCCESS ?
"yes" : "no"),
ctx->return_code);
audit_log_format(ab,
" items=%d"
" ppid=%d pid=%d uid=%u gid=%u euid=%u suid=%u"
" fsuid=%u egid=%u sgid=%u fsgid=%u",
ctx->name_count,
task_ppid_nr(current), task_tgid_nr(current),
from_kuid(&init_user_ns, cred->uid),
from_kgid(&init_user_ns, cred->gid),
from_kuid(&init_user_ns, cred->euid),
from_kuid(&init_user_ns, cred->suid),
from_kuid(&init_user_ns, cred->fsuid),
from_kgid(&init_user_ns, cred->egid),
from_kgid(&init_user_ns, cred->sgid),
from_kgid(&init_user_ns, cred->fsgid));
audit_log_task_context(ab);
audit_log_key(ab, ctx->filterkey);
audit_log_end(ab);
}
static void audit_log_exit(void)
{
int i, call_panic = 0;
struct audit_context *context = audit_context();
struct audit_buffer *ab;
struct audit_aux_data *aux;
struct audit_names *n;
context->personality = current->personality;
switch (context->context) {
case AUDIT_CTX_SYSCALL:
ab = audit_log_start(context, GFP_KERNEL, AUDIT_SYSCALL);
if (!ab)
return;
audit_log_format(ab, "arch=%x syscall=%d",
context->arch, context->major);
if (context->personality != PER_LINUX)
audit_log_format(ab, " per=%lx", context->personality);
if (context->return_valid != AUDITSC_INVALID)
audit_log_format(ab, " success=%s exit=%ld",
(context->return_valid == AUDITSC_SUCCESS ?
"yes" : "no"),
context->return_code);
audit_log_format(ab,
" a0=%lx a1=%lx a2=%lx a3=%lx items=%d",
context->argv[0],
context->argv[1],
context->argv[2],
context->argv[3],
context->name_count);
audit_log_task_info(ab);
audit_log_key(ab, context->filterkey);
audit_log_end(ab);
break;
case AUDIT_CTX_URING:
audit_log_uring(context);
break;
default:
BUG();
break;
}
for (aux = context->aux; aux; aux = aux->next) {
ab = audit_log_start(context, GFP_KERNEL, aux->type);
if (!ab)
continue; /* audit_panic has been called */
switch (aux->type) {
case AUDIT_BPRM_FCAPS: {
struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
audit_log_format(ab, "fver=%x", axs->fcap_ver);
audit_log_cap(ab, "fp", &axs->fcap.permitted);
audit_log_cap(ab, "fi", &axs->fcap.inheritable);
audit_log_format(ab, " fe=%d", axs->fcap.fE);
audit_log_cap(ab, "old_pp", &axs->old_pcap.permitted);
audit_log_cap(ab, "old_pi", &axs->old_pcap.inheritable);
audit_log_cap(ab, "old_pe", &axs->old_pcap.effective);
audit_log_cap(ab, "old_pa", &axs->old_pcap.ambient);
audit_log_cap(ab, "pp", &axs->new_pcap.permitted);
audit_log_cap(ab, "pi", &axs->new_pcap.inheritable);
audit_log_cap(ab, "pe", &axs->new_pcap.effective);
audit_log_cap(ab, "pa", &axs->new_pcap.ambient);
audit_log_format(ab, " frootid=%d",
from_kuid(&init_user_ns,
axs->fcap.rootid));
break; }
}
audit_log_end(ab);
}
if (context->type)
show_special(context, &call_panic);
if (context->fds[0] >= 0) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_FD_PAIR);
if (ab) {
audit_log_format(ab, "fd0=%d fd1=%d",
context->fds[0], context->fds[1]);
audit_log_end(ab);
}
}
if (context->sockaddr_len) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_SOCKADDR);
if (ab) {
audit_log_format(ab, "saddr=");
audit_log_n_hex(ab, (void *)context->sockaddr,
context->sockaddr_len);
audit_log_end(ab);
}
}
for (aux = context->aux_pids; aux; aux = aux->next) {
struct audit_aux_data_pids *axs = (void *)aux;
for (i = 0; i < axs->pid_count; i++)
if (audit_log_pid_context(context, axs->target_pid[i],
axs->target_auid[i],
axs->target_uid[i],
axs->target_sessionid[i],
axs->target_sid[i],
axs->target_comm[i]))
call_panic = 1;
}
if (context->target_pid &&
audit_log_pid_context(context, context->target_pid,
context->target_auid, context->target_uid,
context->target_sessionid,
context->target_sid, context->target_comm))
call_panic = 1;
if (context->pwd.dentry && context->pwd.mnt) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
if (ab) {
audit_log_d_path(ab, "cwd=", &context->pwd);
audit_log_end(ab);
}
}
i = 0;
list_for_each_entry(n, &context->names_list, list) {
if (n->hidden)
continue;
audit_log_name(context, n, NULL, i++, &call_panic);
}
if (context->context == AUDIT_CTX_SYSCALL)
audit_log_proctitle();
/* Send end of event record to help user space know we are finished */
ab = audit_log_start(context, GFP_KERNEL, AUDIT_EOE);
if (ab)
audit_log_end(ab);
if (call_panic)
audit_panic("error in audit_log_exit()");
}
/**
* __audit_free - free a per-task audit context
* @tsk: task whose audit context block to free
*
* Called from copy_process, do_exit, and the io_uring code
*/
void __audit_free(struct task_struct *tsk)
{
struct audit_context *context = tsk->audit_context;
if (!context)
return;
/* this may generate CONFIG_CHANGE records */
if (!list_empty(&context->killed_trees))
audit_kill_trees(context);
/* We are called either by do_exit() or the fork() error handling code;
* in the former case tsk == current and in the latter tsk is a
* random task_struct that doesn't have any meaningful data we
* need to log via audit_log_exit().
*/
if (tsk == current && !context->dummy) {
context->return_valid = AUDITSC_INVALID;
context->return_code = 0;
if (context->context == AUDIT_CTX_SYSCALL) {
audit_filter_syscall(tsk, context);
audit_filter_inodes(tsk, context);
if (context->current_state == AUDIT_STATE_RECORD)
audit_log_exit();
} else if (context->context == AUDIT_CTX_URING) {
/* TODO: verify this case is real and valid */
audit_filter_uring(tsk, context);
audit_filter_inodes(tsk, context);
if (context->current_state == AUDIT_STATE_RECORD)
audit_log_uring(context);
}
}
audit_set_context(tsk, NULL);
audit_free_context(context);
}
/**
* audit_return_fixup - fixup the return codes in the audit_context
* @ctx: the audit_context
* @success: true/false value to indicate if the operation succeeded or not
* @code: operation return code
*
* We need to fixup the return code in the audit logs if the actual return
* codes are later going to be fixed by the arch specific signal handlers.
*/
static void audit_return_fixup(struct audit_context *ctx,
int success, long code)
{
/*
* This is actually a test for:
* (rc == ERESTARTSYS ) || (rc == ERESTARTNOINTR) ||
* (rc == ERESTARTNOHAND) || (rc == ERESTART_RESTARTBLOCK)
*
* but is faster than a bunch of ||
*/
if (unlikely(code <= -ERESTARTSYS) &&
(code >= -ERESTART_RESTARTBLOCK) &&
(code != -ENOIOCTLCMD))
ctx->return_code = -EINTR;
else
ctx->return_code = code;
ctx->return_valid = (success ? AUDITSC_SUCCESS : AUDITSC_FAILURE);
}
/**
* __audit_uring_entry - prepare the kernel task's audit context for io_uring
* @op: the io_uring opcode
*
* This is similar to audit_syscall_entry() but is intended for use by io_uring
* operations. This function should only ever be called from
* audit_uring_entry() as we rely on the audit context checking present in that
* function.
*/
void __audit_uring_entry(u8 op)
{
struct audit_context *ctx = audit_context();
if (ctx->state == AUDIT_STATE_DISABLED)
return;
/*
* NOTE: It's possible that we can be called from the process' context
* before it returns to userspace, and before audit_syscall_exit()
* is called. In this case there is not much to do, just record
* the io_uring details and return.
*/
ctx->uring_op = op;
if (ctx->context == AUDIT_CTX_SYSCALL)
return;
ctx->dummy = !audit_n_rules;
if (!ctx->dummy && ctx->state == AUDIT_STATE_BUILD)
ctx->prio = 0;
ctx->context = AUDIT_CTX_URING;
ctx->current_state = ctx->state;
ktime_get_coarse_real_ts64(&ctx->ctime);
}
/**
* __audit_uring_exit - wrap up the kernel task's audit context after io_uring
* @success: true/false value to indicate if the operation succeeded or not
* @code: operation return code
*
* This is similar to audit_syscall_exit() but is intended for use by io_uring
* operations. This function should only ever be called from
* audit_uring_exit() as we rely on the audit context checking present in that
* function.
*/
void __audit_uring_exit(int success, long code)
{
struct audit_context *ctx = audit_context();
if (ctx->dummy) {
if (ctx->context != AUDIT_CTX_URING)
return;
goto out;
}
audit_return_fixup(ctx, success, code);
if (ctx->context == AUDIT_CTX_SYSCALL) {
/*
* NOTE: See the note in __audit_uring_entry() about the case
* where we may be called from process context before we
* return to userspace via audit_syscall_exit(). In this
* case we simply emit a URINGOP record and bail, the
* normal syscall exit handling will take care of
* everything else.
* It is also worth mentioning that when we are called,
* the current process creds may differ from the creds
* used during the normal syscall processing; keep that
* in mind if/when we move the record generation code.
*/
/*
* We need to filter on the syscall info here to decide if we
* should emit a URINGOP record. I know it seems odd but this
* solves the problem where users have a filter to block *all*
* syscall records in the "exit" filter; we want to preserve
* the behavior here.
*/
audit_filter_syscall(current, ctx);
if (ctx->current_state != AUDIT_STATE_RECORD)
audit_filter_uring(current, ctx);
audit_filter_inodes(current, ctx);
if (ctx->current_state != AUDIT_STATE_RECORD)
return;
audit_log_uring(ctx);
return;
}
/* this may generate CONFIG_CHANGE records */
if (!list_empty(&ctx->killed_trees))
audit_kill_trees(ctx);
/* run through both filters to ensure we set the filterkey properly */
audit_filter_uring(current, ctx);
audit_filter_inodes(current, ctx);
if (ctx->current_state != AUDIT_STATE_RECORD)
goto out;
audit_log_exit();
out:
audit_reset_context(ctx);
}
/**
* __audit_syscall_entry - fill in an audit record at syscall entry
* @major: major syscall type (function)
* @a1: additional syscall register 1
* @a2: additional syscall register 2
* @a3: additional syscall register 3
* @a4: additional syscall register 4
*
* Fill in audit context at syscall entry. This only happens if the
* audit context was created when the task was created and the state or
* filters demand the audit context be built. If the state from the
* per-task filter or from the per-syscall filter is AUDIT_STATE_RECORD,
* then the record will be written at syscall exit time (otherwise, it
* will only be written if another part of the kernel requests that it
* be written).
*/
void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
unsigned long a3, unsigned long a4)
{
struct audit_context *context = audit_context();
enum audit_state state;
if (!audit_enabled || !context)
return;
WARN_ON(context->context != AUDIT_CTX_UNUSED);
WARN_ON(context->name_count);
if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
audit_panic("unrecoverable error in audit_syscall_entry()");
return;
}
state = context->state;
if (state == AUDIT_STATE_DISABLED)
return;
context->dummy = !audit_n_rules;
if (!context->dummy && state == AUDIT_STATE_BUILD) {
context->prio = 0;
if (auditd_test_task(current))
return;
}
context->arch = syscall_get_arch(current);
context->major = major;
context->argv[0] = a1;
context->argv[1] = a2;
context->argv[2] = a3;
context->argv[3] = a4;
context->context = AUDIT_CTX_SYSCALL;
context->current_state = state;
ktime_get_coarse_real_ts64(&context->ctime);
}
/**
* __audit_syscall_exit - deallocate audit context after a system call
* @success: success value of the syscall
* @return_code: return value of the syscall
*
* Tear down after system call. If the audit context has been marked as
* auditable (either because of the AUDIT_STATE_RECORD state from
* filtering, or because some other part of the kernel wrote an audit
* message), then write out the syscall information. In call cases,
* free the names stored from getname().
*/
void __audit_syscall_exit(int success, long return_code)
{
struct audit_context *context = audit_context();
if (!context || context->dummy ||
context->context != AUDIT_CTX_SYSCALL)
goto out;
/* this may generate CONFIG_CHANGE records */
if (!list_empty(&context->killed_trees))
audit_kill_trees(context);
audit_return_fixup(context, success, return_code);
/* run through both filters to ensure we set the filterkey properly */
audit_filter_syscall(current, context);
audit_filter_inodes(current, context);
if (context->current_state != AUDIT_STATE_RECORD)
goto out;
audit_log_exit();
out:
audit_reset_context(context);
}
static inline void handle_one(const struct inode *inode)
{
struct audit_context *context;
struct audit_tree_refs *p;
struct audit_chunk *chunk;
int count;
if (likely(!inode->i_fsnotify_marks))
return;
context = audit_context();
p = context->trees;
count = context->tree_count;
rcu_read_lock();
chunk = audit_tree_lookup(inode);
rcu_read_unlock();
if (!chunk)
return;
if (likely(put_tree_ref(context, chunk)))
return;
if (unlikely(!grow_tree_refs(context))) {
pr_warn("out of memory, audit has lost a tree reference\n");
audit_set_auditable(context);
audit_put_chunk(chunk);
unroll_tree_refs(context, p, count);
return;
}
put_tree_ref(context, chunk);
}
static void handle_path(const struct dentry *dentry)
{
struct audit_context *context;
struct audit_tree_refs *p;
const struct dentry *d, *parent;
struct audit_chunk *drop;
unsigned long seq;
int count;
context = audit_context();
p = context->trees;
count = context->tree_count;
retry:
drop = NULL;
d = dentry;
rcu_read_lock();
seq = read_seqbegin(&rename_lock);
for (;;) {
struct inode *inode = d_backing_inode(d);
if (inode && unlikely(inode->i_fsnotify_marks)) {
struct audit_chunk *chunk;
chunk = audit_tree_lookup(inode);
if (chunk) {
if (unlikely(!put_tree_ref(context, chunk))) {
drop = chunk;
break;
}
}
}
parent = d->d_parent;
if (parent == d)
break;
d = parent;
}
if (unlikely(read_seqretry(&rename_lock, seq) || drop)) { /* in this order */
rcu_read_unlock();
if (!drop) {
/* just a race with rename */
unroll_tree_refs(context, p, count);
goto retry;
}
audit_put_chunk(drop);
if (grow_tree_refs(context)) {
/* OK, got more space */
unroll_tree_refs(context, p, count);
goto retry;
}
/* too bad */
pr_warn("out of memory, audit has lost a tree reference\n");
unroll_tree_refs(context, p, count);
audit_set_auditable(context);
return;
}
rcu_read_unlock();
}
static struct audit_names *audit_alloc_name(struct audit_context *context,
unsigned char type)
{
struct audit_names *aname;
if (context->name_count < AUDIT_NAMES) {
aname = &context->preallocated_names[context->name_count];
memset(aname, 0, sizeof(*aname));
} else {
aname = kzalloc(sizeof(*aname), GFP_NOFS);
if (!aname)
return NULL;
aname->should_free = true;
}
aname->ino = AUDIT_INO_UNSET;
aname->type = type;
list_add_tail(&aname->list, &context->names_list);
context->name_count++;
if (!context->pwd.dentry)
get_fs_pwd(current->fs, &context->pwd);
return aname;
}
/**
* __audit_reusename - fill out filename with info from existing entry
* @uptr: userland ptr to pathname
*
* Search the audit_names list for the current audit context. If there is an
* existing entry with a matching "uptr" then return the filename
* associated with that audit_name. If not, return NULL.
*/
struct filename *
__audit_reusename(const __user char *uptr)
{
struct audit_context *context = audit_context();
struct audit_names *n;
list_for_each_entry(n, &context->names_list, list) {
if (!n->name)
continue;
if (n->name->uptr == uptr) {
n->name->refcnt++;
return n->name;
}
}
return NULL;
}
/**
* __audit_getname - add a name to the list
* @name: name to add
*
* Add a name to the list of audit names for this context.
* Called from fs/namei.c:getname().
*/
void __audit_getname(struct filename *name)
{
struct audit_context *context = audit_context();
struct audit_names *n;
if (context->context == AUDIT_CTX_UNUSED)
return;
n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
if (!n)
return;
n->name = name;
n->name_len = AUDIT_NAME_FULL;
name->aname = n;
name->refcnt++;
}
static inline int audit_copy_fcaps(struct audit_names *name,
const struct dentry *dentry)
{
struct cpu_vfs_cap_data caps;
int rc;
if (!dentry)
return 0;
rc = get_vfs_caps_from_disk(&nop_mnt_idmap, dentry, &caps);
if (rc)
return rc;
name->fcap.permitted = caps.permitted;
name->fcap.inheritable = caps.inheritable;
name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
name->fcap.rootid = caps.rootid;
name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
VFS_CAP_REVISION_SHIFT;
return 0;
}
/* Copy inode data into an audit_names. */
static void audit_copy_inode(struct audit_names *name,
const struct dentry *dentry,
struct inode *inode, unsigned int flags)
{
name->ino = inode->i_ino;
name->dev = inode->i_sb->s_dev;
name->mode = inode->i_mode;
name->uid = inode->i_uid;
name->gid = inode->i_gid;
name->rdev = inode->i_rdev;
security_inode_getsecid(inode, &name->osid);
if (flags & AUDIT_INODE_NOEVAL) {
name->fcap_ver = -1;
return;
}
audit_copy_fcaps(name, dentry);
}
/**
* __audit_inode - store the inode and device from a lookup
* @name: name being audited
* @dentry: dentry being audited
* @flags: attributes for this particular entry
*/
void __audit_inode(struct filename *name, const struct dentry *dentry,
unsigned int flags)
{
struct audit_context *context = audit_context();
struct inode *inode = d_backing_inode(dentry);
struct audit_names *n;
bool parent = flags & AUDIT_INODE_PARENT;
struct audit_entry *e;
struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
int i;
if (context->context == AUDIT_CTX_UNUSED)
return;
rcu_read_lock();
list_for_each_entry_rcu(e, list, list) {
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
if (f->type == AUDIT_FSTYPE
&& audit_comparator(inode->i_sb->s_magic,
f->op, f->val)
&& e->rule.action == AUDIT_NEVER) {
rcu_read_unlock();
return;
}
}
}
rcu_read_unlock();
if (!name)
goto out_alloc;
/*
* If we have a pointer to an audit_names entry already, then we can
* just use it directly if the type is correct.
*/
n = name->aname;
if (n) {
if (parent) {
if (n->type == AUDIT_TYPE_PARENT ||
n->type == AUDIT_TYPE_UNKNOWN)
goto out;
} else {
if (n->type != AUDIT_TYPE_PARENT)
goto out;
}
}
list_for_each_entry_reverse(n, &context->names_list, list) {
if (n->ino) {
/* valid inode number, use that for the comparison */
if (n->ino != inode->i_ino ||
n->dev != inode->i_sb->s_dev)
continue;
} else if (n->name) {
/* inode number has not been set, check the name */
if (strcmp(n->name->name, name->name))
continue;
} else
/* no inode and no name (?!) ... this is odd ... */
continue;
/* match the correct record type */
if (parent) {
if (n->type == AUDIT_TYPE_PARENT ||
n->type == AUDIT_TYPE_UNKNOWN)
goto out;
} else {
if (n->type != AUDIT_TYPE_PARENT)
goto out;
}
}
out_alloc:
/* unable to find an entry with both a matching name and type */
n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
if (!n)
return;
if (name) {
n->name = name;
name->refcnt++;
}
out:
if (parent) {
n->name_len = n->name ? parent_len(n->name->name) : AUDIT_NAME_FULL;
n->type = AUDIT_TYPE_PARENT;
if (flags & AUDIT_INODE_HIDDEN)
n->hidden = true;
} else {
n->name_len = AUDIT_NAME_FULL;
n->type = AUDIT_TYPE_NORMAL;
}
handle_path(dentry);
audit_copy_inode(n, dentry, inode, flags & AUDIT_INODE_NOEVAL);
}
void __audit_file(const struct file *file)
{
__audit_inode(NULL, file->f_path.dentry, 0);
}
/**
* __audit_inode_child - collect inode info for created/removed objects
* @parent: inode of dentry parent
* @dentry: dentry being audited
* @type: AUDIT_TYPE_* value that we're looking for
*
* For syscalls that create or remove filesystem objects, audit_inode
* can only collect information for the filesystem object's parent.
* This call updates the audit context with the child's information.
* Syscalls that create a new filesystem object must be hooked after
* the object is created. Syscalls that remove a filesystem object
* must be hooked prior, in order to capture the target inode during
* unsuccessful attempts.
*/
void __audit_inode_child(struct inode *parent,
const struct dentry *dentry,
const unsigned char type)
{
struct audit_context *context = audit_context();
struct inode *inode = d_backing_inode(dentry);
const struct qstr *dname = &dentry->d_name;
struct audit_names *n, *found_parent = NULL, *found_child = NULL;
struct audit_entry *e;
struct list_head *list = &audit_filter_list[AUDIT_FILTER_FS];
int i;
if (context->context == AUDIT_CTX_UNUSED)
return;
rcu_read_lock();
list_for_each_entry_rcu(e, list, list) {
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
if (f->type == AUDIT_FSTYPE
&& audit_comparator(parent->i_sb->s_magic,
f->op, f->val)
&& e->rule.action == AUDIT_NEVER) {
rcu_read_unlock();
return;
}
}
}
rcu_read_unlock();
if (inode)
handle_one(inode);
/* look for a parent entry first */
list_for_each_entry(n, &context->names_list, list) {
if (!n->name ||
(n->type != AUDIT_TYPE_PARENT &&
n->type != AUDIT_TYPE_UNKNOWN))
continue;
if (n->ino == parent->i_ino && n->dev == parent->i_sb->s_dev &&
!audit_compare_dname_path(dname,
n->name->name, n->name_len)) {
if (n->type == AUDIT_TYPE_UNKNOWN)
n->type = AUDIT_TYPE_PARENT;
found_parent = n;
break;
}
}
cond_resched();
/* is there a matching child entry? */
list_for_each_entry(n, &context->names_list, list) {
/* can only match entries that have a name */
if (!n->name ||
(n->type != type && n->type != AUDIT_TYPE_UNKNOWN))
continue;
if (!strcmp(dname->name, n->name->name) ||
!audit_compare_dname_path(dname, n->name->name,
found_parent ?
found_parent->name_len :
AUDIT_NAME_FULL)) {
if (n->type == AUDIT_TYPE_UNKNOWN)
n->type = type;
found_child = n;
break;
}
}
if (!found_parent) {
/* create a new, "anonymous" parent record */
n = audit_alloc_name(context, AUDIT_TYPE_PARENT);
if (!n)
return;
audit_copy_inode(n, NULL, parent, 0);
}
if (!found_child) {
found_child = audit_alloc_name(context, type);
if (!found_child)
return;
/* Re-use the name belonging to the slot for a matching parent
* directory. All names for this context are relinquished in
* audit_free_names() */
if (found_parent) {
found_child->name = found_parent->name;
found_child->name_len = AUDIT_NAME_FULL;
found_child->name->refcnt++;
}
}
if (inode)
audit_copy_inode(found_child, dentry, inode, 0);
else
found_child->ino = AUDIT_INO_UNSET;
}
EXPORT_SYMBOL_GPL(__audit_inode_child);
/**
* auditsc_get_stamp - get local copies of audit_context values
* @ctx: audit_context for the task
* @t: timespec64 to store time recorded in the audit_context
* @serial: serial value that is recorded in the audit_context
*
* Also sets the context as auditable.
*/
int auditsc_get_stamp(struct audit_context *ctx,
struct timespec64 *t, unsigned int *serial)
{
if (ctx->context == AUDIT_CTX_UNUSED)
return 0;
if (!ctx->serial)
ctx->serial = audit_serial();
t->tv_sec = ctx->ctime.tv_sec;
t->tv_nsec = ctx->ctime.tv_nsec;
*serial = ctx->serial;
if (!ctx->prio) {
ctx->prio = 1;
ctx->current_state = AUDIT_STATE_RECORD;
}
return 1;
}
/**
* __audit_mq_open - record audit data for a POSIX MQ open
* @oflag: open flag
* @mode: mode bits
* @attr: queue attributes
*
*/
void __audit_mq_open(int oflag, umode_t mode, struct mq_attr *attr)
{
struct audit_context *context = audit_context();
if (attr)
memcpy(&context->mq_open.attr, attr, sizeof(struct mq_attr));
else
memset(&context->mq_open.attr, 0, sizeof(struct mq_attr));
context->mq_open.oflag = oflag;
context->mq_open.mode = mode;
context->type = AUDIT_MQ_OPEN;
}
/**
* __audit_mq_sendrecv - record audit data for a POSIX MQ timed send/receive
* @mqdes: MQ descriptor
* @msg_len: Message length
* @msg_prio: Message priority
* @abs_timeout: Message timeout in absolute time
*
*/
void __audit_mq_sendrecv(mqd_t mqdes, size_t msg_len, unsigned int msg_prio,
const struct timespec64 *abs_timeout)
{
struct audit_context *context = audit_context();
struct timespec64 *p = &context->mq_sendrecv.abs_timeout;
if (abs_timeout)
memcpy(p, abs_timeout, sizeof(*p));
else
memset(p, 0, sizeof(*p));
context->mq_sendrecv.mqdes = mqdes;
context->mq_sendrecv.msg_len = msg_len;
context->mq_sendrecv.msg_prio = msg_prio;
context->type = AUDIT_MQ_SENDRECV;
}
/**
* __audit_mq_notify - record audit data for a POSIX MQ notify
* @mqdes: MQ descriptor
* @notification: Notification event
*
*/
void __audit_mq_notify(mqd_t mqdes, const struct sigevent *notification)
{
struct audit_context *context = audit_context();
if (notification)
context->mq_notify.sigev_signo = notification->sigev_signo;
else
context->mq_notify.sigev_signo = 0;
context->mq_notify.mqdes = mqdes;
context->type = AUDIT_MQ_NOTIFY;
}
/**
* __audit_mq_getsetattr - record audit data for a POSIX MQ get/set attribute
* @mqdes: MQ descriptor
* @mqstat: MQ flags
*
*/
void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
{
struct audit_context *context = audit_context();
context->mq_getsetattr.mqdes = mqdes;
context->mq_getsetattr.mqstat = *mqstat;
context->type = AUDIT_MQ_GETSETATTR;
}
/**
* __audit_ipc_obj - record audit data for ipc object
* @ipcp: ipc permissions
*
*/
void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
{
struct audit_context *context = audit_context();
context->ipc.uid = ipcp->uid;
context->ipc.gid = ipcp->gid;
context->ipc.mode = ipcp->mode;
context->ipc.has_perm = 0;
security_ipc_getsecid(ipcp, &context->ipc.osid);
context->type = AUDIT_IPC;
}
/**
* __audit_ipc_set_perm - record audit data for new ipc permissions
* @qbytes: msgq bytes
* @uid: msgq user id
* @gid: msgq group id
* @mode: msgq mode (permissions)
*
* Called only after audit_ipc_obj().
*/
void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode)
{
struct audit_context *context = audit_context();
context->ipc.qbytes = qbytes;
context->ipc.perm_uid = uid;
context->ipc.perm_gid = gid;
context->ipc.perm_mode = mode;
context->ipc.has_perm = 1;
}
void __audit_bprm(struct linux_binprm *bprm)
{
struct audit_context *context = audit_context();
context->type = AUDIT_EXECVE;
context->execve.argc = bprm->argc;
}
/**
* __audit_socketcall - record audit data for sys_socketcall
* @nargs: number of args, which should not be more than AUDITSC_ARGS.
* @args: args array
*
*/
int __audit_socketcall(int nargs, unsigned long *args)
{
struct audit_context *context = audit_context();
if (nargs <= 0 || nargs > AUDITSC_ARGS || !args)
return -EINVAL;
context->type = AUDIT_SOCKETCALL;
context->socketcall.nargs = nargs;
memcpy(context->socketcall.args, args, nargs * sizeof(unsigned long));
return 0;
}
/**
* __audit_fd_pair - record audit data for pipe and socketpair
* @fd1: the first file descriptor
* @fd2: the second file descriptor
*
*/
void __audit_fd_pair(int fd1, int fd2)
{
struct audit_context *context = audit_context();
context->fds[0] = fd1;
context->fds[1] = fd2;
}
/**
* __audit_sockaddr - record audit data for sys_bind, sys_connect, sys_sendto
* @len: data length in user space
* @a: data address in kernel space
*
* Returns 0 for success or NULL context or < 0 on error.
*/
int __audit_sockaddr(int len, void *a)
{
struct audit_context *context = audit_context();
if (!context->sockaddr) {
void *p = kmalloc(sizeof(struct sockaddr_storage), GFP_KERNEL);
if (!p)
return -ENOMEM;
context->sockaddr = p;
}
context->sockaddr_len = len;
memcpy(context->sockaddr, a, len);
return 0;
}
void __audit_ptrace(struct task_struct *t)
{
struct audit_context *context = audit_context();
context->target_pid = task_tgid_nr(t);
context->target_auid = audit_get_loginuid(t);
context->target_uid = task_uid(t);
context->target_sessionid = audit_get_sessionid(t);
security_task_getsecid_obj(t, &context->target_sid);
memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
}
/**
* audit_signal_info_syscall - record signal info for syscalls
* @t: task being signaled
*
* If the audit subsystem is being terminated, record the task (pid)
* and uid that is doing that.
*/
int audit_signal_info_syscall(struct task_struct *t)
{
struct audit_aux_data_pids *axp;
struct audit_context *ctx = audit_context();
kuid_t t_uid = task_uid(t);
if (!audit_signals || audit_dummy_context())
return 0;
/* optimize the common case by putting first signal recipient directly
* in audit_context */
if (!ctx->target_pid) {
ctx->target_pid = task_tgid_nr(t);
ctx->target_auid = audit_get_loginuid(t);
ctx->target_uid = t_uid;
ctx->target_sessionid = audit_get_sessionid(t);
security_task_getsecid_obj(t, &ctx->target_sid);
memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
return 0;
}
axp = (void *)ctx->aux_pids;
if (!axp || axp->pid_count == AUDIT_AUX_PIDS) {
axp = kzalloc(sizeof(*axp), GFP_ATOMIC);
if (!axp)
return -ENOMEM;
axp->d.type = AUDIT_OBJ_PID;
axp->d.next = ctx->aux_pids;
ctx->aux_pids = (void *)axp;
}
BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);
axp->target_pid[axp->pid_count] = task_tgid_nr(t);
axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
axp->target_uid[axp->pid_count] = t_uid;
axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
security_task_getsecid_obj(t, &axp->target_sid[axp->pid_count]);
memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
axp->pid_count++;
return 0;
}
/**
* __audit_log_bprm_fcaps - store information about a loading bprm and relevant fcaps
* @bprm: pointer to the bprm being processed
* @new: the proposed new credentials
* @old: the old credentials
*
* Simply check if the proc already has the caps given by the file and if not
* store the priv escalation info for later auditing at the end of the syscall
*
* -Eric
*/
int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
const struct cred *new, const struct cred *old)
{
struct audit_aux_data_bprm_fcaps *ax;
struct audit_context *context = audit_context();
struct cpu_vfs_cap_data vcaps;
ax = kmalloc(sizeof(*ax), GFP_KERNEL);
if (!ax)
return -ENOMEM;
ax->d.type = AUDIT_BPRM_FCAPS;
ax->d.next = context->aux;
context->aux = (void *)ax;
get_vfs_caps_from_disk(&nop_mnt_idmap,
bprm->file->f_path.dentry, &vcaps);
ax->fcap.permitted = vcaps.permitted;
ax->fcap.inheritable = vcaps.inheritable;
ax->fcap.fE = !!(vcaps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
ax->fcap.rootid = vcaps.rootid;
ax->fcap_ver = (vcaps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;
ax->old_pcap.permitted = old->cap_permitted;
ax->old_pcap.inheritable = old->cap_inheritable;
ax->old_pcap.effective = old->cap_effective;
ax->old_pcap.ambient = old->cap_ambient;
ax->new_pcap.permitted = new->cap_permitted;
ax->new_pcap.inheritable = new->cap_inheritable;
ax->new_pcap.effective = new->cap_effective;
ax->new_pcap.ambient = new->cap_ambient;
return 0;
}
/**
* __audit_log_capset - store information about the arguments to the capset syscall
* @new: the new credentials
* @old: the old (current) credentials
*
* Record the arguments userspace sent to sys_capset for later printing by the
* audit system if applicable
*/
void __audit_log_capset(const struct cred *new, const struct cred *old)
{
struct audit_context *context = audit_context();
context->capset.pid = task_tgid_nr(current);
context->capset.cap.effective = new->cap_effective;
context->capset.cap.inheritable = new->cap_effective;
context->capset.cap.permitted = new->cap_permitted;
context->capset.cap.ambient = new->cap_ambient;
context->type = AUDIT_CAPSET;
}
void __audit_mmap_fd(int fd, int flags)
{
struct audit_context *context = audit_context();
context->mmap.fd = fd;
context->mmap.flags = flags;
context->type = AUDIT_MMAP;
}
void __audit_openat2_how(struct open_how *how)
{
struct audit_context *context = audit_context();
context->openat2.flags = how->flags;
context->openat2.mode = how->mode;
context->openat2.resolve = how->resolve;
context->type = AUDIT_OPENAT2;
}
void __audit_log_kern_module(char *name)
{
struct audit_context *context = audit_context();
context->module.name = kstrdup(name, GFP_KERNEL);
if (!context->module.name)
audit_log_lost("out of memory in __audit_log_kern_module");
context->type = AUDIT_KERN_MODULE;
}
void __audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar)
{
/* {subj,obj}_trust values are {0,1,2}: no,yes,unknown */
switch (friar->hdr.type) {
case FAN_RESPONSE_INFO_NONE:
audit_log(audit_context(), GFP_KERNEL, AUDIT_FANOTIFY,
"resp=%u fan_type=%u fan_info=0 subj_trust=2 obj_trust=2",
response, FAN_RESPONSE_INFO_NONE);
break;
case FAN_RESPONSE_INFO_AUDIT_RULE:
audit_log(audit_context(), GFP_KERNEL, AUDIT_FANOTIFY,
"resp=%u fan_type=%u fan_info=%X subj_trust=%u obj_trust=%u",
response, friar->hdr.type, friar->rule_number,
friar->subj_trust, friar->obj_trust);
}
}
void __audit_tk_injoffset(struct timespec64 offset)
{
struct audit_context *context = audit_context();
/* only set type if not already set by NTP */
if (!context->type)
context->type = AUDIT_TIME_INJOFFSET;
memcpy(&context->time.tk_injoffset, &offset, sizeof(offset));
}
void __audit_ntp_log(const struct audit_ntp_data *ad)
{
struct audit_context *context = audit_context();
int type;
for (type = 0; type < AUDIT_NTP_NVALS; type++)
if (ad->vals[type].newval != ad->vals[type].oldval) {
/* unconditionally set type, overwriting TK */
context->type = AUDIT_TIME_ADJNTPVAL;
memcpy(&context->time.ntp_data, ad, sizeof(*ad));
break;
}
}
void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
enum audit_nfcfgop op, gfp_t gfp)
{
struct audit_buffer *ab;
char comm[sizeof(current->comm)];
ab = audit_log_start(audit_context(), gfp, AUDIT_NETFILTER_CFG);
if (!ab)
return;
audit_log_format(ab, "table=%s family=%u entries=%u op=%s",
name, af, nentries, audit_nfcfgs[op].s);
audit_log_format(ab, " pid=%u", task_pid_nr(current));
audit_log_task_context(ab); /* subj= */
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, current));
audit_log_end(ab);
}
EXPORT_SYMBOL_GPL(__audit_log_nfcfg);
static void audit_log_task(struct audit_buffer *ab)
{
kuid_t auid, uid;
kgid_t gid;
unsigned int sessionid;
char comm[sizeof(current->comm)];
auid = audit_get_loginuid(current);
sessionid = audit_get_sessionid(current);
current_uid_gid(&uid, &gid);
audit_log_format(ab, "auid=%u uid=%u gid=%u ses=%u",
from_kuid(&init_user_ns, auid),
from_kuid(&init_user_ns, uid),
from_kgid(&init_user_ns, gid),
sessionid);
audit_log_task_context(ab);
audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
audit_log_untrustedstring(ab, get_task_comm(comm, current));
audit_log_d_path_exe(ab, current->mm);
}
/**
* audit_core_dumps - record information about processes that end abnormally
* @signr: signal value
*
* If a process ends with a core dump, something fishy is going on and we
* should record the event for investigation.
*/
void audit_core_dumps(long signr)
{
struct audit_buffer *ab;
if (!audit_enabled)
return;
if (signr == SIGQUIT) /* don't care for those */
return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND);
if (unlikely(!ab))
return;
audit_log_task(ab);
audit_log_format(ab, " sig=%ld res=1", signr);
audit_log_end(ab);
}
/**
* audit_seccomp - record information about a seccomp action
* @syscall: syscall number
* @signr: signal value
* @code: the seccomp action
*
* Record the information associated with a seccomp action. Event filtering for
* seccomp actions that are not to be logged is done in seccomp_log().
* Therefore, this function forces auditing independent of the audit_enabled
* and dummy context state because seccomp actions should be logged even when
* audit is not in use.
*/
void audit_seccomp(unsigned long syscall, long signr, int code)
{
struct audit_buffer *ab;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_SECCOMP);
if (unlikely(!ab))
return;
audit_log_task(ab);
audit_log_format(ab, " sig=%ld arch=%x syscall=%ld compat=%d ip=0x%lx code=0x%x",
signr, syscall_get_arch(current), syscall,
in_compat_syscall(), KSTK_EIP(current), code);
audit_log_end(ab);
}
void audit_seccomp_actions_logged(const char *names, const char *old_names,
int res)
{
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_KERNEL,
AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return;
audit_log_format(ab,
"op=seccomp-logging actions=%s old-actions=%s res=%d",
names, old_names, res);
audit_log_end(ab);
}
struct list_head *audit_killed_trees(void)
{
struct audit_context *ctx = audit_context();
if (likely(!ctx || ctx->context == AUDIT_CTX_UNUSED))
return NULL;
return &ctx->killed_trees;
}
| linux-master | kernel/auditsc.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Detect Hung Task
*
* kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
*
*/
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/nmi.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/lockdep.h>
#include <linux/export.h>
#include <linux/panic_notifier.h>
#include <linux/sysctl.h>
#include <linux/suspend.h>
#include <linux/utsname.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <linux/sched/sysctl.h>
#include <trace/events/sched.h>
/*
* The number of tasks checked:
*/
static int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
/*
* Limit number of tasks checked in a batch.
*
* This value controls the preemptibility of khungtaskd since preemption
* is disabled during the critical section. It also controls the size of
* the RCU grace period. So it needs to be upper-bound.
*/
#define HUNG_TASK_LOCK_BREAK (HZ / 10)
/*
* Zero means infinite timeout - no checking done:
*/
unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
/*
* Zero (default value) means use sysctl_hung_task_timeout_secs:
*/
static unsigned long __read_mostly sysctl_hung_task_check_interval_secs;
static int __read_mostly sysctl_hung_task_warnings = 10;
static int __read_mostly did_panic;
static bool hung_task_show_lock;
static bool hung_task_call_panic;
static bool hung_task_show_all_bt;
static struct task_struct *watchdog_task;
#ifdef CONFIG_SMP
/*
* Should we dump all CPUs backtraces in a hung task event?
* Defaults to 0, can be changed via sysctl.
*/
static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace;
#else
#define sysctl_hung_task_all_cpu_backtrace 0
#endif /* CONFIG_SMP */
/*
* Should we panic (and reboot, if panic_timeout= is set) when a
* hung task is detected:
*/
static unsigned int __read_mostly sysctl_hung_task_panic =
IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC);
static int
hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr)
{
did_panic = 1;
return NOTIFY_DONE;
}
static struct notifier_block panic_block = {
.notifier_call = hung_task_panic,
};
static void check_hung_task(struct task_struct *t, unsigned long timeout)
{
unsigned long switch_count = t->nvcsw + t->nivcsw;
/*
* Ensure the task is not frozen.
* Also, skip vfork and any other user process that freezer should skip.
*/
if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN))
return;
/*
* When a freshly created task is scheduled once, changes its state to
* TASK_UNINTERRUPTIBLE without having ever been switched out once, it
* musn't be checked.
*/
if (unlikely(!switch_count))
return;
if (switch_count != t->last_switch_count) {
t->last_switch_count = switch_count;
t->last_switch_time = jiffies;
return;
}
if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))
return;
trace_sched_process_hang(t);
if (sysctl_hung_task_panic) {
console_verbose();
hung_task_show_lock = true;
hung_task_call_panic = true;
}
/*
* Ok, the task did not get scheduled for more than 2 minutes,
* complain:
*/
if (sysctl_hung_task_warnings) {
if (sysctl_hung_task_warnings > 0)
sysctl_hung_task_warnings--;
pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);
pr_err(" %s %s %.*s\n",
print_tainted(), init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
" disables this message.\n");
sched_show_task(t);
hung_task_show_lock = true;
if (sysctl_hung_task_all_cpu_backtrace)
hung_task_show_all_bt = true;
if (!sysctl_hung_task_warnings)
pr_info("Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings\n");
}
touch_nmi_watchdog();
}
/*
* To avoid extending the RCU grace period for an unbounded amount of time,
* periodically exit the critical section and enter a new one.
*
* For preemptible RCU it is sufficient to call rcu_read_unlock in order
* to exit the grace period. For classic RCU, a reschedule is required.
*/
static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
{
bool can_cont;
get_task_struct(g);
get_task_struct(t);
rcu_read_unlock();
cond_resched();
rcu_read_lock();
can_cont = pid_alive(g) && pid_alive(t);
put_task_struct(t);
put_task_struct(g);
return can_cont;
}
/*
* Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
* a really long time (120 seconds). If that happens, print out
* a warning.
*/
static void check_hung_uninterruptible_tasks(unsigned long timeout)
{
int max_count = sysctl_hung_task_check_count;
unsigned long last_break = jiffies;
struct task_struct *g, *t;
/*
* If the system crashed already then all bets are off,
* do not report extra hung tasks:
*/
if (test_taint(TAINT_DIE) || did_panic)
return;
hung_task_show_lock = false;
rcu_read_lock();
for_each_process_thread(g, t) {
unsigned int state;
if (!max_count--)
goto unlock;
if (time_after(jiffies, last_break + HUNG_TASK_LOCK_BREAK)) {
if (!rcu_lock_break(g, t))
goto unlock;
last_break = jiffies;
}
/*
* skip the TASK_KILLABLE tasks -- these can be killed
* skip the TASK_IDLE tasks -- those are genuinely idle
*/
state = READ_ONCE(t->__state);
if ((state & TASK_UNINTERRUPTIBLE) &&
!(state & TASK_WAKEKILL) &&
!(state & TASK_NOLOAD))
check_hung_task(t, timeout);
}
unlock:
rcu_read_unlock();
if (hung_task_show_lock)
debug_show_all_locks();
if (hung_task_show_all_bt) {
hung_task_show_all_bt = false;
trigger_all_cpu_backtrace();
}
if (hung_task_call_panic)
panic("hung_task: blocked tasks");
}
static long hung_timeout_jiffies(unsigned long last_checked,
unsigned long timeout)
{
/* timeout of 0 will disable the watchdog */
return timeout ? last_checked - jiffies + timeout * HZ :
MAX_SCHEDULE_TIMEOUT;
}
#ifdef CONFIG_SYSCTL
/*
* Process updating of timeout sysctl
*/
static int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
void *buffer,
size_t *lenp, loff_t *ppos)
{
int ret;
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
goto out;
wake_up_process(watchdog_task);
out:
return ret;
}
/*
* This is needed for proc_doulongvec_minmax of sysctl_hung_task_timeout_secs
* and hung_task_check_interval_secs
*/
static const unsigned long hung_task_timeout_max = (LONG_MAX / HZ);
static struct ctl_table hung_task_sysctls[] = {
#ifdef CONFIG_SMP
{
.procname = "hung_task_all_cpu_backtrace",
.data = &sysctl_hung_task_all_cpu_backtrace,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif /* CONFIG_SMP */
{
.procname = "hung_task_panic",
.data = &sysctl_hung_task_panic,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "hung_task_check_count",
.data = &sysctl_hung_task_check_count,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
{
.procname = "hung_task_timeout_secs",
.data = &sysctl_hung_task_timeout_secs,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = proc_dohung_task_timeout_secs,
.extra2 = (void *)&hung_task_timeout_max,
},
{
.procname = "hung_task_check_interval_secs",
.data = &sysctl_hung_task_check_interval_secs,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = proc_dohung_task_timeout_secs,
.extra2 = (void *)&hung_task_timeout_max,
},
{
.procname = "hung_task_warnings",
.data = &sysctl_hung_task_warnings,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_NEG_ONE,
},
{}
};
static void __init hung_task_sysctl_init(void)
{
register_sysctl_init("kernel", hung_task_sysctls);
}
#else
#define hung_task_sysctl_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
static atomic_t reset_hung_task = ATOMIC_INIT(0);
void reset_hung_task_detector(void)
{
atomic_set(&reset_hung_task, 1);
}
EXPORT_SYMBOL_GPL(reset_hung_task_detector);
static bool hung_detector_suspended;
static int hungtask_pm_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
switch (action) {
case PM_SUSPEND_PREPARE:
case PM_HIBERNATION_PREPARE:
case PM_RESTORE_PREPARE:
hung_detector_suspended = true;
break;
case PM_POST_SUSPEND:
case PM_POST_HIBERNATION:
case PM_POST_RESTORE:
hung_detector_suspended = false;
break;
default:
break;
}
return NOTIFY_OK;
}
/*
* kthread which checks for tasks stuck in D state
*/
static int watchdog(void *dummy)
{
unsigned long hung_last_checked = jiffies;
set_user_nice(current, 0);
for ( ; ; ) {
unsigned long timeout = sysctl_hung_task_timeout_secs;
unsigned long interval = sysctl_hung_task_check_interval_secs;
long t;
if (interval == 0)
interval = timeout;
interval = min_t(unsigned long, interval, timeout);
t = hung_timeout_jiffies(hung_last_checked, interval);
if (t <= 0) {
if (!atomic_xchg(&reset_hung_task, 0) &&
!hung_detector_suspended)
check_hung_uninterruptible_tasks(timeout);
hung_last_checked = jiffies;
continue;
}
schedule_timeout_interruptible(t);
}
return 0;
}
static int __init hung_task_init(void)
{
atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
/* Disable hung task detector on suspend */
pm_notifier(hungtask_pm_notify, 0);
watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");
hung_task_sysctl_init();
return 0;
}
subsys_initcall(hung_task_init);
| linux-master | kernel/hung_task.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/crash_dump.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/export.h>
/*
* stores the physical address of elf header of crash image
*
* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by
* is_kdump_kernel() to determine if we are booting after a panic. Hence put
* it under CONFIG_CRASH_DUMP and not CONFIG_PROC_VMCORE.
*/
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
EXPORT_SYMBOL_GPL(elfcorehdr_addr);
/*
* stores the size of elf header of crash image
*/
unsigned long long elfcorehdr_size;
/*
* elfcorehdr= specifies the location of elf core header stored by the crashed
* kernel. This option will be passed by kexec loader to the capture kernel.
*
* Syntax: elfcorehdr=[size[KMG]@]offset[KMG]
*/
static int __init setup_elfcorehdr(char *arg)
{
char *end;
if (!arg)
return -EINVAL;
elfcorehdr_addr = memparse(arg, &end);
if (*end == '@') {
elfcorehdr_size = elfcorehdr_addr;
elfcorehdr_addr = memparse(end + 1, &end);
}
return end > arg ? 0 : -EINVAL;
}
early_param("elfcorehdr", setup_elfcorehdr);
| linux-master | kernel/crash_dump.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/stat.h>
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/hash.h>
#include <linux/kmemleak.h>
#include <linux/user_namespace.h>
struct ucounts init_ucounts = {
.ns = &init_user_ns,
.uid = GLOBAL_ROOT_UID,
.count = ATOMIC_INIT(1),
};
#define UCOUNTS_HASHTABLE_BITS 10
static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)];
static DEFINE_SPINLOCK(ucounts_lock);
#define ucounts_hashfn(ns, uid) \
hash_long((unsigned long)__kuid_val(uid) + (unsigned long)(ns), \
UCOUNTS_HASHTABLE_BITS)
#define ucounts_hashentry(ns, uid) \
(ucounts_hashtable + ucounts_hashfn(ns, uid))
#ifdef CONFIG_SYSCTL
static struct ctl_table_set *
set_lookup(struct ctl_table_root *root)
{
return ¤t_user_ns()->set;
}
static int set_is_seen(struct ctl_table_set *set)
{
return ¤t_user_ns()->set == set;
}
static int set_permissions(struct ctl_table_header *head,
struct ctl_table *table)
{
struct user_namespace *user_ns =
container_of(head->set, struct user_namespace, set);
int mode;
/* Allow users with CAP_SYS_RESOURCE unrestrained access */
if (ns_capable(user_ns, CAP_SYS_RESOURCE))
mode = (table->mode & S_IRWXU) >> 6;
else
/* Allow all others at most read-only access */
mode = table->mode & S_IROTH;
return (mode << 6) | (mode << 3) | mode;
}
static struct ctl_table_root set_root = {
.lookup = set_lookup,
.permissions = set_permissions,
};
static long ue_zero = 0;
static long ue_int_max = INT_MAX;
#define UCOUNT_ENTRY(name) \
{ \
.procname = name, \
.maxlen = sizeof(long), \
.mode = 0644, \
.proc_handler = proc_doulongvec_minmax, \
.extra1 = &ue_zero, \
.extra2 = &ue_int_max, \
}
static struct ctl_table user_table[] = {
UCOUNT_ENTRY("max_user_namespaces"),
UCOUNT_ENTRY("max_pid_namespaces"),
UCOUNT_ENTRY("max_uts_namespaces"),
UCOUNT_ENTRY("max_ipc_namespaces"),
UCOUNT_ENTRY("max_net_namespaces"),
UCOUNT_ENTRY("max_mnt_namespaces"),
UCOUNT_ENTRY("max_cgroup_namespaces"),
UCOUNT_ENTRY("max_time_namespaces"),
#ifdef CONFIG_INOTIFY_USER
UCOUNT_ENTRY("max_inotify_instances"),
UCOUNT_ENTRY("max_inotify_watches"),
#endif
#ifdef CONFIG_FANOTIFY
UCOUNT_ENTRY("max_fanotify_groups"),
UCOUNT_ENTRY("max_fanotify_marks"),
#endif
{ }
};
#endif /* CONFIG_SYSCTL */
bool setup_userns_sysctls(struct user_namespace *ns)
{
#ifdef CONFIG_SYSCTL
struct ctl_table *tbl;
BUILD_BUG_ON(ARRAY_SIZE(user_table) != UCOUNT_COUNTS + 1);
setup_sysctl_set(&ns->set, &set_root, set_is_seen);
tbl = kmemdup(user_table, sizeof(user_table), GFP_KERNEL);
if (tbl) {
int i;
for (i = 0; i < UCOUNT_COUNTS; i++) {
tbl[i].data = &ns->ucount_max[i];
}
ns->sysctls = __register_sysctl_table(&ns->set, "user", tbl,
ARRAY_SIZE(user_table));
}
if (!ns->sysctls) {
kfree(tbl);
retire_sysctl_set(&ns->set);
return false;
}
#endif
return true;
}
void retire_userns_sysctls(struct user_namespace *ns)
{
#ifdef CONFIG_SYSCTL
struct ctl_table *tbl;
tbl = ns->sysctls->ctl_table_arg;
unregister_sysctl_table(ns->sysctls);
retire_sysctl_set(&ns->set);
kfree(tbl);
#endif
}
static struct ucounts *find_ucounts(struct user_namespace *ns, kuid_t uid, struct hlist_head *hashent)
{
struct ucounts *ucounts;
hlist_for_each_entry(ucounts, hashent, node) {
if (uid_eq(ucounts->uid, uid) && (ucounts->ns == ns))
return ucounts;
}
return NULL;
}
static void hlist_add_ucounts(struct ucounts *ucounts)
{
struct hlist_head *hashent = ucounts_hashentry(ucounts->ns, ucounts->uid);
spin_lock_irq(&ucounts_lock);
hlist_add_head(&ucounts->node, hashent);
spin_unlock_irq(&ucounts_lock);
}
static inline bool get_ucounts_or_wrap(struct ucounts *ucounts)
{
/* Returns true on a successful get, false if the count wraps. */
return !atomic_add_negative(1, &ucounts->count);
}
struct ucounts *get_ucounts(struct ucounts *ucounts)
{
if (!get_ucounts_or_wrap(ucounts)) {
put_ucounts(ucounts);
ucounts = NULL;
}
return ucounts;
}
struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid)
{
struct hlist_head *hashent = ucounts_hashentry(ns, uid);
struct ucounts *ucounts, *new;
bool wrapped;
spin_lock_irq(&ucounts_lock);
ucounts = find_ucounts(ns, uid, hashent);
if (!ucounts) {
spin_unlock_irq(&ucounts_lock);
new = kzalloc(sizeof(*new), GFP_KERNEL);
if (!new)
return NULL;
new->ns = ns;
new->uid = uid;
atomic_set(&new->count, 1);
spin_lock_irq(&ucounts_lock);
ucounts = find_ucounts(ns, uid, hashent);
if (ucounts) {
kfree(new);
} else {
hlist_add_head(&new->node, hashent);
get_user_ns(new->ns);
spin_unlock_irq(&ucounts_lock);
return new;
}
}
wrapped = !get_ucounts_or_wrap(ucounts);
spin_unlock_irq(&ucounts_lock);
if (wrapped) {
put_ucounts(ucounts);
return NULL;
}
return ucounts;
}
void put_ucounts(struct ucounts *ucounts)
{
unsigned long flags;
if (atomic_dec_and_lock_irqsave(&ucounts->count, &ucounts_lock, flags)) {
hlist_del_init(&ucounts->node);
spin_unlock_irqrestore(&ucounts_lock, flags);
put_user_ns(ucounts->ns);
kfree(ucounts);
}
}
static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
{
long c, old;
c = atomic_long_read(v);
for (;;) {
if (unlikely(c >= u))
return false;
old = atomic_long_cmpxchg(v, c, c+1);
if (likely(old == c))
return true;
c = old;
}
}
struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
enum ucount_type type)
{
struct ucounts *ucounts, *iter, *bad;
struct user_namespace *tns;
ucounts = alloc_ucounts(ns, uid);
for (iter = ucounts; iter; iter = tns->ucounts) {
long max;
tns = iter->ns;
max = READ_ONCE(tns->ucount_max[type]);
if (!atomic_long_inc_below(&iter->ucount[type], max))
goto fail;
}
return ucounts;
fail:
bad = iter;
for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
atomic_long_dec(&iter->ucount[type]);
put_ucounts(ucounts);
return NULL;
}
void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
{
struct ucounts *iter;
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
long dec = atomic_long_dec_if_positive(&iter->ucount[type]);
WARN_ON_ONCE(dec < 0);
}
put_ucounts(ucounts);
}
long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
{
struct ucounts *iter;
long max = LONG_MAX;
long ret = 0;
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
long new = atomic_long_add_return(v, &iter->rlimit[type]);
if (new < 0 || new > max)
ret = LONG_MAX;
else if (iter == ucounts)
ret = new;
max = get_userns_rlimit_max(iter->ns, type);
}
return ret;
}
bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
{
struct ucounts *iter;
long new = -1; /* Silence compiler warning */
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
WARN_ON_ONCE(dec < 0);
if (iter == ucounts)
new = dec;
}
return (new == 0);
}
static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
struct ucounts *last, enum rlimit_type type)
{
struct ucounts *iter, *next;
for (iter = ucounts; iter != last; iter = next) {
long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
WARN_ON_ONCE(dec < 0);
next = iter->ns->ucounts;
if (dec == 0)
put_ucounts(iter);
}
}
void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type)
{
do_dec_rlimit_put_ucounts(ucounts, NULL, type);
}
long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
{
/* Caller must hold a reference to ucounts */
struct ucounts *iter;
long max = LONG_MAX;
long dec, ret = 0;
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
long new = atomic_long_add_return(1, &iter->rlimit[type]);
if (new < 0 || new > max)
goto unwind;
if (iter == ucounts)
ret = new;
max = get_userns_rlimit_max(iter->ns, type);
/*
* Grab an extra ucount reference for the caller when
* the rlimit count was previously 0.
*/
if (new != 1)
continue;
if (!get_ucounts(iter))
goto dec_unwind;
}
return ret;
dec_unwind:
dec = atomic_long_sub_return(1, &iter->rlimit[type]);
WARN_ON_ONCE(dec < 0);
unwind:
do_dec_rlimit_put_ucounts(ucounts, iter, type);
return 0;
}
bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long rlimit)
{
struct ucounts *iter;
long max = rlimit;
if (rlimit > LONG_MAX)
max = LONG_MAX;
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
long val = get_rlimit_value(iter, type);
if (val < 0 || val > max)
return true;
max = get_userns_rlimit_max(iter->ns, type);
}
return false;
}
static __init int user_namespace_sysctl_init(void)
{
#ifdef CONFIG_SYSCTL
static struct ctl_table_header *user_header;
static struct ctl_table empty[1];
/*
* It is necessary to register the user directory in the
* default set so that registrations in the child sets work
* properly.
*/
user_header = register_sysctl_sz("user", empty, 0);
kmemleak_ignore(user_header);
BUG_ON(!user_header);
BUG_ON(!setup_userns_sysctls(&init_user_ns));
#endif
hlist_add_ucounts(&init_ucounts);
inc_rlimit_ucounts(&init_ucounts, UCOUNT_RLIMIT_NPROC, 1);
return 0;
}
subsys_initcall(user_namespace_sysctl_init);
| linux-master | kernel/ucount.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/acct.c
*
* BSD Process Accounting for Linux
*
* Author: Marco van Wieringen <[email protected]>
*
* Some code based on ideas and code from:
* Thomas K. Dyas <[email protected]>
*
* This file implements BSD-style process accounting. Whenever any
* process exits, an accounting record of type "struct acct" is
* written to the file specified with the acct() system call. It is
* up to user-level programs to do useful things with the accounting
* log. The kernel just provides the raw accounting information.
*
* (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V.
*
* Plugged two leaks. 1) It didn't return acct_file into the free_filps if
* the file happened to be read-only. 2) If the accounting was suspended
* due to the lack of space it happily allowed to reopen it and completely
* lost the old acct_file. 3/10/98, Al Viro.
*
* Now we silently close acct_file on attempt to reopen. Cleaned sys_acct().
* XTerms and EMACS are manifestations of pure evil. 21/10/98, AV.
*
* Fixed a nasty interaction with sys_umount(). If the accounting
* was suspeneded we failed to stop it on umount(). Messy.
* Another one: remount to readonly didn't stop accounting.
* Question: what should we do if we have CAP_SYS_ADMIN but not
* CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY
* unless we are messing with the root. In that case we are getting a
* real mess with do_remount_sb(). 9/11/98, AV.
*
* Fixed a bunch of races (and pair of leaks). Probably not the best way,
* but this one obviously doesn't introduce deadlocks. Later. BTW, found
* one race (and leak) in BSD implementation.
* OK, that's better. ANOTHER race and leak in BSD variant. There always
* is one more bug... 10/11/98, AV.
*
* Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold
* ->mmap_lock to walk the vma list of current->mm. Nasty, since it leaks
* a struct file opened for write. Fixed. 2/6/2000, AV.
*/
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/acct.h>
#include <linux/capability.h>
#include <linux/file.h>
#include <linux/tty.h>
#include <linux/security.h>
#include <linux/vfs.h>
#include <linux/jiffies.h>
#include <linux/times.h>
#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/uaccess.h>
#include <linux/sched/cputime.h>
#include <asm/div64.h>
#include <linux/pid_namespace.h>
#include <linux/fs_pin.h>
/*
* These constants control the amount of freespace that suspend and
* resume the process accounting system, and the time delay between
* each check.
* Turned into sysctl-controllable parameters. AV, 12/11/98
*/
static int acct_parm[3] = {4, 2, 30};
#define RESUME (acct_parm[0]) /* >foo% free space - resume */
#define SUSPEND (acct_parm[1]) /* <foo% free space - suspend */
#define ACCT_TIMEOUT (acct_parm[2]) /* foo second timeout between checks */
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_acct_table[] = {
{
.procname = "acct",
.data = &acct_parm,
.maxlen = 3*sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static __init int kernel_acct_sysctls_init(void)
{
register_sysctl_init("kernel", kern_acct_table);
return 0;
}
late_initcall(kernel_acct_sysctls_init);
#endif /* CONFIG_SYSCTL */
/*
* External references and all of the globals.
*/
struct bsd_acct_struct {
struct fs_pin pin;
atomic_long_t count;
struct rcu_head rcu;
struct mutex lock;
int active;
unsigned long needcheck;
struct file *file;
struct pid_namespace *ns;
struct work_struct work;
struct completion done;
};
static void do_acct_process(struct bsd_acct_struct *acct);
/*
* Check the amount of free space and suspend/resume accordingly.
*/
static int check_free_space(struct bsd_acct_struct *acct)
{
struct kstatfs sbuf;
if (time_is_after_jiffies(acct->needcheck))
goto out;
/* May block */
if (vfs_statfs(&acct->file->f_path, &sbuf))
goto out;
if (acct->active) {
u64 suspend = sbuf.f_blocks * SUSPEND;
do_div(suspend, 100);
if (sbuf.f_bavail <= suspend) {
acct->active = 0;
pr_info("Process accounting paused\n");
}
} else {
u64 resume = sbuf.f_blocks * RESUME;
do_div(resume, 100);
if (sbuf.f_bavail >= resume) {
acct->active = 1;
pr_info("Process accounting resumed\n");
}
}
acct->needcheck = jiffies + ACCT_TIMEOUT*HZ;
out:
return acct->active;
}
static void acct_put(struct bsd_acct_struct *p)
{
if (atomic_long_dec_and_test(&p->count))
kfree_rcu(p, rcu);
}
static inline struct bsd_acct_struct *to_acct(struct fs_pin *p)
{
return p ? container_of(p, struct bsd_acct_struct, pin) : NULL;
}
static struct bsd_acct_struct *acct_get(struct pid_namespace *ns)
{
struct bsd_acct_struct *res;
again:
smp_rmb();
rcu_read_lock();
res = to_acct(READ_ONCE(ns->bacct));
if (!res) {
rcu_read_unlock();
return NULL;
}
if (!atomic_long_inc_not_zero(&res->count)) {
rcu_read_unlock();
cpu_relax();
goto again;
}
rcu_read_unlock();
mutex_lock(&res->lock);
if (res != to_acct(READ_ONCE(ns->bacct))) {
mutex_unlock(&res->lock);
acct_put(res);
goto again;
}
return res;
}
static void acct_pin_kill(struct fs_pin *pin)
{
struct bsd_acct_struct *acct = to_acct(pin);
mutex_lock(&acct->lock);
do_acct_process(acct);
schedule_work(&acct->work);
wait_for_completion(&acct->done);
cmpxchg(&acct->ns->bacct, pin, NULL);
mutex_unlock(&acct->lock);
pin_remove(pin);
acct_put(acct);
}
static void close_work(struct work_struct *work)
{
struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work);
struct file *file = acct->file;
if (file->f_op->flush)
file->f_op->flush(file, NULL);
__fput_sync(file);
complete(&acct->done);
}
static int acct_on(struct filename *pathname)
{
struct file *file;
struct vfsmount *mnt, *internal;
struct pid_namespace *ns = task_active_pid_ns(current);
struct bsd_acct_struct *acct;
struct fs_pin *old;
int err;
acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL);
if (!acct)
return -ENOMEM;
/* Difference from BSD - they don't do O_APPEND */
file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
if (IS_ERR(file)) {
kfree(acct);
return PTR_ERR(file);
}
if (!S_ISREG(file_inode(file)->i_mode)) {
kfree(acct);
filp_close(file, NULL);
return -EACCES;
}
if (!(file->f_mode & FMODE_CAN_WRITE)) {
kfree(acct);
filp_close(file, NULL);
return -EIO;
}
internal = mnt_clone_internal(&file->f_path);
if (IS_ERR(internal)) {
kfree(acct);
filp_close(file, NULL);
return PTR_ERR(internal);
}
err = __mnt_want_write(internal);
if (err) {
mntput(internal);
kfree(acct);
filp_close(file, NULL);
return err;
}
mnt = file->f_path.mnt;
file->f_path.mnt = internal;
atomic_long_set(&acct->count, 1);
init_fs_pin(&acct->pin, acct_pin_kill);
acct->file = file;
acct->needcheck = jiffies;
acct->ns = ns;
mutex_init(&acct->lock);
INIT_WORK(&acct->work, close_work);
init_completion(&acct->done);
mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */
pin_insert(&acct->pin, mnt);
rcu_read_lock();
old = xchg(&ns->bacct, &acct->pin);
mutex_unlock(&acct->lock);
pin_kill(old);
__mnt_drop_write(mnt);
mntput(mnt);
return 0;
}
static DEFINE_MUTEX(acct_on_mutex);
/**
* sys_acct - enable/disable process accounting
* @name: file name for accounting records or NULL to shutdown accounting
*
* sys_acct() is the only system call needed to implement process
* accounting. It takes the name of the file where accounting records
* should be written. If the filename is NULL, accounting will be
* shutdown.
*
* Returns: 0 for success or negative errno values for failure.
*/
SYSCALL_DEFINE1(acct, const char __user *, name)
{
int error = 0;
if (!capable(CAP_SYS_PACCT))
return -EPERM;
if (name) {
struct filename *tmp = getname(name);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
mutex_lock(&acct_on_mutex);
error = acct_on(tmp);
mutex_unlock(&acct_on_mutex);
putname(tmp);
} else {
rcu_read_lock();
pin_kill(task_active_pid_ns(current)->bacct);
}
return error;
}
void acct_exit_ns(struct pid_namespace *ns)
{
rcu_read_lock();
pin_kill(ns->bacct);
}
/*
* encode an u64 into a comp_t
*
* This routine has been adopted from the encode_comp_t() function in
* the kern_acct.c file of the FreeBSD operating system. The encoding
* is a 13-bit fraction with a 3-bit (base 8) exponent.
*/
#define MANTSIZE 13 /* 13 bit mantissa. */
#define EXPSIZE 3 /* Base 8 (3 bit) exponent. */
#define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */
static comp_t encode_comp_t(u64 value)
{
int exp, rnd;
exp = rnd = 0;
while (value > MAXFRACT) {
rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */
value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */
exp++;
}
/*
* If we need to round up, do it (and handle overflow correctly).
*/
if (rnd && (++value > MAXFRACT)) {
value >>= EXPSIZE;
exp++;
}
if (exp > (((comp_t) ~0U) >> MANTSIZE))
return (comp_t) ~0U;
/*
* Clean it up and polish it off.
*/
exp <<= MANTSIZE; /* Shift the exponent into place */
exp += value; /* and add on the mantissa. */
return exp;
}
#if ACCT_VERSION == 1 || ACCT_VERSION == 2
/*
* encode an u64 into a comp2_t (24 bits)
*
* Format: 5 bit base 2 exponent, 20 bits mantissa.
* The leading bit of the mantissa is not stored, but implied for
* non-zero exponents.
* Largest encodable value is 50 bits.
*/
#define MANTSIZE2 20 /* 20 bit mantissa. */
#define EXPSIZE2 5 /* 5 bit base 2 exponent. */
#define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */
#define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */
static comp2_t encode_comp2_t(u64 value)
{
int exp, rnd;
exp = (value > (MAXFRACT2>>1));
rnd = 0;
while (value > MAXFRACT2) {
rnd = value & 1;
value >>= 1;
exp++;
}
/*
* If we need to round up, do it (and handle overflow correctly).
*/
if (rnd && (++value > MAXFRACT2)) {
value >>= 1;
exp++;
}
if (exp > MAXEXP2) {
/* Overflow. Return largest representable number instead. */
return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1;
} else {
return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1));
}
}
#elif ACCT_VERSION == 3
/*
* encode an u64 into a 32 bit IEEE float
*/
static u32 encode_float(u64 value)
{
unsigned exp = 190;
unsigned u;
if (value == 0)
return 0;
while ((s64)value > 0) {
value <<= 1;
exp--;
}
u = (u32)(value >> 40) & 0x7fffffu;
return u | (exp << 23);
}
#endif
/*
* Write an accounting entry for an exiting process
*
* The acct_process() call is the workhorse of the process
* accounting system. The struct acct is built here and then written
* into the accounting file. This function should only be called from
* do_exit() or when switching to a different output file.
*/
static void fill_ac(acct_t *ac)
{
struct pacct_struct *pacct = ¤t->signal->pacct;
u64 elapsed, run_time;
time64_t btime;
struct tty_struct *tty;
/*
* Fill the accounting struct with the needed info as recorded
* by the different kernel functions.
*/
memset(ac, 0, sizeof(acct_t));
ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
strscpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
/* calculate run_time in nsec*/
run_time = ktime_get_ns();
run_time -= current->group_leader->start_time;
/* convert nsec -> AHZ */
elapsed = nsec_to_AHZ(run_time);
#if ACCT_VERSION == 3
ac->ac_etime = encode_float(elapsed);
#else
ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
(unsigned long) elapsed : (unsigned long) -1l);
#endif
#if ACCT_VERSION == 1 || ACCT_VERSION == 2
{
/* new enlarged etime field */
comp2_t etime = encode_comp2_t(elapsed);
ac->ac_etime_hi = etime >> 16;
ac->ac_etime_lo = (u16) etime;
}
#endif
do_div(elapsed, AHZ);
btime = ktime_get_real_seconds() - elapsed;
ac->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX);
#if ACCT_VERSION == 2
ac->ac_ahz = AHZ;
#endif
spin_lock_irq(¤t->sighand->siglock);
tty = current->signal->tty; /* Safe as we hold the siglock */
ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime));
ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime));
ac->ac_flag = pacct->ac_flag;
ac->ac_mem = encode_comp_t(pacct->ac_mem);
ac->ac_minflt = encode_comp_t(pacct->ac_minflt);
ac->ac_majflt = encode_comp_t(pacct->ac_majflt);
ac->ac_exitcode = pacct->ac_exitcode;
spin_unlock_irq(¤t->sighand->siglock);
}
/*
* do_acct_process does all actual work. Caller holds the reference to file.
*/
static void do_acct_process(struct bsd_acct_struct *acct)
{
acct_t ac;
unsigned long flim;
const struct cred *orig_cred;
struct file *file = acct->file;
/*
* Accounting records are not subject to resource limits.
*/
flim = rlimit(RLIMIT_FSIZE);
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
/* Perform file operations on behalf of whoever enabled accounting */
orig_cred = override_creds(file->f_cred);
/*
* First check to see if there is enough free_space to continue
* the process accounting system.
*/
if (!check_free_space(acct))
goto out;
fill_ac(&ac);
/* we really need to bite the bullet and change layout */
ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid);
ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid);
#if ACCT_VERSION == 1 || ACCT_VERSION == 2
/* backward-compatible 16 bit fields */
ac.ac_uid16 = ac.ac_uid;
ac.ac_gid16 = ac.ac_gid;
#elif ACCT_VERSION == 3
{
struct pid_namespace *ns = acct->ns;
ac.ac_pid = task_tgid_nr_ns(current, ns);
rcu_read_lock();
ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent),
ns);
rcu_read_unlock();
}
#endif
/*
* Get freeze protection. If the fs is frozen, just skip the write
* as we could deadlock the system otherwise.
*/
if (file_start_write_trylock(file)) {
/* it's been opened O_APPEND, so position is irrelevant */
loff_t pos = 0;
__kernel_write(file, &ac, sizeof(acct_t), &pos);
file_end_write(file);
}
out:
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
revert_creds(orig_cred);
}
/**
* acct_collect - collect accounting information into pacct_struct
* @exitcode: task exit code
* @group_dead: not 0, if this thread is the last one in the process.
*/
void acct_collect(long exitcode, int group_dead)
{
struct pacct_struct *pacct = ¤t->signal->pacct;
u64 utime, stime;
unsigned long vsize = 0;
if (group_dead && current->mm) {
struct mm_struct *mm = current->mm;
VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
mmap_read_lock(mm);
for_each_vma(vmi, vma)
vsize += vma->vm_end - vma->vm_start;
mmap_read_unlock(mm);
}
spin_lock_irq(¤t->sighand->siglock);
if (group_dead)
pacct->ac_mem = vsize / 1024;
if (thread_group_leader(current)) {
pacct->ac_exitcode = exitcode;
if (current->flags & PF_FORKNOEXEC)
pacct->ac_flag |= AFORK;
}
if (current->flags & PF_SUPERPRIV)
pacct->ac_flag |= ASU;
if (current->flags & PF_DUMPCORE)
pacct->ac_flag |= ACORE;
if (current->flags & PF_SIGNALED)
pacct->ac_flag |= AXSIG;
task_cputime(current, &utime, &stime);
pacct->ac_utime += utime;
pacct->ac_stime += stime;
pacct->ac_minflt += current->min_flt;
pacct->ac_majflt += current->maj_flt;
spin_unlock_irq(¤t->sighand->siglock);
}
static void slow_acct_process(struct pid_namespace *ns)
{
for ( ; ns; ns = ns->parent) {
struct bsd_acct_struct *acct = acct_get(ns);
if (acct) {
do_acct_process(acct);
mutex_unlock(&acct->lock);
acct_put(acct);
}
}
}
/**
* acct_process - handles process accounting for an exiting task
*/
void acct_process(void)
{
struct pid_namespace *ns;
/*
* This loop is safe lockless, since current is still
* alive and holds its namespace, which in turn holds
* its parent.
*/
for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) {
if (ns->bacct)
break;
}
if (unlikely(ns))
slow_acct_process(ns);
}
| linux-master | kernel/acct.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2008-2014 Mathieu Desnoyers
*/
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/types.h>
#include <linux/jhash.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/tracepoint.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/static_key.h>
enum tp_func_state {
TP_FUNC_0,
TP_FUNC_1,
TP_FUNC_2,
TP_FUNC_N,
};
extern tracepoint_ptr_t __start___tracepoints_ptrs[];
extern tracepoint_ptr_t __stop___tracepoints_ptrs[];
DEFINE_SRCU(tracepoint_srcu);
EXPORT_SYMBOL_GPL(tracepoint_srcu);
enum tp_transition_sync {
TP_TRANSITION_SYNC_1_0_1,
TP_TRANSITION_SYNC_N_2_1,
_NR_TP_TRANSITION_SYNC,
};
struct tp_transition_snapshot {
unsigned long rcu;
unsigned long srcu;
bool ongoing;
};
/* Protected by tracepoints_mutex */
static struct tp_transition_snapshot tp_transition_snapshot[_NR_TP_TRANSITION_SYNC];
static void tp_rcu_get_state(enum tp_transition_sync sync)
{
struct tp_transition_snapshot *snapshot = &tp_transition_snapshot[sync];
/* Keep the latest get_state snapshot. */
snapshot->rcu = get_state_synchronize_rcu();
snapshot->srcu = start_poll_synchronize_srcu(&tracepoint_srcu);
snapshot->ongoing = true;
}
static void tp_rcu_cond_sync(enum tp_transition_sync sync)
{
struct tp_transition_snapshot *snapshot = &tp_transition_snapshot[sync];
if (!snapshot->ongoing)
return;
cond_synchronize_rcu(snapshot->rcu);
if (!poll_state_synchronize_srcu(&tracepoint_srcu, snapshot->srcu))
synchronize_srcu(&tracepoint_srcu);
snapshot->ongoing = false;
}
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
#ifdef CONFIG_MODULES
/*
* Tracepoint module list mutex protects the local module list.
*/
static DEFINE_MUTEX(tracepoint_module_list_mutex);
/* Local list of struct tp_module */
static LIST_HEAD(tracepoint_module_list);
#endif /* CONFIG_MODULES */
/*
* tracepoints_mutex protects the builtin and module tracepoints.
* tracepoints_mutex nests inside tracepoint_module_list_mutex.
*/
static DEFINE_MUTEX(tracepoints_mutex);
static struct rcu_head *early_probes;
static bool ok_to_free_tracepoints;
/*
* Note about RCU :
* It is used to delay the free of multiple probes array until a quiescent
* state is reached.
*/
struct tp_probes {
struct rcu_head rcu;
struct tracepoint_func probes[];
};
/* Called in removal of a func but failed to allocate a new tp_funcs */
static void tp_stub_func(void)
{
return;
}
static inline void *allocate_probes(int count)
{
struct tp_probes *p = kmalloc(struct_size(p, probes, count),
GFP_KERNEL);
return p == NULL ? NULL : p->probes;
}
static void srcu_free_old_probes(struct rcu_head *head)
{
kfree(container_of(head, struct tp_probes, rcu));
}
static void rcu_free_old_probes(struct rcu_head *head)
{
call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
}
static __init int release_early_probes(void)
{
struct rcu_head *tmp;
ok_to_free_tracepoints = true;
while (early_probes) {
tmp = early_probes;
early_probes = tmp->next;
call_rcu(tmp, rcu_free_old_probes);
}
return 0;
}
/* SRCU is initialized at core_initcall */
postcore_initcall(release_early_probes);
static inline void release_probes(struct tracepoint_func *old)
{
if (old) {
struct tp_probes *tp_probes = container_of(old,
struct tp_probes, probes[0]);
/*
* We can't free probes if SRCU is not initialized yet.
* Postpone the freeing till after SRCU is initialized.
*/
if (unlikely(!ok_to_free_tracepoints)) {
tp_probes->rcu.next = early_probes;
early_probes = &tp_probes->rcu;
return;
}
/*
* Tracepoint probes are protected by both sched RCU and SRCU,
* by calling the SRCU callback in the sched RCU callback we
* cover both cases. So let us chain the SRCU and sched RCU
* callbacks to wait for both grace periods.
*/
call_rcu(&tp_probes->rcu, rcu_free_old_probes);
}
}
static void debug_print_probes(struct tracepoint_func *funcs)
{
int i;
if (!tracepoint_debug || !funcs)
return;
for (i = 0; funcs[i].func; i++)
printk(KERN_DEBUG "Probe %d : %p\n", i, funcs[i].func);
}
static struct tracepoint_func *
func_add(struct tracepoint_func **funcs, struct tracepoint_func *tp_func,
int prio)
{
struct tracepoint_func *old, *new;
int iter_probes; /* Iterate over old probe array. */
int nr_probes = 0; /* Counter for probes */
int pos = -1; /* Insertion position into new array */
if (WARN_ON(!tp_func->func))
return ERR_PTR(-EINVAL);
debug_print_probes(*funcs);
old = *funcs;
if (old) {
/* (N -> N+1), (N != 0, 1) probes */
for (iter_probes = 0; old[iter_probes].func; iter_probes++) {
if (old[iter_probes].func == tp_stub_func)
continue; /* Skip stub functions. */
if (old[iter_probes].func == tp_func->func &&
old[iter_probes].data == tp_func->data)
return ERR_PTR(-EEXIST);
nr_probes++;
}
}
/* + 2 : one for new probe, one for NULL func */
new = allocate_probes(nr_probes + 2);
if (new == NULL)
return ERR_PTR(-ENOMEM);
if (old) {
nr_probes = 0;
for (iter_probes = 0; old[iter_probes].func; iter_probes++) {
if (old[iter_probes].func == tp_stub_func)
continue;
/* Insert before probes of lower priority */
if (pos < 0 && old[iter_probes].prio < prio)
pos = nr_probes++;
new[nr_probes++] = old[iter_probes];
}
if (pos < 0)
pos = nr_probes++;
/* nr_probes now points to the end of the new array */
} else {
pos = 0;
nr_probes = 1; /* must point at end of array */
}
new[pos] = *tp_func;
new[nr_probes].func = NULL;
*funcs = new;
debug_print_probes(*funcs);
return old;
}
static void *func_remove(struct tracepoint_func **funcs,
struct tracepoint_func *tp_func)
{
int nr_probes = 0, nr_del = 0, i;
struct tracepoint_func *old, *new;
old = *funcs;
if (!old)
return ERR_PTR(-ENOENT);
debug_print_probes(*funcs);
/* (N -> M), (N > 1, M >= 0) probes */
if (tp_func->func) {
for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
if ((old[nr_probes].func == tp_func->func &&
old[nr_probes].data == tp_func->data) ||
old[nr_probes].func == tp_stub_func)
nr_del++;
}
}
/*
* If probe is NULL, then nr_probes = nr_del = 0, and then the
* entire entry will be removed.
*/
if (nr_probes - nr_del == 0) {
/* N -> 0, (N > 1) */
*funcs = NULL;
debug_print_probes(*funcs);
return old;
} else {
int j = 0;
/* N -> M, (N > 1, M > 0) */
/* + 1 for NULL */
new = allocate_probes(nr_probes - nr_del + 1);
if (new) {
for (i = 0; old[i].func; i++) {
if ((old[i].func != tp_func->func ||
old[i].data != tp_func->data) &&
old[i].func != tp_stub_func)
new[j++] = old[i];
}
new[nr_probes - nr_del].func = NULL;
*funcs = new;
} else {
/*
* Failed to allocate, replace the old function
* with calls to tp_stub_func.
*/
for (i = 0; old[i].func; i++) {
if (old[i].func == tp_func->func &&
old[i].data == tp_func->data)
WRITE_ONCE(old[i].func, tp_stub_func);
}
*funcs = old;
}
}
debug_print_probes(*funcs);
return old;
}
/*
* Count the number of functions (enum tp_func_state) in a tp_funcs array.
*/
static enum tp_func_state nr_func_state(const struct tracepoint_func *tp_funcs)
{
if (!tp_funcs)
return TP_FUNC_0;
if (!tp_funcs[1].func)
return TP_FUNC_1;
if (!tp_funcs[2].func)
return TP_FUNC_2;
return TP_FUNC_N; /* 3 or more */
}
static void tracepoint_update_call(struct tracepoint *tp, struct tracepoint_func *tp_funcs)
{
void *func = tp->iterator;
/* Synthetic events do not have static call sites */
if (!tp->static_call_key)
return;
if (nr_func_state(tp_funcs) == TP_FUNC_1)
func = tp_funcs[0].func;
__static_call_update(tp->static_call_key, tp->static_call_tramp, func);
}
/*
* Add the probe function to a tracepoint.
*/
static int tracepoint_add_func(struct tracepoint *tp,
struct tracepoint_func *func, int prio,
bool warn)
{
struct tracepoint_func *old, *tp_funcs;
int ret;
if (tp->regfunc && !static_key_enabled(&tp->key)) {
ret = tp->regfunc();
if (ret < 0)
return ret;
}
tp_funcs = rcu_dereference_protected(tp->funcs,
lockdep_is_held(&tracepoints_mutex));
old = func_add(&tp_funcs, func, prio);
if (IS_ERR(old)) {
WARN_ON_ONCE(warn && PTR_ERR(old) != -ENOMEM);
return PTR_ERR(old);
}
/*
* rcu_assign_pointer has as smp_store_release() which makes sure
* that the new probe callbacks array is consistent before setting
* a pointer to it. This array is referenced by __DO_TRACE from
* include/linux/tracepoint.h using rcu_dereference_sched().
*/
switch (nr_func_state(tp_funcs)) {
case TP_FUNC_1: /* 0->1 */
/*
* Make sure new static func never uses old data after a
* 1->0->1 transition sequence.
*/
tp_rcu_cond_sync(TP_TRANSITION_SYNC_1_0_1);
/* Set static call to first function */
tracepoint_update_call(tp, tp_funcs);
/* Both iterator and static call handle NULL tp->funcs */
rcu_assign_pointer(tp->funcs, tp_funcs);
static_key_enable(&tp->key);
break;
case TP_FUNC_2: /* 1->2 */
/* Set iterator static call */
tracepoint_update_call(tp, tp_funcs);
/*
* Iterator callback installed before updating tp->funcs.
* Requires ordering between RCU assign/dereference and
* static call update/call.
*/
fallthrough;
case TP_FUNC_N: /* N->N+1 (N>1) */
rcu_assign_pointer(tp->funcs, tp_funcs);
/*
* Make sure static func never uses incorrect data after a
* N->...->2->1 (N>1) transition sequence.
*/
if (tp_funcs[0].data != old[0].data)
tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
break;
default:
WARN_ON_ONCE(1);
break;
}
release_probes(old);
return 0;
}
/*
* Remove a probe function from a tracepoint.
* Note: only waiting an RCU period after setting elem->call to the empty
* function insures that the original callback is not used anymore. This insured
* by preempt_disable around the call site.
*/
static int tracepoint_remove_func(struct tracepoint *tp,
struct tracepoint_func *func)
{
struct tracepoint_func *old, *tp_funcs;
tp_funcs = rcu_dereference_protected(tp->funcs,
lockdep_is_held(&tracepoints_mutex));
old = func_remove(&tp_funcs, func);
if (WARN_ON_ONCE(IS_ERR(old)))
return PTR_ERR(old);
if (tp_funcs == old)
/* Failed allocating new tp_funcs, replaced func with stub */
return 0;
switch (nr_func_state(tp_funcs)) {
case TP_FUNC_0: /* 1->0 */
/* Removed last function */
if (tp->unregfunc && static_key_enabled(&tp->key))
tp->unregfunc();
static_key_disable(&tp->key);
/* Set iterator static call */
tracepoint_update_call(tp, tp_funcs);
/* Both iterator and static call handle NULL tp->funcs */
rcu_assign_pointer(tp->funcs, NULL);
/*
* Make sure new static func never uses old data after a
* 1->0->1 transition sequence.
*/
tp_rcu_get_state(TP_TRANSITION_SYNC_1_0_1);
break;
case TP_FUNC_1: /* 2->1 */
rcu_assign_pointer(tp->funcs, tp_funcs);
/*
* Make sure static func never uses incorrect data after a
* N->...->2->1 (N>2) transition sequence. If the first
* element's data has changed, then force the synchronization
* to prevent current readers that have loaded the old data
* from calling the new function.
*/
if (tp_funcs[0].data != old[0].data)
tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
tp_rcu_cond_sync(TP_TRANSITION_SYNC_N_2_1);
/* Set static call to first function */
tracepoint_update_call(tp, tp_funcs);
break;
case TP_FUNC_2: /* N->N-1 (N>2) */
fallthrough;
case TP_FUNC_N:
rcu_assign_pointer(tp->funcs, tp_funcs);
/*
* Make sure static func never uses incorrect data after a
* N->...->2->1 (N>2) transition sequence.
*/
if (tp_funcs[0].data != old[0].data)
tp_rcu_get_state(TP_TRANSITION_SYNC_N_2_1);
break;
default:
WARN_ON_ONCE(1);
break;
}
release_probes(old);
return 0;
}
/**
* tracepoint_probe_register_prio_may_exist - Connect a probe to a tracepoint with priority
* @tp: tracepoint
* @probe: probe handler
* @data: tracepoint data
* @prio: priority of this function over other registered functions
*
* Same as tracepoint_probe_register_prio() except that it will not warn
* if the tracepoint is already registered.
*/
int tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe,
void *data, int prio)
{
struct tracepoint_func tp_func;
int ret;
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
tp_func.prio = prio;
ret = tracepoint_add_func(tp, &tp_func, prio, false);
mutex_unlock(&tracepoints_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio_may_exist);
/**
* tracepoint_probe_register_prio - Connect a probe to a tracepoint with priority
* @tp: tracepoint
* @probe: probe handler
* @data: tracepoint data
* @prio: priority of this function over other registered functions
*
* Returns 0 if ok, error value on error.
* Note: if @tp is within a module, the caller is responsible for
* unregistering the probe before the module is gone. This can be
* performed either with a tracepoint module going notifier, or from
* within module exit functions.
*/
int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
void *data, int prio)
{
struct tracepoint_func tp_func;
int ret;
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
tp_func.prio = prio;
ret = tracepoint_add_func(tp, &tp_func, prio, true);
mutex_unlock(&tracepoints_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register_prio);
/**
* tracepoint_probe_register - Connect a probe to a tracepoint
* @tp: tracepoint
* @probe: probe handler
* @data: tracepoint data
*
* Returns 0 if ok, error value on error.
* Note: if @tp is within a module, the caller is responsible for
* unregistering the probe before the module is gone. This can be
* performed either with a tracepoint module going notifier, or from
* within module exit functions.
*/
int tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data)
{
return tracepoint_probe_register_prio(tp, probe, data, TRACEPOINT_DEFAULT_PRIO);
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
/**
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
* @tp: tracepoint
* @probe: probe function pointer
* @data: tracepoint data
*
* Returns 0 if ok, error value on error.
*/
int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
{
struct tracepoint_func tp_func;
int ret;
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
ret = tracepoint_remove_func(tp, &tp_func);
mutex_unlock(&tracepoints_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
static void for_each_tracepoint_range(
tracepoint_ptr_t *begin, tracepoint_ptr_t *end,
void (*fct)(struct tracepoint *tp, void *priv),
void *priv)
{
tracepoint_ptr_t *iter;
if (!begin)
return;
for (iter = begin; iter < end; iter++)
fct(tracepoint_ptr_deref(iter), priv);
}
#ifdef CONFIG_MODULES
bool trace_module_has_bad_taint(struct module *mod)
{
return mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP) |
(1 << TAINT_UNSIGNED_MODULE) | (1 << TAINT_TEST) |
(1 << TAINT_LIVEPATCH));
}
static BLOCKING_NOTIFIER_HEAD(tracepoint_notify_list);
/**
* register_tracepoint_module_notifier - register tracepoint coming/going notifier
* @nb: notifier block
*
* Notifiers registered with this function are called on module
* coming/going with the tracepoint_module_list_mutex held.
* The notifier block callback should expect a "struct tp_module" data
* pointer.
*/
int register_tracepoint_module_notifier(struct notifier_block *nb)
{
struct tp_module *tp_mod;
int ret;
mutex_lock(&tracepoint_module_list_mutex);
ret = blocking_notifier_chain_register(&tracepoint_notify_list, nb);
if (ret)
goto end;
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
(void) nb->notifier_call(nb, MODULE_STATE_COMING, tp_mod);
end:
mutex_unlock(&tracepoint_module_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(register_tracepoint_module_notifier);
/**
* unregister_tracepoint_module_notifier - unregister tracepoint coming/going notifier
* @nb: notifier block
*
* The notifier block callback should expect a "struct tp_module" data
* pointer.
*/
int unregister_tracepoint_module_notifier(struct notifier_block *nb)
{
struct tp_module *tp_mod;
int ret;
mutex_lock(&tracepoint_module_list_mutex);
ret = blocking_notifier_chain_unregister(&tracepoint_notify_list, nb);
if (ret)
goto end;
list_for_each_entry(tp_mod, &tracepoint_module_list, list)
(void) nb->notifier_call(nb, MODULE_STATE_GOING, tp_mod);
end:
mutex_unlock(&tracepoint_module_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
/*
* Ensure the tracer unregistered the module's probes before the module
* teardown is performed. Prevents leaks of probe and data pointers.
*/
static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
{
WARN_ON_ONCE(tp->funcs);
}
static int tracepoint_module_coming(struct module *mod)
{
struct tp_module *tp_mod;
if (!mod->num_tracepoints)
return 0;
/*
* We skip modules that taint the kernel, especially those with different
* module headers (for forced load), to make sure we don't cause a crash.
* Staging, out-of-tree, unsigned GPL, and test modules are fine.
*/
if (trace_module_has_bad_taint(mod))
return 0;
tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL);
if (!tp_mod)
return -ENOMEM;
tp_mod->mod = mod;
mutex_lock(&tracepoint_module_list_mutex);
list_add_tail(&tp_mod->list, &tracepoint_module_list);
blocking_notifier_call_chain(&tracepoint_notify_list,
MODULE_STATE_COMING, tp_mod);
mutex_unlock(&tracepoint_module_list_mutex);
return 0;
}
static void tracepoint_module_going(struct module *mod)
{
struct tp_module *tp_mod;
if (!mod->num_tracepoints)
return;
mutex_lock(&tracepoint_module_list_mutex);
list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
if (tp_mod->mod == mod) {
blocking_notifier_call_chain(&tracepoint_notify_list,
MODULE_STATE_GOING, tp_mod);
list_del(&tp_mod->list);
kfree(tp_mod);
/*
* Called the going notifier before checking for
* quiescence.
*/
for_each_tracepoint_range(mod->tracepoints_ptrs,
mod->tracepoints_ptrs + mod->num_tracepoints,
tp_module_going_check_quiescent, NULL);
break;
}
}
/*
* In the case of modules that were tainted at "coming", we'll simply
* walk through the list without finding it. We cannot use the "tainted"
* flag on "going", in case a module taints the kernel only after being
* loaded.
*/
mutex_unlock(&tracepoint_module_list_mutex);
}
static int tracepoint_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
int ret = 0;
switch (val) {
case MODULE_STATE_COMING:
ret = tracepoint_module_coming(mod);
break;
case MODULE_STATE_LIVE:
break;
case MODULE_STATE_GOING:
tracepoint_module_going(mod);
break;
case MODULE_STATE_UNFORMED:
break;
}
return notifier_from_errno(ret);
}
static struct notifier_block tracepoint_module_nb = {
.notifier_call = tracepoint_module_notify,
.priority = 0,
};
static __init int init_tracepoints(void)
{
int ret;
ret = register_module_notifier(&tracepoint_module_nb);
if (ret)
pr_warn("Failed to register tracepoint module enter notifier\n");
return ret;
}
__initcall(init_tracepoints);
#endif /* CONFIG_MODULES */
/**
* for_each_kernel_tracepoint - iteration on all kernel tracepoints
* @fct: callback
* @priv: private data
*/
void for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
void *priv)
{
for_each_tracepoint_range(__start___tracepoints_ptrs,
__stop___tracepoints_ptrs, fct, priv);
}
EXPORT_SYMBOL_GPL(for_each_kernel_tracepoint);
#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
static int sys_tracepoint_refcount;
int syscall_regfunc(void)
{
struct task_struct *p, *t;
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
set_task_syscall_work(t, SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}
sys_tracepoint_refcount++;
return 0;
}
void syscall_unregfunc(void)
{
struct task_struct *p, *t;
sys_tracepoint_refcount--;
if (!sys_tracepoint_refcount) {
read_lock(&tasklist_lock);
for_each_process_thread(p, t) {
clear_task_syscall_work(t, SYSCALL_TRACEPOINT);
}
read_unlock(&tasklist_lock);
}
}
#endif
| linux-master | kernel/tracepoint.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/reboot.c
*
* Copyright (C) 2013 Linus Torvalds
*/
#define pr_fmt(fmt) "reboot: " fmt
#include <linux/atomic.h>
#include <linux/ctype.h>
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/kmod.h>
#include <linux/kmsg_dump.h>
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/syscore_ops.h>
#include <linux/uaccess.h>
/*
* this indicates whether you can reboot with ctrl-alt-del: the default is yes
*/
static int C_A_D = 1;
struct pid *cad_pid;
EXPORT_SYMBOL(cad_pid);
#if defined(CONFIG_ARM)
#define DEFAULT_REBOOT_MODE = REBOOT_HARD
#else
#define DEFAULT_REBOOT_MODE
#endif
enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
EXPORT_SYMBOL_GPL(reboot_mode);
enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
/*
* This variable is used privately to keep track of whether or not
* reboot_type is still set to its default value (i.e., reboot= hasn't
* been set on the command line). This is needed so that we can
* suppress DMI scanning for reboot quirks. Without it, it's
* impossible to override a faulty reboot quirk without recompiling.
*/
int reboot_default = 1;
int reboot_cpu;
enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
struct sys_off_handler {
struct notifier_block nb;
int (*sys_off_cb)(struct sys_off_data *data);
void *cb_data;
enum sys_off_mode mode;
bool blocking;
void *list;
};
/*
* Temporary stub that prevents linkage failure while we're in process
* of removing all uses of legacy pm_power_off() around the kernel.
*/
void __weak (*pm_power_off)(void);
/**
* emergency_restart - reboot the system
*
* Without shutting down any hardware or taking any locks
* reboot the system. This is called when we know we are in
* trouble so this is our best effort to reboot. This is
* safe to call in interrupt context.
*/
void emergency_restart(void)
{
kmsg_dump(KMSG_DUMP_EMERG);
machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);
void kernel_restart_prepare(char *cmd)
{
blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
system_state = SYSTEM_RESTART;
usermodehelper_disable();
device_shutdown();
}
/**
* register_reboot_notifier - Register function to be called at reboot time
* @nb: Info about notifier function to be called
*
* Registers a function with the list of functions
* to be called at reboot time.
*
* Currently always returns zero, as blocking_notifier_chain_register()
* always returns zero.
*/
int register_reboot_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&reboot_notifier_list, nb);
}
EXPORT_SYMBOL(register_reboot_notifier);
/**
* unregister_reboot_notifier - Unregister previously registered reboot notifier
* @nb: Hook to be unregistered
*
* Unregisters a previously registered reboot
* notifier function.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int unregister_reboot_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
}
EXPORT_SYMBOL(unregister_reboot_notifier);
static void devm_unregister_reboot_notifier(struct device *dev, void *res)
{
WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
}
int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
{
struct notifier_block **rcnb;
int ret;
rcnb = devres_alloc(devm_unregister_reboot_notifier,
sizeof(*rcnb), GFP_KERNEL);
if (!rcnb)
return -ENOMEM;
ret = register_reboot_notifier(nb);
if (!ret) {
*rcnb = nb;
devres_add(dev, rcnb);
} else {
devres_free(rcnb);
}
return ret;
}
EXPORT_SYMBOL(devm_register_reboot_notifier);
/*
* Notifier list for kernel code which wants to be called
* to restart the system.
*/
static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
/**
* register_restart_handler - Register function to be called to reset
* the system
* @nb: Info about handler function to be called
* @nb->priority: Handler priority. Handlers should follow the
* following guidelines for setting priorities.
* 0: Restart handler of last resort,
* with limited restart capabilities
* 128: Default restart handler; use if no other
* restart handler is expected to be available,
* and/or if restart functionality is
* sufficient to restart the entire system
* 255: Highest priority restart handler, will
* preempt all other restart handlers
*
* Registers a function with code to be called to restart the
* system.
*
* Registered functions will be called from machine_restart as last
* step of the restart sequence (if the architecture specific
* machine_restart function calls do_kernel_restart - see below
* for details).
* Registered functions are expected to restart the system immediately.
* If more than one function is registered, the restart handler priority
* selects which function will be called first.
*
* Restart handlers are expected to be registered from non-architecture
* code, typically from drivers. A typical use case would be a system
* where restart functionality is provided through a watchdog. Multiple
* restart handlers may exist; for example, one restart handler might
* restart the entire system, while another only restarts the CPU.
* In such cases, the restart handler which only restarts part of the
* hardware is expected to register with low priority to ensure that
* it only runs if no other means to restart the system is available.
*
* Currently always returns zero, as atomic_notifier_chain_register()
* always returns zero.
*/
int register_restart_handler(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&restart_handler_list, nb);
}
EXPORT_SYMBOL(register_restart_handler);
/**
* unregister_restart_handler - Unregister previously registered
* restart handler
* @nb: Hook to be unregistered
*
* Unregisters a previously registered restart handler function.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int unregister_restart_handler(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&restart_handler_list, nb);
}
EXPORT_SYMBOL(unregister_restart_handler);
/**
* do_kernel_restart - Execute kernel restart handler call chain
*
* Calls functions registered with register_restart_handler.
*
* Expected to be called from machine_restart as last step of the restart
* sequence.
*
* Restarts the system immediately if a restart handler function has been
* registered. Otherwise does nothing.
*/
void do_kernel_restart(char *cmd)
{
atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
}
void migrate_to_reboot_cpu(void)
{
/* The boot cpu is always logical cpu 0 */
int cpu = reboot_cpu;
cpu_hotplug_disable();
/* Make certain the cpu I'm about to reboot on is online */
if (!cpu_online(cpu))
cpu = cpumask_first(cpu_online_mask);
/* Prevent races with other tasks migrating this task */
current->flags |= PF_NO_SETAFFINITY;
/* Make certain I only run on the appropriate processor */
set_cpus_allowed_ptr(current, cpumask_of(cpu));
}
/*
* Notifier list for kernel code which wants to be called
* to prepare system for restart.
*/
static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list);
static void do_kernel_restart_prepare(void)
{
blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL);
}
/**
* kernel_restart - reboot the system
* @cmd: pointer to buffer containing command to execute for restart
* or %NULL
*
* Shutdown everything and perform a clean reboot.
* This is not safe to call in interrupt context.
*/
void kernel_restart(char *cmd)
{
kernel_restart_prepare(cmd);
do_kernel_restart_prepare();
migrate_to_reboot_cpu();
syscore_shutdown();
if (!cmd)
pr_emerg("Restarting system\n");
else
pr_emerg("Restarting system with command '%s'\n", cmd);
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_restart(cmd);
}
EXPORT_SYMBOL_GPL(kernel_restart);
static void kernel_shutdown_prepare(enum system_states state)
{
blocking_notifier_call_chain(&reboot_notifier_list,
(state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
system_state = state;
usermodehelper_disable();
device_shutdown();
}
/**
* kernel_halt - halt the system
*
* Shutdown everything and perform a clean system halt.
*/
void kernel_halt(void)
{
kernel_shutdown_prepare(SYSTEM_HALT);
migrate_to_reboot_cpu();
syscore_shutdown();
pr_emerg("System halted\n");
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_halt();
}
EXPORT_SYMBOL_GPL(kernel_halt);
/*
* Notifier list for kernel code which wants to be called
* to prepare system for power off.
*/
static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list);
/*
* Notifier list for kernel code which wants to be called
* to power off system.
*/
static ATOMIC_NOTIFIER_HEAD(power_off_handler_list);
static int sys_off_notify(struct notifier_block *nb,
unsigned long mode, void *cmd)
{
struct sys_off_handler *handler;
struct sys_off_data data = {};
handler = container_of(nb, struct sys_off_handler, nb);
data.cb_data = handler->cb_data;
data.mode = mode;
data.cmd = cmd;
return handler->sys_off_cb(&data);
}
static struct sys_off_handler platform_sys_off_handler;
static struct sys_off_handler *alloc_sys_off_handler(int priority)
{
struct sys_off_handler *handler;
gfp_t flags;
/*
* Platforms like m68k can't allocate sys_off handler dynamically
* at the early boot time because memory allocator isn't available yet.
*/
if (priority == SYS_OFF_PRIO_PLATFORM) {
handler = &platform_sys_off_handler;
if (handler->cb_data)
return ERR_PTR(-EBUSY);
} else {
if (system_state > SYSTEM_RUNNING)
flags = GFP_ATOMIC;
else
flags = GFP_KERNEL;
handler = kzalloc(sizeof(*handler), flags);
if (!handler)
return ERR_PTR(-ENOMEM);
}
return handler;
}
static void free_sys_off_handler(struct sys_off_handler *handler)
{
if (handler == &platform_sys_off_handler)
memset(handler, 0, sizeof(*handler));
else
kfree(handler);
}
/**
* register_sys_off_handler - Register sys-off handler
* @mode: Sys-off mode
* @priority: Handler priority
* @callback: Callback function
* @cb_data: Callback argument
*
* Registers system power-off or restart handler that will be invoked
* at the step corresponding to the given sys-off mode. Handler's callback
* should return NOTIFY_DONE to permit execution of the next handler in
* the call chain or NOTIFY_STOP to break the chain (in error case for
* example).
*
* Multiple handlers can be registered at the default priority level.
*
* Only one handler can be registered at the non-default priority level,
* otherwise ERR_PTR(-EBUSY) is returned.
*
* Returns a new instance of struct sys_off_handler on success, or
* an ERR_PTR()-encoded error code otherwise.
*/
struct sys_off_handler *
register_sys_off_handler(enum sys_off_mode mode,
int priority,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
struct sys_off_handler *handler;
int err;
handler = alloc_sys_off_handler(priority);
if (IS_ERR(handler))
return handler;
switch (mode) {
case SYS_OFF_MODE_POWER_OFF_PREPARE:
handler->list = &power_off_prep_handler_list;
handler->blocking = true;
break;
case SYS_OFF_MODE_POWER_OFF:
handler->list = &power_off_handler_list;
break;
case SYS_OFF_MODE_RESTART_PREPARE:
handler->list = &restart_prep_handler_list;
handler->blocking = true;
break;
case SYS_OFF_MODE_RESTART:
handler->list = &restart_handler_list;
break;
default:
free_sys_off_handler(handler);
return ERR_PTR(-EINVAL);
}
handler->nb.notifier_call = sys_off_notify;
handler->nb.priority = priority;
handler->sys_off_cb = callback;
handler->cb_data = cb_data;
handler->mode = mode;
if (handler->blocking) {
if (priority == SYS_OFF_PRIO_DEFAULT)
err = blocking_notifier_chain_register(handler->list,
&handler->nb);
else
err = blocking_notifier_chain_register_unique_prio(handler->list,
&handler->nb);
} else {
if (priority == SYS_OFF_PRIO_DEFAULT)
err = atomic_notifier_chain_register(handler->list,
&handler->nb);
else
err = atomic_notifier_chain_register_unique_prio(handler->list,
&handler->nb);
}
if (err) {
free_sys_off_handler(handler);
return ERR_PTR(err);
}
return handler;
}
EXPORT_SYMBOL_GPL(register_sys_off_handler);
/**
* unregister_sys_off_handler - Unregister sys-off handler
* @handler: Sys-off handler
*
* Unregisters given sys-off handler.
*/
void unregister_sys_off_handler(struct sys_off_handler *handler)
{
int err;
if (IS_ERR_OR_NULL(handler))
return;
if (handler->blocking)
err = blocking_notifier_chain_unregister(handler->list,
&handler->nb);
else
err = atomic_notifier_chain_unregister(handler->list,
&handler->nb);
/* sanity check, shall never happen */
WARN_ON(err);
free_sys_off_handler(handler);
}
EXPORT_SYMBOL_GPL(unregister_sys_off_handler);
static void devm_unregister_sys_off_handler(void *data)
{
struct sys_off_handler *handler = data;
unregister_sys_off_handler(handler);
}
/**
* devm_register_sys_off_handler - Register sys-off handler
* @dev: Device that registers handler
* @mode: Sys-off mode
* @priority: Handler priority
* @callback: Callback function
* @cb_data: Callback argument
*
* Registers resource-managed sys-off handler.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_sys_off_handler(struct device *dev,
enum sys_off_mode mode,
int priority,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
struct sys_off_handler *handler;
handler = register_sys_off_handler(mode, priority, callback, cb_data);
if (IS_ERR(handler))
return PTR_ERR(handler);
return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
handler);
}
EXPORT_SYMBOL_GPL(devm_register_sys_off_handler);
/**
* devm_register_power_off_handler - Register power-off handler
* @dev: Device that registers callback
* @callback: Callback function
* @cb_data: Callback's argument
*
* Registers resource-managed sys-off handler with a default priority
* and using power-off mode.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_power_off_handler(struct device *dev,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
return devm_register_sys_off_handler(dev,
SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_DEFAULT,
callback, cb_data);
}
EXPORT_SYMBOL_GPL(devm_register_power_off_handler);
/**
* devm_register_restart_handler - Register restart handler
* @dev: Device that registers callback
* @callback: Callback function
* @cb_data: Callback's argument
*
* Registers resource-managed sys-off handler with a default priority
* and using restart mode.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_restart_handler(struct device *dev,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
return devm_register_sys_off_handler(dev,
SYS_OFF_MODE_RESTART,
SYS_OFF_PRIO_DEFAULT,
callback, cb_data);
}
EXPORT_SYMBOL_GPL(devm_register_restart_handler);
static struct sys_off_handler *platform_power_off_handler;
static int platform_power_off_notify(struct sys_off_data *data)
{
void (*platform_power_power_off_cb)(void) = data->cb_data;
platform_power_power_off_cb();
return NOTIFY_DONE;
}
/**
* register_platform_power_off - Register platform-level power-off callback
* @power_off: Power-off callback
*
* Registers power-off callback that will be called as last step
* of the power-off sequence. This callback is expected to be invoked
* for the last resort. Only one platform power-off callback is allowed
* to be registered at a time.
*
* Returns zero on success, or error code on failure.
*/
int register_platform_power_off(void (*power_off)(void))
{
struct sys_off_handler *handler;
handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_PLATFORM,
platform_power_off_notify,
power_off);
if (IS_ERR(handler))
return PTR_ERR(handler);
platform_power_off_handler = handler;
return 0;
}
EXPORT_SYMBOL_GPL(register_platform_power_off);
/**
* unregister_platform_power_off - Unregister platform-level power-off callback
* @power_off: Power-off callback
*
* Unregisters previously registered platform power-off callback.
*/
void unregister_platform_power_off(void (*power_off)(void))
{
if (platform_power_off_handler &&
platform_power_off_handler->cb_data == power_off) {
unregister_sys_off_handler(platform_power_off_handler);
platform_power_off_handler = NULL;
}
}
EXPORT_SYMBOL_GPL(unregister_platform_power_off);
static int legacy_pm_power_off(struct sys_off_data *data)
{
if (pm_power_off)
pm_power_off();
return NOTIFY_DONE;
}
static void do_kernel_power_off_prepare(void)
{
blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
}
/**
* do_kernel_power_off - Execute kernel power-off handler call chain
*
* Expected to be called as last step of the power-off sequence.
*
* Powers off the system immediately if a power-off handler function has
* been registered. Otherwise does nothing.
*/
void do_kernel_power_off(void)
{
struct sys_off_handler *sys_off = NULL;
/*
* Register sys-off handlers for legacy PM callback. This allows
* legacy PM callbacks temporary co-exist with the new sys-off API.
*
* TODO: Remove legacy handlers once all legacy PM users will be
* switched to the sys-off based APIs.
*/
if (pm_power_off)
sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_DEFAULT,
legacy_pm_power_off, NULL);
atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);
unregister_sys_off_handler(sys_off);
}
/**
* kernel_can_power_off - check whether system can be powered off
*
* Returns true if power-off handler is registered and system can be
* powered off, false otherwise.
*/
bool kernel_can_power_off(void)
{
return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) ||
pm_power_off;
}
EXPORT_SYMBOL_GPL(kernel_can_power_off);
/**
* kernel_power_off - power_off the system
*
* Shutdown everything and perform a clean system power_off.
*/
void kernel_power_off(void)
{
kernel_shutdown_prepare(SYSTEM_POWER_OFF);
do_kernel_power_off_prepare();
migrate_to_reboot_cpu();
syscore_shutdown();
pr_emerg("Power down\n");
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_power_off();
}
EXPORT_SYMBOL_GPL(kernel_power_off);
DEFINE_MUTEX(system_transition_mutex);
/*
* Reboot system call: for obvious reasons only root may call it,
* and even root needs to set up some magic numbers in the registers
* so that some mistake won't make this reboot the whole machine.
* You can also set the meaning of the ctrl-alt-del-key here.
*
* reboot doesn't sync: do that yourself before calling this.
*/
SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
void __user *, arg)
{
struct pid_namespace *pid_ns = task_active_pid_ns(current);
char buffer[256];
int ret = 0;
/* We only trust the superuser with rebooting the system. */
if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
return -EPERM;
/* For safety, we require "magic" arguments. */
if (magic1 != LINUX_REBOOT_MAGIC1 ||
(magic2 != LINUX_REBOOT_MAGIC2 &&
magic2 != LINUX_REBOOT_MAGIC2A &&
magic2 != LINUX_REBOOT_MAGIC2B &&
magic2 != LINUX_REBOOT_MAGIC2C))
return -EINVAL;
/*
* If pid namespaces are enabled and the current task is in a child
* pid_namespace, the command is handled by reboot_pid_ns() which will
* call do_exit().
*/
ret = reboot_pid_ns(pid_ns, cmd);
if (ret)
return ret;
/* Instead of trying to make the power_off code look like
* halt when pm_power_off is not set do it the easy way.
*/
if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off())
cmd = LINUX_REBOOT_CMD_HALT;
mutex_lock(&system_transition_mutex);
switch (cmd) {
case LINUX_REBOOT_CMD_RESTART:
kernel_restart(NULL);
break;
case LINUX_REBOOT_CMD_CAD_ON:
C_A_D = 1;
break;
case LINUX_REBOOT_CMD_CAD_OFF:
C_A_D = 0;
break;
case LINUX_REBOOT_CMD_HALT:
kernel_halt();
do_exit(0);
case LINUX_REBOOT_CMD_POWER_OFF:
kernel_power_off();
do_exit(0);
break;
case LINUX_REBOOT_CMD_RESTART2:
ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
if (ret < 0) {
ret = -EFAULT;
break;
}
buffer[sizeof(buffer) - 1] = '\0';
kernel_restart(buffer);
break;
#ifdef CONFIG_KEXEC_CORE
case LINUX_REBOOT_CMD_KEXEC:
ret = kernel_kexec();
break;
#endif
#ifdef CONFIG_HIBERNATION
case LINUX_REBOOT_CMD_SW_SUSPEND:
ret = hibernate();
break;
#endif
default:
ret = -EINVAL;
break;
}
mutex_unlock(&system_transition_mutex);
return ret;
}
static void deferred_cad(struct work_struct *dummy)
{
kernel_restart(NULL);
}
/*
* This function gets called by ctrl-alt-del - ie the keyboard interrupt.
* As it's called within an interrupt, it may NOT sync: the only choice
* is whether to reboot at once, or just ignore the ctrl-alt-del.
*/
void ctrl_alt_del(void)
{
static DECLARE_WORK(cad_work, deferred_cad);
if (C_A_D)
schedule_work(&cad_work);
else
kill_cad_pid(SIGINT, 1);
}
#define POWEROFF_CMD_PATH_LEN 256
static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
static const char reboot_cmd[] = "/sbin/reboot";
static int run_cmd(const char *cmd)
{
char **argv;
static char *envp[] = {
"HOME=/",
"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
NULL
};
int ret;
argv = argv_split(GFP_KERNEL, cmd, NULL);
if (argv) {
ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
argv_free(argv);
} else {
ret = -ENOMEM;
}
return ret;
}
static int __orderly_reboot(void)
{
int ret;
ret = run_cmd(reboot_cmd);
if (ret) {
pr_warn("Failed to start orderly reboot: forcing the issue\n");
emergency_sync();
kernel_restart(NULL);
}
return ret;
}
static int __orderly_poweroff(bool force)
{
int ret;
ret = run_cmd(poweroff_cmd);
if (ret && force) {
pr_warn("Failed to start orderly shutdown: forcing the issue\n");
/*
* I guess this should try to kick off some daemon to sync and
* poweroff asap. Or not even bother syncing if we're doing an
* emergency shutdown?
*/
emergency_sync();
kernel_power_off();
}
return ret;
}
static bool poweroff_force;
static void poweroff_work_func(struct work_struct *work)
{
__orderly_poweroff(poweroff_force);
}
static DECLARE_WORK(poweroff_work, poweroff_work_func);
/**
* orderly_poweroff - Trigger an orderly system poweroff
* @force: force poweroff if command execution fails
*
* This may be called from any context to trigger a system shutdown.
* If the orderly shutdown fails, it will force an immediate shutdown.
*/
void orderly_poweroff(bool force)
{
if (force) /* do not override the pending "true" */
poweroff_force = true;
schedule_work(&poweroff_work);
}
EXPORT_SYMBOL_GPL(orderly_poweroff);
static void reboot_work_func(struct work_struct *work)
{
__orderly_reboot();
}
static DECLARE_WORK(reboot_work, reboot_work_func);
/**
* orderly_reboot - Trigger an orderly system reboot
*
* This may be called from any context to trigger a system reboot.
* If the orderly reboot fails, it will force an immediate reboot.
*/
void orderly_reboot(void)
{
schedule_work(&reboot_work);
}
EXPORT_SYMBOL_GPL(orderly_reboot);
/**
* hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
* @work: work_struct associated with the emergency poweroff function
*
* This function is called in very critical situations to force
* a kernel poweroff after a configurable timeout value.
*/
static void hw_failure_emergency_poweroff_func(struct work_struct *work)
{
/*
* We have reached here after the emergency shutdown waiting period has
* expired. This means orderly_poweroff has not been able to shut off
* the system for some reason.
*
* Try to shut down the system immediately using kernel_power_off
* if populated
*/
pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
kernel_power_off();
/*
* Worst of the worst case trigger emergency restart
*/
pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
emergency_restart();
}
static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
hw_failure_emergency_poweroff_func);
/**
* hw_failure_emergency_poweroff - Trigger an emergency system poweroff
*
* This may be called from any critical situation to trigger a system shutdown
* after a given period of time. If time is negative this is not scheduled.
*/
static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
{
if (poweroff_delay_ms <= 0)
return;
schedule_delayed_work(&hw_failure_emergency_poweroff_work,
msecs_to_jiffies(poweroff_delay_ms));
}
/**
* hw_protection_shutdown - Trigger an emergency system poweroff
*
* @reason: Reason of emergency shutdown to be printed.
* @ms_until_forced: Time to wait for orderly shutdown before tiggering a
* forced shudown. Negative value disables the forced
* shutdown.
*
* Initiate an emergency system shutdown in order to protect hardware from
* further damage. Usage examples include a thermal protection or a voltage or
* current regulator failures.
* NOTE: The request is ignored if protection shutdown is already pending even
* if the previous request has given a large timeout for forced shutdown.
* Can be called from any context.
*/
void hw_protection_shutdown(const char *reason, int ms_until_forced)
{
static atomic_t allow_proceed = ATOMIC_INIT(1);
pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
/* Shutdown should be initiated only once. */
if (!atomic_dec_and_test(&allow_proceed))
return;
/*
* Queue a backup emergency shutdown in the event of
* orderly_poweroff failure
*/
hw_failure_emergency_poweroff(ms_until_forced);
orderly_poweroff(true);
}
EXPORT_SYMBOL_GPL(hw_protection_shutdown);
static int __init reboot_setup(char *str)
{
for (;;) {
enum reboot_mode *mode;
/*
* Having anything passed on the command line via
* reboot= will cause us to disable DMI checking
* below.
*/
reboot_default = 0;
if (!strncmp(str, "panic_", 6)) {
mode = &panic_reboot_mode;
str += 6;
} else {
mode = &reboot_mode;
}
switch (*str) {
case 'w':
*mode = REBOOT_WARM;
break;
case 'c':
*mode = REBOOT_COLD;
break;
case 'h':
*mode = REBOOT_HARD;
break;
case 's':
/*
* reboot_cpu is s[mp]#### with #### being the processor
* to be used for rebooting. Skip 's' or 'smp' prefix.
*/
str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
if (isdigit(str[0])) {
int cpu = simple_strtoul(str, NULL, 0);
if (cpu >= num_possible_cpus()) {
pr_err("Ignoring the CPU number in reboot= option. "
"CPU %d exceeds possible cpu number %d\n",
cpu, num_possible_cpus());
break;
}
reboot_cpu = cpu;
} else
*mode = REBOOT_SOFT;
break;
case 'g':
*mode = REBOOT_GPIO;
break;
case 'b':
case 'a':
case 'k':
case 't':
case 'e':
case 'p':
reboot_type = *str;
break;
case 'f':
reboot_force = 1;
break;
}
str = strchr(str, ',');
if (str)
str++;
else
break;
}
return 1;
}
__setup("reboot=", reboot_setup);
#ifdef CONFIG_SYSFS
#define REBOOT_COLD_STR "cold"
#define REBOOT_WARM_STR "warm"
#define REBOOT_HARD_STR "hard"
#define REBOOT_SOFT_STR "soft"
#define REBOOT_GPIO_STR "gpio"
#define REBOOT_UNDEFINED_STR "undefined"
#define BOOT_TRIPLE_STR "triple"
#define BOOT_KBD_STR "kbd"
#define BOOT_BIOS_STR "bios"
#define BOOT_ACPI_STR "acpi"
#define BOOT_EFI_STR "efi"
#define BOOT_PCI_STR "pci"
static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
const char *val;
switch (reboot_mode) {
case REBOOT_COLD:
val = REBOOT_COLD_STR;
break;
case REBOOT_WARM:
val = REBOOT_WARM_STR;
break;
case REBOOT_HARD:
val = REBOOT_HARD_STR;
break;
case REBOOT_SOFT:
val = REBOOT_SOFT_STR;
break;
case REBOOT_GPIO:
val = REBOOT_GPIO_STR;
break;
default:
val = REBOOT_UNDEFINED_STR;
}
return sprintf(buf, "%s\n", val);
}
static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
reboot_mode = REBOOT_COLD;
else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
reboot_mode = REBOOT_WARM;
else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
reboot_mode = REBOOT_HARD;
else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
reboot_mode = REBOOT_SOFT;
else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
reboot_mode = REBOOT_GPIO;
else
return -EINVAL;
reboot_default = 0;
return count;
}
static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
#ifdef CONFIG_X86
static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", reboot_force);
}
static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
bool res;
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (kstrtobool(buf, &res))
return -EINVAL;
reboot_default = 0;
reboot_force = res;
return count;
}
static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
const char *val;
switch (reboot_type) {
case BOOT_TRIPLE:
val = BOOT_TRIPLE_STR;
break;
case BOOT_KBD:
val = BOOT_KBD_STR;
break;
case BOOT_BIOS:
val = BOOT_BIOS_STR;
break;
case BOOT_ACPI:
val = BOOT_ACPI_STR;
break;
case BOOT_EFI:
val = BOOT_EFI_STR;
break;
case BOOT_CF9_FORCE:
val = BOOT_PCI_STR;
break;
default:
val = REBOOT_UNDEFINED_STR;
}
return sprintf(buf, "%s\n", val);
}
static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
reboot_type = BOOT_TRIPLE;
else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
reboot_type = BOOT_KBD;
else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
reboot_type = BOOT_BIOS;
else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
reboot_type = BOOT_ACPI;
else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
reboot_type = BOOT_EFI;
else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
reboot_type = BOOT_CF9_FORCE;
else
return -EINVAL;
reboot_default = 0;
return count;
}
static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
#endif
#ifdef CONFIG_SMP
static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", reboot_cpu);
}
static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned int cpunum;
int rc;
if (!capable(CAP_SYS_BOOT))
return -EPERM;
rc = kstrtouint(buf, 0, &cpunum);
if (rc)
return rc;
if (cpunum >= num_possible_cpus())
return -ERANGE;
reboot_default = 0;
reboot_cpu = cpunum;
return count;
}
static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
#endif
static struct attribute *reboot_attrs[] = {
&reboot_mode_attr.attr,
#ifdef CONFIG_X86
&reboot_force_attr.attr,
&reboot_type_attr.attr,
#endif
#ifdef CONFIG_SMP
&reboot_cpu_attr.attr,
#endif
NULL,
};
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_reboot_table[] = {
{
.procname = "poweroff_cmd",
.data = &poweroff_cmd,
.maxlen = POWEROFF_CMD_PATH_LEN,
.mode = 0644,
.proc_handler = proc_dostring,
},
{
.procname = "ctrl-alt-del",
.data = &C_A_D,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static void __init kernel_reboot_sysctls_init(void)
{
register_sysctl_init("kernel", kern_reboot_table);
}
#else
#define kernel_reboot_sysctls_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
static const struct attribute_group reboot_attr_group = {
.attrs = reboot_attrs,
};
static int __init reboot_ksysfs_init(void)
{
struct kobject *reboot_kobj;
int ret;
reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
if (!reboot_kobj)
return -ENOMEM;
ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
if (ret) {
kobject_put(reboot_kobj);
return ret;
}
kernel_reboot_sysctls_init();
return 0;
}
late_initcall(reboot_ksysfs_init);
#endif
| linux-master | kernel/reboot.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/seccomp.c
*
* Copyright 2004-2005 Andrea Arcangeli <[email protected]>
*
* Copyright (C) 2012 Google, Inc.
* Will Drewry <[email protected]>
*
* This defines a simple but solid secure-computing facility.
*
* Mode 1 uses a fixed list of allowed system calls.
* Mode 2 allows user-defined system call filters in the form
* of Berkeley Packet Filters/Linux Socket Filters.
*/
#define pr_fmt(fmt) "seccomp: " fmt
#include <linux/refcount.h>
#include <linux/audit.h>
#include <linux/compat.h>
#include <linux/coredump.h>
#include <linux/kmemleak.h>
#include <linux/nospec.h>
#include <linux/prctl.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/seccomp.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/sysctl.h>
/* Not exposed in headers: strictly internal use only. */
#define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1)
#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
#include <asm/syscall.h>
#endif
#ifdef CONFIG_SECCOMP_FILTER
#include <linux/file.h>
#include <linux/filter.h>
#include <linux/pid.h>
#include <linux/ptrace.h>
#include <linux/capability.h>
#include <linux/uaccess.h>
#include <linux/anon_inodes.h>
#include <linux/lockdep.h>
/*
* When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the
* wrong direction flag in the ioctl number. This is the broken one,
* which the kernel needs to keep supporting until all userspaces stop
* using the wrong command number.
*/
#define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR SECCOMP_IOR(2, __u64)
enum notify_state {
SECCOMP_NOTIFY_INIT,
SECCOMP_NOTIFY_SENT,
SECCOMP_NOTIFY_REPLIED,
};
struct seccomp_knotif {
/* The struct pid of the task whose filter triggered the notification */
struct task_struct *task;
/* The "cookie" for this request; this is unique for this filter. */
u64 id;
/*
* The seccomp data. This pointer is valid the entire time this
* notification is active, since it comes from __seccomp_filter which
* eclipses the entire lifecycle here.
*/
const struct seccomp_data *data;
/*
* Notification states. When SECCOMP_RET_USER_NOTIF is returned, a
* struct seccomp_knotif is created and starts out in INIT. Once the
* handler reads the notification off of an FD, it transitions to SENT.
* If a signal is received the state transitions back to INIT and
* another message is sent. When the userspace handler replies, state
* transitions to REPLIED.
*/
enum notify_state state;
/* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */
int error;
long val;
u32 flags;
/*
* Signals when this has changed states, such as the listener
* dying, a new seccomp addfd message, or changing to REPLIED
*/
struct completion ready;
struct list_head list;
/* outstanding addfd requests */
struct list_head addfd;
};
/**
* struct seccomp_kaddfd - container for seccomp_addfd ioctl messages
*
* @file: A reference to the file to install in the other task
* @fd: The fd number to install it at. If the fd number is -1, it means the
* installing process should allocate the fd as normal.
* @flags: The flags for the new file descriptor. At the moment, only O_CLOEXEC
* is allowed.
* @ioctl_flags: The flags used for the seccomp_addfd ioctl.
* @setfd: whether or not SECCOMP_ADDFD_FLAG_SETFD was set during notify_addfd
* @ret: The return value of the installing process. It is set to the fd num
* upon success (>= 0).
* @completion: Indicates that the installing process has completed fd
* installation, or gone away (either due to successful
* reply, or signal)
* @list: list_head for chaining seccomp_kaddfd together.
*
*/
struct seccomp_kaddfd {
struct file *file;
int fd;
unsigned int flags;
__u32 ioctl_flags;
union {
bool setfd;
/* To only be set on reply */
int ret;
};
struct completion completion;
struct list_head list;
};
/**
* struct notification - container for seccomp userspace notifications. Since
* most seccomp filters will not have notification listeners attached and this
* structure is fairly large, we store the notification-specific stuff in a
* separate structure.
*
* @requests: A semaphore that users of this notification can wait on for
* changes. Actual reads and writes are still controlled with
* filter->notify_lock.
* @flags: A set of SECCOMP_USER_NOTIF_FD_* flags.
* @next_id: The id of the next request.
* @notifications: A list of struct seccomp_knotif elements.
*/
struct notification {
atomic_t requests;
u32 flags;
u64 next_id;
struct list_head notifications;
};
#ifdef SECCOMP_ARCH_NATIVE
/**
* struct action_cache - per-filter cache of seccomp actions per
* arch/syscall pair
*
* @allow_native: A bitmap where each bit represents whether the
* filter will always allow the syscall, for the
* native architecture.
* @allow_compat: A bitmap where each bit represents whether the
* filter will always allow the syscall, for the
* compat architecture.
*/
struct action_cache {
DECLARE_BITMAP(allow_native, SECCOMP_ARCH_NATIVE_NR);
#ifdef SECCOMP_ARCH_COMPAT
DECLARE_BITMAP(allow_compat, SECCOMP_ARCH_COMPAT_NR);
#endif
};
#else
struct action_cache { };
static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter,
const struct seccomp_data *sd)
{
return false;
}
static inline void seccomp_cache_prepare(struct seccomp_filter *sfilter)
{
}
#endif /* SECCOMP_ARCH_NATIVE */
/**
* struct seccomp_filter - container for seccomp BPF programs
*
* @refs: Reference count to manage the object lifetime.
* A filter's reference count is incremented for each directly
* attached task, once for the dependent filter, and if
* requested for the user notifier. When @refs reaches zero,
* the filter can be freed.
* @users: A filter's @users count is incremented for each directly
* attached task (filter installation, fork(), thread_sync),
* and once for the dependent filter (tracked in filter->prev).
* When it reaches zero it indicates that no direct or indirect
* users of that filter exist. No new tasks can get associated with
* this filter after reaching 0. The @users count is always smaller
* or equal to @refs. Hence, reaching 0 for @users does not mean
* the filter can be freed.
* @cache: cache of arch/syscall mappings to actions
* @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
* @wait_killable_recv: Put notifying process in killable state once the
* notification is received by the userspace listener.
* @prev: points to a previously installed, or inherited, filter
* @prog: the BPF program to evaluate
* @notif: the struct that holds all notification related information
* @notify_lock: A lock for all notification-related accesses.
* @wqh: A wait queue for poll if a notifier is in use.
*
* seccomp_filter objects are organized in a tree linked via the @prev
* pointer. For any task, it appears to be a singly-linked list starting
* with current->seccomp.filter, the most recently attached or inherited filter.
* However, multiple filters may share a @prev node, by way of fork(), which
* results in a unidirectional tree existing in memory. This is similar to
* how namespaces work.
*
* seccomp_filter objects should never be modified after being attached
* to a task_struct (other than @refs).
*/
struct seccomp_filter {
refcount_t refs;
refcount_t users;
bool log;
bool wait_killable_recv;
struct action_cache cache;
struct seccomp_filter *prev;
struct bpf_prog *prog;
struct notification *notif;
struct mutex notify_lock;
wait_queue_head_t wqh;
};
/* Limit any path through the tree to 256KB worth of instructions. */
#define MAX_INSNS_PER_PATH ((1 << 18) / sizeof(struct sock_filter))
/*
* Endianness is explicitly ignored and left for BPF program authors to manage
* as per the specific architecture.
*/
static void populate_seccomp_data(struct seccomp_data *sd)
{
/*
* Instead of using current_pt_reg(), we're already doing the work
* to safely fetch "current", so just use "task" everywhere below.
*/
struct task_struct *task = current;
struct pt_regs *regs = task_pt_regs(task);
unsigned long args[6];
sd->nr = syscall_get_nr(task, regs);
sd->arch = syscall_get_arch(task);
syscall_get_arguments(task, regs, args);
sd->args[0] = args[0];
sd->args[1] = args[1];
sd->args[2] = args[2];
sd->args[3] = args[3];
sd->args[4] = args[4];
sd->args[5] = args[5];
sd->instruction_pointer = KSTK_EIP(task);
}
/**
* seccomp_check_filter - verify seccomp filter code
* @filter: filter to verify
* @flen: length of filter
*
* Takes a previously checked filter (by bpf_check_classic) and
* redirects all filter code that loads struct sk_buff data
* and related data through seccomp_bpf_load. It also
* enforces length and alignment checking of those loads.
*
* Returns 0 if the rule set is legal or -EINVAL if not.
*/
static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
{
int pc;
for (pc = 0; pc < flen; pc++) {
struct sock_filter *ftest = &filter[pc];
u16 code = ftest->code;
u32 k = ftest->k;
switch (code) {
case BPF_LD | BPF_W | BPF_ABS:
ftest->code = BPF_LDX | BPF_W | BPF_ABS;
/* 32-bit aligned and not out of bounds. */
if (k >= sizeof(struct seccomp_data) || k & 3)
return -EINVAL;
continue;
case BPF_LD | BPF_W | BPF_LEN:
ftest->code = BPF_LD | BPF_IMM;
ftest->k = sizeof(struct seccomp_data);
continue;
case BPF_LDX | BPF_W | BPF_LEN:
ftest->code = BPF_LDX | BPF_IMM;
ftest->k = sizeof(struct seccomp_data);
continue;
/* Explicitly include allowed calls. */
case BPF_RET | BPF_K:
case BPF_RET | BPF_A:
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU | BPF_LSH | BPF_K:
case BPF_ALU | BPF_LSH | BPF_X:
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU | BPF_RSH | BPF_X:
case BPF_ALU | BPF_NEG:
case BPF_LD | BPF_IMM:
case BPF_LDX | BPF_IMM:
case BPF_MISC | BPF_TAX:
case BPF_MISC | BPF_TXA:
case BPF_LD | BPF_MEM:
case BPF_LDX | BPF_MEM:
case BPF_ST:
case BPF_STX:
case BPF_JMP | BPF_JA:
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP | BPF_JSET | BPF_X:
continue;
default:
return -EINVAL;
}
}
return 0;
}
#ifdef SECCOMP_ARCH_NATIVE
static inline bool seccomp_cache_check_allow_bitmap(const void *bitmap,
size_t bitmap_size,
int syscall_nr)
{
if (unlikely(syscall_nr < 0 || syscall_nr >= bitmap_size))
return false;
syscall_nr = array_index_nospec(syscall_nr, bitmap_size);
return test_bit(syscall_nr, bitmap);
}
/**
* seccomp_cache_check_allow - lookup seccomp cache
* @sfilter: The seccomp filter
* @sd: The seccomp data to lookup the cache with
*
* Returns true if the seccomp_data is cached and allowed.
*/
static inline bool seccomp_cache_check_allow(const struct seccomp_filter *sfilter,
const struct seccomp_data *sd)
{
int syscall_nr = sd->nr;
const struct action_cache *cache = &sfilter->cache;
#ifndef SECCOMP_ARCH_COMPAT
/* A native-only architecture doesn't need to check sd->arch. */
return seccomp_cache_check_allow_bitmap(cache->allow_native,
SECCOMP_ARCH_NATIVE_NR,
syscall_nr);
#else
if (likely(sd->arch == SECCOMP_ARCH_NATIVE))
return seccomp_cache_check_allow_bitmap(cache->allow_native,
SECCOMP_ARCH_NATIVE_NR,
syscall_nr);
if (likely(sd->arch == SECCOMP_ARCH_COMPAT))
return seccomp_cache_check_allow_bitmap(cache->allow_compat,
SECCOMP_ARCH_COMPAT_NR,
syscall_nr);
#endif /* SECCOMP_ARCH_COMPAT */
WARN_ON_ONCE(true);
return false;
}
#endif /* SECCOMP_ARCH_NATIVE */
#define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL)))
/**
* seccomp_run_filters - evaluates all seccomp filters against @sd
* @sd: optional seccomp data to be passed to filters
* @match: stores struct seccomp_filter that resulted in the return value,
* unless filter returned SECCOMP_RET_ALLOW, in which case it will
* be unchanged.
*
* Returns valid seccomp BPF response codes.
*/
static u32 seccomp_run_filters(const struct seccomp_data *sd,
struct seccomp_filter **match)
{
u32 ret = SECCOMP_RET_ALLOW;
/* Make sure cross-thread synced filter points somewhere sane. */
struct seccomp_filter *f =
READ_ONCE(current->seccomp.filter);
/* Ensure unexpected behavior doesn't result in failing open. */
if (WARN_ON(f == NULL))
return SECCOMP_RET_KILL_PROCESS;
if (seccomp_cache_check_allow(f, sd))
return SECCOMP_RET_ALLOW;
/*
* All filters in the list are evaluated and the lowest BPF return
* value always takes priority (ignoring the DATA).
*/
for (; f; f = f->prev) {
u32 cur_ret = bpf_prog_run_pin_on_cpu(f->prog, sd);
if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) {
ret = cur_ret;
*match = f;
}
}
return ret;
}
#endif /* CONFIG_SECCOMP_FILTER */
static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
{
assert_spin_locked(¤t->sighand->siglock);
if (current->seccomp.mode && current->seccomp.mode != seccomp_mode)
return false;
return true;
}
void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { }
static inline void seccomp_assign_mode(struct task_struct *task,
unsigned long seccomp_mode,
unsigned long flags)
{
assert_spin_locked(&task->sighand->siglock);
task->seccomp.mode = seccomp_mode;
/*
* Make sure SYSCALL_WORK_SECCOMP cannot be set before the mode (and
* filter) is set.
*/
smp_mb__before_atomic();
/* Assume default seccomp processes want spec flaw mitigation. */
if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0)
arch_seccomp_spec_mitigate(task);
set_task_syscall_work(task, SECCOMP);
}
#ifdef CONFIG_SECCOMP_FILTER
/* Returns 1 if the parent is an ancestor of the child. */
static int is_ancestor(struct seccomp_filter *parent,
struct seccomp_filter *child)
{
/* NULL is the root ancestor. */
if (parent == NULL)
return 1;
for (; child; child = child->prev)
if (child == parent)
return 1;
return 0;
}
/**
* seccomp_can_sync_threads: checks if all threads can be synchronized
*
* Expects sighand and cred_guard_mutex locks to be held.
*
* Returns 0 on success, -ve on error, or the pid of a thread which was
* either not in the correct seccomp mode or did not have an ancestral
* seccomp filter.
*/
static inline pid_t seccomp_can_sync_threads(void)
{
struct task_struct *thread, *caller;
BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex));
assert_spin_locked(¤t->sighand->siglock);
/* Validate all threads being eligible for synchronization. */
caller = current;
for_each_thread(caller, thread) {
pid_t failed;
/* Skip current, since it is initiating the sync. */
if (thread == caller)
continue;
if (thread->seccomp.mode == SECCOMP_MODE_DISABLED ||
(thread->seccomp.mode == SECCOMP_MODE_FILTER &&
is_ancestor(thread->seccomp.filter,
caller->seccomp.filter)))
continue;
/* Return the first thread that cannot be synchronized. */
failed = task_pid_vnr(thread);
/* If the pid cannot be resolved, then return -ESRCH */
if (WARN_ON(failed == 0))
failed = -ESRCH;
return failed;
}
return 0;
}
static inline void seccomp_filter_free(struct seccomp_filter *filter)
{
if (filter) {
bpf_prog_destroy(filter->prog);
kfree(filter);
}
}
static void __seccomp_filter_orphan(struct seccomp_filter *orig)
{
while (orig && refcount_dec_and_test(&orig->users)) {
if (waitqueue_active(&orig->wqh))
wake_up_poll(&orig->wqh, EPOLLHUP);
orig = orig->prev;
}
}
static void __put_seccomp_filter(struct seccomp_filter *orig)
{
/* Clean up single-reference branches iteratively. */
while (orig && refcount_dec_and_test(&orig->refs)) {
struct seccomp_filter *freeme = orig;
orig = orig->prev;
seccomp_filter_free(freeme);
}
}
static void __seccomp_filter_release(struct seccomp_filter *orig)
{
/* Notify about any unused filters in the task's former filter tree. */
__seccomp_filter_orphan(orig);
/* Finally drop all references to the task's former tree. */
__put_seccomp_filter(orig);
}
/**
* seccomp_filter_release - Detach the task from its filter tree,
* drop its reference count, and notify
* about unused filters
*
* @tsk: task the filter should be released from.
*
* This function should only be called when the task is exiting as
* it detaches it from its filter tree. As such, READ_ONCE() and
* barriers are not needed here, as would normally be needed.
*/
void seccomp_filter_release(struct task_struct *tsk)
{
struct seccomp_filter *orig = tsk->seccomp.filter;
/* We are effectively holding the siglock by not having any sighand. */
WARN_ON(tsk->sighand != NULL);
/* Detach task from its filter tree. */
tsk->seccomp.filter = NULL;
__seccomp_filter_release(orig);
}
/**
* seccomp_sync_threads: sets all threads to use current's filter
*
* @flags: SECCOMP_FILTER_FLAG_* flags to set during sync.
*
* Expects sighand and cred_guard_mutex locks to be held, and for
* seccomp_can_sync_threads() to have returned success already
* without dropping the locks.
*
*/
static inline void seccomp_sync_threads(unsigned long flags)
{
struct task_struct *thread, *caller;
BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex));
assert_spin_locked(¤t->sighand->siglock);
/* Synchronize all threads. */
caller = current;
for_each_thread(caller, thread) {
/* Skip current, since it needs no changes. */
if (thread == caller)
continue;
/* Get a task reference for the new leaf node. */
get_seccomp_filter(caller);
/*
* Drop the task reference to the shared ancestor since
* current's path will hold a reference. (This also
* allows a put before the assignment.)
*/
__seccomp_filter_release(thread->seccomp.filter);
/* Make our new filter tree visible. */
smp_store_release(&thread->seccomp.filter,
caller->seccomp.filter);
atomic_set(&thread->seccomp.filter_count,
atomic_read(&caller->seccomp.filter_count));
/*
* Don't let an unprivileged task work around
* the no_new_privs restriction by creating
* a thread that sets it up, enters seccomp,
* then dies.
*/
if (task_no_new_privs(caller))
task_set_no_new_privs(thread);
/*
* Opt the other thread into seccomp if needed.
* As threads are considered to be trust-realm
* equivalent (see ptrace_may_access), it is safe to
* allow one thread to transition the other.
*/
if (thread->seccomp.mode == SECCOMP_MODE_DISABLED)
seccomp_assign_mode(thread, SECCOMP_MODE_FILTER,
flags);
}
}
/**
* seccomp_prepare_filter: Prepares a seccomp filter for use.
* @fprog: BPF program to install
*
* Returns filter on success or an ERR_PTR on failure.
*/
static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
{
struct seccomp_filter *sfilter;
int ret;
const bool save_orig =
#if defined(CONFIG_CHECKPOINT_RESTORE) || defined(SECCOMP_ARCH_NATIVE)
true;
#else
false;
#endif
if (fprog->len == 0 || fprog->len > BPF_MAXINSNS)
return ERR_PTR(-EINVAL);
BUG_ON(INT_MAX / fprog->len < sizeof(struct sock_filter));
/*
* Installing a seccomp filter requires that the task has
* CAP_SYS_ADMIN in its namespace or be running with no_new_privs.
* This avoids scenarios where unprivileged tasks can affect the
* behavior of privileged children.
*/
if (!task_no_new_privs(current) &&
!ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN))
return ERR_PTR(-EACCES);
/* Allocate a new seccomp_filter */
sfilter = kzalloc(sizeof(*sfilter), GFP_KERNEL | __GFP_NOWARN);
if (!sfilter)
return ERR_PTR(-ENOMEM);
mutex_init(&sfilter->notify_lock);
ret = bpf_prog_create_from_user(&sfilter->prog, fprog,
seccomp_check_filter, save_orig);
if (ret < 0) {
kfree(sfilter);
return ERR_PTR(ret);
}
refcount_set(&sfilter->refs, 1);
refcount_set(&sfilter->users, 1);
init_waitqueue_head(&sfilter->wqh);
return sfilter;
}
/**
* seccomp_prepare_user_filter - prepares a user-supplied sock_fprog
* @user_filter: pointer to the user data containing a sock_fprog.
*
* Returns 0 on success and non-zero otherwise.
*/
static struct seccomp_filter *
seccomp_prepare_user_filter(const char __user *user_filter)
{
struct sock_fprog fprog;
struct seccomp_filter *filter = ERR_PTR(-EFAULT);
#ifdef CONFIG_COMPAT
if (in_compat_syscall()) {
struct compat_sock_fprog fprog32;
if (copy_from_user(&fprog32, user_filter, sizeof(fprog32)))
goto out;
fprog.len = fprog32.len;
fprog.filter = compat_ptr(fprog32.filter);
} else /* falls through to the if below. */
#endif
if (copy_from_user(&fprog, user_filter, sizeof(fprog)))
goto out;
filter = seccomp_prepare_filter(&fprog);
out:
return filter;
}
#ifdef SECCOMP_ARCH_NATIVE
/**
* seccomp_is_const_allow - check if filter is constant allow with given data
* @fprog: The BPF programs
* @sd: The seccomp data to check against, only syscall number and arch
* number are considered constant.
*/
static bool seccomp_is_const_allow(struct sock_fprog_kern *fprog,
struct seccomp_data *sd)
{
unsigned int reg_value = 0;
unsigned int pc;
bool op_res;
if (WARN_ON_ONCE(!fprog))
return false;
for (pc = 0; pc < fprog->len; pc++) {
struct sock_filter *insn = &fprog->filter[pc];
u16 code = insn->code;
u32 k = insn->k;
switch (code) {
case BPF_LD | BPF_W | BPF_ABS:
switch (k) {
case offsetof(struct seccomp_data, nr):
reg_value = sd->nr;
break;
case offsetof(struct seccomp_data, arch):
reg_value = sd->arch;
break;
default:
/* can't optimize (non-constant value load) */
return false;
}
break;
case BPF_RET | BPF_K:
/* reached return with constant values only, check allow */
return k == SECCOMP_RET_ALLOW;
case BPF_JMP | BPF_JA:
pc += insn->k;
break;
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JSET | BPF_K:
switch (BPF_OP(code)) {
case BPF_JEQ:
op_res = reg_value == k;
break;
case BPF_JGE:
op_res = reg_value >= k;
break;
case BPF_JGT:
op_res = reg_value > k;
break;
case BPF_JSET:
op_res = !!(reg_value & k);
break;
default:
/* can't optimize (unknown jump) */
return false;
}
pc += op_res ? insn->jt : insn->jf;
break;
case BPF_ALU | BPF_AND | BPF_K:
reg_value &= k;
break;
default:
/* can't optimize (unknown insn) */
return false;
}
}
/* ran off the end of the filter?! */
WARN_ON(1);
return false;
}
static void seccomp_cache_prepare_bitmap(struct seccomp_filter *sfilter,
void *bitmap, const void *bitmap_prev,
size_t bitmap_size, int arch)
{
struct sock_fprog_kern *fprog = sfilter->prog->orig_prog;
struct seccomp_data sd;
int nr;
if (bitmap_prev) {
/* The new filter must be as restrictive as the last. */
bitmap_copy(bitmap, bitmap_prev, bitmap_size);
} else {
/* Before any filters, all syscalls are always allowed. */
bitmap_fill(bitmap, bitmap_size);
}
for (nr = 0; nr < bitmap_size; nr++) {
/* No bitmap change: not a cacheable action. */
if (!test_bit(nr, bitmap))
continue;
sd.nr = nr;
sd.arch = arch;
/* No bitmap change: continue to always allow. */
if (seccomp_is_const_allow(fprog, &sd))
continue;
/*
* Not a cacheable action: always run filters.
* atomic clear_bit() not needed, filter not visible yet.
*/
__clear_bit(nr, bitmap);
}
}
/**
* seccomp_cache_prepare - emulate the filter to find cacheable syscalls
* @sfilter: The seccomp filter
*
* Returns 0 if successful or -errno if error occurred.
*/
static void seccomp_cache_prepare(struct seccomp_filter *sfilter)
{
struct action_cache *cache = &sfilter->cache;
const struct action_cache *cache_prev =
sfilter->prev ? &sfilter->prev->cache : NULL;
seccomp_cache_prepare_bitmap(sfilter, cache->allow_native,
cache_prev ? cache_prev->allow_native : NULL,
SECCOMP_ARCH_NATIVE_NR,
SECCOMP_ARCH_NATIVE);
#ifdef SECCOMP_ARCH_COMPAT
seccomp_cache_prepare_bitmap(sfilter, cache->allow_compat,
cache_prev ? cache_prev->allow_compat : NULL,
SECCOMP_ARCH_COMPAT_NR,
SECCOMP_ARCH_COMPAT);
#endif /* SECCOMP_ARCH_COMPAT */
}
#endif /* SECCOMP_ARCH_NATIVE */
/**
* seccomp_attach_filter: validate and attach filter
* @flags: flags to change filter behavior
* @filter: seccomp filter to add to the current process
*
* Caller must be holding current->sighand->siglock lock.
*
* Returns 0 on success, -ve on error, or
* - in TSYNC mode: the pid of a thread which was either not in the correct
* seccomp mode or did not have an ancestral seccomp filter
* - in NEW_LISTENER mode: the fd of the new listener
*/
static long seccomp_attach_filter(unsigned int flags,
struct seccomp_filter *filter)
{
unsigned long total_insns;
struct seccomp_filter *walker;
assert_spin_locked(¤t->sighand->siglock);
/* Validate resulting filter length. */
total_insns = filter->prog->len;
for (walker = current->seccomp.filter; walker; walker = walker->prev)
total_insns += walker->prog->len + 4; /* 4 instr penalty */
if (total_insns > MAX_INSNS_PER_PATH)
return -ENOMEM;
/* If thread sync has been requested, check that it is possible. */
if (flags & SECCOMP_FILTER_FLAG_TSYNC) {
int ret;
ret = seccomp_can_sync_threads();
if (ret) {
if (flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH)
return -ESRCH;
else
return ret;
}
}
/* Set log flag, if present. */
if (flags & SECCOMP_FILTER_FLAG_LOG)
filter->log = true;
/* Set wait killable flag, if present. */
if (flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV)
filter->wait_killable_recv = true;
/*
* If there is an existing filter, make it the prev and don't drop its
* task reference.
*/
filter->prev = current->seccomp.filter;
seccomp_cache_prepare(filter);
current->seccomp.filter = filter;
atomic_inc(¤t->seccomp.filter_count);
/* Now that the new filter is in place, synchronize to all threads. */
if (flags & SECCOMP_FILTER_FLAG_TSYNC)
seccomp_sync_threads(flags);
return 0;
}
static void __get_seccomp_filter(struct seccomp_filter *filter)
{
refcount_inc(&filter->refs);
}
/* get_seccomp_filter - increments the reference count of the filter on @tsk */
void get_seccomp_filter(struct task_struct *tsk)
{
struct seccomp_filter *orig = tsk->seccomp.filter;
if (!orig)
return;
__get_seccomp_filter(orig);
refcount_inc(&orig->users);
}
#endif /* CONFIG_SECCOMP_FILTER */
/* For use with seccomp_actions_logged */
#define SECCOMP_LOG_KILL_PROCESS (1 << 0)
#define SECCOMP_LOG_KILL_THREAD (1 << 1)
#define SECCOMP_LOG_TRAP (1 << 2)
#define SECCOMP_LOG_ERRNO (1 << 3)
#define SECCOMP_LOG_TRACE (1 << 4)
#define SECCOMP_LOG_LOG (1 << 5)
#define SECCOMP_LOG_ALLOW (1 << 6)
#define SECCOMP_LOG_USER_NOTIF (1 << 7)
static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS |
SECCOMP_LOG_KILL_THREAD |
SECCOMP_LOG_TRAP |
SECCOMP_LOG_ERRNO |
SECCOMP_LOG_USER_NOTIF |
SECCOMP_LOG_TRACE |
SECCOMP_LOG_LOG;
static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
bool requested)
{
bool log = false;
switch (action) {
case SECCOMP_RET_ALLOW:
break;
case SECCOMP_RET_TRAP:
log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP;
break;
case SECCOMP_RET_ERRNO:
log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO;
break;
case SECCOMP_RET_TRACE:
log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE;
break;
case SECCOMP_RET_USER_NOTIF:
log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF;
break;
case SECCOMP_RET_LOG:
log = seccomp_actions_logged & SECCOMP_LOG_LOG;
break;
case SECCOMP_RET_KILL_THREAD:
log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD;
break;
case SECCOMP_RET_KILL_PROCESS:
default:
log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS;
}
/*
* Emit an audit message when the action is RET_KILL_*, RET_LOG, or the
* FILTER_FLAG_LOG bit was set. The admin has the ability to silence
* any action from being logged by removing the action name from the
* seccomp_actions_logged sysctl.
*/
if (!log)
return;
audit_seccomp(syscall, signr, action);
}
/*
* Secure computing mode 1 allows only read/write/exit/sigreturn.
* To be fully secure this must be combined with rlimit
* to limit the stack allocations too.
*/
static const int mode1_syscalls[] = {
__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
-1, /* negative terminated */
};
static void __secure_computing_strict(int this_syscall)
{
const int *allowed_syscalls = mode1_syscalls;
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
allowed_syscalls = get_compat_mode1_syscalls();
#endif
do {
if (*allowed_syscalls == this_syscall)
return;
} while (*++allowed_syscalls != -1);
#ifdef SECCOMP_DEBUG
dump_stack();
#endif
current->seccomp.mode = SECCOMP_MODE_DEAD;
seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true);
do_exit(SIGKILL);
}
#ifndef CONFIG_HAVE_ARCH_SECCOMP_FILTER
void secure_computing_strict(int this_syscall)
{
int mode = current->seccomp.mode;
if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
return;
if (mode == SECCOMP_MODE_DISABLED)
return;
else if (mode == SECCOMP_MODE_STRICT)
__secure_computing_strict(this_syscall);
else
BUG();
}
#else
#ifdef CONFIG_SECCOMP_FILTER
static u64 seccomp_next_notify_id(struct seccomp_filter *filter)
{
/*
* Note: overflow is ok here, the id just needs to be unique per
* filter.
*/
lockdep_assert_held(&filter->notify_lock);
return filter->notif->next_id++;
}
static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_knotif *n)
{
int fd;
/*
* Remove the notification, and reset the list pointers, indicating
* that it has been handled.
*/
list_del_init(&addfd->list);
if (!addfd->setfd)
fd = receive_fd(addfd->file, addfd->flags);
else
fd = receive_fd_replace(addfd->fd, addfd->file, addfd->flags);
addfd->ret = fd;
if (addfd->ioctl_flags & SECCOMP_ADDFD_FLAG_SEND) {
/* If we fail reset and return an error to the notifier */
if (fd < 0) {
n->state = SECCOMP_NOTIFY_SENT;
} else {
/* Return the FD we just added */
n->flags = 0;
n->error = 0;
n->val = fd;
}
}
/*
* Mark the notification as completed. From this point, addfd mem
* might be invalidated and we can't safely read it anymore.
*/
complete(&addfd->completion);
}
static bool should_sleep_killable(struct seccomp_filter *match,
struct seccomp_knotif *n)
{
return match->wait_killable_recv && n->state == SECCOMP_NOTIFY_SENT;
}
static int seccomp_do_user_notification(int this_syscall,
struct seccomp_filter *match,
const struct seccomp_data *sd)
{
int err;
u32 flags = 0;
long ret = 0;
struct seccomp_knotif n = {};
struct seccomp_kaddfd *addfd, *tmp;
mutex_lock(&match->notify_lock);
err = -ENOSYS;
if (!match->notif)
goto out;
n.task = current;
n.state = SECCOMP_NOTIFY_INIT;
n.data = sd;
n.id = seccomp_next_notify_id(match);
init_completion(&n.ready);
list_add_tail(&n.list, &match->notif->notifications);
INIT_LIST_HEAD(&n.addfd);
atomic_inc(&match->notif->requests);
if (match->notif->flags & SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP)
wake_up_poll_on_current_cpu(&match->wqh, EPOLLIN | EPOLLRDNORM);
else
wake_up_poll(&match->wqh, EPOLLIN | EPOLLRDNORM);
/*
* This is where we wait for a reply from userspace.
*/
do {
bool wait_killable = should_sleep_killable(match, &n);
mutex_unlock(&match->notify_lock);
if (wait_killable)
err = wait_for_completion_killable(&n.ready);
else
err = wait_for_completion_interruptible(&n.ready);
mutex_lock(&match->notify_lock);
if (err != 0) {
/*
* Check to see if the notifcation got picked up and
* whether we should switch to wait killable.
*/
if (!wait_killable && should_sleep_killable(match, &n))
continue;
goto interrupted;
}
addfd = list_first_entry_or_null(&n.addfd,
struct seccomp_kaddfd, list);
/* Check if we were woken up by a addfd message */
if (addfd)
seccomp_handle_addfd(addfd, &n);
} while (n.state != SECCOMP_NOTIFY_REPLIED);
ret = n.val;
err = n.error;
flags = n.flags;
interrupted:
/* If there were any pending addfd calls, clear them out */
list_for_each_entry_safe(addfd, tmp, &n.addfd, list) {
/* The process went away before we got a chance to handle it */
addfd->ret = -ESRCH;
list_del_init(&addfd->list);
complete(&addfd->completion);
}
/*
* Note that it's possible the listener died in between the time when
* we were notified of a response (or a signal) and when we were able to
* re-acquire the lock, so only delete from the list if the
* notification actually exists.
*
* Also note that this test is only valid because there's no way to
* *reattach* to a notifier right now. If one is added, we'll need to
* keep track of the notif itself and make sure they match here.
*/
if (match->notif)
list_del(&n.list);
out:
mutex_unlock(&match->notify_lock);
/* Userspace requests to continue the syscall. */
if (flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE)
return 0;
syscall_set_return_value(current, current_pt_regs(),
err, ret);
return -1;
}
static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
const bool recheck_after_trace)
{
u32 filter_ret, action;
struct seccomp_filter *match = NULL;
int data;
struct seccomp_data sd_local;
/*
* Make sure that any changes to mode from another thread have
* been seen after SYSCALL_WORK_SECCOMP was seen.
*/
smp_rmb();
if (!sd) {
populate_seccomp_data(&sd_local);
sd = &sd_local;
}
filter_ret = seccomp_run_filters(sd, &match);
data = filter_ret & SECCOMP_RET_DATA;
action = filter_ret & SECCOMP_RET_ACTION_FULL;
switch (action) {
case SECCOMP_RET_ERRNO:
/* Set low-order bits as an errno, capped at MAX_ERRNO. */
if (data > MAX_ERRNO)
data = MAX_ERRNO;
syscall_set_return_value(current, current_pt_regs(),
-data, 0);
goto skip;
case SECCOMP_RET_TRAP:
/* Show the handler the original registers. */
syscall_rollback(current, current_pt_regs());
/* Let the filter pass back 16 bits of data. */
force_sig_seccomp(this_syscall, data, false);
goto skip;
case SECCOMP_RET_TRACE:
/* We've been put in this state by the ptracer already. */
if (recheck_after_trace)
return 0;
/* ENOSYS these calls if there is no tracer attached. */
if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) {
syscall_set_return_value(current,
current_pt_regs(),
-ENOSYS, 0);
goto skip;
}
/* Allow the BPF to provide the event message */
ptrace_event(PTRACE_EVENT_SECCOMP, data);
/*
* The delivery of a fatal signal during event
* notification may silently skip tracer notification,
* which could leave us with a potentially unmodified
* syscall that the tracer would have liked to have
* changed. Since the process is about to die, we just
* force the syscall to be skipped and let the signal
* kill the process and correctly handle any tracer exit
* notifications.
*/
if (fatal_signal_pending(current))
goto skip;
/* Check if the tracer forced the syscall to be skipped. */
this_syscall = syscall_get_nr(current, current_pt_regs());
if (this_syscall < 0)
goto skip;
/*
* Recheck the syscall, since it may have changed. This
* intentionally uses a NULL struct seccomp_data to force
* a reload of all registers. This does not goto skip since
* a skip would have already been reported.
*/
if (__seccomp_filter(this_syscall, NULL, true))
return -1;
return 0;
case SECCOMP_RET_USER_NOTIF:
if (seccomp_do_user_notification(this_syscall, match, sd))
goto skip;
return 0;
case SECCOMP_RET_LOG:
seccomp_log(this_syscall, 0, action, true);
return 0;
case SECCOMP_RET_ALLOW:
/*
* Note that the "match" filter will always be NULL for
* this action since SECCOMP_RET_ALLOW is the starting
* state in seccomp_run_filters().
*/
return 0;
case SECCOMP_RET_KILL_THREAD:
case SECCOMP_RET_KILL_PROCESS:
default:
current->seccomp.mode = SECCOMP_MODE_DEAD;
seccomp_log(this_syscall, SIGSYS, action, true);
/* Dump core only if this is the last remaining thread. */
if (action != SECCOMP_RET_KILL_THREAD ||
(atomic_read(¤t->signal->live) == 1)) {
/* Show the original registers in the dump. */
syscall_rollback(current, current_pt_regs());
/* Trigger a coredump with SIGSYS */
force_sig_seccomp(this_syscall, data, true);
} else {
do_exit(SIGSYS);
}
return -1; /* skip the syscall go directly to signal handling */
}
unreachable();
skip:
seccomp_log(this_syscall, 0, action, match ? match->log : false);
return -1;
}
#else
static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
const bool recheck_after_trace)
{
BUG();
return -1;
}
#endif
int __secure_computing(const struct seccomp_data *sd)
{
int mode = current->seccomp.mode;
int this_syscall;
if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&
unlikely(current->ptrace & PT_SUSPEND_SECCOMP))
return 0;
this_syscall = sd ? sd->nr :
syscall_get_nr(current, current_pt_regs());
switch (mode) {
case SECCOMP_MODE_STRICT:
__secure_computing_strict(this_syscall); /* may call do_exit */
return 0;
case SECCOMP_MODE_FILTER:
return __seccomp_filter(this_syscall, sd, false);
/* Surviving SECCOMP_RET_KILL_* must be proactively impossible. */
case SECCOMP_MODE_DEAD:
WARN_ON_ONCE(1);
do_exit(SIGKILL);
return -1;
default:
BUG();
}
}
#endif /* CONFIG_HAVE_ARCH_SECCOMP_FILTER */
long prctl_get_seccomp(void)
{
return current->seccomp.mode;
}
/**
* seccomp_set_mode_strict: internal function for setting strict seccomp
*
* Once current->seccomp.mode is non-zero, it may not be changed.
*
* Returns 0 on success or -EINVAL on failure.
*/
static long seccomp_set_mode_strict(void)
{
const unsigned long seccomp_mode = SECCOMP_MODE_STRICT;
long ret = -EINVAL;
spin_lock_irq(¤t->sighand->siglock);
if (!seccomp_may_assign_mode(seccomp_mode))
goto out;
#ifdef TIF_NOTSC
disable_TSC();
#endif
seccomp_assign_mode(current, seccomp_mode, 0);
ret = 0;
out:
spin_unlock_irq(¤t->sighand->siglock);
return ret;
}
#ifdef CONFIG_SECCOMP_FILTER
static void seccomp_notify_free(struct seccomp_filter *filter)
{
kfree(filter->notif);
filter->notif = NULL;
}
static void seccomp_notify_detach(struct seccomp_filter *filter)
{
struct seccomp_knotif *knotif;
if (!filter)
return;
mutex_lock(&filter->notify_lock);
/*
* If this file is being closed because e.g. the task who owned it
* died, let's wake everyone up who was waiting on us.
*/
list_for_each_entry(knotif, &filter->notif->notifications, list) {
if (knotif->state == SECCOMP_NOTIFY_REPLIED)
continue;
knotif->state = SECCOMP_NOTIFY_REPLIED;
knotif->error = -ENOSYS;
knotif->val = 0;
/*
* We do not need to wake up any pending addfd messages, as
* the notifier will do that for us, as this just looks
* like a standard reply.
*/
complete(&knotif->ready);
}
seccomp_notify_free(filter);
mutex_unlock(&filter->notify_lock);
}
static int seccomp_notify_release(struct inode *inode, struct file *file)
{
struct seccomp_filter *filter = file->private_data;
seccomp_notify_detach(filter);
__put_seccomp_filter(filter);
return 0;
}
/* must be called with notif_lock held */
static inline struct seccomp_knotif *
find_notification(struct seccomp_filter *filter, u64 id)
{
struct seccomp_knotif *cur;
lockdep_assert_held(&filter->notify_lock);
list_for_each_entry(cur, &filter->notif->notifications, list) {
if (cur->id == id)
return cur;
}
return NULL;
}
static int recv_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync,
void *key)
{
/* Avoid a wakeup if event not interesting for us. */
if (key && !(key_to_poll(key) & (EPOLLIN | EPOLLERR)))
return 0;
return autoremove_wake_function(wait, mode, sync, key);
}
static int recv_wait_event(struct seccomp_filter *filter)
{
DEFINE_WAIT_FUNC(wait, recv_wake_function);
int ret;
if (atomic_dec_if_positive(&filter->notif->requests) >= 0)
return 0;
for (;;) {
ret = prepare_to_wait_event(&filter->wqh, &wait, TASK_INTERRUPTIBLE);
if (atomic_dec_if_positive(&filter->notif->requests) >= 0)
break;
if (ret)
return ret;
schedule();
}
finish_wait(&filter->wqh, &wait);
return 0;
}
static long seccomp_notify_recv(struct seccomp_filter *filter,
void __user *buf)
{
struct seccomp_knotif *knotif = NULL, *cur;
struct seccomp_notif unotif;
ssize_t ret;
/* Verify that we're not given garbage to keep struct extensible. */
ret = check_zeroed_user(buf, sizeof(unotif));
if (ret < 0)
return ret;
if (!ret)
return -EINVAL;
memset(&unotif, 0, sizeof(unotif));
ret = recv_wait_event(filter);
if (ret < 0)
return ret;
mutex_lock(&filter->notify_lock);
list_for_each_entry(cur, &filter->notif->notifications, list) {
if (cur->state == SECCOMP_NOTIFY_INIT) {
knotif = cur;
break;
}
}
/*
* If we didn't find a notification, it could be that the task was
* interrupted by a fatal signal between the time we were woken and
* when we were able to acquire the rw lock.
*/
if (!knotif) {
ret = -ENOENT;
goto out;
}
unotif.id = knotif->id;
unotif.pid = task_pid_vnr(knotif->task);
unotif.data = *(knotif->data);
knotif->state = SECCOMP_NOTIFY_SENT;
wake_up_poll(&filter->wqh, EPOLLOUT | EPOLLWRNORM);
ret = 0;
out:
mutex_unlock(&filter->notify_lock);
if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) {
ret = -EFAULT;
/*
* Userspace screwed up. To make sure that we keep this
* notification alive, let's reset it back to INIT. It
* may have died when we released the lock, so we need to make
* sure it's still around.
*/
mutex_lock(&filter->notify_lock);
knotif = find_notification(filter, unotif.id);
if (knotif) {
/* Reset the process to make sure it's not stuck */
if (should_sleep_killable(filter, knotif))
complete(&knotif->ready);
knotif->state = SECCOMP_NOTIFY_INIT;
atomic_inc(&filter->notif->requests);
wake_up_poll(&filter->wqh, EPOLLIN | EPOLLRDNORM);
}
mutex_unlock(&filter->notify_lock);
}
return ret;
}
static long seccomp_notify_send(struct seccomp_filter *filter,
void __user *buf)
{
struct seccomp_notif_resp resp = {};
struct seccomp_knotif *knotif;
long ret;
if (copy_from_user(&resp, buf, sizeof(resp)))
return -EFAULT;
if (resp.flags & ~SECCOMP_USER_NOTIF_FLAG_CONTINUE)
return -EINVAL;
if ((resp.flags & SECCOMP_USER_NOTIF_FLAG_CONTINUE) &&
(resp.error || resp.val))
return -EINVAL;
ret = mutex_lock_interruptible(&filter->notify_lock);
if (ret < 0)
return ret;
knotif = find_notification(filter, resp.id);
if (!knotif) {
ret = -ENOENT;
goto out;
}
/* Allow exactly one reply. */
if (knotif->state != SECCOMP_NOTIFY_SENT) {
ret = -EINPROGRESS;
goto out;
}
ret = 0;
knotif->state = SECCOMP_NOTIFY_REPLIED;
knotif->error = resp.error;
knotif->val = resp.val;
knotif->flags = resp.flags;
if (filter->notif->flags & SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP)
complete_on_current_cpu(&knotif->ready);
else
complete(&knotif->ready);
out:
mutex_unlock(&filter->notify_lock);
return ret;
}
static long seccomp_notify_id_valid(struct seccomp_filter *filter,
void __user *buf)
{
struct seccomp_knotif *knotif;
u64 id;
long ret;
if (copy_from_user(&id, buf, sizeof(id)))
return -EFAULT;
ret = mutex_lock_interruptible(&filter->notify_lock);
if (ret < 0)
return ret;
knotif = find_notification(filter, id);
if (knotif && knotif->state == SECCOMP_NOTIFY_SENT)
ret = 0;
else
ret = -ENOENT;
mutex_unlock(&filter->notify_lock);
return ret;
}
static long seccomp_notify_set_flags(struct seccomp_filter *filter,
unsigned long flags)
{
long ret;
if (flags & ~SECCOMP_USER_NOTIF_FD_SYNC_WAKE_UP)
return -EINVAL;
ret = mutex_lock_interruptible(&filter->notify_lock);
if (ret < 0)
return ret;
filter->notif->flags = flags;
mutex_unlock(&filter->notify_lock);
return 0;
}
static long seccomp_notify_addfd(struct seccomp_filter *filter,
struct seccomp_notif_addfd __user *uaddfd,
unsigned int size)
{
struct seccomp_notif_addfd addfd;
struct seccomp_knotif *knotif;
struct seccomp_kaddfd kaddfd;
int ret;
BUILD_BUG_ON(sizeof(addfd) < SECCOMP_NOTIFY_ADDFD_SIZE_VER0);
BUILD_BUG_ON(sizeof(addfd) != SECCOMP_NOTIFY_ADDFD_SIZE_LATEST);
if (size < SECCOMP_NOTIFY_ADDFD_SIZE_VER0 || size >= PAGE_SIZE)
return -EINVAL;
ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size);
if (ret)
return ret;
if (addfd.newfd_flags & ~O_CLOEXEC)
return -EINVAL;
if (addfd.flags & ~(SECCOMP_ADDFD_FLAG_SETFD | SECCOMP_ADDFD_FLAG_SEND))
return -EINVAL;
if (addfd.newfd && !(addfd.flags & SECCOMP_ADDFD_FLAG_SETFD))
return -EINVAL;
kaddfd.file = fget(addfd.srcfd);
if (!kaddfd.file)
return -EBADF;
kaddfd.ioctl_flags = addfd.flags;
kaddfd.flags = addfd.newfd_flags;
kaddfd.setfd = addfd.flags & SECCOMP_ADDFD_FLAG_SETFD;
kaddfd.fd = addfd.newfd;
init_completion(&kaddfd.completion);
ret = mutex_lock_interruptible(&filter->notify_lock);
if (ret < 0)
goto out;
knotif = find_notification(filter, addfd.id);
if (!knotif) {
ret = -ENOENT;
goto out_unlock;
}
/*
* We do not want to allow for FD injection to occur before the
* notification has been picked up by a userspace handler, or after
* the notification has been replied to.
*/
if (knotif->state != SECCOMP_NOTIFY_SENT) {
ret = -EINPROGRESS;
goto out_unlock;
}
if (addfd.flags & SECCOMP_ADDFD_FLAG_SEND) {
/*
* Disallow queuing an atomic addfd + send reply while there are
* some addfd requests still to process.
*
* There is no clear reason to support it and allows us to keep
* the loop on the other side straight-forward.
*/
if (!list_empty(&knotif->addfd)) {
ret = -EBUSY;
goto out_unlock;
}
/* Allow exactly only one reply */
knotif->state = SECCOMP_NOTIFY_REPLIED;
}
list_add(&kaddfd.list, &knotif->addfd);
complete(&knotif->ready);
mutex_unlock(&filter->notify_lock);
/* Now we wait for it to be processed or be interrupted */
ret = wait_for_completion_interruptible(&kaddfd.completion);
if (ret == 0) {
/*
* We had a successful completion. The other side has already
* removed us from the addfd queue, and
* wait_for_completion_interruptible has a memory barrier upon
* success that lets us read this value directly without
* locking.
*/
ret = kaddfd.ret;
goto out;
}
mutex_lock(&filter->notify_lock);
/*
* Even though we were woken up by a signal and not a successful
* completion, a completion may have happened in the mean time.
*
* We need to check again if the addfd request has been handled,
* and if not, we will remove it from the queue.
*/
if (list_empty(&kaddfd.list))
ret = kaddfd.ret;
else
list_del(&kaddfd.list);
out_unlock:
mutex_unlock(&filter->notify_lock);
out:
fput(kaddfd.file);
return ret;
}
static long seccomp_notify_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct seccomp_filter *filter = file->private_data;
void __user *buf = (void __user *)arg;
/* Fixed-size ioctls */
switch (cmd) {
case SECCOMP_IOCTL_NOTIF_RECV:
return seccomp_notify_recv(filter, buf);
case SECCOMP_IOCTL_NOTIF_SEND:
return seccomp_notify_send(filter, buf);
case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR:
case SECCOMP_IOCTL_NOTIF_ID_VALID:
return seccomp_notify_id_valid(filter, buf);
case SECCOMP_IOCTL_NOTIF_SET_FLAGS:
return seccomp_notify_set_flags(filter, arg);
}
/* Extensible Argument ioctls */
#define EA_IOCTL(cmd) ((cmd) & ~(IOC_INOUT | IOCSIZE_MASK))
switch (EA_IOCTL(cmd)) {
case EA_IOCTL(SECCOMP_IOCTL_NOTIF_ADDFD):
return seccomp_notify_addfd(filter, buf, _IOC_SIZE(cmd));
default:
return -EINVAL;
}
}
static __poll_t seccomp_notify_poll(struct file *file,
struct poll_table_struct *poll_tab)
{
struct seccomp_filter *filter = file->private_data;
__poll_t ret = 0;
struct seccomp_knotif *cur;
poll_wait(file, &filter->wqh, poll_tab);
if (mutex_lock_interruptible(&filter->notify_lock) < 0)
return EPOLLERR;
list_for_each_entry(cur, &filter->notif->notifications, list) {
if (cur->state == SECCOMP_NOTIFY_INIT)
ret |= EPOLLIN | EPOLLRDNORM;
if (cur->state == SECCOMP_NOTIFY_SENT)
ret |= EPOLLOUT | EPOLLWRNORM;
if ((ret & EPOLLIN) && (ret & EPOLLOUT))
break;
}
mutex_unlock(&filter->notify_lock);
if (refcount_read(&filter->users) == 0)
ret |= EPOLLHUP;
return ret;
}
static const struct file_operations seccomp_notify_ops = {
.poll = seccomp_notify_poll,
.release = seccomp_notify_release,
.unlocked_ioctl = seccomp_notify_ioctl,
.compat_ioctl = seccomp_notify_ioctl,
};
static struct file *init_listener(struct seccomp_filter *filter)
{
struct file *ret;
ret = ERR_PTR(-ENOMEM);
filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL);
if (!filter->notif)
goto out;
filter->notif->next_id = get_random_u64();
INIT_LIST_HEAD(&filter->notif->notifications);
ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops,
filter, O_RDWR);
if (IS_ERR(ret))
goto out_notif;
/* The file has a reference to it now */
__get_seccomp_filter(filter);
out_notif:
if (IS_ERR(ret))
seccomp_notify_free(filter);
out:
return ret;
}
/*
* Does @new_child have a listener while an ancestor also has a listener?
* If so, we'll want to reject this filter.
* This only has to be tested for the current process, even in the TSYNC case,
* because TSYNC installs @child with the same parent on all threads.
* Note that @new_child is not hooked up to its parent at this point yet, so
* we use current->seccomp.filter.
*/
static bool has_duplicate_listener(struct seccomp_filter *new_child)
{
struct seccomp_filter *cur;
/* must be protected against concurrent TSYNC */
lockdep_assert_held(¤t->sighand->siglock);
if (!new_child->notif)
return false;
for (cur = current->seccomp.filter; cur; cur = cur->prev) {
if (cur->notif)
return true;
}
return false;
}
/**
* seccomp_set_mode_filter: internal function for setting seccomp filter
* @flags: flags to change filter behavior
* @filter: struct sock_fprog containing filter
*
* This function may be called repeatedly to install additional filters.
* Every filter successfully installed will be evaluated (in reverse order)
* for each system call the task makes.
*
* Once current->seccomp.mode is non-zero, it may not be changed.
*
* Returns 0 on success or -EINVAL on failure.
*/
static long seccomp_set_mode_filter(unsigned int flags,
const char __user *filter)
{
const unsigned long seccomp_mode = SECCOMP_MODE_FILTER;
struct seccomp_filter *prepared = NULL;
long ret = -EINVAL;
int listener = -1;
struct file *listener_f = NULL;
/* Validate flags. */
if (flags & ~SECCOMP_FILTER_FLAG_MASK)
return -EINVAL;
/*
* In the successful case, NEW_LISTENER returns the new listener fd.
* But in the failure case, TSYNC returns the thread that died. If you
* combine these two flags, there's no way to tell whether something
* succeeded or failed. So, let's disallow this combination if the user
* has not explicitly requested no errors from TSYNC.
*/
if ((flags & SECCOMP_FILTER_FLAG_TSYNC) &&
(flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) &&
((flags & SECCOMP_FILTER_FLAG_TSYNC_ESRCH) == 0))
return -EINVAL;
/*
* The SECCOMP_FILTER_FLAG_WAIT_KILLABLE_SENT flag doesn't make sense
* without the SECCOMP_FILTER_FLAG_NEW_LISTENER flag.
*/
if ((flags & SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV) &&
((flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) == 0))
return -EINVAL;
/* Prepare the new filter before holding any locks. */
prepared = seccomp_prepare_user_filter(filter);
if (IS_ERR(prepared))
return PTR_ERR(prepared);
if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
listener = get_unused_fd_flags(O_CLOEXEC);
if (listener < 0) {
ret = listener;
goto out_free;
}
listener_f = init_listener(prepared);
if (IS_ERR(listener_f)) {
put_unused_fd(listener);
ret = PTR_ERR(listener_f);
goto out_free;
}
}
/*
* Make sure we cannot change seccomp or nnp state via TSYNC
* while another thread is in the middle of calling exec.
*/
if (flags & SECCOMP_FILTER_FLAG_TSYNC &&
mutex_lock_killable(¤t->signal->cred_guard_mutex))
goto out_put_fd;
spin_lock_irq(¤t->sighand->siglock);
if (!seccomp_may_assign_mode(seccomp_mode))
goto out;
if (has_duplicate_listener(prepared)) {
ret = -EBUSY;
goto out;
}
ret = seccomp_attach_filter(flags, prepared);
if (ret)
goto out;
/* Do not free the successfully attached filter. */
prepared = NULL;
seccomp_assign_mode(current, seccomp_mode, flags);
out:
spin_unlock_irq(¤t->sighand->siglock);
if (flags & SECCOMP_FILTER_FLAG_TSYNC)
mutex_unlock(¤t->signal->cred_guard_mutex);
out_put_fd:
if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
if (ret) {
listener_f->private_data = NULL;
fput(listener_f);
put_unused_fd(listener);
seccomp_notify_detach(prepared);
} else {
fd_install(listener, listener_f);
ret = listener;
}
}
out_free:
seccomp_filter_free(prepared);
return ret;
}
#else
static inline long seccomp_set_mode_filter(unsigned int flags,
const char __user *filter)
{
return -EINVAL;
}
#endif
static long seccomp_get_action_avail(const char __user *uaction)
{
u32 action;
if (copy_from_user(&action, uaction, sizeof(action)))
return -EFAULT;
switch (action) {
case SECCOMP_RET_KILL_PROCESS:
case SECCOMP_RET_KILL_THREAD:
case SECCOMP_RET_TRAP:
case SECCOMP_RET_ERRNO:
case SECCOMP_RET_USER_NOTIF:
case SECCOMP_RET_TRACE:
case SECCOMP_RET_LOG:
case SECCOMP_RET_ALLOW:
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static long seccomp_get_notif_sizes(void __user *usizes)
{
struct seccomp_notif_sizes sizes = {
.seccomp_notif = sizeof(struct seccomp_notif),
.seccomp_notif_resp = sizeof(struct seccomp_notif_resp),
.seccomp_data = sizeof(struct seccomp_data),
};
if (copy_to_user(usizes, &sizes, sizeof(sizes)))
return -EFAULT;
return 0;
}
/* Common entry point for both prctl and syscall. */
static long do_seccomp(unsigned int op, unsigned int flags,
void __user *uargs)
{
switch (op) {
case SECCOMP_SET_MODE_STRICT:
if (flags != 0 || uargs != NULL)
return -EINVAL;
return seccomp_set_mode_strict();
case SECCOMP_SET_MODE_FILTER:
return seccomp_set_mode_filter(flags, uargs);
case SECCOMP_GET_ACTION_AVAIL:
if (flags != 0)
return -EINVAL;
return seccomp_get_action_avail(uargs);
case SECCOMP_GET_NOTIF_SIZES:
if (flags != 0)
return -EINVAL;
return seccomp_get_notif_sizes(uargs);
default:
return -EINVAL;
}
}
SYSCALL_DEFINE3(seccomp, unsigned int, op, unsigned int, flags,
void __user *, uargs)
{
return do_seccomp(op, flags, uargs);
}
/**
* prctl_set_seccomp: configures current->seccomp.mode
* @seccomp_mode: requested mode to use
* @filter: optional struct sock_fprog for use with SECCOMP_MODE_FILTER
*
* Returns 0 on success or -EINVAL on failure.
*/
long prctl_set_seccomp(unsigned long seccomp_mode, void __user *filter)
{
unsigned int op;
void __user *uargs;
switch (seccomp_mode) {
case SECCOMP_MODE_STRICT:
op = SECCOMP_SET_MODE_STRICT;
/*
* Setting strict mode through prctl always ignored filter,
* so make sure it is always NULL here to pass the internal
* check in do_seccomp().
*/
uargs = NULL;
break;
case SECCOMP_MODE_FILTER:
op = SECCOMP_SET_MODE_FILTER;
uargs = filter;
break;
default:
return -EINVAL;
}
/* prctl interface doesn't have flags, so they are always zero. */
return do_seccomp(op, 0, uargs);
}
#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)
static struct seccomp_filter *get_nth_filter(struct task_struct *task,
unsigned long filter_off)
{
struct seccomp_filter *orig, *filter;
unsigned long count;
/*
* Note: this is only correct because the caller should be the (ptrace)
* tracer of the task, otherwise lock_task_sighand is needed.
*/
spin_lock_irq(&task->sighand->siglock);
if (task->seccomp.mode != SECCOMP_MODE_FILTER) {
spin_unlock_irq(&task->sighand->siglock);
return ERR_PTR(-EINVAL);
}
orig = task->seccomp.filter;
__get_seccomp_filter(orig);
spin_unlock_irq(&task->sighand->siglock);
count = 0;
for (filter = orig; filter; filter = filter->prev)
count++;
if (filter_off >= count) {
filter = ERR_PTR(-ENOENT);
goto out;
}
count -= filter_off;
for (filter = orig; filter && count > 1; filter = filter->prev)
count--;
if (WARN_ON(count != 1 || !filter)) {
filter = ERR_PTR(-ENOENT);
goto out;
}
__get_seccomp_filter(filter);
out:
__put_seccomp_filter(orig);
return filter;
}
long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
void __user *data)
{
struct seccomp_filter *filter;
struct sock_fprog_kern *fprog;
long ret;
if (!capable(CAP_SYS_ADMIN) ||
current->seccomp.mode != SECCOMP_MODE_DISABLED) {
return -EACCES;
}
filter = get_nth_filter(task, filter_off);
if (IS_ERR(filter))
return PTR_ERR(filter);
fprog = filter->prog->orig_prog;
if (!fprog) {
/* This must be a new non-cBPF filter, since we save
* every cBPF filter's orig_prog above when
* CONFIG_CHECKPOINT_RESTORE is enabled.
*/
ret = -EMEDIUMTYPE;
goto out;
}
ret = fprog->len;
if (!data)
goto out;
if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
ret = -EFAULT;
out:
__put_seccomp_filter(filter);
return ret;
}
long seccomp_get_metadata(struct task_struct *task,
unsigned long size, void __user *data)
{
long ret;
struct seccomp_filter *filter;
struct seccomp_metadata kmd = {};
if (!capable(CAP_SYS_ADMIN) ||
current->seccomp.mode != SECCOMP_MODE_DISABLED) {
return -EACCES;
}
size = min_t(unsigned long, size, sizeof(kmd));
if (size < sizeof(kmd.filter_off))
return -EINVAL;
if (copy_from_user(&kmd.filter_off, data, sizeof(kmd.filter_off)))
return -EFAULT;
filter = get_nth_filter(task, kmd.filter_off);
if (IS_ERR(filter))
return PTR_ERR(filter);
if (filter->log)
kmd.flags |= SECCOMP_FILTER_FLAG_LOG;
ret = size;
if (copy_to_user(data, &kmd, size))
ret = -EFAULT;
__put_seccomp_filter(filter);
return ret;
}
#endif
#ifdef CONFIG_SYSCTL
/* Human readable action names for friendly sysctl interaction */
#define SECCOMP_RET_KILL_PROCESS_NAME "kill_process"
#define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
#define SECCOMP_RET_TRAP_NAME "trap"
#define SECCOMP_RET_ERRNO_NAME "errno"
#define SECCOMP_RET_USER_NOTIF_NAME "user_notif"
#define SECCOMP_RET_TRACE_NAME "trace"
#define SECCOMP_RET_LOG_NAME "log"
#define SECCOMP_RET_ALLOW_NAME "allow"
static const char seccomp_actions_avail[] =
SECCOMP_RET_KILL_PROCESS_NAME " "
SECCOMP_RET_KILL_THREAD_NAME " "
SECCOMP_RET_TRAP_NAME " "
SECCOMP_RET_ERRNO_NAME " "
SECCOMP_RET_USER_NOTIF_NAME " "
SECCOMP_RET_TRACE_NAME " "
SECCOMP_RET_LOG_NAME " "
SECCOMP_RET_ALLOW_NAME;
struct seccomp_log_name {
u32 log;
const char *name;
};
static const struct seccomp_log_name seccomp_log_names[] = {
{ SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME },
{ SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
{ SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
{ SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
{ SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME },
{ SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },
{ SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME },
{ SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME },
{ }
};
static bool seccomp_names_from_actions_logged(char *names, size_t size,
u32 actions_logged,
const char *sep)
{
const struct seccomp_log_name *cur;
bool append_sep = false;
for (cur = seccomp_log_names; cur->name && size; cur++) {
ssize_t ret;
if (!(actions_logged & cur->log))
continue;
if (append_sep) {
ret = strscpy(names, sep, size);
if (ret < 0)
return false;
names += ret;
size -= ret;
} else
append_sep = true;
ret = strscpy(names, cur->name, size);
if (ret < 0)
return false;
names += ret;
size -= ret;
}
return true;
}
static bool seccomp_action_logged_from_name(u32 *action_logged,
const char *name)
{
const struct seccomp_log_name *cur;
for (cur = seccomp_log_names; cur->name; cur++) {
if (!strcmp(cur->name, name)) {
*action_logged = cur->log;
return true;
}
}
return false;
}
static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names)
{
char *name;
*actions_logged = 0;
while ((name = strsep(&names, " ")) && *name) {
u32 action_logged = 0;
if (!seccomp_action_logged_from_name(&action_logged, name))
return false;
*actions_logged |= action_logged;
}
return true;
}
static int read_actions_logged(struct ctl_table *ro_table, void *buffer,
size_t *lenp, loff_t *ppos)
{
char names[sizeof(seccomp_actions_avail)];
struct ctl_table table;
memset(names, 0, sizeof(names));
if (!seccomp_names_from_actions_logged(names, sizeof(names),
seccomp_actions_logged, " "))
return -EINVAL;
table = *ro_table;
table.data = names;
table.maxlen = sizeof(names);
return proc_dostring(&table, 0, buffer, lenp, ppos);
}
static int write_actions_logged(struct ctl_table *ro_table, void *buffer,
size_t *lenp, loff_t *ppos, u32 *actions_logged)
{
char names[sizeof(seccomp_actions_avail)];
struct ctl_table table;
int ret;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
memset(names, 0, sizeof(names));
table = *ro_table;
table.data = names;
table.maxlen = sizeof(names);
ret = proc_dostring(&table, 1, buffer, lenp, ppos);
if (ret)
return ret;
if (!seccomp_actions_logged_from_names(actions_logged, table.data))
return -EINVAL;
if (*actions_logged & SECCOMP_LOG_ALLOW)
return -EINVAL;
seccomp_actions_logged = *actions_logged;
return 0;
}
static void audit_actions_logged(u32 actions_logged, u32 old_actions_logged,
int ret)
{
char names[sizeof(seccomp_actions_avail)];
char old_names[sizeof(seccomp_actions_avail)];
const char *new = names;
const char *old = old_names;
if (!audit_enabled)
return;
memset(names, 0, sizeof(names));
memset(old_names, 0, sizeof(old_names));
if (ret)
new = "?";
else if (!actions_logged)
new = "(none)";
else if (!seccomp_names_from_actions_logged(names, sizeof(names),
actions_logged, ","))
new = "?";
if (!old_actions_logged)
old = "(none)";
else if (!seccomp_names_from_actions_logged(old_names,
sizeof(old_names),
old_actions_logged, ","))
old = "?";
return audit_seccomp_actions_logged(new, old, !ret);
}
static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
void *buffer, size_t *lenp,
loff_t *ppos)
{
int ret;
if (write) {
u32 actions_logged = 0;
u32 old_actions_logged = seccomp_actions_logged;
ret = write_actions_logged(ro_table, buffer, lenp, ppos,
&actions_logged);
audit_actions_logged(actions_logged, old_actions_logged, ret);
} else
ret = read_actions_logged(ro_table, buffer, lenp, ppos);
return ret;
}
static struct ctl_table seccomp_sysctl_table[] = {
{
.procname = "actions_avail",
.data = (void *) &seccomp_actions_avail,
.maxlen = sizeof(seccomp_actions_avail),
.mode = 0444,
.proc_handler = proc_dostring,
},
{
.procname = "actions_logged",
.mode = 0644,
.proc_handler = seccomp_actions_logged_handler,
},
{ }
};
static int __init seccomp_sysctl_init(void)
{
register_sysctl_init("kernel/seccomp", seccomp_sysctl_table);
return 0;
}
device_initcall(seccomp_sysctl_init)
#endif /* CONFIG_SYSCTL */
#ifdef CONFIG_SECCOMP_CACHE_DEBUG
/* Currently CONFIG_SECCOMP_CACHE_DEBUG implies SECCOMP_ARCH_NATIVE */
static void proc_pid_seccomp_cache_arch(struct seq_file *m, const char *name,
const void *bitmap, size_t bitmap_size)
{
int nr;
for (nr = 0; nr < bitmap_size; nr++) {
bool cached = test_bit(nr, bitmap);
char *status = cached ? "ALLOW" : "FILTER";
seq_printf(m, "%s %d %s\n", name, nr, status);
}
}
int proc_pid_seccomp_cache(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
struct seccomp_filter *f;
unsigned long flags;
/*
* We don't want some sandboxed process to know what their seccomp
* filters consist of.
*/
if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
return -EACCES;
if (!lock_task_sighand(task, &flags))
return -ESRCH;
f = READ_ONCE(task->seccomp.filter);
if (!f) {
unlock_task_sighand(task, &flags);
return 0;
}
/* prevent filter from being freed while we are printing it */
__get_seccomp_filter(f);
unlock_task_sighand(task, &flags);
proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_NATIVE_NAME,
f->cache.allow_native,
SECCOMP_ARCH_NATIVE_NR);
#ifdef SECCOMP_ARCH_COMPAT
proc_pid_seccomp_cache_arch(m, SECCOMP_ARCH_COMPAT_NAME,
f->cache.allow_compat,
SECCOMP_ARCH_COMPAT_NR);
#endif /* SECCOMP_ARCH_COMPAT */
__put_seccomp_filter(f);
return 0;
}
#endif /* CONFIG_SECCOMP_CACHE_DEBUG */
| linux-master | kernel/seccomp.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/fdtable.h>
#include <linux/string.h>
#include <linux/random.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/cache.h>
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/kcmp.h>
#include <linux/capability.h>
#include <linux/list.h>
#include <linux/eventpoll.h>
#include <linux/file.h>
#include <asm/unistd.h>
/*
* We don't expose the real in-memory order of objects for security reasons.
* But still the comparison results should be suitable for sorting. So we
* obfuscate kernel pointers values and compare the production instead.
*
* The obfuscation is done in two steps. First we xor the kernel pointer with
* a random value, which puts pointer into a new position in a reordered space.
* Secondly we multiply the xor production with a large odd random number to
* permute its bits even more (the odd multiplier guarantees that the product
* is unique ever after the high bits are truncated, since any odd number is
* relative prime to 2^n).
*
* Note also that the obfuscation itself is invisible to userspace and if needed
* it can be changed to an alternate scheme.
*/
static unsigned long cookies[KCMP_TYPES][2] __read_mostly;
static long kptr_obfuscate(long v, int type)
{
return (v ^ cookies[type][0]) * cookies[type][1];
}
/*
* 0 - equal, i.e. v1 = v2
* 1 - less than, i.e. v1 < v2
* 2 - greater than, i.e. v1 > v2
* 3 - not equal but ordering unavailable (reserved for future)
*/
static int kcmp_ptr(void *v1, void *v2, enum kcmp_type type)
{
long t1, t2;
t1 = kptr_obfuscate((long)v1, type);
t2 = kptr_obfuscate((long)v2, type);
return (t1 < t2) | ((t1 > t2) << 1);
}
/* The caller must have pinned the task */
static struct file *
get_file_raw_ptr(struct task_struct *task, unsigned int idx)
{
struct file *file;
rcu_read_lock();
file = task_lookup_fd_rcu(task, idx);
rcu_read_unlock();
return file;
}
static void kcmp_unlock(struct rw_semaphore *l1, struct rw_semaphore *l2)
{
if (likely(l2 != l1))
up_read(l2);
up_read(l1);
}
static int kcmp_lock(struct rw_semaphore *l1, struct rw_semaphore *l2)
{
int err;
if (l2 > l1)
swap(l1, l2);
err = down_read_killable(l1);
if (!err && likely(l1 != l2)) {
err = down_read_killable_nested(l2, SINGLE_DEPTH_NESTING);
if (err)
up_read(l1);
}
return err;
}
#ifdef CONFIG_EPOLL
static int kcmp_epoll_target(struct task_struct *task1,
struct task_struct *task2,
unsigned long idx1,
struct kcmp_epoll_slot __user *uslot)
{
struct file *filp, *filp_epoll, *filp_tgt;
struct kcmp_epoll_slot slot;
if (copy_from_user(&slot, uslot, sizeof(slot)))
return -EFAULT;
filp = get_file_raw_ptr(task1, idx1);
if (!filp)
return -EBADF;
filp_epoll = fget_task(task2, slot.efd);
if (!filp_epoll)
return -EBADF;
filp_tgt = get_epoll_tfile_raw_ptr(filp_epoll, slot.tfd, slot.toff);
fput(filp_epoll);
if (IS_ERR(filp_tgt))
return PTR_ERR(filp_tgt);
return kcmp_ptr(filp, filp_tgt, KCMP_FILE);
}
#else
static int kcmp_epoll_target(struct task_struct *task1,
struct task_struct *task2,
unsigned long idx1,
struct kcmp_epoll_slot __user *uslot)
{
return -EOPNOTSUPP;
}
#endif
SYSCALL_DEFINE5(kcmp, pid_t, pid1, pid_t, pid2, int, type,
unsigned long, idx1, unsigned long, idx2)
{
struct task_struct *task1, *task2;
int ret;
rcu_read_lock();
/*
* Tasks are looked up in caller's PID namespace only.
*/
task1 = find_task_by_vpid(pid1);
task2 = find_task_by_vpid(pid2);
if (!task1 || !task2)
goto err_no_task;
get_task_struct(task1);
get_task_struct(task2);
rcu_read_unlock();
/*
* One should have enough rights to inspect task details.
*/
ret = kcmp_lock(&task1->signal->exec_update_lock,
&task2->signal->exec_update_lock);
if (ret)
goto err;
if (!ptrace_may_access(task1, PTRACE_MODE_READ_REALCREDS) ||
!ptrace_may_access(task2, PTRACE_MODE_READ_REALCREDS)) {
ret = -EPERM;
goto err_unlock;
}
switch (type) {
case KCMP_FILE: {
struct file *filp1, *filp2;
filp1 = get_file_raw_ptr(task1, idx1);
filp2 = get_file_raw_ptr(task2, idx2);
if (filp1 && filp2)
ret = kcmp_ptr(filp1, filp2, KCMP_FILE);
else
ret = -EBADF;
break;
}
case KCMP_VM:
ret = kcmp_ptr(task1->mm, task2->mm, KCMP_VM);
break;
case KCMP_FILES:
ret = kcmp_ptr(task1->files, task2->files, KCMP_FILES);
break;
case KCMP_FS:
ret = kcmp_ptr(task1->fs, task2->fs, KCMP_FS);
break;
case KCMP_SIGHAND:
ret = kcmp_ptr(task1->sighand, task2->sighand, KCMP_SIGHAND);
break;
case KCMP_IO:
ret = kcmp_ptr(task1->io_context, task2->io_context, KCMP_IO);
break;
case KCMP_SYSVSEM:
#ifdef CONFIG_SYSVIPC
ret = kcmp_ptr(task1->sysvsem.undo_list,
task2->sysvsem.undo_list,
KCMP_SYSVSEM);
#else
ret = -EOPNOTSUPP;
#endif
break;
case KCMP_EPOLL_TFD:
ret = kcmp_epoll_target(task1, task2, idx1, (void *)idx2);
break;
default:
ret = -EINVAL;
break;
}
err_unlock:
kcmp_unlock(&task1->signal->exec_update_lock,
&task2->signal->exec_update_lock);
err:
put_task_struct(task1);
put_task_struct(task2);
return ret;
err_no_task:
rcu_read_unlock();
return -ESRCH;
}
static __init int kcmp_cookies_init(void)
{
int i;
get_random_bytes(cookies, sizeof(cookies));
for (i = 0; i < KCMP_TYPES; i++)
cookies[i][1] |= (~(~0UL >> 1) | 1);
return 0;
}
arch_initcall(kcmp_cookies_init);
| linux-master | kernel/kcmp.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Provide kernel headers useful to build tracing programs
* such as for running eBPF tracing tools.
*
* (Borrowed code from kernel/configs.c)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/init.h>
/*
* Define kernel_headers_data and kernel_headers_data_end, within which the
* compressed kernel headers are stored. The file is first compressed with xz.
*/
asm (
" .pushsection .rodata, \"a\" \n"
" .global kernel_headers_data \n"
"kernel_headers_data: \n"
" .incbin \"kernel/kheaders_data.tar.xz\" \n"
" .global kernel_headers_data_end \n"
"kernel_headers_data_end: \n"
" .popsection \n"
);
extern char kernel_headers_data[];
extern char kernel_headers_data_end[];
static ssize_t
ikheaders_read(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t len)
{
memcpy(buf, &kernel_headers_data[off], len);
return len;
}
static struct bin_attribute kheaders_attr __ro_after_init = {
.attr = {
.name = "kheaders.tar.xz",
.mode = 0444,
},
.read = &ikheaders_read,
};
static int __init ikheaders_init(void)
{
kheaders_attr.size = (kernel_headers_data_end -
kernel_headers_data);
return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
}
static void __exit ikheaders_cleanup(void)
{
sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
}
module_init(ikheaders_init);
module_exit(ikheaders_cleanup);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Joel Fernandes");
MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");
| linux-master | kernel/kheaders.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* crash.c - kernel crash support code.
* Copyright (C) 2002-2004 Eric Biederman <[email protected]>
*/
#include <linux/buildid.h>
#include <linux/crash_core.h>
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/kexec.h>
#include <linux/memory.h>
#include <linux/cpuhotplug.h>
#include <asm/page.h>
#include <asm/sections.h>
#include <crypto/sha1.h>
#include "kallsyms_internal.h"
#include "kexec_internal.h"
/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;
/* vmcoreinfo stuff */
unsigned char *vmcoreinfo_data;
size_t vmcoreinfo_size;
u32 *vmcoreinfo_note;
/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
static unsigned char *vmcoreinfo_data_safecopy;
/*
* parsing the "crashkernel" commandline
*
* this code is intended to be called from architecture specific code
*/
/*
* This function parses command lines in the format
*
* crashkernel=ramsize-range:size[,...][@offset]
*
* The function returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_mem(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
char *cur = cmdline, *tmp;
unsigned long long total_mem = system_ram;
/*
* Firmware sometimes reserves some memory regions for its own use,
* so the system memory size is less than the actual physical memory
* size. Work around this by rounding up the total size to 128M,
* which is enough for most test cases.
*/
total_mem = roundup(total_mem, SZ_128M);
/* for each entry of the comma-separated list */
do {
unsigned long long start, end = ULLONG_MAX, size;
/* get the start of the range */
start = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("crashkernel: Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (*cur != '-') {
pr_warn("crashkernel: '-' expected\n");
return -EINVAL;
}
cur++;
/* if no ':' is here, than we read the end */
if (*cur != ':') {
end = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("crashkernel: Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (end <= start) {
pr_warn("crashkernel: end <= start\n");
return -EINVAL;
}
}
if (*cur != ':') {
pr_warn("crashkernel: ':' expected\n");
return -EINVAL;
}
cur++;
size = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("Memory value expected\n");
return -EINVAL;
}
cur = tmp;
if (size >= total_mem) {
pr_warn("crashkernel: invalid size\n");
return -EINVAL;
}
/* match ? */
if (total_mem >= start && total_mem < end) {
*crash_size = size;
break;
}
} while (*cur++ == ',');
if (*crash_size > 0) {
while (*cur && *cur != ' ' && *cur != '@')
cur++;
if (*cur == '@') {
cur++;
*crash_base = memparse(cur, &tmp);
if (cur == tmp) {
pr_warn("Memory value expected after '@'\n");
return -EINVAL;
}
}
} else
pr_info("crashkernel size resulted in zero bytes\n");
return 0;
}
/*
* That function parses "simple" (old) crashkernel command lines like
*
* crashkernel=size[@offset]
*
* It returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_simple(char *cmdline,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
char *cur = cmdline;
*crash_size = memparse(cmdline, &cur);
if (cmdline == cur) {
pr_warn("crashkernel: memory value expected\n");
return -EINVAL;
}
if (*cur == '@')
*crash_base = memparse(cur+1, &cur);
else if (*cur != ' ' && *cur != '\0') {
pr_warn("crashkernel: unrecognized char: %c\n", *cur);
return -EINVAL;
}
return 0;
}
#define SUFFIX_HIGH 0
#define SUFFIX_LOW 1
#define SUFFIX_NULL 2
static __initdata char *suffix_tbl[] = {
[SUFFIX_HIGH] = ",high",
[SUFFIX_LOW] = ",low",
[SUFFIX_NULL] = NULL,
};
/*
* That function parses "suffix" crashkernel command lines like
*
* crashkernel=size,[high|low]
*
* It returns 0 on success and -EINVAL on failure.
*/
static int __init parse_crashkernel_suffix(char *cmdline,
unsigned long long *crash_size,
const char *suffix)
{
char *cur = cmdline;
*crash_size = memparse(cmdline, &cur);
if (cmdline == cur) {
pr_warn("crashkernel: memory value expected\n");
return -EINVAL;
}
/* check with suffix */
if (strncmp(cur, suffix, strlen(suffix))) {
pr_warn("crashkernel: unrecognized char: %c\n", *cur);
return -EINVAL;
}
cur += strlen(suffix);
if (*cur != ' ' && *cur != '\0') {
pr_warn("crashkernel: unrecognized char: %c\n", *cur);
return -EINVAL;
}
return 0;
}
static __init char *get_last_crashkernel(char *cmdline,
const char *name,
const char *suffix)
{
char *p = cmdline, *ck_cmdline = NULL;
/* find crashkernel and use the last one if there are more */
p = strstr(p, name);
while (p) {
char *end_p = strchr(p, ' ');
char *q;
if (!end_p)
end_p = p + strlen(p);
if (!suffix) {
int i;
/* skip the one with any known suffix */
for (i = 0; suffix_tbl[i]; i++) {
q = end_p - strlen(suffix_tbl[i]);
if (!strncmp(q, suffix_tbl[i],
strlen(suffix_tbl[i])))
goto next;
}
ck_cmdline = p;
} else {
q = end_p - strlen(suffix);
if (!strncmp(q, suffix, strlen(suffix)))
ck_cmdline = p;
}
next:
p = strstr(p+1, name);
}
return ck_cmdline;
}
static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
const char *name,
const char *suffix)
{
char *first_colon, *first_space;
char *ck_cmdline;
BUG_ON(!crash_size || !crash_base);
*crash_size = 0;
*crash_base = 0;
ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
if (!ck_cmdline)
return -ENOENT;
ck_cmdline += strlen(name);
if (suffix)
return parse_crashkernel_suffix(ck_cmdline, crash_size,
suffix);
/*
* if the commandline contains a ':', then that's the extended
* syntax -- if not, it must be the classic syntax
*/
first_colon = strchr(ck_cmdline, ':');
first_space = strchr(ck_cmdline, ' ');
if (first_colon && (!first_space || first_colon < first_space))
return parse_crashkernel_mem(ck_cmdline, system_ram,
crash_size, crash_base);
return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
}
/*
* That function is the entry point for command line parsing and should be
* called from the arch-specific code.
*/
int __init parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", NULL);
}
int __init parse_crashkernel_high(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
}
int __init parse_crashkernel_low(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base)
{
return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
"crashkernel=", suffix_tbl[SUFFIX_LOW]);
}
/*
* Add a dummy early_param handler to mark crashkernel= as a known command line
* parameter and suppress incorrect warnings in init/main.c.
*/
static int __init parse_crashkernel_dummy(char *arg)
{
return 0;
}
early_param("crashkernel", parse_crashkernel_dummy);
int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
void **addr, unsigned long *sz)
{
Elf64_Ehdr *ehdr;
Elf64_Phdr *phdr;
unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
unsigned char *buf;
unsigned int cpu, i;
unsigned long long notes_addr;
unsigned long mstart, mend;
/* extra phdr for vmcoreinfo ELF note */
nr_phdr = nr_cpus + 1;
nr_phdr += mem->nr_ranges;
/*
* kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
* area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
* I think this is required by tools like gdb. So same physical
* memory will be mapped in two ELF headers. One will contain kernel
* text virtual addresses and other will have __va(physical) addresses.
*/
nr_phdr++;
elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
buf = vzalloc(elf_sz);
if (!buf)
return -ENOMEM;
ehdr = (Elf64_Ehdr *)buf;
phdr = (Elf64_Phdr *)(ehdr + 1);
memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
ehdr->e_ident[EI_CLASS] = ELFCLASS64;
ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
ehdr->e_ident[EI_OSABI] = ELF_OSABI;
memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
ehdr->e_type = ET_CORE;
ehdr->e_machine = ELF_ARCH;
ehdr->e_version = EV_CURRENT;
ehdr->e_phoff = sizeof(Elf64_Ehdr);
ehdr->e_ehsize = sizeof(Elf64_Ehdr);
ehdr->e_phentsize = sizeof(Elf64_Phdr);
/* Prepare one phdr of type PT_NOTE for each possible CPU */
for_each_possible_cpu(cpu) {
phdr->p_type = PT_NOTE;
notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
phdr->p_offset = phdr->p_paddr = notes_addr;
phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
(ehdr->e_phnum)++;
phdr++;
}
/* Prepare one PT_NOTE header for vmcoreinfo */
phdr->p_type = PT_NOTE;
phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
(ehdr->e_phnum)++;
phdr++;
/* Prepare PT_LOAD type program header for kernel text region */
if (need_kernel_map) {
phdr->p_type = PT_LOAD;
phdr->p_flags = PF_R|PF_W|PF_X;
phdr->p_vaddr = (unsigned long) _text;
phdr->p_filesz = phdr->p_memsz = _end - _text;
phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
ehdr->e_phnum++;
phdr++;
}
/* Go through all the ranges in mem->ranges[] and prepare phdr */
for (i = 0; i < mem->nr_ranges; i++) {
mstart = mem->ranges[i].start;
mend = mem->ranges[i].end;
phdr->p_type = PT_LOAD;
phdr->p_flags = PF_R|PF_W|PF_X;
phdr->p_offset = mstart;
phdr->p_paddr = mstart;
phdr->p_vaddr = (unsigned long) __va(mstart);
phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
phdr->p_align = 0;
ehdr->e_phnum++;
pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
ehdr->e_phnum, phdr->p_offset);
phdr++;
}
*addr = buf;
*sz = elf_sz;
return 0;
}
int crash_exclude_mem_range(struct crash_mem *mem,
unsigned long long mstart, unsigned long long mend)
{
int i, j;
unsigned long long start, end, p_start, p_end;
struct range temp_range = {0, 0};
for (i = 0; i < mem->nr_ranges; i++) {
start = mem->ranges[i].start;
end = mem->ranges[i].end;
p_start = mstart;
p_end = mend;
if (mstart > end || mend < start)
continue;
/* Truncate any area outside of range */
if (mstart < start)
p_start = start;
if (mend > end)
p_end = end;
/* Found completely overlapping range */
if (p_start == start && p_end == end) {
mem->ranges[i].start = 0;
mem->ranges[i].end = 0;
if (i < mem->nr_ranges - 1) {
/* Shift rest of the ranges to left */
for (j = i; j < mem->nr_ranges - 1; j++) {
mem->ranges[j].start =
mem->ranges[j+1].start;
mem->ranges[j].end =
mem->ranges[j+1].end;
}
/*
* Continue to check if there are another overlapping ranges
* from the current position because of shifting the above
* mem ranges.
*/
i--;
mem->nr_ranges--;
continue;
}
mem->nr_ranges--;
return 0;
}
if (p_start > start && p_end < end) {
/* Split original range */
mem->ranges[i].end = p_start - 1;
temp_range.start = p_end + 1;
temp_range.end = end;
} else if (p_start != start)
mem->ranges[i].end = p_start - 1;
else
mem->ranges[i].start = p_end + 1;
break;
}
/* If a split happened, add the split to array */
if (!temp_range.end)
return 0;
/* Split happened */
if (i == mem->max_nr_ranges - 1)
return -ENOMEM;
/* Location where new range should go */
j = i + 1;
if (j < mem->nr_ranges) {
/* Move over all ranges one slot towards the end */
for (i = mem->nr_ranges - 1; i >= j; i--)
mem->ranges[i + 1] = mem->ranges[i];
}
mem->ranges[j].start = temp_range.start;
mem->ranges[j].end = temp_range.end;
mem->nr_ranges++;
return 0;
}
Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len)
{
struct elf_note *note = (struct elf_note *)buf;
note->n_namesz = strlen(name) + 1;
note->n_descsz = data_len;
note->n_type = type;
buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
memcpy(buf, name, note->n_namesz);
buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
memcpy(buf, data, data_len);
buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
return buf;
}
void final_note(Elf_Word *buf)
{
memset(buf, 0, sizeof(struct elf_note));
}
static void update_vmcoreinfo_note(void)
{
u32 *buf = vmcoreinfo_note;
if (!vmcoreinfo_size)
return;
buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
vmcoreinfo_size);
final_note(buf);
}
void crash_update_vmcoreinfo_safecopy(void *ptr)
{
if (ptr)
memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
vmcoreinfo_data_safecopy = ptr;
}
void crash_save_vmcoreinfo(void)
{
if (!vmcoreinfo_note)
return;
/* Use the safe copy to generate vmcoreinfo note if have */
if (vmcoreinfo_data_safecopy)
vmcoreinfo_data = vmcoreinfo_data_safecopy;
vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
update_vmcoreinfo_note();
}
void vmcoreinfo_append_str(const char *fmt, ...)
{
va_list args;
char buf[0x50];
size_t r;
va_start(args, fmt);
r = vscnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
vmcoreinfo_size += r;
WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
"vmcoreinfo data exceeds allocated size, truncating");
}
/*
* provide an empty default implementation here -- architecture
* code may override this
*/
void __weak arch_crash_save_vmcoreinfo(void)
{}
phys_addr_t __weak paddr_vmcoreinfo_note(void)
{
return __pa(vmcoreinfo_note);
}
EXPORT_SYMBOL(paddr_vmcoreinfo_note);
static int __init crash_save_vmcoreinfo_init(void)
{
vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
if (!vmcoreinfo_data) {
pr_warn("Memory allocation for vmcoreinfo_data failed\n");
return -ENOMEM;
}
vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
GFP_KERNEL | __GFP_ZERO);
if (!vmcoreinfo_note) {
free_page((unsigned long)vmcoreinfo_data);
vmcoreinfo_data = NULL;
pr_warn("Memory allocation for vmcoreinfo_note failed\n");
return -ENOMEM;
}
VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
VMCOREINFO_BUILD_ID();
VMCOREINFO_PAGESIZE(PAGE_SIZE);
VMCOREINFO_SYMBOL(init_uts_ns);
VMCOREINFO_OFFSET(uts_namespace, name);
VMCOREINFO_SYMBOL(node_online_map);
#ifdef CONFIG_MMU
VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
#endif
VMCOREINFO_SYMBOL(_stext);
VMCOREINFO_SYMBOL(vmap_area_list);
#ifndef CONFIG_NUMA
VMCOREINFO_SYMBOL(mem_map);
VMCOREINFO_SYMBOL(contig_page_data);
#endif
#ifdef CONFIG_SPARSEMEM
VMCOREINFO_SYMBOL_ARRAY(mem_section);
VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
VMCOREINFO_STRUCT_SIZE(mem_section);
VMCOREINFO_OFFSET(mem_section, section_mem_map);
VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
#endif
VMCOREINFO_STRUCT_SIZE(page);
VMCOREINFO_STRUCT_SIZE(pglist_data);
VMCOREINFO_STRUCT_SIZE(zone);
VMCOREINFO_STRUCT_SIZE(free_area);
VMCOREINFO_STRUCT_SIZE(list_head);
VMCOREINFO_SIZE(nodemask_t);
VMCOREINFO_OFFSET(page, flags);
VMCOREINFO_OFFSET(page, _refcount);
VMCOREINFO_OFFSET(page, mapping);
VMCOREINFO_OFFSET(page, lru);
VMCOREINFO_OFFSET(page, _mapcount);
VMCOREINFO_OFFSET(page, private);
VMCOREINFO_OFFSET(page, compound_head);
VMCOREINFO_OFFSET(pglist_data, node_zones);
VMCOREINFO_OFFSET(pglist_data, nr_zones);
#ifdef CONFIG_FLATMEM
VMCOREINFO_OFFSET(pglist_data, node_mem_map);
#endif
VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
VMCOREINFO_OFFSET(pglist_data, node_id);
VMCOREINFO_OFFSET(zone, free_area);
VMCOREINFO_OFFSET(zone, vm_stat);
VMCOREINFO_OFFSET(zone, spanned_pages);
VMCOREINFO_OFFSET(free_area, free_list);
VMCOREINFO_OFFSET(list_head, next);
VMCOREINFO_OFFSET(list_head, prev);
VMCOREINFO_OFFSET(vmap_area, va_start);
VMCOREINFO_OFFSET(vmap_area, list);
VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
log_buf_vmcoreinfo_setup();
VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
VMCOREINFO_NUMBER(NR_FREE_PAGES);
VMCOREINFO_NUMBER(PG_lru);
VMCOREINFO_NUMBER(PG_private);
VMCOREINFO_NUMBER(PG_swapcache);
VMCOREINFO_NUMBER(PG_swapbacked);
VMCOREINFO_NUMBER(PG_slab);
#ifdef CONFIG_MEMORY_FAILURE
VMCOREINFO_NUMBER(PG_hwpoison);
#endif
VMCOREINFO_NUMBER(PG_head_mask);
#define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#ifdef CONFIG_HUGETLB_PAGE
VMCOREINFO_NUMBER(PG_hugetlb);
#define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline)
VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
#endif
#ifdef CONFIG_KALLSYMS
VMCOREINFO_SYMBOL(kallsyms_names);
VMCOREINFO_SYMBOL(kallsyms_num_syms);
VMCOREINFO_SYMBOL(kallsyms_token_table);
VMCOREINFO_SYMBOL(kallsyms_token_index);
#ifdef CONFIG_KALLSYMS_BASE_RELATIVE
VMCOREINFO_SYMBOL(kallsyms_offsets);
VMCOREINFO_SYMBOL(kallsyms_relative_base);
#else
VMCOREINFO_SYMBOL(kallsyms_addresses);
#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
#endif /* CONFIG_KALLSYMS */
arch_crash_save_vmcoreinfo();
update_vmcoreinfo_note();
return 0;
}
subsys_initcall(crash_save_vmcoreinfo_init);
static int __init crash_notes_memory_init(void)
{
/* Allocate memory for saving cpu registers. */
size_t size, align;
/*
* crash_notes could be allocated across 2 vmalloc pages when percpu
* is vmalloc based . vmalloc doesn't guarantee 2 continuous vmalloc
* pages are also on 2 continuous physical pages. In this case the
* 2nd part of crash_notes in 2nd page could be lost since only the
* starting address and size of crash_notes are exported through sysfs.
* Here round up the size of crash_notes to the nearest power of two
* and pass it to __alloc_percpu as align value. This can make sure
* crash_notes is allocated inside one physical page.
*/
size = sizeof(note_buf_t);
align = min(roundup_pow_of_two(sizeof(note_buf_t)), PAGE_SIZE);
/*
* Break compile if size is bigger than PAGE_SIZE since crash_notes
* definitely will be in 2 pages with that.
*/
BUILD_BUG_ON(size > PAGE_SIZE);
crash_notes = __alloc_percpu(size, align);
if (!crash_notes) {
pr_warn("Memory allocation for saving cpu register states failed\n");
return -ENOMEM;
}
return 0;
}
subsys_initcall(crash_notes_memory_init);
#ifdef CONFIG_CRASH_HOTPLUG
#undef pr_fmt
#define pr_fmt(fmt) "crash hp: " fmt
/*
* This routine utilized when the crash_hotplug sysfs node is read.
* It reflects the kernel's ability/permission to update the crash
* elfcorehdr directly.
*/
int crash_check_update_elfcorehdr(void)
{
int rc = 0;
/* Obtain lock while reading crash information */
if (!kexec_trylock()) {
pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
return 0;
}
if (kexec_crash_image) {
if (kexec_crash_image->file_mode)
rc = 1;
else
rc = kexec_crash_image->update_elfcorehdr;
}
/* Release lock now that update complete */
kexec_unlock();
return rc;
}
/*
* To accurately reflect hot un/plug changes of cpu and memory resources
* (including onling and offlining of those resources), the elfcorehdr
* (which is passed to the crash kernel via the elfcorehdr= parameter)
* must be updated with the new list of CPUs and memories.
*
* In order to make changes to elfcorehdr, two conditions are needed:
* First, the segment containing the elfcorehdr must be large enough
* to permit a growing number of resources; the elfcorehdr memory size
* is based on NR_CPUS_DEFAULT and CRASH_MAX_MEMORY_RANGES.
* Second, purgatory must explicitly exclude the elfcorehdr from the
* list of segments it checks (since the elfcorehdr changes and thus
* would require an update to purgatory itself to update the digest).
*/
static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
{
struct kimage *image;
/* Obtain lock while changing crash information */
if (!kexec_trylock()) {
pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n");
return;
}
/* Check kdump is not loaded */
if (!kexec_crash_image)
goto out;
image = kexec_crash_image;
/* Check that updating elfcorehdr is permitted */
if (!(image->file_mode || image->update_elfcorehdr))
goto out;
if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
else
pr_debug("hp_action %u\n", hp_action);
/*
* The elfcorehdr_index is set to -1 when the struct kimage
* is allocated. Find the segment containing the elfcorehdr,
* if not already found.
*/
if (image->elfcorehdr_index < 0) {
unsigned long mem;
unsigned char *ptr;
unsigned int n;
for (n = 0; n < image->nr_segments; n++) {
mem = image->segment[n].mem;
ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
if (ptr) {
/* The segment containing elfcorehdr */
if (memcmp(ptr, ELFMAG, SELFMAG) == 0)
image->elfcorehdr_index = (int)n;
kunmap_local(ptr);
}
}
}
if (image->elfcorehdr_index < 0) {
pr_err("unable to locate elfcorehdr segment");
goto out;
}
/* Needed in order for the segments to be updated */
arch_kexec_unprotect_crashkres();
/* Differentiate between normal load and hotplug update */
image->hp_action = hp_action;
/* Now invoke arch-specific update handler */
arch_crash_handle_hotplug_event(image);
/* No longer handling a hotplug event */
image->hp_action = KEXEC_CRASH_HP_NONE;
image->elfcorehdr_updated = true;
/* Change back to read-only */
arch_kexec_protect_crashkres();
/* Errors in the callback is not a reason to rollback state */
out:
/* Release lock now that update complete */
kexec_unlock();
}
static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
{
switch (val) {
case MEM_ONLINE:
crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
KEXEC_CRASH_HP_INVALID_CPU);
break;
case MEM_OFFLINE:
crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
KEXEC_CRASH_HP_INVALID_CPU);
break;
}
return NOTIFY_OK;
}
static struct notifier_block crash_memhp_nb = {
.notifier_call = crash_memhp_notifier,
.priority = 0
};
static int crash_cpuhp_online(unsigned int cpu)
{
crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
return 0;
}
static int crash_cpuhp_offline(unsigned int cpu)
{
crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
return 0;
}
static int __init crash_hotplug_init(void)
{
int result = 0;
if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
register_memory_notifier(&crash_memhp_nb);
if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
result = cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN,
"crash/cpuhp", crash_cpuhp_online, crash_cpuhp_offline);
}
return result;
}
subsys_initcall(crash_hotplug_init);
#endif
| linux-master | kernel/crash_core.c |
// SPDX-License-Identifier: GPL-2.0
/* Watch queue and general notification mechanism, built on pipes
*
* Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* See Documentation/core-api/watch_queue.rst
*/
#define pr_fmt(fmt) "watchq: " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/printk.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/file.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/sched/signal.h>
#include <linux/watch_queue.h>
#include <linux/pipe_fs_i.h>
MODULE_DESCRIPTION("Watch queue");
MODULE_AUTHOR("Red Hat, Inc.");
#define WATCH_QUEUE_NOTE_SIZE 128
#define WATCH_QUEUE_NOTES_PER_PAGE (PAGE_SIZE / WATCH_QUEUE_NOTE_SIZE)
/*
* This must be called under the RCU read-lock, which makes
* sure that the wqueue still exists. It can then take the lock,
* and check that the wqueue hasn't been destroyed, which in
* turn makes sure that the notification pipe still exists.
*/
static inline bool lock_wqueue(struct watch_queue *wqueue)
{
spin_lock_bh(&wqueue->lock);
if (unlikely(!wqueue->pipe)) {
spin_unlock_bh(&wqueue->lock);
return false;
}
return true;
}
static inline void unlock_wqueue(struct watch_queue *wqueue)
{
spin_unlock_bh(&wqueue->lock);
}
static void watch_queue_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct watch_queue *wqueue = (struct watch_queue *)buf->private;
struct page *page;
unsigned int bit;
/* We need to work out which note within the page this refers to, but
* the note might have been maximum size, so merely ANDing the offset
* off doesn't work. OTOH, the note must've been more than zero size.
*/
bit = buf->offset + buf->len;
if ((bit & (WATCH_QUEUE_NOTE_SIZE - 1)) == 0)
bit -= WATCH_QUEUE_NOTE_SIZE;
bit /= WATCH_QUEUE_NOTE_SIZE;
page = buf->page;
bit += page->index;
set_bit(bit, wqueue->notes_bitmap);
generic_pipe_buf_release(pipe, buf);
}
// No try_steal function => no stealing
#define watch_queue_pipe_buf_try_steal NULL
/* New data written to a pipe may be appended to a buffer with this type. */
static const struct pipe_buf_operations watch_queue_pipe_buf_ops = {
.release = watch_queue_pipe_buf_release,
.try_steal = watch_queue_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
/*
* Post a notification to a watch queue.
*
* Must be called with the RCU lock for reading, and the
* watch_queue lock held, which guarantees that the pipe
* hasn't been released.
*/
static bool post_one_notification(struct watch_queue *wqueue,
struct watch_notification *n)
{
void *p;
struct pipe_inode_info *pipe = wqueue->pipe;
struct pipe_buffer *buf;
struct page *page;
unsigned int head, tail, mask, note, offset, len;
bool done = false;
spin_lock_irq(&pipe->rd_wait.lock);
mask = pipe->ring_size - 1;
head = pipe->head;
tail = pipe->tail;
if (pipe_full(head, tail, pipe->ring_size))
goto lost;
note = find_first_bit(wqueue->notes_bitmap, wqueue->nr_notes);
if (note >= wqueue->nr_notes)
goto lost;
page = wqueue->notes[note / WATCH_QUEUE_NOTES_PER_PAGE];
offset = note % WATCH_QUEUE_NOTES_PER_PAGE * WATCH_QUEUE_NOTE_SIZE;
get_page(page);
len = n->info & WATCH_INFO_LENGTH;
p = kmap_atomic(page);
memcpy(p + offset, n, len);
kunmap_atomic(p);
buf = &pipe->bufs[head & mask];
buf->page = page;
buf->private = (unsigned long)wqueue;
buf->ops = &watch_queue_pipe_buf_ops;
buf->offset = offset;
buf->len = len;
buf->flags = PIPE_BUF_FLAG_WHOLE;
smp_store_release(&pipe->head, head + 1); /* vs pipe_read() */
if (!test_and_clear_bit(note, wqueue->notes_bitmap)) {
spin_unlock_irq(&pipe->rd_wait.lock);
BUG();
}
wake_up_interruptible_sync_poll_locked(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
done = true;
out:
spin_unlock_irq(&pipe->rd_wait.lock);
if (done)
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
return done;
lost:
buf = &pipe->bufs[(head - 1) & mask];
buf->flags |= PIPE_BUF_FLAG_LOSS;
goto out;
}
/*
* Apply filter rules to a notification.
*/
static bool filter_watch_notification(const struct watch_filter *wf,
const struct watch_notification *n)
{
const struct watch_type_filter *wt;
unsigned int st_bits = sizeof(wt->subtype_filter[0]) * 8;
unsigned int st_index = n->subtype / st_bits;
unsigned int st_bit = 1U << (n->subtype % st_bits);
int i;
if (!test_bit(n->type, wf->type_filter))
return false;
for (i = 0; i < wf->nr_filters; i++) {
wt = &wf->filters[i];
if (n->type == wt->type &&
(wt->subtype_filter[st_index] & st_bit) &&
(n->info & wt->info_mask) == wt->info_filter)
return true;
}
return false; /* If there is a filter, the default is to reject. */
}
/**
* __post_watch_notification - Post an event notification
* @wlist: The watch list to post the event to.
* @n: The notification record to post.
* @cred: The creds of the process that triggered the notification.
* @id: The ID to match on the watch.
*
* Post a notification of an event into a set of watch queues and let the users
* know.
*
* The size of the notification should be set in n->info & WATCH_INFO_LENGTH and
* should be in units of sizeof(*n).
*/
void __post_watch_notification(struct watch_list *wlist,
struct watch_notification *n,
const struct cred *cred,
u64 id)
{
const struct watch_filter *wf;
struct watch_queue *wqueue;
struct watch *watch;
if (((n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT) == 0) {
WARN_ON(1);
return;
}
rcu_read_lock();
hlist_for_each_entry_rcu(watch, &wlist->watchers, list_node) {
if (watch->id != id)
continue;
n->info &= ~WATCH_INFO_ID;
n->info |= watch->info_id;
wqueue = rcu_dereference(watch->queue);
wf = rcu_dereference(wqueue->filter);
if (wf && !filter_watch_notification(wf, n))
continue;
if (security_post_notification(watch->cred, cred, n) < 0)
continue;
if (lock_wqueue(wqueue)) {
post_one_notification(wqueue, n);
unlock_wqueue(wqueue);
}
}
rcu_read_unlock();
}
EXPORT_SYMBOL(__post_watch_notification);
/*
* Allocate sufficient pages to preallocation for the requested number of
* notifications.
*/
long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes)
{
struct watch_queue *wqueue = pipe->watch_queue;
struct page **pages;
unsigned long *bitmap;
unsigned long user_bufs;
int ret, i, nr_pages;
if (!wqueue)
return -ENODEV;
if (wqueue->notes)
return -EBUSY;
if (nr_notes < 1 ||
nr_notes > 512) /* TODO: choose a better hard limit */
return -EINVAL;
nr_pages = (nr_notes + WATCH_QUEUE_NOTES_PER_PAGE - 1);
nr_pages /= WATCH_QUEUE_NOTES_PER_PAGE;
user_bufs = account_pipe_buffers(pipe->user, pipe->nr_accounted, nr_pages);
if (nr_pages > pipe->max_usage &&
(too_many_pipe_buffers_hard(user_bufs) ||
too_many_pipe_buffers_soft(user_bufs)) &&
pipe_is_unprivileged_user()) {
ret = -EPERM;
goto error;
}
nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE;
ret = pipe_resize_ring(pipe, roundup_pow_of_two(nr_notes));
if (ret < 0)
goto error;
ret = -ENOMEM;
pages = kcalloc(sizeof(struct page *), nr_pages, GFP_KERNEL);
if (!pages)
goto error;
for (i = 0; i < nr_pages; i++) {
pages[i] = alloc_page(GFP_KERNEL);
if (!pages[i])
goto error_p;
pages[i]->index = i * WATCH_QUEUE_NOTES_PER_PAGE;
}
bitmap = bitmap_alloc(nr_notes, GFP_KERNEL);
if (!bitmap)
goto error_p;
bitmap_fill(bitmap, nr_notes);
wqueue->notes = pages;
wqueue->notes_bitmap = bitmap;
wqueue->nr_pages = nr_pages;
wqueue->nr_notes = nr_notes;
return 0;
error_p:
while (--i >= 0)
__free_page(pages[i]);
kfree(pages);
error:
(void) account_pipe_buffers(pipe->user, nr_pages, pipe->nr_accounted);
return ret;
}
/*
* Set the filter on a watch queue.
*/
long watch_queue_set_filter(struct pipe_inode_info *pipe,
struct watch_notification_filter __user *_filter)
{
struct watch_notification_type_filter *tf;
struct watch_notification_filter filter;
struct watch_type_filter *q;
struct watch_filter *wfilter;
struct watch_queue *wqueue = pipe->watch_queue;
int ret, nr_filter = 0, i;
if (!wqueue)
return -ENODEV;
if (!_filter) {
/* Remove the old filter */
wfilter = NULL;
goto set;
}
/* Grab the user's filter specification */
if (copy_from_user(&filter, _filter, sizeof(filter)) != 0)
return -EFAULT;
if (filter.nr_filters == 0 ||
filter.nr_filters > 16 ||
filter.__reserved != 0)
return -EINVAL;
tf = memdup_user(_filter->filters, filter.nr_filters * sizeof(*tf));
if (IS_ERR(tf))
return PTR_ERR(tf);
ret = -EINVAL;
for (i = 0; i < filter.nr_filters; i++) {
if ((tf[i].info_filter & ~tf[i].info_mask) ||
tf[i].info_mask & WATCH_INFO_LENGTH)
goto err_filter;
/* Ignore any unknown types */
if (tf[i].type >= WATCH_TYPE__NR)
continue;
nr_filter++;
}
/* Now we need to build the internal filter from only the relevant
* user-specified filters.
*/
ret = -ENOMEM;
wfilter = kzalloc(struct_size(wfilter, filters, nr_filter), GFP_KERNEL);
if (!wfilter)
goto err_filter;
wfilter->nr_filters = nr_filter;
q = wfilter->filters;
for (i = 0; i < filter.nr_filters; i++) {
if (tf[i].type >= WATCH_TYPE__NR)
continue;
q->type = tf[i].type;
q->info_filter = tf[i].info_filter;
q->info_mask = tf[i].info_mask;
q->subtype_filter[0] = tf[i].subtype_filter[0];
__set_bit(q->type, wfilter->type_filter);
q++;
}
kfree(tf);
set:
pipe_lock(pipe);
wfilter = rcu_replace_pointer(wqueue->filter, wfilter,
lockdep_is_held(&pipe->mutex));
pipe_unlock(pipe);
if (wfilter)
kfree_rcu(wfilter, rcu);
return 0;
err_filter:
kfree(tf);
return ret;
}
static void __put_watch_queue(struct kref *kref)
{
struct watch_queue *wqueue =
container_of(kref, struct watch_queue, usage);
struct watch_filter *wfilter;
int i;
for (i = 0; i < wqueue->nr_pages; i++)
__free_page(wqueue->notes[i]);
kfree(wqueue->notes);
bitmap_free(wqueue->notes_bitmap);
wfilter = rcu_access_pointer(wqueue->filter);
if (wfilter)
kfree_rcu(wfilter, rcu);
kfree_rcu(wqueue, rcu);
}
/**
* put_watch_queue - Dispose of a ref on a watchqueue.
* @wqueue: The watch queue to unref.
*/
void put_watch_queue(struct watch_queue *wqueue)
{
kref_put(&wqueue->usage, __put_watch_queue);
}
EXPORT_SYMBOL(put_watch_queue);
static void free_watch(struct rcu_head *rcu)
{
struct watch *watch = container_of(rcu, struct watch, rcu);
put_watch_queue(rcu_access_pointer(watch->queue));
atomic_dec(&watch->cred->user->nr_watches);
put_cred(watch->cred);
kfree(watch);
}
static void __put_watch(struct kref *kref)
{
struct watch *watch = container_of(kref, struct watch, usage);
call_rcu(&watch->rcu, free_watch);
}
/*
* Discard a watch.
*/
static void put_watch(struct watch *watch)
{
kref_put(&watch->usage, __put_watch);
}
/**
* init_watch - Initialise a watch
* @watch: The watch to initialise.
* @wqueue: The queue to assign.
*
* Initialise a watch and set the watch queue.
*/
void init_watch(struct watch *watch, struct watch_queue *wqueue)
{
kref_init(&watch->usage);
INIT_HLIST_NODE(&watch->list_node);
INIT_HLIST_NODE(&watch->queue_node);
rcu_assign_pointer(watch->queue, wqueue);
}
static int add_one_watch(struct watch *watch, struct watch_list *wlist, struct watch_queue *wqueue)
{
const struct cred *cred;
struct watch *w;
hlist_for_each_entry(w, &wlist->watchers, list_node) {
struct watch_queue *wq = rcu_access_pointer(w->queue);
if (wqueue == wq && watch->id == w->id)
return -EBUSY;
}
cred = current_cred();
if (atomic_inc_return(&cred->user->nr_watches) > task_rlimit(current, RLIMIT_NOFILE)) {
atomic_dec(&cred->user->nr_watches);
return -EAGAIN;
}
watch->cred = get_cred(cred);
rcu_assign_pointer(watch->watch_list, wlist);
kref_get(&wqueue->usage);
kref_get(&watch->usage);
hlist_add_head(&watch->queue_node, &wqueue->watches);
hlist_add_head_rcu(&watch->list_node, &wlist->watchers);
return 0;
}
/**
* add_watch_to_object - Add a watch on an object to a watch list
* @watch: The watch to add
* @wlist: The watch list to add to
*
* @watch->queue must have been set to point to the queue to post notifications
* to and the watch list of the object to be watched. @watch->cred must also
* have been set to the appropriate credentials and a ref taken on them.
*
* The caller must pin the queue and the list both and must hold the list
* locked against racing watch additions/removals.
*/
int add_watch_to_object(struct watch *watch, struct watch_list *wlist)
{
struct watch_queue *wqueue;
int ret = -ENOENT;
rcu_read_lock();
wqueue = rcu_access_pointer(watch->queue);
if (lock_wqueue(wqueue)) {
spin_lock(&wlist->lock);
ret = add_one_watch(watch, wlist, wqueue);
spin_unlock(&wlist->lock);
unlock_wqueue(wqueue);
}
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(add_watch_to_object);
/**
* remove_watch_from_object - Remove a watch or all watches from an object.
* @wlist: The watch list to remove from
* @wq: The watch queue of interest (ignored if @all is true)
* @id: The ID of the watch to remove (ignored if @all is true)
* @all: True to remove all objects
*
* Remove a specific watch or all watches from an object. A notification is
* sent to the watcher to tell them that this happened.
*/
int remove_watch_from_object(struct watch_list *wlist, struct watch_queue *wq,
u64 id, bool all)
{
struct watch_notification_removal n;
struct watch_queue *wqueue;
struct watch *watch;
int ret = -EBADSLT;
rcu_read_lock();
again:
spin_lock(&wlist->lock);
hlist_for_each_entry(watch, &wlist->watchers, list_node) {
if (all ||
(watch->id == id && rcu_access_pointer(watch->queue) == wq))
goto found;
}
spin_unlock(&wlist->lock);
goto out;
found:
ret = 0;
hlist_del_init_rcu(&watch->list_node);
rcu_assign_pointer(watch->watch_list, NULL);
spin_unlock(&wlist->lock);
/* We now own the reference on watch that used to belong to wlist. */
n.watch.type = WATCH_TYPE_META;
n.watch.subtype = WATCH_META_REMOVAL_NOTIFICATION;
n.watch.info = watch->info_id | watch_sizeof(n.watch);
n.id = id;
if (id != 0)
n.watch.info = watch->info_id | watch_sizeof(n);
wqueue = rcu_dereference(watch->queue);
if (lock_wqueue(wqueue)) {
post_one_notification(wqueue, &n.watch);
if (!hlist_unhashed(&watch->queue_node)) {
hlist_del_init_rcu(&watch->queue_node);
put_watch(watch);
}
unlock_wqueue(wqueue);
}
if (wlist->release_watch) {
void (*release_watch)(struct watch *);
release_watch = wlist->release_watch;
rcu_read_unlock();
(*release_watch)(watch);
rcu_read_lock();
}
put_watch(watch);
if (all && !hlist_empty(&wlist->watchers))
goto again;
out:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL(remove_watch_from_object);
/*
* Remove all the watches that are contributory to a queue. This has the
* potential to race with removal of the watches by the destruction of the
* objects being watched or with the distribution of notifications.
*/
void watch_queue_clear(struct watch_queue *wqueue)
{
struct watch_list *wlist;
struct watch *watch;
bool release;
rcu_read_lock();
spin_lock_bh(&wqueue->lock);
/*
* This pipe can be freed by callers like free_pipe_info().
* Removing this reference also prevents new notifications.
*/
wqueue->pipe = NULL;
while (!hlist_empty(&wqueue->watches)) {
watch = hlist_entry(wqueue->watches.first, struct watch, queue_node);
hlist_del_init_rcu(&watch->queue_node);
/* We now own a ref on the watch. */
spin_unlock_bh(&wqueue->lock);
/* We can't do the next bit under the queue lock as we need to
* get the list lock - which would cause a deadlock if someone
* was removing from the opposite direction at the same time or
* posting a notification.
*/
wlist = rcu_dereference(watch->watch_list);
if (wlist) {
void (*release_watch)(struct watch *);
spin_lock(&wlist->lock);
release = !hlist_unhashed(&watch->list_node);
if (release) {
hlist_del_init_rcu(&watch->list_node);
rcu_assign_pointer(watch->watch_list, NULL);
/* We now own a second ref on the watch. */
}
release_watch = wlist->release_watch;
spin_unlock(&wlist->lock);
if (release) {
if (release_watch) {
rcu_read_unlock();
/* This might need to call dput(), so
* we have to drop all the locks.
*/
(*release_watch)(watch);
rcu_read_lock();
}
put_watch(watch);
}
}
put_watch(watch);
spin_lock_bh(&wqueue->lock);
}
spin_unlock_bh(&wqueue->lock);
rcu_read_unlock();
}
/**
* get_watch_queue - Get a watch queue from its file descriptor.
* @fd: The fd to query.
*/
struct watch_queue *get_watch_queue(int fd)
{
struct pipe_inode_info *pipe;
struct watch_queue *wqueue = ERR_PTR(-EINVAL);
struct fd f;
f = fdget(fd);
if (f.file) {
pipe = get_pipe_info(f.file, false);
if (pipe && pipe->watch_queue) {
wqueue = pipe->watch_queue;
kref_get(&wqueue->usage);
}
fdput(f);
}
return wqueue;
}
EXPORT_SYMBOL(get_watch_queue);
/*
* Initialise a watch queue
*/
int watch_queue_init(struct pipe_inode_info *pipe)
{
struct watch_queue *wqueue;
wqueue = kzalloc(sizeof(*wqueue), GFP_KERNEL);
if (!wqueue)
return -ENOMEM;
wqueue->pipe = pipe;
kref_init(&wqueue->usage);
spin_lock_init(&wqueue->lock);
INIT_HLIST_HEAD(&wqueue->watches);
pipe->watch_queue = wqueue;
return 0;
}
| linux-master | kernel/watch_queue.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Range add and subtract
*/
#include <linux/init.h>
#include <linux/minmax.h>
#include <linux/printk.h>
#include <linux/sort.h>
#include <linux/string.h>
#include <linux/range.h>
int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
{
if (start >= end)
return nr_range;
/* Out of slots: */
if (nr_range >= az)
return nr_range;
range[nr_range].start = start;
range[nr_range].end = end;
nr_range++;
return nr_range;
}
int add_range_with_merge(struct range *range, int az, int nr_range,
u64 start, u64 end)
{
int i;
if (start >= end)
return nr_range;
/* get new start/end: */
for (i = 0; i < nr_range; i++) {
u64 common_start, common_end;
if (!range[i].end)
continue;
common_start = max(range[i].start, start);
common_end = min(range[i].end, end);
if (common_start > common_end)
continue;
/* new start/end, will add it back at last */
start = min(range[i].start, start);
end = max(range[i].end, end);
memmove(&range[i], &range[i + 1],
(nr_range - (i + 1)) * sizeof(range[i]));
range[nr_range - 1].start = 0;
range[nr_range - 1].end = 0;
nr_range--;
i--;
}
/* Need to add it: */
return add_range(range, az, nr_range, start, end);
}
void subtract_range(struct range *range, int az, u64 start, u64 end)
{
int i, j;
if (start >= end)
return;
for (j = 0; j < az; j++) {
if (!range[j].end)
continue;
if (start <= range[j].start && end >= range[j].end) {
range[j].start = 0;
range[j].end = 0;
continue;
}
if (start <= range[j].start && end < range[j].end &&
range[j].start < end) {
range[j].start = end;
continue;
}
if (start > range[j].start && end >= range[j].end &&
range[j].end > start) {
range[j].end = start;
continue;
}
if (start > range[j].start && end < range[j].end) {
/* Find the new spare: */
for (i = 0; i < az; i++) {
if (range[i].end == 0)
break;
}
if (i < az) {
range[i].end = range[j].end;
range[i].start = end;
} else {
pr_err("%s: run out of slot in ranges\n",
__func__);
}
range[j].end = start;
continue;
}
}
}
static int cmp_range(const void *x1, const void *x2)
{
const struct range *r1 = x1;
const struct range *r2 = x2;
if (r1->start < r2->start)
return -1;
if (r1->start > r2->start)
return 1;
return 0;
}
int clean_sort_range(struct range *range, int az)
{
int i, j, k = az - 1, nr_range = az;
for (i = 0; i < k; i++) {
if (range[i].end)
continue;
for (j = k; j > i; j--) {
if (range[j].end) {
k = j;
break;
}
}
if (j == i)
break;
range[i].start = range[k].start;
range[i].end = range[k].end;
range[k].start = 0;
range[k].end = 0;
k--;
}
/* count it */
for (i = 0; i < az; i++) {
if (!range[i].end) {
nr_range = i;
break;
}
}
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
return nr_range;
}
void sort_range(struct range *range, int nr_range)
{
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
}
| linux-master | kernel/range.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Detect hard and soft lockups on a system
*
* started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
*
* Note: Most of this code is borrowed heavily from the original softlockup
* detector, so thanks to Ingo for the initial implementation.
* Some chunks also taken from the old x86-specific nmi watchdog code, thanks
* to those contributors as well.
*/
#define pr_fmt(fmt) "watchdog: " fmt
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/nmi.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sysctl.h>
#include <linux/tick.h>
#include <linux/sched/clock.h>
#include <linux/sched/debug.h>
#include <linux/sched/isolation.h>
#include <linux/stop_machine.h>
#include <asm/irq_regs.h>
#include <linux/kvm_para.h>
static DEFINE_MUTEX(watchdog_mutex);
#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
# define WATCHDOG_HARDLOCKUP_DEFAULT 1
#else
# define WATCHDOG_HARDLOCKUP_DEFAULT 0
#endif
unsigned long __read_mostly watchdog_enabled;
int __read_mostly watchdog_user_enabled = 1;
static int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT;
static int __read_mostly watchdog_softlockup_user_enabled = 1;
int __read_mostly watchdog_thresh = 10;
static int __read_mostly watchdog_hardlockup_available;
struct cpumask watchdog_cpumask __read_mostly;
unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
#ifdef CONFIG_HARDLOCKUP_DETECTOR
# ifdef CONFIG_SMP
int __read_mostly sysctl_hardlockup_all_cpu_backtrace;
# endif /* CONFIG_SMP */
/*
* Should we panic when a soft-lockup or hard-lockup occurs:
*/
unsigned int __read_mostly hardlockup_panic =
IS_ENABLED(CONFIG_BOOTPARAM_HARDLOCKUP_PANIC);
/*
* We may not want to enable hard lockup detection by default in all cases,
* for example when running the kernel as a guest on a hypervisor. In these
* cases this function can be called to disable hard lockup detection. This
* function should only be executed once by the boot processor before the
* kernel command line parameters are parsed, because otherwise it is not
* possible to override this in hardlockup_panic_setup().
*/
void __init hardlockup_detector_disable(void)
{
watchdog_hardlockup_user_enabled = 0;
}
static int __init hardlockup_panic_setup(char *str)
{
if (!strncmp(str, "panic", 5))
hardlockup_panic = 1;
else if (!strncmp(str, "nopanic", 7))
hardlockup_panic = 0;
else if (!strncmp(str, "0", 1))
watchdog_hardlockup_user_enabled = 0;
else if (!strncmp(str, "1", 1))
watchdog_hardlockup_user_enabled = 1;
return 1;
}
__setup("nmi_watchdog=", hardlockup_panic_setup);
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
#if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER)
static DEFINE_PER_CPU(atomic_t, hrtimer_interrupts);
static DEFINE_PER_CPU(int, hrtimer_interrupts_saved);
static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned);
static DEFINE_PER_CPU(bool, watchdog_hardlockup_touched);
static unsigned long watchdog_hardlockup_all_cpu_dumped;
notrace void arch_touch_nmi_watchdog(void)
{
/*
* Using __raw here because some code paths have
* preemption enabled. If preemption is enabled
* then interrupts should be enabled too, in which
* case we shouldn't have to worry about the watchdog
* going off.
*/
raw_cpu_write(watchdog_hardlockup_touched, true);
}
EXPORT_SYMBOL(arch_touch_nmi_watchdog);
void watchdog_hardlockup_touch_cpu(unsigned int cpu)
{
per_cpu(watchdog_hardlockup_touched, cpu) = true;
}
static bool is_hardlockup(unsigned int cpu)
{
int hrint = atomic_read(&per_cpu(hrtimer_interrupts, cpu));
if (per_cpu(hrtimer_interrupts_saved, cpu) == hrint)
return true;
/*
* NOTE: we don't need any fancy atomic_t or READ_ONCE/WRITE_ONCE
* for hrtimer_interrupts_saved. hrtimer_interrupts_saved is
* written/read by a single CPU.
*/
per_cpu(hrtimer_interrupts_saved, cpu) = hrint;
return false;
}
static void watchdog_hardlockup_kick(void)
{
int new_interrupts;
new_interrupts = atomic_inc_return(this_cpu_ptr(&hrtimer_interrupts));
watchdog_buddy_check_hardlockup(new_interrupts);
}
void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
{
if (per_cpu(watchdog_hardlockup_touched, cpu)) {
per_cpu(watchdog_hardlockup_touched, cpu) = false;
return;
}
/*
* Check for a hardlockup by making sure the CPU's timer
* interrupt is incrementing. The timer interrupt should have
* fired multiple times before we overflow'd. If it hasn't
* then this is a good indication the cpu is stuck
*/
if (is_hardlockup(cpu)) {
unsigned int this_cpu = smp_processor_id();
/* Only print hardlockups once. */
if (per_cpu(watchdog_hardlockup_warned, cpu))
return;
pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n", cpu);
print_modules();
print_irqtrace_events(current);
if (cpu == this_cpu) {
if (regs)
show_regs(regs);
else
dump_stack();
} else {
trigger_single_cpu_backtrace(cpu);
}
/*
* Perform multi-CPU dump only once to avoid multiple
* hardlockups generating interleaving traces
*/
if (sysctl_hardlockup_all_cpu_backtrace &&
!test_and_set_bit(0, &watchdog_hardlockup_all_cpu_dumped))
trigger_allbutcpu_cpu_backtrace(cpu);
if (hardlockup_panic)
nmi_panic(regs, "Hard LOCKUP");
per_cpu(watchdog_hardlockup_warned, cpu) = true;
} else {
per_cpu(watchdog_hardlockup_warned, cpu) = false;
}
}
#else /* CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */
static inline void watchdog_hardlockup_kick(void) { }
#endif /* !CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER */
/*
* These functions can be overridden based on the configured hardlockdup detector.
*
* watchdog_hardlockup_enable/disable can be implemented to start and stop when
* softlockup watchdog start and stop. The detector must select the
* SOFTLOCKUP_DETECTOR Kconfig.
*/
void __weak watchdog_hardlockup_enable(unsigned int cpu) { }
void __weak watchdog_hardlockup_disable(unsigned int cpu) { }
/*
* Watchdog-detector specific API.
*
* Return 0 when hardlockup watchdog is available, negative value otherwise.
* Note that the negative value means that a delayed probe might
* succeed later.
*/
int __weak __init watchdog_hardlockup_probe(void)
{
return -ENODEV;
}
/**
* watchdog_hardlockup_stop - Stop the watchdog for reconfiguration
*
* The reconfiguration steps are:
* watchdog_hardlockup_stop();
* update_variables();
* watchdog_hardlockup_start();
*/
void __weak watchdog_hardlockup_stop(void) { }
/**
* watchdog_hardlockup_start - Start the watchdog after reconfiguration
*
* Counterpart to watchdog_hardlockup_stop().
*
* The following variables have been updated in update_variables() and
* contain the currently valid configuration:
* - watchdog_enabled
* - watchdog_thresh
* - watchdog_cpumask
*/
void __weak watchdog_hardlockup_start(void) { }
/**
* lockup_detector_update_enable - Update the sysctl enable bit
*
* Caller needs to make sure that the hard watchdogs are off, so this
* can't race with watchdog_hardlockup_disable().
*/
static void lockup_detector_update_enable(void)
{
watchdog_enabled = 0;
if (!watchdog_user_enabled)
return;
if (watchdog_hardlockup_available && watchdog_hardlockup_user_enabled)
watchdog_enabled |= WATCHDOG_HARDLOCKUP_ENABLED;
if (watchdog_softlockup_user_enabled)
watchdog_enabled |= WATCHDOG_SOFTOCKUP_ENABLED;
}
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
/*
* Delay the soflockup report when running a known slow code.
* It does _not_ affect the timestamp of the last successdul reschedule.
*/
#define SOFTLOCKUP_DELAY_REPORT ULONG_MAX
#ifdef CONFIG_SMP
int __read_mostly sysctl_softlockup_all_cpu_backtrace;
#endif
static struct cpumask watchdog_allowed_mask __read_mostly;
/* Global variables, exported for sysctl */
unsigned int __read_mostly softlockup_panic =
IS_ENABLED(CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC);
static bool softlockup_initialized __read_mostly;
static u64 __read_mostly sample_period;
/* Timestamp taken after the last successful reschedule. */
static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
/* Timestamp of the last softlockup report. */
static DEFINE_PER_CPU(unsigned long, watchdog_report_ts);
static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
static DEFINE_PER_CPU(bool, softlockup_touch_sync);
static unsigned long soft_lockup_nmi_warn;
static int __init nowatchdog_setup(char *str)
{
watchdog_user_enabled = 0;
return 1;
}
__setup("nowatchdog", nowatchdog_setup);
static int __init nosoftlockup_setup(char *str)
{
watchdog_softlockup_user_enabled = 0;
return 1;
}
__setup("nosoftlockup", nosoftlockup_setup);
static int __init watchdog_thresh_setup(char *str)
{
get_option(&str, &watchdog_thresh);
return 1;
}
__setup("watchdog_thresh=", watchdog_thresh_setup);
static void __lockup_detector_cleanup(void);
/*
* Hard-lockup warnings should be triggered after just a few seconds. Soft-
* lockups can have false positives under extreme conditions. So we generally
* want a higher threshold for soft lockups than for hard lockups. So we couple
* the thresholds with a factor: we make the soft threshold twice the amount of
* time the hard threshold is.
*/
static int get_softlockup_thresh(void)
{
return watchdog_thresh * 2;
}
/*
* Returns seconds, approximately. We don't need nanosecond
* resolution, and we don't need to waste time with a big divide when
* 2^30ns == 1.074s.
*/
static unsigned long get_timestamp(void)
{
return running_clock() >> 30LL; /* 2^30 ~= 10^9 */
}
static void set_sample_period(void)
{
/*
* convert watchdog_thresh from seconds to ns
* the divide by 5 is to give hrtimer several chances (two
* or three with the current relation between the soft
* and hard thresholds) to increment before the
* hardlockup detector generates a warning
*/
sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5);
watchdog_update_hrtimer_threshold(sample_period);
}
static void update_report_ts(void)
{
__this_cpu_write(watchdog_report_ts, get_timestamp());
}
/* Commands for resetting the watchdog */
static void update_touch_ts(void)
{
__this_cpu_write(watchdog_touch_ts, get_timestamp());
update_report_ts();
}
/**
* touch_softlockup_watchdog_sched - touch watchdog on scheduler stalls
*
* Call when the scheduler may have stalled for legitimate reasons
* preventing the watchdog task from executing - e.g. the scheduler
* entering idle state. This should only be used for scheduler events.
* Use touch_softlockup_watchdog() for everything else.
*/
notrace void touch_softlockup_watchdog_sched(void)
{
/*
* Preemption can be enabled. It doesn't matter which CPU's watchdog
* report period gets restarted here, so use the raw_ operation.
*/
raw_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT);
}
notrace void touch_softlockup_watchdog(void)
{
touch_softlockup_watchdog_sched();
wq_watchdog_touch(raw_smp_processor_id());
}
EXPORT_SYMBOL(touch_softlockup_watchdog);
void touch_all_softlockup_watchdogs(void)
{
int cpu;
/*
* watchdog_mutex cannpt be taken here, as this might be called
* from (soft)interrupt context, so the access to
* watchdog_allowed_cpumask might race with a concurrent update.
*
* The watchdog time stamp can race against a concurrent real
* update as well, the only side effect might be a cycle delay for
* the softlockup check.
*/
for_each_cpu(cpu, &watchdog_allowed_mask) {
per_cpu(watchdog_report_ts, cpu) = SOFTLOCKUP_DELAY_REPORT;
wq_watchdog_touch(cpu);
}
}
void touch_softlockup_watchdog_sync(void)
{
__this_cpu_write(softlockup_touch_sync, true);
__this_cpu_write(watchdog_report_ts, SOFTLOCKUP_DELAY_REPORT);
}
static int is_softlockup(unsigned long touch_ts,
unsigned long period_ts,
unsigned long now)
{
if ((watchdog_enabled & WATCHDOG_SOFTOCKUP_ENABLED) && watchdog_thresh) {
/* Warn about unreasonable delays. */
if (time_after(now, period_ts + get_softlockup_thresh()))
return now - touch_ts;
}
return 0;
}
/* watchdog detector functions */
static DEFINE_PER_CPU(struct completion, softlockup_completion);
static DEFINE_PER_CPU(struct cpu_stop_work, softlockup_stop_work);
/*
* The watchdog feed function - touches the timestamp.
*
* It only runs once every sample_period seconds (4 seconds by
* default) to reset the softlockup timestamp. If this gets delayed
* for more than 2*watchdog_thresh seconds then the debug-printout
* triggers in watchdog_timer_fn().
*/
static int softlockup_fn(void *data)
{
update_touch_ts();
complete(this_cpu_ptr(&softlockup_completion));
return 0;
}
/* watchdog kicker functions */
static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
{
unsigned long touch_ts, period_ts, now;
struct pt_regs *regs = get_irq_regs();
int duration;
int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace;
if (!watchdog_enabled)
return HRTIMER_NORESTART;
watchdog_hardlockup_kick();
/* kick the softlockup detector */
if (completion_done(this_cpu_ptr(&softlockup_completion))) {
reinit_completion(this_cpu_ptr(&softlockup_completion));
stop_one_cpu_nowait(smp_processor_id(),
softlockup_fn, NULL,
this_cpu_ptr(&softlockup_stop_work));
}
/* .. and repeat */
hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
/*
* Read the current timestamp first. It might become invalid anytime
* when a virtual machine is stopped by the host or when the watchog
* is touched from NMI.
*/
now = get_timestamp();
/*
* If a virtual machine is stopped by the host it can look to
* the watchdog like a soft lockup. This function touches the watchdog.
*/
kvm_check_and_clear_guest_paused();
/*
* The stored timestamp is comparable with @now only when not touched.
* It might get touched anytime from NMI. Make sure that is_softlockup()
* uses the same (valid) value.
*/
period_ts = READ_ONCE(*this_cpu_ptr(&watchdog_report_ts));
/* Reset the interval when touched by known problematic code. */
if (period_ts == SOFTLOCKUP_DELAY_REPORT) {
if (unlikely(__this_cpu_read(softlockup_touch_sync))) {
/*
* If the time stamp was touched atomically
* make sure the scheduler tick is up to date.
*/
__this_cpu_write(softlockup_touch_sync, false);
sched_clock_tick();
}
update_report_ts();
return HRTIMER_RESTART;
}
/* Check for a softlockup. */
touch_ts = __this_cpu_read(watchdog_touch_ts);
duration = is_softlockup(touch_ts, period_ts, now);
if (unlikely(duration)) {
/*
* Prevent multiple soft-lockup reports if one cpu is already
* engaged in dumping all cpu back traces.
*/
if (softlockup_all_cpu_backtrace) {
if (test_and_set_bit_lock(0, &soft_lockup_nmi_warn))
return HRTIMER_RESTART;
}
/* Start period for the next softlockup warning. */
update_report_ts();
pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
smp_processor_id(), duration,
current->comm, task_pid_nr(current));
print_modules();
print_irqtrace_events(current);
if (regs)
show_regs(regs);
else
dump_stack();
if (softlockup_all_cpu_backtrace) {
trigger_allbutcpu_cpu_backtrace(smp_processor_id());
clear_bit_unlock(0, &soft_lockup_nmi_warn);
}
add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
if (softlockup_panic)
panic("softlockup: hung tasks");
}
return HRTIMER_RESTART;
}
static void watchdog_enable(unsigned int cpu)
{
struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
struct completion *done = this_cpu_ptr(&softlockup_completion);
WARN_ON_ONCE(cpu != smp_processor_id());
init_completion(done);
complete(done);
/*
* Start the timer first to prevent the hardlockup watchdog triggering
* before the timer has a chance to fire.
*/
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
hrtimer->function = watchdog_timer_fn;
hrtimer_start(hrtimer, ns_to_ktime(sample_period),
HRTIMER_MODE_REL_PINNED_HARD);
/* Initialize timestamp */
update_touch_ts();
/* Enable the hardlockup detector */
if (watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED)
watchdog_hardlockup_enable(cpu);
}
static void watchdog_disable(unsigned int cpu)
{
struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);
WARN_ON_ONCE(cpu != smp_processor_id());
/*
* Disable the hardlockup detector first. That prevents that a large
* delay between disabling the timer and disabling the hardlockup
* detector causes a false positive.
*/
watchdog_hardlockup_disable(cpu);
hrtimer_cancel(hrtimer);
wait_for_completion(this_cpu_ptr(&softlockup_completion));
}
static int softlockup_stop_fn(void *data)
{
watchdog_disable(smp_processor_id());
return 0;
}
static void softlockup_stop_all(void)
{
int cpu;
if (!softlockup_initialized)
return;
for_each_cpu(cpu, &watchdog_allowed_mask)
smp_call_on_cpu(cpu, softlockup_stop_fn, NULL, false);
cpumask_clear(&watchdog_allowed_mask);
}
static int softlockup_start_fn(void *data)
{
watchdog_enable(smp_processor_id());
return 0;
}
static void softlockup_start_all(void)
{
int cpu;
cpumask_copy(&watchdog_allowed_mask, &watchdog_cpumask);
for_each_cpu(cpu, &watchdog_allowed_mask)
smp_call_on_cpu(cpu, softlockup_start_fn, NULL, false);
}
int lockup_detector_online_cpu(unsigned int cpu)
{
if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
watchdog_enable(cpu);
return 0;
}
int lockup_detector_offline_cpu(unsigned int cpu)
{
if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
watchdog_disable(cpu);
return 0;
}
static void __lockup_detector_reconfigure(void)
{
cpus_read_lock();
watchdog_hardlockup_stop();
softlockup_stop_all();
set_sample_period();
lockup_detector_update_enable();
if (watchdog_enabled && watchdog_thresh)
softlockup_start_all();
watchdog_hardlockup_start();
cpus_read_unlock();
/*
* Must be called outside the cpus locked section to prevent
* recursive locking in the perf code.
*/
__lockup_detector_cleanup();
}
void lockup_detector_reconfigure(void)
{
mutex_lock(&watchdog_mutex);
__lockup_detector_reconfigure();
mutex_unlock(&watchdog_mutex);
}
/*
* Create the watchdog infrastructure and configure the detector(s).
*/
static __init void lockup_detector_setup(void)
{
/*
* If sysctl is off and watchdog got disabled on the command line,
* nothing to do here.
*/
lockup_detector_update_enable();
if (!IS_ENABLED(CONFIG_SYSCTL) &&
!(watchdog_enabled && watchdog_thresh))
return;
mutex_lock(&watchdog_mutex);
__lockup_detector_reconfigure();
softlockup_initialized = true;
mutex_unlock(&watchdog_mutex);
}
#else /* CONFIG_SOFTLOCKUP_DETECTOR */
static void __lockup_detector_reconfigure(void)
{
cpus_read_lock();
watchdog_hardlockup_stop();
lockup_detector_update_enable();
watchdog_hardlockup_start();
cpus_read_unlock();
}
void lockup_detector_reconfigure(void)
{
__lockup_detector_reconfigure();
}
static inline void lockup_detector_setup(void)
{
__lockup_detector_reconfigure();
}
#endif /* !CONFIG_SOFTLOCKUP_DETECTOR */
static void __lockup_detector_cleanup(void)
{
lockdep_assert_held(&watchdog_mutex);
hardlockup_detector_perf_cleanup();
}
/**
* lockup_detector_cleanup - Cleanup after cpu hotplug or sysctl changes
*
* Caller must not hold the cpu hotplug rwsem.
*/
void lockup_detector_cleanup(void)
{
mutex_lock(&watchdog_mutex);
__lockup_detector_cleanup();
mutex_unlock(&watchdog_mutex);
}
/**
* lockup_detector_soft_poweroff - Interface to stop lockup detector(s)
*
* Special interface for parisc. It prevents lockup detector warnings from
* the default pm_poweroff() function which busy loops forever.
*/
void lockup_detector_soft_poweroff(void)
{
watchdog_enabled = 0;
}
#ifdef CONFIG_SYSCTL
/* Propagate any changes to the watchdog infrastructure */
static void proc_watchdog_update(void)
{
/* Remove impossible cpus to keep sysctl output clean. */
cpumask_and(&watchdog_cpumask, &watchdog_cpumask, cpu_possible_mask);
__lockup_detector_reconfigure();
}
/*
* common function for watchdog, nmi_watchdog and soft_watchdog parameter
*
* caller | table->data points to | 'which'
* -------------------|----------------------------------|-------------------------------
* proc_watchdog | watchdog_user_enabled | WATCHDOG_HARDLOCKUP_ENABLED |
* | | WATCHDOG_SOFTOCKUP_ENABLED
* -------------------|----------------------------------|-------------------------------
* proc_nmi_watchdog | watchdog_hardlockup_user_enabled | WATCHDOG_HARDLOCKUP_ENABLED
* -------------------|----------------------------------|-------------------------------
* proc_soft_watchdog | watchdog_softlockup_user_enabled | WATCHDOG_SOFTOCKUP_ENABLED
*/
static int proc_watchdog_common(int which, struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int err, old, *param = table->data;
mutex_lock(&watchdog_mutex);
if (!write) {
/*
* On read synchronize the userspace interface. This is a
* racy snapshot.
*/
*param = (watchdog_enabled & which) != 0;
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
} else {
old = READ_ONCE(*param);
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (!err && old != READ_ONCE(*param))
proc_watchdog_update();
}
mutex_unlock(&watchdog_mutex);
return err;
}
/*
* /proc/sys/kernel/watchdog
*/
int proc_watchdog(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED |
WATCHDOG_SOFTOCKUP_ENABLED,
table, write, buffer, lenp, ppos);
}
/*
* /proc/sys/kernel/nmi_watchdog
*/
int proc_nmi_watchdog(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
if (!watchdog_hardlockup_available && write)
return -ENOTSUPP;
return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED,
table, write, buffer, lenp, ppos);
}
/*
* /proc/sys/kernel/soft_watchdog
*/
int proc_soft_watchdog(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
return proc_watchdog_common(WATCHDOG_SOFTOCKUP_ENABLED,
table, write, buffer, lenp, ppos);
}
/*
* /proc/sys/kernel/watchdog_thresh
*/
int proc_watchdog_thresh(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int err, old;
mutex_lock(&watchdog_mutex);
old = READ_ONCE(watchdog_thresh);
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (!err && write && old != READ_ONCE(watchdog_thresh))
proc_watchdog_update();
mutex_unlock(&watchdog_mutex);
return err;
}
/*
* The cpumask is the mask of possible cpus that the watchdog can run
* on, not the mask of cpus it is actually running on. This allows the
* user to specify a mask that will include cpus that have not yet
* been brought online, if desired.
*/
int proc_watchdog_cpumask(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
int err;
mutex_lock(&watchdog_mutex);
err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
if (!err && write)
proc_watchdog_update();
mutex_unlock(&watchdog_mutex);
return err;
}
static const int sixty = 60;
static struct ctl_table watchdog_sysctls[] = {
{
.procname = "watchdog",
.data = &watchdog_user_enabled,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_watchdog,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "watchdog_thresh",
.data = &watchdog_thresh,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_watchdog_thresh,
.extra1 = SYSCTL_ZERO,
.extra2 = (void *)&sixty,
},
{
.procname = "watchdog_cpumask",
.data = &watchdog_cpumask_bits,
.maxlen = NR_CPUS,
.mode = 0644,
.proc_handler = proc_watchdog_cpumask,
},
#ifdef CONFIG_SOFTLOCKUP_DETECTOR
{
.procname = "soft_watchdog",
.data = &watchdog_softlockup_user_enabled,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_soft_watchdog,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "softlockup_panic",
.data = &softlockup_panic,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#ifdef CONFIG_SMP
{
.procname = "softlockup_all_cpu_backtrace",
.data = &sysctl_softlockup_all_cpu_backtrace,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif /* CONFIG_SMP */
#endif
#ifdef CONFIG_HARDLOCKUP_DETECTOR
{
.procname = "hardlockup_panic",
.data = &hardlockup_panic,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#ifdef CONFIG_SMP
{
.procname = "hardlockup_all_cpu_backtrace",
.data = &sysctl_hardlockup_all_cpu_backtrace,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
#endif /* CONFIG_SMP */
#endif
{}
};
static struct ctl_table watchdog_hardlockup_sysctl[] = {
{
.procname = "nmi_watchdog",
.data = &watchdog_hardlockup_user_enabled,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = proc_nmi_watchdog,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{}
};
static void __init watchdog_sysctl_init(void)
{
register_sysctl_init("kernel", watchdog_sysctls);
if (watchdog_hardlockup_available)
watchdog_hardlockup_sysctl[0].mode = 0644;
register_sysctl_init("kernel", watchdog_hardlockup_sysctl);
}
#else
#define watchdog_sysctl_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
static void __init lockup_detector_delay_init(struct work_struct *work);
static bool allow_lockup_detector_init_retry __initdata;
static struct work_struct detector_work __initdata =
__WORK_INITIALIZER(detector_work, lockup_detector_delay_init);
static void __init lockup_detector_delay_init(struct work_struct *work)
{
int ret;
ret = watchdog_hardlockup_probe();
if (ret) {
pr_info("Delayed init of the lockup detector failed: %d\n", ret);
pr_info("Hard watchdog permanently disabled\n");
return;
}
allow_lockup_detector_init_retry = false;
watchdog_hardlockup_available = true;
lockup_detector_setup();
}
/*
* lockup_detector_retry_init - retry init lockup detector if possible.
*
* Retry hardlockup detector init. It is useful when it requires some
* functionality that has to be initialized later on a particular
* platform.
*/
void __init lockup_detector_retry_init(void)
{
/* Must be called before late init calls */
if (!allow_lockup_detector_init_retry)
return;
schedule_work(&detector_work);
}
/*
* Ensure that optional delayed hardlockup init is proceed before
* the init code and memory is freed.
*/
static int __init lockup_detector_check(void)
{
/* Prevent any later retry. */
allow_lockup_detector_init_retry = false;
/* Make sure no work is pending. */
flush_work(&detector_work);
watchdog_sysctl_init();
return 0;
}
late_initcall_sync(lockup_detector_check);
void __init lockup_detector_init(void)
{
if (tick_nohz_full_enabled())
pr_info("Disabling watchdog on nohz_full cores by default\n");
cpumask_copy(&watchdog_cpumask,
housekeeping_cpumask(HK_TYPE_TIMER));
if (!watchdog_hardlockup_probe())
watchdog_hardlockup_available = true;
else
allow_lockup_detector_init_retry = true;
lockup_detector_setup();
}
| linux-master | kernel/watchdog.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/dma.c: A DMA channel allocator. Inspired by linux/kernel/irq.c.
*
* Written by Hennus Bergman, 1992.
*
* 1994/12/26: Changes by Alex Nash to fix a minor bug in /proc/dma.
* In the previous version the reported device could end up being wrong,
* if a device requested a DMA channel that was already in use.
* [It also happened to remove the sizeof(char *) == sizeof(int)
* assumption introduced because of those /proc/dma patches. -- Hennus]
*/
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <asm/dma.h>
/* A note on resource allocation:
*
* All drivers needing DMA channels, should allocate and release them
* through the public routines `request_dma()' and `free_dma()'.
*
* In order to avoid problems, all processes should allocate resources in
* the same sequence and release them in the reverse order.
*
* So, when allocating DMAs and IRQs, first allocate the IRQ, then the DMA.
* When releasing them, first release the DMA, then release the IRQ.
* If you don't, you may cause allocation requests to fail unnecessarily.
* This doesn't really matter now, but it will once we get real semaphores
* in the kernel.
*/
DEFINE_SPINLOCK(dma_spin_lock);
/*
* If our port doesn't define this it has no PC like DMA
*/
#ifdef MAX_DMA_CHANNELS
/* Channel n is busy iff dma_chan_busy[n].lock != 0.
* DMA0 used to be reserved for DRAM refresh, but apparently not any more...
* DMA4 is reserved for cascading.
*/
struct dma_chan {
int lock;
const char *device_id;
};
static struct dma_chan dma_chan_busy[MAX_DMA_CHANNELS] = {
[4] = { 1, "cascade" },
};
/**
* request_dma - request and reserve a system DMA channel
* @dmanr: DMA channel number
* @device_id: reserving device ID string, used in /proc/dma
*/
int request_dma(unsigned int dmanr, const char * device_id)
{
if (dmanr >= MAX_DMA_CHANNELS)
return -EINVAL;
if (xchg(&dma_chan_busy[dmanr].lock, 1) != 0)
return -EBUSY;
dma_chan_busy[dmanr].device_id = device_id;
/* old flag was 0, now contains 1 to indicate busy */
return 0;
} /* request_dma */
/**
* free_dma - free a reserved system DMA channel
* @dmanr: DMA channel number
*/
void free_dma(unsigned int dmanr)
{
if (dmanr >= MAX_DMA_CHANNELS) {
printk(KERN_WARNING "Trying to free DMA%d\n", dmanr);
return;
}
if (xchg(&dma_chan_busy[dmanr].lock, 0) == 0) {
printk(KERN_WARNING "Trying to free free DMA%d\n", dmanr);
return;
}
} /* free_dma */
#else
int request_dma(unsigned int dmanr, const char *device_id)
{
return -EINVAL;
}
void free_dma(unsigned int dmanr)
{
}
#endif
#ifdef CONFIG_PROC_FS
#ifdef MAX_DMA_CHANNELS
static int proc_dma_show(struct seq_file *m, void *v)
{
int i;
for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
if (dma_chan_busy[i].lock) {
seq_printf(m, "%2d: %s\n", i,
dma_chan_busy[i].device_id);
}
}
return 0;
}
#else
static int proc_dma_show(struct seq_file *m, void *v)
{
seq_puts(m, "No DMA\n");
return 0;
}
#endif /* MAX_DMA_CHANNELS */
static int __init proc_dma_init(void)
{
proc_create_single("dma", 0, NULL, proc_dma_show);
return 0;
}
__initcall(proc_dma_init);
#endif
EXPORT_SYMBOL(request_dma);
EXPORT_SYMBOL(free_dma);
EXPORT_SYMBOL(dma_spin_lock);
| linux-master | kernel/dma.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2021 Oracle Corporation
*/
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/sched/task.h>
#include <linux/sched/vhost_task.h>
#include <linux/sched/signal.h>
enum vhost_task_flags {
VHOST_TASK_FLAGS_STOP,
};
struct vhost_task {
bool (*fn)(void *data);
void *data;
struct completion exited;
unsigned long flags;
struct task_struct *task;
};
static int vhost_task_fn(void *data)
{
struct vhost_task *vtsk = data;
bool dead = false;
for (;;) {
bool did_work;
if (!dead && signal_pending(current)) {
struct ksignal ksig;
/*
* Calling get_signal will block in SIGSTOP,
* or clear fatal_signal_pending, but remember
* what was set.
*
* This thread won't actually exit until all
* of the file descriptors are closed, and
* the release function is called.
*/
dead = get_signal(&ksig);
if (dead)
clear_thread_flag(TIF_SIGPENDING);
}
/* mb paired w/ vhost_task_stop */
set_current_state(TASK_INTERRUPTIBLE);
if (test_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags)) {
__set_current_state(TASK_RUNNING);
break;
}
did_work = vtsk->fn(vtsk->data);
if (!did_work)
schedule();
}
complete(&vtsk->exited);
do_exit(0);
}
/**
* vhost_task_wake - wakeup the vhost_task
* @vtsk: vhost_task to wake
*
* wake up the vhost_task worker thread
*/
void vhost_task_wake(struct vhost_task *vtsk)
{
wake_up_process(vtsk->task);
}
EXPORT_SYMBOL_GPL(vhost_task_wake);
/**
* vhost_task_stop - stop a vhost_task
* @vtsk: vhost_task to stop
*
* vhost_task_fn ensures the worker thread exits after
* VHOST_TASK_FLAGS_SOP becomes true.
*/
void vhost_task_stop(struct vhost_task *vtsk)
{
set_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags);
vhost_task_wake(vtsk);
/*
* Make sure vhost_task_fn is no longer accessing the vhost_task before
* freeing it below.
*/
wait_for_completion(&vtsk->exited);
kfree(vtsk);
}
EXPORT_SYMBOL_GPL(vhost_task_stop);
/**
* vhost_task_create - create a copy of a task to be used by the kernel
* @fn: vhost worker function
* @arg: data to be passed to fn
* @name: the thread's name
*
* This returns a specialized task for use by the vhost layer or NULL on
* failure. The returned task is inactive, and the caller must fire it up
* through vhost_task_start().
*/
struct vhost_task *vhost_task_create(bool (*fn)(void *), void *arg,
const char *name)
{
struct kernel_clone_args args = {
.flags = CLONE_FS | CLONE_UNTRACED | CLONE_VM |
CLONE_THREAD | CLONE_SIGHAND,
.exit_signal = 0,
.fn = vhost_task_fn,
.name = name,
.user_worker = 1,
.no_files = 1,
};
struct vhost_task *vtsk;
struct task_struct *tsk;
vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL);
if (!vtsk)
return NULL;
init_completion(&vtsk->exited);
vtsk->data = arg;
vtsk->fn = fn;
args.fn_arg = vtsk;
tsk = copy_process(NULL, 0, NUMA_NO_NODE, &args);
if (IS_ERR(tsk)) {
kfree(vtsk);
return NULL;
}
vtsk->task = tsk;
return vtsk;
}
EXPORT_SYMBOL_GPL(vhost_task_create);
/**
* vhost_task_start - start a vhost_task created with vhost_task_create
* @vtsk: vhost_task to wake up
*/
void vhost_task_start(struct vhost_task *vtsk)
{
wake_up_new_task(vtsk->task);
}
EXPORT_SYMBOL_GPL(vhost_task_start);
| linux-master | kernel/vhost_task.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/softirq.c
*
* Copyright (C) 1992 Linus Torvalds
*
* Rewritten. Old one was good in 2.2, but in 2.3 it was immoral. --ANK (990903)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/export.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/local_lock.h>
#include <linux/mm.h>
#include <linux/notifier.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/rcupdate.h>
#include <linux/ftrace.h>
#include <linux/smp.h>
#include <linux/smpboot.h>
#include <linux/tick.h>
#include <linux/irq.h>
#include <linux/wait_bit.h>
#include <asm/softirq_stack.h>
#define CREATE_TRACE_POINTS
#include <trace/events/irq.h>
/*
- No shared variables, all the data are CPU local.
- If a softirq needs serialization, let it serialize itself
by its own spinlocks.
- Even if softirq is serialized, only local cpu is marked for
execution. Hence, we get something sort of weak cpu binding.
Though it is still not clear, will it result in better locality
or will not.
Examples:
- NET RX softirq. It is multithreaded and does not require
any global serialization.
- NET TX softirq. It kicks software netdevice queues, hence
it is logically serialized per device, but this serialization
is invisible to common code.
- Tasklets: serialized wrt itself.
*/
#ifndef __ARCH_IRQ_STAT
DEFINE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
EXPORT_PER_CPU_SYMBOL(irq_stat);
#endif
static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;
DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
const char * const softirq_to_name[NR_SOFTIRQS] = {
"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "IRQ_POLL",
"TASKLET", "SCHED", "HRTIMER", "RCU"
};
/*
* we cannot loop indefinitely here to avoid userspace starvation,
* but we also don't want to introduce a worst case 1/HZ latency
* to the pending events, so lets the scheduler to balance
* the softirq load for us.
*/
static void wakeup_softirqd(void)
{
/* Interrupts are disabled: no need to stop preemption */
struct task_struct *tsk = __this_cpu_read(ksoftirqd);
if (tsk)
wake_up_process(tsk);
}
#ifdef CONFIG_TRACE_IRQFLAGS
DEFINE_PER_CPU(int, hardirqs_enabled);
DEFINE_PER_CPU(int, hardirq_context);
EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
#endif
/*
* SOFTIRQ_OFFSET usage:
*
* On !RT kernels 'count' is the preempt counter, on RT kernels this applies
* to a per CPU counter and to task::softirqs_disabled_cnt.
*
* - count is changed by SOFTIRQ_OFFSET on entering or leaving softirq
* processing.
*
* - count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
* on local_bh_disable or local_bh_enable.
*
* This lets us distinguish between whether we are currently processing
* softirq and whether we just have bh disabled.
*/
#ifdef CONFIG_PREEMPT_RT
/*
* RT accounts for BH disabled sections in task::softirqs_disabled_cnt and
* also in per CPU softirq_ctrl::cnt. This is necessary to allow tasks in a
* softirq disabled section to be preempted.
*
* The per task counter is used for softirq_count(), in_softirq() and
* in_serving_softirqs() because these counts are only valid when the task
* holding softirq_ctrl::lock is running.
*
* The per CPU counter prevents pointless wakeups of ksoftirqd in case that
* the task which is in a softirq disabled section is preempted or blocks.
*/
struct softirq_ctrl {
local_lock_t lock;
int cnt;
};
static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = {
.lock = INIT_LOCAL_LOCK(softirq_ctrl.lock),
};
/**
* local_bh_blocked() - Check for idle whether BH processing is blocked
*
* Returns false if the per CPU softirq::cnt is 0 otherwise true.
*
* This is invoked from the idle task to guard against false positive
* softirq pending warnings, which would happen when the task which holds
* softirq_ctrl::lock was the only running task on the CPU and blocks on
* some other lock.
*/
bool local_bh_blocked(void)
{
return __this_cpu_read(softirq_ctrl.cnt) != 0;
}
void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
unsigned long flags;
int newcnt;
WARN_ON_ONCE(in_hardirq());
/* First entry of a task into a BH disabled section? */
if (!current->softirq_disable_cnt) {
if (preemptible()) {
local_lock(&softirq_ctrl.lock);
/* Required to meet the RCU bottomhalf requirements. */
rcu_read_lock();
} else {
DEBUG_LOCKS_WARN_ON(this_cpu_read(softirq_ctrl.cnt));
}
}
/*
* Track the per CPU softirq disabled state. On RT this is per CPU
* state to allow preemption of bottom half disabled sections.
*/
newcnt = __this_cpu_add_return(softirq_ctrl.cnt, cnt);
/*
* Reflect the result in the task state to prevent recursion on the
* local lock and to make softirq_count() & al work.
*/
current->softirq_disable_cnt = newcnt;
if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && newcnt == cnt) {
raw_local_irq_save(flags);
lockdep_softirqs_off(ip);
raw_local_irq_restore(flags);
}
}
EXPORT_SYMBOL(__local_bh_disable_ip);
static void __local_bh_enable(unsigned int cnt, bool unlock)
{
unsigned long flags;
int newcnt;
DEBUG_LOCKS_WARN_ON(current->softirq_disable_cnt !=
this_cpu_read(softirq_ctrl.cnt));
if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && softirq_count() == cnt) {
raw_local_irq_save(flags);
lockdep_softirqs_on(_RET_IP_);
raw_local_irq_restore(flags);
}
newcnt = __this_cpu_sub_return(softirq_ctrl.cnt, cnt);
current->softirq_disable_cnt = newcnt;
if (!newcnt && unlock) {
rcu_read_unlock();
local_unlock(&softirq_ctrl.lock);
}
}
void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
{
bool preempt_on = preemptible();
unsigned long flags;
u32 pending;
int curcnt;
WARN_ON_ONCE(in_hardirq());
lockdep_assert_irqs_enabled();
local_irq_save(flags);
curcnt = __this_cpu_read(softirq_ctrl.cnt);
/*
* If this is not reenabling soft interrupts, no point in trying to
* run pending ones.
*/
if (curcnt != cnt)
goto out;
pending = local_softirq_pending();
if (!pending)
goto out;
/*
* If this was called from non preemptible context, wake up the
* softirq daemon.
*/
if (!preempt_on) {
wakeup_softirqd();
goto out;
}
/*
* Adjust softirq count to SOFTIRQ_OFFSET which makes
* in_serving_softirq() become true.
*/
cnt = SOFTIRQ_OFFSET;
__local_bh_enable(cnt, false);
__do_softirq();
out:
__local_bh_enable(cnt, preempt_on);
local_irq_restore(flags);
}
EXPORT_SYMBOL(__local_bh_enable_ip);
/*
* Invoked from ksoftirqd_run() outside of the interrupt disabled section
* to acquire the per CPU local lock for reentrancy protection.
*/
static inline void ksoftirqd_run_begin(void)
{
__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
local_irq_disable();
}
/* Counterpart to ksoftirqd_run_begin() */
static inline void ksoftirqd_run_end(void)
{
__local_bh_enable(SOFTIRQ_OFFSET, true);
WARN_ON_ONCE(in_interrupt());
local_irq_enable();
}
static inline void softirq_handle_begin(void) { }
static inline void softirq_handle_end(void) { }
static inline bool should_wake_ksoftirqd(void)
{
return !this_cpu_read(softirq_ctrl.cnt);
}
static inline void invoke_softirq(void)
{
if (should_wake_ksoftirqd())
wakeup_softirqd();
}
/*
* flush_smp_call_function_queue() can raise a soft interrupt in a function
* call. On RT kernels this is undesired and the only known functionality
* in the block layer which does this is disabled on RT. If soft interrupts
* get raised which haven't been raised before the flush, warn so it can be
* investigated.
*/
void do_softirq_post_smp_call_flush(unsigned int was_pending)
{
if (WARN_ON_ONCE(was_pending != local_softirq_pending()))
invoke_softirq();
}
#else /* CONFIG_PREEMPT_RT */
/*
* This one is for softirq.c-internal use, where hardirqs are disabled
* legitimately:
*/
#ifdef CONFIG_TRACE_IRQFLAGS
void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
unsigned long flags;
WARN_ON_ONCE(in_hardirq());
raw_local_irq_save(flags);
/*
* The preempt tracer hooks into preempt_count_add and will break
* lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
* is set and before current->softirq_enabled is cleared.
* We must manually increment preempt_count here and manually
* call the trace_preempt_off later.
*/
__preempt_count_add(cnt);
/*
* Were softirqs turned off above:
*/
if (softirq_count() == (cnt & SOFTIRQ_MASK))
lockdep_softirqs_off(ip);
raw_local_irq_restore(flags);
if (preempt_count() == cnt) {
#ifdef CONFIG_DEBUG_PREEMPT
current->preempt_disable_ip = get_lock_parent_ip();
#endif
trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
}
}
EXPORT_SYMBOL(__local_bh_disable_ip);
#endif /* CONFIG_TRACE_IRQFLAGS */
static void __local_bh_enable(unsigned int cnt)
{
lockdep_assert_irqs_disabled();
if (preempt_count() == cnt)
trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
if (softirq_count() == (cnt & SOFTIRQ_MASK))
lockdep_softirqs_on(_RET_IP_);
__preempt_count_sub(cnt);
}
/*
* Special-case - softirqs can safely be enabled by __do_softirq(),
* without processing still-pending softirqs:
*/
void _local_bh_enable(void)
{
WARN_ON_ONCE(in_hardirq());
__local_bh_enable(SOFTIRQ_DISABLE_OFFSET);
}
EXPORT_SYMBOL(_local_bh_enable);
void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
{
WARN_ON_ONCE(in_hardirq());
lockdep_assert_irqs_enabled();
#ifdef CONFIG_TRACE_IRQFLAGS
local_irq_disable();
#endif
/*
* Are softirqs going to be turned on now:
*/
if (softirq_count() == SOFTIRQ_DISABLE_OFFSET)
lockdep_softirqs_on(ip);
/*
* Keep preemption disabled until we are done with
* softirq processing:
*/
__preempt_count_sub(cnt - 1);
if (unlikely(!in_interrupt() && local_softirq_pending())) {
/*
* Run softirq if any pending. And do it in its own stack
* as we may be calling this deep in a task call stack already.
*/
do_softirq();
}
preempt_count_dec();
#ifdef CONFIG_TRACE_IRQFLAGS
local_irq_enable();
#endif
preempt_check_resched();
}
EXPORT_SYMBOL(__local_bh_enable_ip);
static inline void softirq_handle_begin(void)
{
__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
}
static inline void softirq_handle_end(void)
{
__local_bh_enable(SOFTIRQ_OFFSET);
WARN_ON_ONCE(in_interrupt());
}
static inline void ksoftirqd_run_begin(void)
{
local_irq_disable();
}
static inline void ksoftirqd_run_end(void)
{
local_irq_enable();
}
static inline bool should_wake_ksoftirqd(void)
{
return true;
}
static inline void invoke_softirq(void)
{
if (!force_irqthreads() || !__this_cpu_read(ksoftirqd)) {
#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
/*
* We can safely execute softirq on the current stack if
* it is the irq stack, because it should be near empty
* at this stage.
*/
__do_softirq();
#else
/*
* Otherwise, irq_exit() is called on the task stack that can
* be potentially deep already. So call softirq in its own stack
* to prevent from any overrun.
*/
do_softirq_own_stack();
#endif
} else {
wakeup_softirqd();
}
}
asmlinkage __visible void do_softirq(void)
{
__u32 pending;
unsigned long flags;
if (in_interrupt())
return;
local_irq_save(flags);
pending = local_softirq_pending();
if (pending)
do_softirq_own_stack();
local_irq_restore(flags);
}
#endif /* !CONFIG_PREEMPT_RT */
/*
* We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
* but break the loop if need_resched() is set or after 2 ms.
* The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in
* certain cases, such as stop_machine(), jiffies may cease to
* increment and so we need the MAX_SOFTIRQ_RESTART limit as
* well to make sure we eventually return from this method.
*
* These limits have been established via experimentation.
* The two things to balance is latency against fairness -
* we want to handle softirqs as soon as possible, but they
* should not be able to lock up the box.
*/
#define MAX_SOFTIRQ_TIME msecs_to_jiffies(2)
#define MAX_SOFTIRQ_RESTART 10
#ifdef CONFIG_TRACE_IRQFLAGS
/*
* When we run softirqs from irq_exit() and thus on the hardirq stack we need
* to keep the lockdep irq context tracking as tight as possible in order to
* not miss-qualify lock contexts and miss possible deadlocks.
*/
static inline bool lockdep_softirq_start(void)
{
bool in_hardirq = false;
if (lockdep_hardirq_context()) {
in_hardirq = true;
lockdep_hardirq_exit();
}
lockdep_softirq_enter();
return in_hardirq;
}
static inline void lockdep_softirq_end(bool in_hardirq)
{
lockdep_softirq_exit();
if (in_hardirq)
lockdep_hardirq_enter();
}
#else
static inline bool lockdep_softirq_start(void) { return false; }
static inline void lockdep_softirq_end(bool in_hardirq) { }
#endif
asmlinkage __visible void __softirq_entry __do_softirq(void)
{
unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
unsigned long old_flags = current->flags;
int max_restart = MAX_SOFTIRQ_RESTART;
struct softirq_action *h;
bool in_hardirq;
__u32 pending;
int softirq_bit;
/*
* Mask out PF_MEMALLOC as the current task context is borrowed for the
* softirq. A softirq handled, such as network RX, might set PF_MEMALLOC
* again if the socket is related to swapping.
*/
current->flags &= ~PF_MEMALLOC;
pending = local_softirq_pending();
softirq_handle_begin();
in_hardirq = lockdep_softirq_start();
account_softirq_enter(current);
restart:
/* Reset the pending bitmask before enabling irqs */
set_softirq_pending(0);
local_irq_enable();
h = softirq_vec;
while ((softirq_bit = ffs(pending))) {
unsigned int vec_nr;
int prev_count;
h += softirq_bit - 1;
vec_nr = h - softirq_vec;
prev_count = preempt_count();
kstat_incr_softirqs_this_cpu(vec_nr);
trace_softirq_entry(vec_nr);
h->action(h);
trace_softirq_exit(vec_nr);
if (unlikely(prev_count != preempt_count())) {
pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
vec_nr, softirq_to_name[vec_nr], h->action,
prev_count, preempt_count());
preempt_count_set(prev_count);
}
h++;
pending >>= softirq_bit;
}
if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
__this_cpu_read(ksoftirqd) == current)
rcu_softirq_qs();
local_irq_disable();
pending = local_softirq_pending();
if (pending) {
if (time_before(jiffies, end) && !need_resched() &&
--max_restart)
goto restart;
wakeup_softirqd();
}
account_softirq_exit(current);
lockdep_softirq_end(in_hardirq);
softirq_handle_end();
current_restore_flags(old_flags, PF_MEMALLOC);
}
/**
* irq_enter_rcu - Enter an interrupt context with RCU watching
*/
void irq_enter_rcu(void)
{
__irq_enter_raw();
if (tick_nohz_full_cpu(smp_processor_id()) ||
(is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET)))
tick_irq_enter();
account_hardirq_enter(current);
}
/**
* irq_enter - Enter an interrupt context including RCU update
*/
void irq_enter(void)
{
ct_irq_enter();
irq_enter_rcu();
}
static inline void tick_irq_exit(void)
{
#ifdef CONFIG_NO_HZ_COMMON
int cpu = smp_processor_id();
/* Make sure that timer wheel updates are propagated */
if ((sched_core_idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) {
if (!in_hardirq())
tick_nohz_irq_exit();
}
#endif
}
static inline void __irq_exit_rcu(void)
{
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
local_irq_disable();
#else
lockdep_assert_irqs_disabled();
#endif
account_hardirq_exit(current);
preempt_count_sub(HARDIRQ_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
tick_irq_exit();
}
/**
* irq_exit_rcu() - Exit an interrupt context without updating RCU
*
* Also processes softirqs if needed and possible.
*/
void irq_exit_rcu(void)
{
__irq_exit_rcu();
/* must be last! */
lockdep_hardirq_exit();
}
/**
* irq_exit - Exit an interrupt context, update RCU and lockdep
*
* Also processes softirqs if needed and possible.
*/
void irq_exit(void)
{
__irq_exit_rcu();
ct_irq_exit();
/* must be last! */
lockdep_hardirq_exit();
}
/*
* This function must run with irqs disabled!
*/
inline void raise_softirq_irqoff(unsigned int nr)
{
__raise_softirq_irqoff(nr);
/*
* If we're in an interrupt or softirq, we're done
* (this also catches softirq-disabled code). We will
* actually run the softirq once we return from
* the irq or softirq.
*
* Otherwise we wake up ksoftirqd to make sure we
* schedule the softirq soon.
*/
if (!in_interrupt() && should_wake_ksoftirqd())
wakeup_softirqd();
}
void raise_softirq(unsigned int nr)
{
unsigned long flags;
local_irq_save(flags);
raise_softirq_irqoff(nr);
local_irq_restore(flags);
}
void __raise_softirq_irqoff(unsigned int nr)
{
lockdep_assert_irqs_disabled();
trace_softirq_raise(nr);
or_softirq_pending(1UL << nr);
}
void open_softirq(int nr, void (*action)(struct softirq_action *))
{
softirq_vec[nr].action = action;
}
/*
* Tasklets
*/
struct tasklet_head {
struct tasklet_struct *head;
struct tasklet_struct **tail;
};
static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);
static void __tasklet_schedule_common(struct tasklet_struct *t,
struct tasklet_head __percpu *headp,
unsigned int softirq_nr)
{
struct tasklet_head *head;
unsigned long flags;
local_irq_save(flags);
head = this_cpu_ptr(headp);
t->next = NULL;
*head->tail = t;
head->tail = &(t->next);
raise_softirq_irqoff(softirq_nr);
local_irq_restore(flags);
}
void __tasklet_schedule(struct tasklet_struct *t)
{
__tasklet_schedule_common(t, &tasklet_vec,
TASKLET_SOFTIRQ);
}
EXPORT_SYMBOL(__tasklet_schedule);
void __tasklet_hi_schedule(struct tasklet_struct *t)
{
__tasklet_schedule_common(t, &tasklet_hi_vec,
HI_SOFTIRQ);
}
EXPORT_SYMBOL(__tasklet_hi_schedule);
static bool tasklet_clear_sched(struct tasklet_struct *t)
{
if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) {
wake_up_var(&t->state);
return true;
}
WARN_ONCE(1, "tasklet SCHED state not set: %s %pS\n",
t->use_callback ? "callback" : "func",
t->use_callback ? (void *)t->callback : (void *)t->func);
return false;
}
static void tasklet_action_common(struct softirq_action *a,
struct tasklet_head *tl_head,
unsigned int softirq_nr)
{
struct tasklet_struct *list;
local_irq_disable();
list = tl_head->head;
tl_head->head = NULL;
tl_head->tail = &tl_head->head;
local_irq_enable();
while (list) {
struct tasklet_struct *t = list;
list = list->next;
if (tasklet_trylock(t)) {
if (!atomic_read(&t->count)) {
if (tasklet_clear_sched(t)) {
if (t->use_callback) {
trace_tasklet_entry(t, t->callback);
t->callback(t);
trace_tasklet_exit(t, t->callback);
} else {
trace_tasklet_entry(t, t->func);
t->func(t->data);
trace_tasklet_exit(t, t->func);
}
}
tasklet_unlock(t);
continue;
}
tasklet_unlock(t);
}
local_irq_disable();
t->next = NULL;
*tl_head->tail = t;
tl_head->tail = &t->next;
__raise_softirq_irqoff(softirq_nr);
local_irq_enable();
}
}
static __latent_entropy void tasklet_action(struct softirq_action *a)
{
tasklet_action_common(a, this_cpu_ptr(&tasklet_vec), TASKLET_SOFTIRQ);
}
static __latent_entropy void tasklet_hi_action(struct softirq_action *a)
{
tasklet_action_common(a, this_cpu_ptr(&tasklet_hi_vec), HI_SOFTIRQ);
}
void tasklet_setup(struct tasklet_struct *t,
void (*callback)(struct tasklet_struct *))
{
t->next = NULL;
t->state = 0;
atomic_set(&t->count, 0);
t->callback = callback;
t->use_callback = true;
t->data = 0;
}
EXPORT_SYMBOL(tasklet_setup);
void tasklet_init(struct tasklet_struct *t,
void (*func)(unsigned long), unsigned long data)
{
t->next = NULL;
t->state = 0;
atomic_set(&t->count, 0);
t->func = func;
t->use_callback = false;
t->data = data;
}
EXPORT_SYMBOL(tasklet_init);
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
/*
* Do not use in new code. Waiting for tasklets from atomic contexts is
* error prone and should be avoided.
*/
void tasklet_unlock_spin_wait(struct tasklet_struct *t)
{
while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
/*
* Prevent a live lock when current preempted soft
* interrupt processing or prevents ksoftirqd from
* running. If the tasklet runs on a different CPU
* then this has no effect other than doing the BH
* disable/enable dance for nothing.
*/
local_bh_disable();
local_bh_enable();
} else {
cpu_relax();
}
}
}
EXPORT_SYMBOL(tasklet_unlock_spin_wait);
#endif
void tasklet_kill(struct tasklet_struct *t)
{
if (in_interrupt())
pr_notice("Attempt to kill tasklet from interrupt\n");
while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state));
tasklet_unlock_wait(t);
tasklet_clear_sched(t);
}
EXPORT_SYMBOL(tasklet_kill);
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
void tasklet_unlock(struct tasklet_struct *t)
{
smp_mb__before_atomic();
clear_bit(TASKLET_STATE_RUN, &t->state);
smp_mb__after_atomic();
wake_up_var(&t->state);
}
EXPORT_SYMBOL_GPL(tasklet_unlock);
void tasklet_unlock_wait(struct tasklet_struct *t)
{
wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state));
}
EXPORT_SYMBOL_GPL(tasklet_unlock_wait);
#endif
void __init softirq_init(void)
{
int cpu;
for_each_possible_cpu(cpu) {
per_cpu(tasklet_vec, cpu).tail =
&per_cpu(tasklet_vec, cpu).head;
per_cpu(tasklet_hi_vec, cpu).tail =
&per_cpu(tasklet_hi_vec, cpu).head;
}
open_softirq(TASKLET_SOFTIRQ, tasklet_action);
open_softirq(HI_SOFTIRQ, tasklet_hi_action);
}
static int ksoftirqd_should_run(unsigned int cpu)
{
return local_softirq_pending();
}
static void run_ksoftirqd(unsigned int cpu)
{
ksoftirqd_run_begin();
if (local_softirq_pending()) {
/*
* We can safely run softirq on inline stack, as we are not deep
* in the task stack here.
*/
__do_softirq();
ksoftirqd_run_end();
cond_resched();
return;
}
ksoftirqd_run_end();
}
#ifdef CONFIG_HOTPLUG_CPU
static int takeover_tasklets(unsigned int cpu)
{
/* CPU is dead, so no lock needed. */
local_irq_disable();
/* Find end, append list for that CPU. */
if (&per_cpu(tasklet_vec, cpu).head != per_cpu(tasklet_vec, cpu).tail) {
*__this_cpu_read(tasklet_vec.tail) = per_cpu(tasklet_vec, cpu).head;
__this_cpu_write(tasklet_vec.tail, per_cpu(tasklet_vec, cpu).tail);
per_cpu(tasklet_vec, cpu).head = NULL;
per_cpu(tasklet_vec, cpu).tail = &per_cpu(tasklet_vec, cpu).head;
}
raise_softirq_irqoff(TASKLET_SOFTIRQ);
if (&per_cpu(tasklet_hi_vec, cpu).head != per_cpu(tasklet_hi_vec, cpu).tail) {
*__this_cpu_read(tasklet_hi_vec.tail) = per_cpu(tasklet_hi_vec, cpu).head;
__this_cpu_write(tasklet_hi_vec.tail, per_cpu(tasklet_hi_vec, cpu).tail);
per_cpu(tasklet_hi_vec, cpu).head = NULL;
per_cpu(tasklet_hi_vec, cpu).tail = &per_cpu(tasklet_hi_vec, cpu).head;
}
raise_softirq_irqoff(HI_SOFTIRQ);
local_irq_enable();
return 0;
}
#else
#define takeover_tasklets NULL
#endif /* CONFIG_HOTPLUG_CPU */
static struct smp_hotplug_thread softirq_threads = {
.store = &ksoftirqd,
.thread_should_run = ksoftirqd_should_run,
.thread_fn = run_ksoftirqd,
.thread_comm = "ksoftirqd/%u",
};
static __init int spawn_ksoftirqd(void)
{
cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
takeover_tasklets);
BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
return 0;
}
early_initcall(spawn_ksoftirqd);
/*
* [ These __weak aliases are kept in a separate compilation unit, so that
* GCC does not inline them incorrectly. ]
*/
int __init __weak early_irq_init(void)
{
return 0;
}
int __init __weak arch_probe_nr_irqs(void)
{
return NR_IRQS_LEGACY;
}
int __init __weak arch_early_irq_init(void)
{
return 0;
}
unsigned int __weak arch_dynirq_lower_bound(unsigned int from)
{
return from;
}
| linux-master | kernel/softirq.c |
// SPDX-License-Identifier: GPL-2.0
/*
* This code fills the used part of the kernel stack with a poison value
* before returning to userspace. It's part of the STACKLEAK feature
* ported from grsecurity/PaX.
*
* Author: Alexander Popov <[email protected]>
*
* STACKLEAK reduces the information which kernel stack leak bugs can
* reveal and blocks some uninitialized stack variable attacks.
*/
#include <linux/stackleak.h>
#include <linux/kprobes.h>
#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
#include <linux/jump_label.h>
#include <linux/sysctl.h>
#include <linux/init.h>
static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass);
#ifdef CONFIG_SYSCTL
static int stack_erasing_sysctl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret = 0;
int state = !static_branch_unlikely(&stack_erasing_bypass);
int prev_state = state;
table->data = &state;
table->maxlen = sizeof(int);
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
state = !!state;
if (ret || !write || state == prev_state)
return ret;
if (state)
static_branch_disable(&stack_erasing_bypass);
else
static_branch_enable(&stack_erasing_bypass);
pr_warn("stackleak: kernel stack erasing is %s\n",
state ? "enabled" : "disabled");
return ret;
}
static struct ctl_table stackleak_sysctls[] = {
{
.procname = "stack_erasing",
.data = NULL,
.maxlen = sizeof(int),
.mode = 0600,
.proc_handler = stack_erasing_sysctl,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{}
};
static int __init stackleak_sysctls_init(void)
{
register_sysctl_init("kernel", stackleak_sysctls);
return 0;
}
late_initcall(stackleak_sysctls_init);
#endif /* CONFIG_SYSCTL */
#define skip_erasing() static_branch_unlikely(&stack_erasing_bypass)
#else
#define skip_erasing() false
#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */
#ifndef __stackleak_poison
static __always_inline void __stackleak_poison(unsigned long erase_low,
unsigned long erase_high,
unsigned long poison)
{
while (erase_low < erase_high) {
*(unsigned long *)erase_low = poison;
erase_low += sizeof(unsigned long);
}
}
#endif
static __always_inline void __stackleak_erase(bool on_task_stack)
{
const unsigned long task_stack_low = stackleak_task_low_bound(current);
const unsigned long task_stack_high = stackleak_task_high_bound(current);
unsigned long erase_low, erase_high;
erase_low = stackleak_find_top_of_poison(task_stack_low,
current->lowest_stack);
#ifdef CONFIG_STACKLEAK_METRICS
current->prev_lowest_stack = erase_low;
#endif
/*
* Write poison to the task's stack between 'erase_low' and
* 'erase_high'.
*
* If we're running on a different stack (e.g. an entry trampoline
* stack) we can erase everything below the pt_regs at the top of the
* task stack.
*
* If we're running on the task stack itself, we must not clobber any
* stack used by this function and its caller. We assume that this
* function has a fixed-size stack frame, and the current stack pointer
* doesn't change while we write poison.
*/
if (on_task_stack)
erase_high = current_stack_pointer;
else
erase_high = task_stack_high;
__stackleak_poison(erase_low, erase_high, STACKLEAK_POISON);
/* Reset the 'lowest_stack' value for the next syscall */
current->lowest_stack = task_stack_high;
}
/*
* Erase and poison the portion of the task stack used since the last erase.
* Can be called from the task stack or an entry stack when the task stack is
* no longer in use.
*/
asmlinkage void noinstr stackleak_erase(void)
{
if (skip_erasing())
return;
__stackleak_erase(on_thread_stack());
}
/*
* Erase and poison the portion of the task stack used since the last erase.
* Can only be called from the task stack.
*/
asmlinkage void noinstr stackleak_erase_on_task_stack(void)
{
if (skip_erasing())
return;
__stackleak_erase(true);
}
/*
* Erase and poison the portion of the task stack used since the last erase.
* Can only be called from a stack other than the task stack.
*/
asmlinkage void noinstr stackleak_erase_off_task_stack(void)
{
if (skip_erasing())
return;
__stackleak_erase(false);
}
void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
{
unsigned long sp = current_stack_pointer;
/*
* Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than
* STACKLEAK_SEARCH_DEPTH makes the poison search in
* stackleak_erase() unreliable. Let's prevent that.
*/
BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH);
/* 'lowest_stack' should be aligned on the register width boundary */
sp = ALIGN(sp, sizeof(unsigned long));
if (sp < current->lowest_stack &&
sp >= stackleak_task_low_bound(current)) {
current->lowest_stack = sp;
}
}
EXPORT_SYMBOL(stackleak_track_stack);
| linux-master | kernel/stackleak.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* audit.c -- Auditing support
* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
* System-call specific features have moved to auditsc.c
*
* Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* Written by Rickard E. (Rik) Faith <[email protected]>
*
* Goals: 1) Integrate fully with Security Modules.
* 2) Minimal run-time overhead:
* a) Minimal when syscall auditing is disabled (audit_enable=0).
* b) Small when syscall auditing is enabled and no audit record
* is generated (defer as much work as possible to record
* generation time):
* i) context is allocated,
* ii) names from getname are stored without a copy, and
* iii) inode information stored from path_lookup.
* 3) Ability to disable syscall auditing at boot time (audit=0).
* 4) Usable by other parts of the kernel (if audit_log* is called,
* then a syscall record will be generated automatically for the
* current syscall).
* 5) Netlink interface to user-space.
* 6) Support low-overhead kernel-based filtering to minimize the
* information that must be passed to user-space.
*
* Audit userspace, documentation, tests, and bug/issue trackers:
* https://github.com/linux-audit
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/file.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/pid.h>
#include <linux/audit.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <linux/skbuff.h>
#include <linux/security.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
#include "audit.h"
/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
* (Initialization happens after skb_init is called.) */
#define AUDIT_DISABLED -1
#define AUDIT_UNINITIALIZED 0
#define AUDIT_INITIALIZED 1
static int audit_initialized = AUDIT_UNINITIALIZED;
u32 audit_enabled = AUDIT_OFF;
bool audit_ever_enabled = !!AUDIT_OFF;
EXPORT_SYMBOL_GPL(audit_enabled);
/* Default state when kernel boots without any parameters. */
static u32 audit_default = AUDIT_OFF;
/* If auditing cannot proceed, audit_failure selects what happens. */
static u32 audit_failure = AUDIT_FAIL_PRINTK;
/* private audit network namespace index */
static unsigned int audit_net_id;
/**
* struct audit_net - audit private network namespace data
* @sk: communication socket
*/
struct audit_net {
struct sock *sk;
};
/**
* struct auditd_connection - kernel/auditd connection state
* @pid: auditd PID
* @portid: netlink portid
* @net: the associated network namespace
* @rcu: RCU head
*
* Description:
* This struct is RCU protected; you must either hold the RCU lock for reading
* or the associated spinlock for writing.
*/
struct auditd_connection {
struct pid *pid;
u32 portid;
struct net *net;
struct rcu_head rcu;
};
static struct auditd_connection __rcu *auditd_conn;
static DEFINE_SPINLOCK(auditd_conn_lock);
/* If audit_rate_limit is non-zero, limit the rate of sending audit records
* to that number per second. This prevents DoS attacks, but results in
* audit records being dropped. */
static u32 audit_rate_limit;
/* Number of outstanding audit_buffers allowed.
* When set to zero, this means unlimited. */
static u32 audit_backlog_limit = 64;
#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
/* The identity of the user shutting down the audit system. */
static kuid_t audit_sig_uid = INVALID_UID;
static pid_t audit_sig_pid = -1;
static u32 audit_sig_sid;
/* Records can be lost in several ways:
0) [suppressed in audit_alloc]
1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
2) out of memory in audit_log_move [alloc_skb]
3) suppressed due to audit_rate_limit
4) suppressed due to audit_backlog_limit
*/
static atomic_t audit_lost = ATOMIC_INIT(0);
/* Monotonically increasing sum of time the kernel has spent
* waiting while the backlog limit is exceeded.
*/
static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
/* Hash for inode-based rules */
struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
static struct kmem_cache *audit_buffer_cache;
/* queue msgs to send via kauditd_task */
static struct sk_buff_head audit_queue;
/* queue msgs due to temporary unicast send problems */
static struct sk_buff_head audit_retry_queue;
/* queue msgs waiting for new auditd connection */
static struct sk_buff_head audit_hold_queue;
/* queue servicing thread */
static struct task_struct *kauditd_task;
static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
/* waitqueue for callers who are blocked on the audit backlog */
static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
.mask = -1,
.features = 0,
.lock = 0,};
static char *audit_feature_names[2] = {
"only_unset_loginuid",
"loginuid_immutable",
};
/**
* struct audit_ctl_mutex - serialize requests from userspace
* @lock: the mutex used for locking
* @owner: the task which owns the lock
*
* Description:
* This is the lock struct used to ensure we only process userspace requests
* in an orderly fashion. We can't simply use a mutex/lock here because we
* need to track lock ownership so we don't end up blocking the lock owner in
* audit_log_start() or similar.
*/
static struct audit_ctl_mutex {
struct mutex lock;
void *owner;
} audit_cmd_mutex;
/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
* audit records. Since printk uses a 1024 byte buffer, this buffer
* should be at least that large. */
#define AUDIT_BUFSIZ 1024
/* The audit_buffer is used when formatting an audit record. The caller
* locks briefly to get the record off the freelist or to allocate the
* buffer, and locks briefly to send the buffer to the netlink layer or
* to place it on a transmit queue. Multiple audit_buffers can be in
* use simultaneously. */
struct audit_buffer {
struct sk_buff *skb; /* formatted skb ready to send */
struct audit_context *ctx; /* NULL or associated context */
gfp_t gfp_mask;
};
struct audit_reply {
__u32 portid;
struct net *net;
struct sk_buff *skb;
};
/**
* auditd_test_task - Check to see if a given task is an audit daemon
* @task: the task to check
*
* Description:
* Return 1 if the task is a registered audit daemon, 0 otherwise.
*/
int auditd_test_task(struct task_struct *task)
{
int rc;
struct auditd_connection *ac;
rcu_read_lock();
ac = rcu_dereference(auditd_conn);
rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
rcu_read_unlock();
return rc;
}
/**
* audit_ctl_lock - Take the audit control lock
*/
void audit_ctl_lock(void)
{
mutex_lock(&audit_cmd_mutex.lock);
audit_cmd_mutex.owner = current;
}
/**
* audit_ctl_unlock - Drop the audit control lock
*/
void audit_ctl_unlock(void)
{
audit_cmd_mutex.owner = NULL;
mutex_unlock(&audit_cmd_mutex.lock);
}
/**
* audit_ctl_owner_current - Test to see if the current task owns the lock
*
* Description:
* Return true if the current task owns the audit control lock, false if it
* doesn't own the lock.
*/
static bool audit_ctl_owner_current(void)
{
return (current == audit_cmd_mutex.owner);
}
/**
* auditd_pid_vnr - Return the auditd PID relative to the namespace
*
* Description:
* Returns the PID in relation to the namespace, 0 on failure.
*/
static pid_t auditd_pid_vnr(void)
{
pid_t pid;
const struct auditd_connection *ac;
rcu_read_lock();
ac = rcu_dereference(auditd_conn);
if (!ac || !ac->pid)
pid = 0;
else
pid = pid_vnr(ac->pid);
rcu_read_unlock();
return pid;
}
/**
* audit_get_sk - Return the audit socket for the given network namespace
* @net: the destination network namespace
*
* Description:
* Returns the sock pointer if valid, NULL otherwise. The caller must ensure
* that a reference is held for the network namespace while the sock is in use.
*/
static struct sock *audit_get_sk(const struct net *net)
{
struct audit_net *aunet;
if (!net)
return NULL;
aunet = net_generic(net, audit_net_id);
return aunet->sk;
}
void audit_panic(const char *message)
{
switch (audit_failure) {
case AUDIT_FAIL_SILENT:
break;
case AUDIT_FAIL_PRINTK:
if (printk_ratelimit())
pr_err("%s\n", message);
break;
case AUDIT_FAIL_PANIC:
panic("audit: %s\n", message);
break;
}
}
static inline int audit_rate_check(void)
{
static unsigned long last_check = 0;
static int messages = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
int retval = 0;
if (!audit_rate_limit)
return 1;
spin_lock_irqsave(&lock, flags);
if (++messages < audit_rate_limit) {
retval = 1;
} else {
now = jiffies;
if (time_after(now, last_check + HZ)) {
last_check = now;
messages = 0;
retval = 1;
}
}
spin_unlock_irqrestore(&lock, flags);
return retval;
}
/**
* audit_log_lost - conditionally log lost audit message event
* @message: the message stating reason for lost audit message
*
* Emit at least 1 message per second, even if audit_rate_check is
* throttling.
* Always increment the lost messages counter.
*/
void audit_log_lost(const char *message)
{
static unsigned long last_msg = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
int print;
atomic_inc(&audit_lost);
print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
if (!print) {
spin_lock_irqsave(&lock, flags);
now = jiffies;
if (time_after(now, last_msg + HZ)) {
print = 1;
last_msg = now;
}
spin_unlock_irqrestore(&lock, flags);
}
if (print) {
if (printk_ratelimit())
pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
atomic_read(&audit_lost),
audit_rate_limit,
audit_backlog_limit);
audit_panic(message);
}
}
static int audit_log_config_change(char *function_name, u32 new, u32 old,
int allow_changes)
{
struct audit_buffer *ab;
int rc = 0;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return rc;
audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
audit_log_session_info(ab);
rc = audit_log_task_context(ab);
if (rc)
allow_changes = 0; /* Something weird, deny request */
audit_log_format(ab, " res=%d", allow_changes);
audit_log_end(ab);
return rc;
}
static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
{
int allow_changes, rc = 0;
u32 old = *to_change;
/* check if we are locked */
if (audit_enabled == AUDIT_LOCKED)
allow_changes = 0;
else
allow_changes = 1;
if (audit_enabled != AUDIT_OFF) {
rc = audit_log_config_change(function_name, new, old, allow_changes);
if (rc)
allow_changes = 0;
}
/* If we are allowed, make the change */
if (allow_changes == 1)
*to_change = new;
/* Not allowed, update reason */
else if (rc == 0)
rc = -EPERM;
return rc;
}
static int audit_set_rate_limit(u32 limit)
{
return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
}
static int audit_set_backlog_limit(u32 limit)
{
return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
}
static int audit_set_backlog_wait_time(u32 timeout)
{
return audit_do_config_change("audit_backlog_wait_time",
&audit_backlog_wait_time, timeout);
}
static int audit_set_enabled(u32 state)
{
int rc;
if (state > AUDIT_LOCKED)
return -EINVAL;
rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
if (!rc)
audit_ever_enabled |= !!state;
return rc;
}
static int audit_set_failure(u32 state)
{
if (state != AUDIT_FAIL_SILENT
&& state != AUDIT_FAIL_PRINTK
&& state != AUDIT_FAIL_PANIC)
return -EINVAL;
return audit_do_config_change("audit_failure", &audit_failure, state);
}
/**
* auditd_conn_free - RCU helper to release an auditd connection struct
* @rcu: RCU head
*
* Description:
* Drop any references inside the auditd connection tracking struct and free
* the memory.
*/
static void auditd_conn_free(struct rcu_head *rcu)
{
struct auditd_connection *ac;
ac = container_of(rcu, struct auditd_connection, rcu);
put_pid(ac->pid);
put_net(ac->net);
kfree(ac);
}
/**
* auditd_set - Set/Reset the auditd connection state
* @pid: auditd PID
* @portid: auditd netlink portid
* @net: auditd network namespace pointer
*
* Description:
* This function will obtain and drop network namespace references as
* necessary. Returns zero on success, negative values on failure.
*/
static int auditd_set(struct pid *pid, u32 portid, struct net *net)
{
unsigned long flags;
struct auditd_connection *ac_old, *ac_new;
if (!pid || !net)
return -EINVAL;
ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
if (!ac_new)
return -ENOMEM;
ac_new->pid = get_pid(pid);
ac_new->portid = portid;
ac_new->net = get_net(net);
spin_lock_irqsave(&auditd_conn_lock, flags);
ac_old = rcu_dereference_protected(auditd_conn,
lockdep_is_held(&auditd_conn_lock));
rcu_assign_pointer(auditd_conn, ac_new);
spin_unlock_irqrestore(&auditd_conn_lock, flags);
if (ac_old)
call_rcu(&ac_old->rcu, auditd_conn_free);
return 0;
}
/**
* kauditd_printk_skb - Print the audit record to the ring buffer
* @skb: audit record
*
* Whatever the reason, this packet may not make it to the auditd connection
* so write it via printk so the information isn't completely lost.
*/
static void kauditd_printk_skb(struct sk_buff *skb)
{
struct nlmsghdr *nlh = nlmsg_hdr(skb);
char *data = nlmsg_data(nlh);
if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
}
/**
* kauditd_rehold_skb - Handle a audit record send failure in the hold queue
* @skb: audit record
* @error: error code (unused)
*
* Description:
* This should only be used by the kauditd_thread when it fails to flush the
* hold queue.
*/
static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error)
{
/* put the record back in the queue */
skb_queue_tail(&audit_hold_queue, skb);
}
/**
* kauditd_hold_skb - Queue an audit record, waiting for auditd
* @skb: audit record
* @error: error code
*
* Description:
* Queue the audit record, waiting for an instance of auditd. When this
* function is called we haven't given up yet on sending the record, but things
* are not looking good. The first thing we want to do is try to write the
* record via printk and then see if we want to try and hold on to the record
* and queue it, if we have room. If we want to hold on to the record, but we
* don't have room, record a record lost message.
*/
static void kauditd_hold_skb(struct sk_buff *skb, int error)
{
/* at this point it is uncertain if we will ever send this to auditd so
* try to send the message via printk before we go any further */
kauditd_printk_skb(skb);
/* can we just silently drop the message? */
if (!audit_default)
goto drop;
/* the hold queue is only for when the daemon goes away completely,
* not -EAGAIN failures; if we are in a -EAGAIN state requeue the
* record on the retry queue unless it's full, in which case drop it
*/
if (error == -EAGAIN) {
if (!audit_backlog_limit ||
skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
skb_queue_tail(&audit_retry_queue, skb);
return;
}
audit_log_lost("kauditd retry queue overflow");
goto drop;
}
/* if we have room in the hold queue, queue the message */
if (!audit_backlog_limit ||
skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
skb_queue_tail(&audit_hold_queue, skb);
return;
}
/* we have no other options - drop the message */
audit_log_lost("kauditd hold queue overflow");
drop:
kfree_skb(skb);
}
/**
* kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
* @skb: audit record
* @error: error code (unused)
*
* Description:
* Not as serious as kauditd_hold_skb() as we still have a connected auditd,
* but for some reason we are having problems sending it audit records so
* queue the given record and attempt to resend.
*/
static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error)
{
if (!audit_backlog_limit ||
skb_queue_len(&audit_retry_queue) < audit_backlog_limit) {
skb_queue_tail(&audit_retry_queue, skb);
return;
}
/* we have to drop the record, send it via printk as a last effort */
kauditd_printk_skb(skb);
audit_log_lost("kauditd retry queue overflow");
kfree_skb(skb);
}
/**
* auditd_reset - Disconnect the auditd connection
* @ac: auditd connection state
*
* Description:
* Break the auditd/kauditd connection and move all the queued records into the
* hold queue in case auditd reconnects. It is important to note that the @ac
* pointer should never be dereferenced inside this function as it may be NULL
* or invalid, you can only compare the memory address! If @ac is NULL then
* the connection will always be reset.
*/
static void auditd_reset(const struct auditd_connection *ac)
{
unsigned long flags;
struct sk_buff *skb;
struct auditd_connection *ac_old;
/* if it isn't already broken, break the connection */
spin_lock_irqsave(&auditd_conn_lock, flags);
ac_old = rcu_dereference_protected(auditd_conn,
lockdep_is_held(&auditd_conn_lock));
if (ac && ac != ac_old) {
/* someone already registered a new auditd connection */
spin_unlock_irqrestore(&auditd_conn_lock, flags);
return;
}
rcu_assign_pointer(auditd_conn, NULL);
spin_unlock_irqrestore(&auditd_conn_lock, flags);
if (ac_old)
call_rcu(&ac_old->rcu, auditd_conn_free);
/* flush the retry queue to the hold queue, but don't touch the main
* queue since we need to process that normally for multicast */
while ((skb = skb_dequeue(&audit_retry_queue)))
kauditd_hold_skb(skb, -ECONNREFUSED);
}
/**
* auditd_send_unicast_skb - Send a record via unicast to auditd
* @skb: audit record
*
* Description:
* Send a skb to the audit daemon, returns positive/zero values on success and
* negative values on failure; in all cases the skb will be consumed by this
* function. If the send results in -ECONNREFUSED the connection with auditd
* will be reset. This function may sleep so callers should not hold any locks
* where this would cause a problem.
*/
static int auditd_send_unicast_skb(struct sk_buff *skb)
{
int rc;
u32 portid;
struct net *net;
struct sock *sk;
struct auditd_connection *ac;
/* NOTE: we can't call netlink_unicast while in the RCU section so
* take a reference to the network namespace and grab local
* copies of the namespace, the sock, and the portid; the
* namespace and sock aren't going to go away while we hold a
* reference and if the portid does become invalid after the RCU
* section netlink_unicast() should safely return an error */
rcu_read_lock();
ac = rcu_dereference(auditd_conn);
if (!ac) {
rcu_read_unlock();
kfree_skb(skb);
rc = -ECONNREFUSED;
goto err;
}
net = get_net(ac->net);
sk = audit_get_sk(net);
portid = ac->portid;
rcu_read_unlock();
rc = netlink_unicast(sk, skb, portid, 0);
put_net(net);
if (rc < 0)
goto err;
return rc;
err:
if (ac && rc == -ECONNREFUSED)
auditd_reset(ac);
return rc;
}
/**
* kauditd_send_queue - Helper for kauditd_thread to flush skb queues
* @sk: the sending sock
* @portid: the netlink destination
* @queue: the skb queue to process
* @retry_limit: limit on number of netlink unicast failures
* @skb_hook: per-skb hook for additional processing
* @err_hook: hook called if the skb fails the netlink unicast send
*
* Description:
* Run through the given queue and attempt to send the audit records to auditd,
* returns zero on success, negative values on failure. It is up to the caller
* to ensure that the @sk is valid for the duration of this function.
*
*/
static int kauditd_send_queue(struct sock *sk, u32 portid,
struct sk_buff_head *queue,
unsigned int retry_limit,
void (*skb_hook)(struct sk_buff *skb),
void (*err_hook)(struct sk_buff *skb, int error))
{
int rc = 0;
struct sk_buff *skb = NULL;
struct sk_buff *skb_tail;
unsigned int failed = 0;
/* NOTE: kauditd_thread takes care of all our locking, we just use
* the netlink info passed to us (e.g. sk and portid) */
skb_tail = skb_peek_tail(queue);
while ((skb != skb_tail) && (skb = skb_dequeue(queue))) {
/* call the skb_hook for each skb we touch */
if (skb_hook)
(*skb_hook)(skb);
/* can we send to anyone via unicast? */
if (!sk) {
if (err_hook)
(*err_hook)(skb, -ECONNREFUSED);
continue;
}
retry:
/* grab an extra skb reference in case of error */
skb_get(skb);
rc = netlink_unicast(sk, skb, portid, 0);
if (rc < 0) {
/* send failed - try a few times unless fatal error */
if (++failed >= retry_limit ||
rc == -ECONNREFUSED || rc == -EPERM) {
sk = NULL;
if (err_hook)
(*err_hook)(skb, rc);
if (rc == -EAGAIN)
rc = 0;
/* continue to drain the queue */
continue;
} else
goto retry;
} else {
/* skb sent - drop the extra reference and continue */
consume_skb(skb);
failed = 0;
}
}
return (rc >= 0 ? 0 : rc);
}
/*
* kauditd_send_multicast_skb - Send a record to any multicast listeners
* @skb: audit record
*
* Description:
* Write a multicast message to anyone listening in the initial network
* namespace. This function doesn't consume an skb as might be expected since
* it has to copy it anyways.
*/
static void kauditd_send_multicast_skb(struct sk_buff *skb)
{
struct sk_buff *copy;
struct sock *sock = audit_get_sk(&init_net);
struct nlmsghdr *nlh;
/* NOTE: we are not taking an additional reference for init_net since
* we don't have to worry about it going away */
if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
return;
/*
* The seemingly wasteful skb_copy() rather than bumping the refcount
* using skb_get() is necessary because non-standard mods are made to
* the skb by the original kaudit unicast socket send routine. The
* existing auditd daemon assumes this breakage. Fixing this would
* require co-ordinating a change in the established protocol between
* the kaudit kernel subsystem and the auditd userspace code. There is
* no reason for new multicast clients to continue with this
* non-compliance.
*/
copy = skb_copy(skb, GFP_KERNEL);
if (!copy)
return;
nlh = nlmsg_hdr(copy);
nlh->nlmsg_len = skb->len;
nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
}
/**
* kauditd_thread - Worker thread to send audit records to userspace
* @dummy: unused
*/
static int kauditd_thread(void *dummy)
{
int rc;
u32 portid = 0;
struct net *net = NULL;
struct sock *sk = NULL;
struct auditd_connection *ac;
#define UNICAST_RETRIES 5
set_freezable();
while (!kthread_should_stop()) {
/* NOTE: see the lock comments in auditd_send_unicast_skb() */
rcu_read_lock();
ac = rcu_dereference(auditd_conn);
if (!ac) {
rcu_read_unlock();
goto main_queue;
}
net = get_net(ac->net);
sk = audit_get_sk(net);
portid = ac->portid;
rcu_read_unlock();
/* attempt to flush the hold queue */
rc = kauditd_send_queue(sk, portid,
&audit_hold_queue, UNICAST_RETRIES,
NULL, kauditd_rehold_skb);
if (rc < 0) {
sk = NULL;
auditd_reset(ac);
goto main_queue;
}
/* attempt to flush the retry queue */
rc = kauditd_send_queue(sk, portid,
&audit_retry_queue, UNICAST_RETRIES,
NULL, kauditd_hold_skb);
if (rc < 0) {
sk = NULL;
auditd_reset(ac);
goto main_queue;
}
main_queue:
/* process the main queue - do the multicast send and attempt
* unicast, dump failed record sends to the retry queue; if
* sk == NULL due to previous failures we will just do the
* multicast send and move the record to the hold queue */
rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
kauditd_send_multicast_skb,
(sk ?
kauditd_retry_skb : kauditd_hold_skb));
if (ac && rc < 0)
auditd_reset(ac);
sk = NULL;
/* drop our netns reference, no auditd sends past this line */
if (net) {
put_net(net);
net = NULL;
}
/* we have processed all the queues so wake everyone */
wake_up(&audit_backlog_wait);
/* NOTE: we want to wake up if there is anything on the queue,
* regardless of if an auditd is connected, as we need to
* do the multicast send and rotate records from the
* main queue to the retry/hold queues */
wait_event_freezable(kauditd_wait,
(skb_queue_len(&audit_queue) ? 1 : 0));
}
return 0;
}
int audit_send_list_thread(void *_dest)
{
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
struct sock *sk = audit_get_sk(dest->net);
/* wait for parent to finish and send an ACK */
audit_ctl_lock();
audit_ctl_unlock();
while ((skb = __skb_dequeue(&dest->q)) != NULL)
netlink_unicast(sk, skb, dest->portid, 0);
put_net(dest->net);
kfree(dest);
return 0;
}
struct sk_buff *audit_make_reply(int seq, int type, int done,
int multi, const void *payload, int size)
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
void *data;
int flags = multi ? NLM_F_MULTI : 0;
int t = done ? NLMSG_DONE : type;
skb = nlmsg_new(size, GFP_KERNEL);
if (!skb)
return NULL;
nlh = nlmsg_put(skb, 0, seq, t, size, flags);
if (!nlh)
goto out_kfree_skb;
data = nlmsg_data(nlh);
memcpy(data, payload, size);
return skb;
out_kfree_skb:
kfree_skb(skb);
return NULL;
}
static void audit_free_reply(struct audit_reply *reply)
{
if (!reply)
return;
kfree_skb(reply->skb);
if (reply->net)
put_net(reply->net);
kfree(reply);
}
static int audit_send_reply_thread(void *arg)
{
struct audit_reply *reply = (struct audit_reply *)arg;
audit_ctl_lock();
audit_ctl_unlock();
/* Ignore failure. It'll only happen if the sender goes away,
because our timeout is set to infinite. */
netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
reply->skb = NULL;
audit_free_reply(reply);
return 0;
}
/**
* audit_send_reply - send an audit reply message via netlink
* @request_skb: skb of request we are replying to (used to target the reply)
* @seq: sequence number
* @type: audit message type
* @done: done (last) flag
* @multi: multi-part message flag
* @payload: payload data
* @size: payload size
*
* Allocates a skb, builds the netlink message, and sends it to the port id.
*/
static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
int multi, const void *payload, int size)
{
struct task_struct *tsk;
struct audit_reply *reply;
reply = kzalloc(sizeof(*reply), GFP_KERNEL);
if (!reply)
return;
reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
if (!reply->skb)
goto err;
reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
reply->portid = NETLINK_CB(request_skb).portid;
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
if (IS_ERR(tsk))
goto err;
return;
err:
audit_free_reply(reply);
}
/*
* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
* control messages.
*/
static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
{
int err = 0;
/* Only support initial user namespace for now. */
/*
* We return ECONNREFUSED because it tricks userspace into thinking
* that audit was not configured into the kernel. Lots of users
* configure their PAM stack (because that's what the distro does)
* to reject login if unable to send messages to audit. If we return
* ECONNREFUSED the PAM stack thinks the kernel does not have audit
* configured in and will let login proceed. If we return EPERM
* userspace will reject all logins. This should be removed when we
* support non init namespaces!!
*/
if (current_user_ns() != &init_user_ns)
return -ECONNREFUSED;
switch (msg_type) {
case AUDIT_LIST:
case AUDIT_ADD:
case AUDIT_DEL:
return -EOPNOTSUPP;
case AUDIT_GET:
case AUDIT_SET:
case AUDIT_GET_FEATURE:
case AUDIT_SET_FEATURE:
case AUDIT_LIST_RULES:
case AUDIT_ADD_RULE:
case AUDIT_DEL_RULE:
case AUDIT_SIGNAL_INFO:
case AUDIT_TTY_GET:
case AUDIT_TTY_SET:
case AUDIT_TRIM:
case AUDIT_MAKE_EQUIV:
/* Only support auditd and auditctl in initial pid namespace
* for now. */
if (task_active_pid_ns(current) != &init_pid_ns)
return -EPERM;
if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
err = -EPERM;
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
if (!netlink_capable(skb, CAP_AUDIT_WRITE))
err = -EPERM;
break;
default: /* bad msg */
err = -EINVAL;
}
return err;
}
static void audit_log_common_recv_msg(struct audit_context *context,
struct audit_buffer **ab, u16 msg_type)
{
uid_t uid = from_kuid(&init_user_ns, current_uid());
pid_t pid = task_tgid_nr(current);
if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
*ab = NULL;
return;
}
*ab = audit_log_start(context, GFP_KERNEL, msg_type);
if (unlikely(!*ab))
return;
audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
audit_log_session_info(*ab);
audit_log_task_context(*ab);
}
static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
u16 msg_type)
{
audit_log_common_recv_msg(NULL, ab, msg_type);
}
static int is_audit_feature_set(int i)
{
return af.features & AUDIT_FEATURE_TO_MASK(i);
}
static int audit_get_feature(struct sk_buff *skb)
{
u32 seq;
seq = nlmsg_hdr(skb)->nlmsg_seq;
audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
return 0;
}
static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
u32 old_lock, u32 new_lock, int res)
{
struct audit_buffer *ab;
if (audit_enabled == AUDIT_OFF)
return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
if (!ab)
return;
audit_log_task_info(ab);
audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
audit_feature_names[which], !!old_feature, !!new_feature,
!!old_lock, !!new_lock, res);
audit_log_end(ab);
}
static int audit_set_feature(struct audit_features *uaf)
{
int i;
BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
/* if there is ever a version 2 we should handle that here */
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
u32 feature = AUDIT_FEATURE_TO_MASK(i);
u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */
if (!(feature & uaf->mask))
continue;
old_feature = af.features & feature;
new_feature = uaf->features & feature;
new_lock = (uaf->lock | af.lock) & feature;
old_lock = af.lock & feature;
/* are we changing a locked feature? */
if (old_lock && (new_feature != old_feature)) {
audit_log_feature_change(i, old_feature, new_feature,
old_lock, new_lock, 0);
return -EPERM;
}
}
/* nothing invalid, do the changes */
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
u32 feature = AUDIT_FEATURE_TO_MASK(i);
u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */
if (!(feature & uaf->mask))
continue;
old_feature = af.features & feature;
new_feature = uaf->features & feature;
old_lock = af.lock & feature;
new_lock = (uaf->lock | af.lock) & feature;
if (new_feature != old_feature)
audit_log_feature_change(i, old_feature, new_feature,
old_lock, new_lock, 1);
if (new_feature)
af.features |= feature;
else
af.features &= ~feature;
af.lock |= new_lock;
}
return 0;
}
static int audit_replace(struct pid *pid)
{
pid_t pvnr;
struct sk_buff *skb;
pvnr = pid_vnr(pid);
skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
if (!skb)
return -ENOMEM;
return auditd_send_unicast_skb(skb);
}
static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
u32 seq;
void *data;
int data_len;
int err;
struct audit_buffer *ab;
u16 msg_type = nlh->nlmsg_type;
struct audit_sig_info *sig_data;
char *ctx = NULL;
u32 len;
err = audit_netlink_ok(skb, msg_type);
if (err)
return err;
seq = nlh->nlmsg_seq;
data = nlmsg_data(nlh);
data_len = nlmsg_len(nlh);
switch (msg_type) {
case AUDIT_GET: {
struct audit_status s;
memset(&s, 0, sizeof(s));
s.enabled = audit_enabled;
s.failure = audit_failure;
/* NOTE: use pid_vnr() so the PID is relative to the current
* namespace */
s.pid = auditd_pid_vnr();
s.rate_limit = audit_rate_limit;
s.backlog_limit = audit_backlog_limit;
s.lost = atomic_read(&audit_lost);
s.backlog = skb_queue_len(&audit_queue);
s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
s.backlog_wait_time = audit_backlog_wait_time;
s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
break;
}
case AUDIT_SET: {
struct audit_status s;
memset(&s, 0, sizeof(s));
/* guard against past and future API changes */
memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
if (s.mask & AUDIT_STATUS_ENABLED) {
err = audit_set_enabled(s.enabled);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_FAILURE) {
err = audit_set_failure(s.failure);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_PID) {
/* NOTE: we are using the vnr PID functions below
* because the s.pid value is relative to the
* namespace of the caller; at present this
* doesn't matter much since you can really only
* run auditd from the initial pid namespace, but
* something to keep in mind if this changes */
pid_t new_pid = s.pid;
pid_t auditd_pid;
struct pid *req_pid = task_tgid(current);
/* Sanity check - PID values must match. Setting
* pid to 0 is how auditd ends auditing. */
if (new_pid && (new_pid != pid_vnr(req_pid)))
return -EINVAL;
/* test the auditd connection */
audit_replace(req_pid);
auditd_pid = auditd_pid_vnr();
if (auditd_pid) {
/* replacing a healthy auditd is not allowed */
if (new_pid) {
audit_log_config_change("audit_pid",
new_pid, auditd_pid, 0);
return -EEXIST;
}
/* only current auditd can unregister itself */
if (pid_vnr(req_pid) != auditd_pid) {
audit_log_config_change("audit_pid",
new_pid, auditd_pid, 0);
return -EACCES;
}
}
if (new_pid) {
/* register a new auditd connection */
err = auditd_set(req_pid,
NETLINK_CB(skb).portid,
sock_net(NETLINK_CB(skb).sk));
if (audit_enabled != AUDIT_OFF)
audit_log_config_change("audit_pid",
new_pid,
auditd_pid,
err ? 0 : 1);
if (err)
return err;
/* try to process any backlog */
wake_up_interruptible(&kauditd_wait);
} else {
if (audit_enabled != AUDIT_OFF)
audit_log_config_change("audit_pid",
new_pid,
auditd_pid, 1);
/* unregister the auditd connection */
auditd_reset(NULL);
}
}
if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
err = audit_set_rate_limit(s.rate_limit);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
err = audit_set_backlog_limit(s.backlog_limit);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
if (sizeof(s) > (size_t)nlh->nlmsg_len)
return -EINVAL;
if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
return -EINVAL;
err = audit_set_backlog_wait_time(s.backlog_wait_time);
if (err < 0)
return err;
}
if (s.mask == AUDIT_STATUS_LOST) {
u32 lost = atomic_xchg(&audit_lost, 0);
audit_log_config_change("lost", 0, lost, 1);
return lost;
}
if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
return actual;
}
break;
}
case AUDIT_GET_FEATURE:
err = audit_get_feature(skb);
if (err)
return err;
break;
case AUDIT_SET_FEATURE:
if (data_len < sizeof(struct audit_features))
return -EINVAL;
err = audit_set_feature(data);
if (err)
return err;
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
if (!audit_enabled && msg_type != AUDIT_USER_AVC)
return 0;
/* exit early if there isn't at least one character to print */
if (data_len < 2)
return -EINVAL;
err = audit_filter(msg_type, AUDIT_FILTER_USER);
if (err == 1) { /* match or error */
char *str = data;
err = 0;
if (msg_type == AUDIT_USER_TTY) {
err = tty_audit_push();
if (err)
break;
}
audit_log_user_recv_msg(&ab, msg_type);
if (msg_type != AUDIT_USER_TTY) {
/* ensure NULL termination */
str[data_len - 1] = '\0';
audit_log_format(ab, " msg='%.*s'",
AUDIT_MESSAGE_TEXT_MAX,
str);
} else {
audit_log_format(ab, " data=");
if (str[data_len - 1] == '\0')
data_len--;
audit_log_n_untrustedstring(ab, str, data_len);
}
audit_log_end(ab);
}
break;
case AUDIT_ADD_RULE:
case AUDIT_DEL_RULE:
if (data_len < sizeof(struct audit_rule_data))
return -EINVAL;
if (audit_enabled == AUDIT_LOCKED) {
audit_log_common_recv_msg(audit_context(), &ab,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=%s audit_enabled=%d res=0",
msg_type == AUDIT_ADD_RULE ?
"add_rule" : "remove_rule",
audit_enabled);
audit_log_end(ab);
return -EPERM;
}
err = audit_rule_change(msg_type, seq, data, data_len);
break;
case AUDIT_LIST_RULES:
err = audit_list_rules_send(skb, seq);
break;
case AUDIT_TRIM:
audit_trim_trees();
audit_log_common_recv_msg(audit_context(), &ab,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=trim res=1");
audit_log_end(ab);
break;
case AUDIT_MAKE_EQUIV: {
void *bufp = data;
u32 sizes[2];
size_t msglen = data_len;
char *old, *new;
err = -EINVAL;
if (msglen < 2 * sizeof(u32))
break;
memcpy(sizes, bufp, 2 * sizeof(u32));
bufp += 2 * sizeof(u32);
msglen -= 2 * sizeof(u32);
old = audit_unpack_string(&bufp, &msglen, sizes[0]);
if (IS_ERR(old)) {
err = PTR_ERR(old);
break;
}
new = audit_unpack_string(&bufp, &msglen, sizes[1]);
if (IS_ERR(new)) {
err = PTR_ERR(new);
kfree(old);
break;
}
/* OK, here comes... */
err = audit_tag_tree(old, new);
audit_log_common_recv_msg(audit_context(), &ab,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=make_equiv old=");
audit_log_untrustedstring(ab, old);
audit_log_format(ab, " new=");
audit_log_untrustedstring(ab, new);
audit_log_format(ab, " res=%d", !err);
audit_log_end(ab);
kfree(old);
kfree(new);
break;
}
case AUDIT_SIGNAL_INFO:
len = 0;
if (audit_sig_sid) {
err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
if (err)
return err;
}
sig_data = kmalloc(struct_size(sig_data, ctx, len), GFP_KERNEL);
if (!sig_data) {
if (audit_sig_sid)
security_release_secctx(ctx, len);
return -ENOMEM;
}
sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
sig_data->pid = audit_sig_pid;
if (audit_sig_sid) {
memcpy(sig_data->ctx, ctx, len);
security_release_secctx(ctx, len);
}
audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
sig_data, struct_size(sig_data, ctx, len));
kfree(sig_data);
break;
case AUDIT_TTY_GET: {
struct audit_tty_status s;
unsigned int t;
t = READ_ONCE(current->signal->audit_tty);
s.enabled = t & AUDIT_TTY_ENABLE;
s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
break;
}
case AUDIT_TTY_SET: {
struct audit_tty_status s, old;
struct audit_buffer *ab;
unsigned int t;
memset(&s, 0, sizeof(s));
/* guard against past and future API changes */
memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
/* check if new data is valid */
if ((s.enabled != 0 && s.enabled != 1) ||
(s.log_passwd != 0 && s.log_passwd != 1))
err = -EINVAL;
if (err)
t = READ_ONCE(current->signal->audit_tty);
else {
t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
t = xchg(¤t->signal->audit_tty, t);
}
old.enabled = t & AUDIT_TTY_ENABLE;
old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
audit_log_common_recv_msg(audit_context(), &ab,
AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
" old-log_passwd=%d new-log_passwd=%d res=%d",
old.enabled, s.enabled, old.log_passwd,
s.log_passwd, !err);
audit_log_end(ab);
break;
}
default:
err = -EINVAL;
break;
}
return err < 0 ? err : 0;
}
/**
* audit_receive - receive messages from a netlink control socket
* @skb: the message buffer
*
* Parse the provided skb and deal with any messages that may be present,
* malformed skbs are discarded.
*/
static void audit_receive(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
/*
* len MUST be signed for nlmsg_next to be able to dec it below 0
* if the nlmsg_len was not aligned
*/
int len;
int err;
nlh = nlmsg_hdr(skb);
len = skb->len;
audit_ctl_lock();
while (nlmsg_ok(nlh, len)) {
err = audit_receive_msg(skb, nlh);
/* if err or if this message says it wants a response */
if (err || (nlh->nlmsg_flags & NLM_F_ACK))
netlink_ack(skb, nlh, err, NULL);
nlh = nlmsg_next(nlh, &len);
}
audit_ctl_unlock();
/* can't block with the ctrl lock, so penalize the sender now */
if (audit_backlog_limit &&
(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
DECLARE_WAITQUEUE(wait, current);
/* wake kauditd to try and flush the queue */
wake_up_interruptible(&kauditd_wait);
add_wait_queue_exclusive(&audit_backlog_wait, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(audit_backlog_wait_time);
remove_wait_queue(&audit_backlog_wait, &wait);
}
}
/* Log information about who is connecting to the audit multicast socket */
static void audit_log_multicast(int group, const char *op, int err)
{
const struct cred *cred;
struct tty_struct *tty;
char comm[sizeof(current->comm)];
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
if (!ab)
return;
cred = current_cred();
tty = audit_get_tty();
audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
task_pid_nr(current),
from_kuid(&init_user_ns, cred->uid),
from_kuid(&init_user_ns, audit_get_loginuid(current)),
tty ? tty_name(tty) : "(none)",
audit_get_sessionid(current));
audit_put_tty(tty);
audit_log_task_context(ab); /* subj= */
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, current));
audit_log_d_path_exe(ab, current->mm); /* exe= */
audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
audit_log_end(ab);
}
/* Run custom bind function on netlink socket group connect or bind requests. */
static int audit_multicast_bind(struct net *net, int group)
{
int err = 0;
if (!capable(CAP_AUDIT_READ))
err = -EPERM;
audit_log_multicast(group, "connect", err);
return err;
}
static void audit_multicast_unbind(struct net *net, int group)
{
audit_log_multicast(group, "disconnect", 0);
}
static int __net_init audit_net_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.input = audit_receive,
.bind = audit_multicast_bind,
.unbind = audit_multicast_unbind,
.flags = NL_CFG_F_NONROOT_RECV,
.groups = AUDIT_NLGRP_MAX,
};
struct audit_net *aunet = net_generic(net, audit_net_id);
aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
if (aunet->sk == NULL) {
audit_panic("cannot initialize netlink socket in namespace");
return -ENOMEM;
}
/* limit the timeout in case auditd is blocked/stopped */
aunet->sk->sk_sndtimeo = HZ / 10;
return 0;
}
static void __net_exit audit_net_exit(struct net *net)
{
struct audit_net *aunet = net_generic(net, audit_net_id);
/* NOTE: you would think that we would want to check the auditd
* connection and potentially reset it here if it lives in this
* namespace, but since the auditd connection tracking struct holds a
* reference to this namespace (see auditd_set()) we are only ever
* going to get here after that connection has been released */
netlink_kernel_release(aunet->sk);
}
static struct pernet_operations audit_net_ops __net_initdata = {
.init = audit_net_init,
.exit = audit_net_exit,
.id = &audit_net_id,
.size = sizeof(struct audit_net),
};
/* Initialize audit support at boot time. */
static int __init audit_init(void)
{
int i;
if (audit_initialized == AUDIT_DISABLED)
return 0;
audit_buffer_cache = kmem_cache_create("audit_buffer",
sizeof(struct audit_buffer),
0, SLAB_PANIC, NULL);
skb_queue_head_init(&audit_queue);
skb_queue_head_init(&audit_retry_queue);
skb_queue_head_init(&audit_hold_queue);
for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
INIT_LIST_HEAD(&audit_inode_hash[i]);
mutex_init(&audit_cmd_mutex.lock);
audit_cmd_mutex.owner = NULL;
pr_info("initializing netlink subsys (%s)\n",
audit_default ? "enabled" : "disabled");
register_pernet_subsys(&audit_net_ops);
audit_initialized = AUDIT_INITIALIZED;
kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
if (IS_ERR(kauditd_task)) {
int err = PTR_ERR(kauditd_task);
panic("audit: failed to start the kauditd thread (%d)\n", err);
}
audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
"state=initialized audit_enabled=%u res=1",
audit_enabled);
return 0;
}
postcore_initcall(audit_init);
/*
* Process kernel command-line parameter at boot time.
* audit={0|off} or audit={1|on}.
*/
static int __init audit_enable(char *str)
{
if (!strcasecmp(str, "off") || !strcmp(str, "0"))
audit_default = AUDIT_OFF;
else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
audit_default = AUDIT_ON;
else {
pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
audit_default = AUDIT_ON;
}
if (audit_default == AUDIT_OFF)
audit_initialized = AUDIT_DISABLED;
if (audit_set_enabled(audit_default))
pr_err("audit: error setting audit state (%d)\n",
audit_default);
pr_info("%s\n", audit_default ?
"enabled (after initialization)" : "disabled (until reboot)");
return 1;
}
__setup("audit=", audit_enable);
/* Process kernel command-line parameter at boot time.
* audit_backlog_limit=<n> */
static int __init audit_backlog_limit_set(char *str)
{
u32 audit_backlog_limit_arg;
pr_info("audit_backlog_limit: ");
if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
pr_cont("using default of %u, unable to parse %s\n",
audit_backlog_limit, str);
return 1;
}
audit_backlog_limit = audit_backlog_limit_arg;
pr_cont("%d\n", audit_backlog_limit);
return 1;
}
__setup("audit_backlog_limit=", audit_backlog_limit_set);
static void audit_buffer_free(struct audit_buffer *ab)
{
if (!ab)
return;
kfree_skb(ab->skb);
kmem_cache_free(audit_buffer_cache, ab);
}
static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
gfp_t gfp_mask, int type)
{
struct audit_buffer *ab;
ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
if (!ab)
return NULL;
ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
if (!ab->skb)
goto err;
if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
goto err;
ab->ctx = ctx;
ab->gfp_mask = gfp_mask;
return ab;
err:
audit_buffer_free(ab);
return NULL;
}
/**
* audit_serial - compute a serial number for the audit record
*
* Compute a serial number for the audit record. Audit records are
* written to user-space as soon as they are generated, so a complete
* audit record may be written in several pieces. The timestamp of the
* record and this serial number are used by the user-space tools to
* determine which pieces belong to the same audit record. The
* (timestamp,serial) tuple is unique for each syscall and is live from
* syscall entry to syscall exit.
*
* NOTE: Another possibility is to store the formatted records off the
* audit context (for those records that have a context), and emit them
* all at syscall exit. However, this could delay the reporting of
* significant errors until syscall exit (or never, if the system
* halts).
*/
unsigned int audit_serial(void)
{
static atomic_t serial = ATOMIC_INIT(0);
return atomic_inc_return(&serial);
}
static inline void audit_get_stamp(struct audit_context *ctx,
struct timespec64 *t, unsigned int *serial)
{
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
ktime_get_coarse_real_ts64(t);
*serial = audit_serial();
}
}
/**
* audit_log_start - obtain an audit buffer
* @ctx: audit_context (may be NULL)
* @gfp_mask: type of allocation
* @type: audit message type
*
* Returns audit_buffer pointer on success or NULL on error.
*
* Obtain an audit buffer. This routine does locking to obtain the
* audit buffer, but then no locking is required for calls to
* audit_log_*format. If the task (ctx) is a task that is currently in a
* syscall, then the syscall is marked as auditable and an audit record
* will be written at syscall exit. If there is no associated task, then
* task context (ctx) should be NULL.
*/
struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
int type)
{
struct audit_buffer *ab;
struct timespec64 t;
unsigned int serial;
if (audit_initialized != AUDIT_INITIALIZED)
return NULL;
if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
return NULL;
/* NOTE: don't ever fail/sleep on these two conditions:
* 1. auditd generated record - since we need auditd to drain the
* queue; also, when we are checking for auditd, compare PIDs using
* task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
* using a PID anchored in the caller's namespace
* 2. generator holding the audit_cmd_mutex - we don't want to block
* while holding the mutex, although we do penalize the sender
* later in audit_receive() when it is safe to block
*/
if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
long stime = audit_backlog_wait_time;
while (audit_backlog_limit &&
(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
/* wake kauditd to try and flush the queue */
wake_up_interruptible(&kauditd_wait);
/* sleep if we are allowed and we haven't exhausted our
* backlog wait limit */
if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
long rtime = stime;
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&audit_backlog_wait,
&wait);
set_current_state(TASK_UNINTERRUPTIBLE);
stime = schedule_timeout(rtime);
atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
remove_wait_queue(&audit_backlog_wait, &wait);
} else {
if (audit_rate_check() && printk_ratelimit())
pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
skb_queue_len(&audit_queue),
audit_backlog_limit);
audit_log_lost("backlog limit exceeded");
return NULL;
}
}
}
ab = audit_buffer_alloc(ctx, gfp_mask, type);
if (!ab) {
audit_log_lost("out of memory in audit_log_start");
return NULL;
}
audit_get_stamp(ab->ctx, &t, &serial);
/* cancel dummy context to enable supporting records */
if (ctx)
ctx->dummy = 0;
audit_log_format(ab, "audit(%llu.%03lu:%u): ",
(unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
return ab;
}
/**
* audit_expand - expand skb in the audit buffer
* @ab: audit_buffer
* @extra: space to add at tail of the skb
*
* Returns 0 (no space) on failed expansion, or available space if
* successful.
*/
static inline int audit_expand(struct audit_buffer *ab, int extra)
{
struct sk_buff *skb = ab->skb;
int oldtail = skb_tailroom(skb);
int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
int newtail = skb_tailroom(skb);
if (ret < 0) {
audit_log_lost("out of memory in audit_expand");
return 0;
}
skb->truesize += newtail - oldtail;
return newtail;
}
/*
* Format an audit message into the audit buffer. If there isn't enough
* room in the audit buffer, more room will be allocated and vsnprint
* will be called a second time. Currently, we assume that a printk
* can't format message larger than 1024 bytes, so we don't either.
*/
static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
va_list args)
{
int len, avail;
struct sk_buff *skb;
va_list args2;
if (!ab)
return;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
if (avail == 0) {
avail = audit_expand(ab, AUDIT_BUFSIZ);
if (!avail)
goto out;
}
va_copy(args2, args);
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
if (len >= avail) {
/* The printk buffer is 1024 bytes long, so if we get
* here and AUDIT_BUFSIZ is at least 1024, then we can
* log everything that printk could have logged. */
avail = audit_expand(ab,
max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
if (!avail)
goto out_va_end;
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
}
if (len > 0)
skb_put(skb, len);
out_va_end:
va_end(args2);
out:
return;
}
/**
* audit_log_format - format a message into the audit buffer.
* @ab: audit_buffer
* @fmt: format string
* @...: optional parameters matching @fmt string
*
* All the work is done in audit_log_vformat.
*/
void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
{
va_list args;
if (!ab)
return;
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
}
/**
* audit_log_n_hex - convert a buffer to hex and append it to the audit skb
* @ab: the audit_buffer
* @buf: buffer to convert to hex
* @len: length of @buf to be converted
*
* No return value; failure to expand is silently ignored.
*
* This function will take the passed buf and convert it into a string of
* ascii hex digits. The new string is placed onto the skb.
*/
void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
size_t len)
{
int i, avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
if (!ab)
return;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = len<<1;
if (new_len >= avail) {
/* Round the buffer request up to the next multiple */
new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
for (i = 0; i < len; i++)
ptr = hex_byte_pack_upper(ptr, buf[i]);
*ptr = 0;
skb_put(skb, len << 1); /* new string is twice the old string */
}
/*
* Format a string of no more than slen characters into the audit buffer,
* enclosed in quote marks.
*/
void audit_log_n_string(struct audit_buffer *ab, const char *string,
size_t slen)
{
int avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
if (!ab)
return;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = slen + 3; /* enclosing quotes + null terminator */
if (new_len > avail) {
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
*ptr++ = '"';
memcpy(ptr, string, slen);
ptr += slen;
*ptr++ = '"';
*ptr = 0;
skb_put(skb, slen + 2); /* don't include null terminator */
}
/**
* audit_string_contains_control - does a string need to be logged in hex
* @string: string to be checked
* @len: max length of the string to check
*/
bool audit_string_contains_control(const char *string, size_t len)
{
const unsigned char *p;
for (p = string; p < (const unsigned char *)string + len; p++) {
if (*p == '"' || *p < 0x21 || *p > 0x7e)
return true;
}
return false;
}
/**
* audit_log_n_untrustedstring - log a string that may contain random characters
* @ab: audit_buffer
* @len: length of string (not including trailing null)
* @string: string to be logged
*
* This code will escape a string that is passed to it if the string
* contains a control character, unprintable character, double quote mark,
* or a space. Unescaped strings will start and end with a double quote mark.
* Strings that are escaped are printed in hex (2 digits per char).
*
* The caller specifies the number of characters in the string to log, which may
* or may not be the entire string.
*/
void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
size_t len)
{
if (audit_string_contains_control(string, len))
audit_log_n_hex(ab, string, len);
else
audit_log_n_string(ab, string, len);
}
/**
* audit_log_untrustedstring - log a string that may contain random characters
* @ab: audit_buffer
* @string: string to be logged
*
* Same as audit_log_n_untrustedstring(), except that strlen is used to
* determine string length.
*/
void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
{
audit_log_n_untrustedstring(ab, string, strlen(string));
}
/* This is a helper-function to print the escaped d_path */
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
const struct path *path)
{
char *p, *pathname;
if (prefix)
audit_log_format(ab, "%s", prefix);
/* We will allow 11 spaces for ' (deleted)' to be appended */
pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
if (!pathname) {
audit_log_format(ab, "\"<no_memory>\"");
return;
}
p = d_path(path, pathname, PATH_MAX+11);
if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
/* FIXME: can we save some information here? */
audit_log_format(ab, "\"<too_long>\"");
} else
audit_log_untrustedstring(ab, p);
kfree(pathname);
}
void audit_log_session_info(struct audit_buffer *ab)
{
unsigned int sessionid = audit_get_sessionid(current);
uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
}
void audit_log_key(struct audit_buffer *ab, char *key)
{
audit_log_format(ab, " key=");
if (key)
audit_log_untrustedstring(ab, key);
else
audit_log_format(ab, "(null)");
}
int audit_log_task_context(struct audit_buffer *ab)
{
char *ctx = NULL;
unsigned len;
int error;
u32 sid;
security_current_getsecid_subj(&sid);
if (!sid)
return 0;
error = security_secid_to_secctx(sid, &ctx, &len);
if (error) {
if (error != -EINVAL)
goto error_path;
return 0;
}
audit_log_format(ab, " subj=%s", ctx);
security_release_secctx(ctx, len);
return 0;
error_path:
audit_panic("error in audit_log_task_context");
return error;
}
EXPORT_SYMBOL(audit_log_task_context);
void audit_log_d_path_exe(struct audit_buffer *ab,
struct mm_struct *mm)
{
struct file *exe_file;
if (!mm)
goto out_null;
exe_file = get_mm_exe_file(mm);
if (!exe_file)
goto out_null;
audit_log_d_path(ab, " exe=", &exe_file->f_path);
fput(exe_file);
return;
out_null:
audit_log_format(ab, " exe=(null)");
}
struct tty_struct *audit_get_tty(void)
{
struct tty_struct *tty = NULL;
unsigned long flags;
spin_lock_irqsave(¤t->sighand->siglock, flags);
if (current->signal)
tty = tty_kref_get(current->signal->tty);
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
return tty;
}
void audit_put_tty(struct tty_struct *tty)
{
tty_kref_put(tty);
}
void audit_log_task_info(struct audit_buffer *ab)
{
const struct cred *cred;
char comm[sizeof(current->comm)];
struct tty_struct *tty;
if (!ab)
return;
cred = current_cred();
tty = audit_get_tty();
audit_log_format(ab,
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
" euid=%u suid=%u fsuid=%u"
" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
task_ppid_nr(current),
task_tgid_nr(current),
from_kuid(&init_user_ns, audit_get_loginuid(current)),
from_kuid(&init_user_ns, cred->uid),
from_kgid(&init_user_ns, cred->gid),
from_kuid(&init_user_ns, cred->euid),
from_kuid(&init_user_ns, cred->suid),
from_kuid(&init_user_ns, cred->fsuid),
from_kgid(&init_user_ns, cred->egid),
from_kgid(&init_user_ns, cred->sgid),
from_kgid(&init_user_ns, cred->fsgid),
tty ? tty_name(tty) : "(none)",
audit_get_sessionid(current));
audit_put_tty(tty);
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, current));
audit_log_d_path_exe(ab, current->mm);
audit_log_task_context(ab);
}
EXPORT_SYMBOL(audit_log_task_info);
/**
* audit_log_path_denied - report a path restriction denial
* @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
* @operation: specific operation name
*/
void audit_log_path_denied(int type, const char *operation)
{
struct audit_buffer *ab;
if (!audit_enabled || audit_dummy_context())
return;
/* Generate log with subject, operation, outcome. */
ab = audit_log_start(audit_context(), GFP_KERNEL, type);
if (!ab)
return;
audit_log_format(ab, "op=%s", operation);
audit_log_task_info(ab);
audit_log_format(ab, " res=0");
audit_log_end(ab);
}
/* global counter which is incremented every time something logs in */
static atomic_t session_id = ATOMIC_INIT(0);
static int audit_set_loginuid_perm(kuid_t loginuid)
{
/* if we are unset, we don't need privs */
if (!audit_loginuid_set(current))
return 0;
/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
return -EPERM;
/* it is set, you need permission */
if (!capable(CAP_AUDIT_CONTROL))
return -EPERM;
/* reject if this is not an unset and we don't allow that */
if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
&& uid_valid(loginuid))
return -EPERM;
return 0;
}
static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
unsigned int oldsessionid,
unsigned int sessionid, int rc)
{
struct audit_buffer *ab;
uid_t uid, oldloginuid, loginuid;
struct tty_struct *tty;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
if (!ab)
return;
uid = from_kuid(&init_user_ns, task_uid(current));
oldloginuid = from_kuid(&init_user_ns, koldloginuid);
loginuid = from_kuid(&init_user_ns, kloginuid);
tty = audit_get_tty();
audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
audit_log_task_context(ab);
audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
oldsessionid, sessionid, !rc);
audit_put_tty(tty);
audit_log_end(ab);
}
/**
* audit_set_loginuid - set current task's loginuid
* @loginuid: loginuid value
*
* Returns 0.
*
* Called (set) from fs/proc/base.c::proc_loginuid_write().
*/
int audit_set_loginuid(kuid_t loginuid)
{
unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
kuid_t oldloginuid;
int rc;
oldloginuid = audit_get_loginuid(current);
oldsessionid = audit_get_sessionid(current);
rc = audit_set_loginuid_perm(loginuid);
if (rc)
goto out;
/* are we setting or clearing? */
if (uid_valid(loginuid)) {
sessionid = (unsigned int)atomic_inc_return(&session_id);
if (unlikely(sessionid == AUDIT_SID_UNSET))
sessionid = (unsigned int)atomic_inc_return(&session_id);
}
current->sessionid = sessionid;
current->loginuid = loginuid;
out:
audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
return rc;
}
/**
* audit_signal_info - record signal info for shutting down audit subsystem
* @sig: signal value
* @t: task being signaled
*
* If the audit subsystem is being terminated, record the task (pid)
* and uid that is doing that.
*/
int audit_signal_info(int sig, struct task_struct *t)
{
kuid_t uid = current_uid(), auid;
if (auditd_test_task(t) &&
(sig == SIGTERM || sig == SIGHUP ||
sig == SIGUSR1 || sig == SIGUSR2)) {
audit_sig_pid = task_tgid_nr(current);
auid = audit_get_loginuid(current);
if (uid_valid(auid))
audit_sig_uid = auid;
else
audit_sig_uid = uid;
security_current_getsecid_subj(&audit_sig_sid);
}
return audit_signal_info_syscall(t);
}
/**
* audit_log_end - end one audit record
* @ab: the audit_buffer
*
* We can not do a netlink send inside an irq context because it blocks (last
* arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
* queue and a kthread is scheduled to remove them from the queue outside the
* irq context. May be called in any context.
*/
void audit_log_end(struct audit_buffer *ab)
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
if (!ab)
return;
if (audit_rate_check()) {
skb = ab->skb;
ab->skb = NULL;
/* setup the netlink header, see the comments in
* kauditd_send_multicast_skb() for length quirks */
nlh = nlmsg_hdr(skb);
nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
/* queue the netlink packet and poke the kauditd thread */
skb_queue_tail(&audit_queue, skb);
wake_up_interruptible(&kauditd_wait);
} else
audit_log_lost("rate limit exceeded");
audit_buffer_free(ab);
}
/**
* audit_log - Log an audit record
* @ctx: audit context
* @gfp_mask: type of allocation
* @type: audit message type
* @fmt: format string to use
* @...: variable parameters matching the format string
*
* This is a convenience function that calls audit_log_start,
* audit_log_vformat, and audit_log_end. It may be called
* in any context.
*/
void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
const char *fmt, ...)
{
struct audit_buffer *ab;
va_list args;
ab = audit_log_start(ctx, gfp_mask, type);
if (ab) {
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
audit_log_end(ab);
}
}
EXPORT_SYMBOL(audit_log_start);
EXPORT_SYMBOL(audit_log_end);
EXPORT_SYMBOL(audit_log_format);
EXPORT_SYMBOL(audit_log);
| linux-master | kernel/audit.c |
// SPDX-License-Identifier: GPL-2.0+
//
// Torture test for smp_call_function() and friends.
//
// Copyright (C) Facebook, 2020.
//
// Author: Paul E. McKenney <[email protected]>
#define pr_fmt(fmt) fmt
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/rcupdate_trace.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/stat.h>
#include <linux/srcu.h>
#include <linux/slab.h>
#include <linux/torture.h>
#include <linux/types.h>
#define SCFTORT_STRING "scftorture"
#define SCFTORT_FLAG SCFTORT_STRING ": "
#define VERBOSE_SCFTORTOUT(s, x...) \
do { if (verbose) pr_alert(SCFTORT_FLAG s "\n", ## x); } while (0)
#define SCFTORTOUT_ERRSTRING(s, x...) pr_alert(SCFTORT_FLAG "!!! " s "\n", ## x)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <[email protected]>");
// Wait until there are multiple CPUs before starting test.
torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
"Holdoff time before test start (s)");
torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
torture_param(int, weight_single_rpc, -1, "Testing weight for single-CPU RPC operations.");
torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations.");
torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
char *torture_type = "";
#ifdef MODULE
# define SCFTORT_SHUTDOWN 0
#else
# define SCFTORT_SHUTDOWN 1
#endif
torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
struct scf_statistics {
struct task_struct *task;
int cpu;
long long n_resched;
long long n_single;
long long n_single_ofl;
long long n_single_rpc;
long long n_single_rpc_ofl;
long long n_single_wait;
long long n_single_wait_ofl;
long long n_many;
long long n_many_wait;
long long n_all;
long long n_all_wait;
};
static struct scf_statistics *scf_stats_p;
static struct task_struct *scf_torture_stats_task;
static DEFINE_PER_CPU(long long, scf_invoked_count);
// Data for random primitive selection
#define SCF_PRIM_RESCHED 0
#define SCF_PRIM_SINGLE 1
#define SCF_PRIM_SINGLE_RPC 2
#define SCF_PRIM_MANY 3
#define SCF_PRIM_ALL 4
#define SCF_NPRIMS 8 // Need wait and no-wait versions of each,
// except for SCF_PRIM_RESCHED and
// SCF_PRIM_SINGLE_RPC.
static char *scf_prim_name[] = {
"resched_cpu",
"smp_call_function_single",
"smp_call_function_single_rpc",
"smp_call_function_many",
"smp_call_function",
};
struct scf_selector {
unsigned long scfs_weight;
int scfs_prim;
bool scfs_wait;
};
static struct scf_selector scf_sel_array[SCF_NPRIMS];
static int scf_sel_array_len;
static unsigned long scf_sel_totweight;
// Communicate between caller and handler.
struct scf_check {
bool scfc_in;
bool scfc_out;
int scfc_cpu; // -1 for not _single().
bool scfc_wait;
bool scfc_rpc;
struct completion scfc_completion;
};
// Use to wait for all threads to start.
static atomic_t n_started;
static atomic_t n_errs;
static atomic_t n_mb_in_errs;
static atomic_t n_mb_out_errs;
static atomic_t n_alloc_errs;
static bool scfdone;
static char *bangstr = "";
static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
extern void resched_cpu(int cpu); // An alternative IPI vector.
// Print torture statistics. Caller must ensure serialization.
static void scf_torture_stats_print(void)
{
int cpu;
int i;
long long invoked_count = 0;
bool isdone = READ_ONCE(scfdone);
struct scf_statistics scfs = {};
for_each_possible_cpu(cpu)
invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
for (i = 0; i < nthreads; i++) {
scfs.n_resched += scf_stats_p[i].n_resched;
scfs.n_single += scf_stats_p[i].n_single;
scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
scfs.n_single_rpc += scf_stats_p[i].n_single_rpc;
scfs.n_single_wait += scf_stats_p[i].n_single_wait;
scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl;
scfs.n_many += scf_stats_p[i].n_many;
scfs.n_many_wait += scf_stats_p[i].n_many_wait;
scfs.n_all += scf_stats_p[i].n_all;
scfs.n_all_wait += scf_stats_p[i].n_all_wait;
}
if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
atomic_read(&n_mb_out_errs) ||
(!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs)))
bangstr = "!!! ";
pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld single_rpc: %lld single_rpc_ofl: %lld many: %lld/%lld all: %lld/%lld ",
SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
scfs.n_single_rpc, scfs.n_single_rpc_ofl,
scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
torture_onoff_stats();
pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs),
atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs),
atomic_read(&n_alloc_errs));
}
// Periodically prints torture statistics, if periodic statistics printing
// was specified via the stat_interval module parameter.
static int
scf_torture_stats(void *arg)
{
VERBOSE_TOROUT_STRING("scf_torture_stats task started");
do {
schedule_timeout_interruptible(stat_interval * HZ);
scf_torture_stats_print();
torture_shutdown_absorb("scf_torture_stats");
} while (!torture_must_stop());
torture_kthread_stopping("scf_torture_stats");
return 0;
}
// Add a primitive to the scf_sel_array[].
static void scf_sel_add(unsigned long weight, int prim, bool wait)
{
struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len];
// If no weight, if array would overflow, if computing three-place
// percentages would overflow, or if the scf_prim_name[] array would
// overflow, don't bother. In the last three two cases, complain.
if (!weight ||
WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) ||
WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) ||
WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name)))
return;
scf_sel_totweight += weight;
scfsp->scfs_weight = scf_sel_totweight;
scfsp->scfs_prim = prim;
scfsp->scfs_wait = wait;
scf_sel_array_len++;
}
// Dump out weighting percentages for scf_prim_name[] array.
static void scf_sel_dump(void)
{
int i;
unsigned long oldw = 0;
struct scf_selector *scfsp;
unsigned long w;
for (i = 0; i < scf_sel_array_len; i++) {
scfsp = &scf_sel_array[i];
w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight;
pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000,
scf_prim_name[scfsp->scfs_prim],
scfsp->scfs_wait ? "wait" : "nowait");
oldw = scfsp->scfs_weight;
}
}
// Randomly pick a primitive and wait/nowait, based on weightings.
static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp)
{
int i;
unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1);
for (i = 0; i < scf_sel_array_len; i++)
if (scf_sel_array[i].scfs_weight >= w)
return &scf_sel_array[i];
WARN_ON_ONCE(1);
return &scf_sel_array[0];
}
// Update statistics and occasionally burn up mass quantities of CPU time,
// if told to do so via scftorture.longwait. Otherwise, occasionally burn
// a little bit.
static void scf_handler(void *scfc_in)
{
int i;
int j;
unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
struct scf_check *scfcp = scfc_in;
if (likely(scfcp)) {
WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers.
if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in))))
atomic_inc(&n_mb_in_errs);
}
this_cpu_inc(scf_invoked_count);
if (longwait <= 0) {
if (!(r & 0xffc0)) {
udelay(r & 0x3f);
goto out;
}
}
if (r & 0xfff)
goto out;
r = (r >> 12);
if (longwait <= 0) {
udelay((r & 0xff) + 1);
goto out;
}
r = r % longwait + 1;
for (i = 0; i < r; i++) {
for (j = 0; j < 1000; j++) {
udelay(1000);
cpu_relax();
}
}
out:
if (unlikely(!scfcp))
return;
if (scfcp->scfc_wait) {
WRITE_ONCE(scfcp->scfc_out, true);
if (scfcp->scfc_rpc)
complete(&scfcp->scfc_completion);
} else {
kfree(scfcp);
}
}
// As above, but check for correct CPU.
static void scf_handler_1(void *scfc_in)
{
struct scf_check *scfcp = scfc_in;
if (likely(scfcp) && WARN_ONCE(smp_processor_id() != scfcp->scfc_cpu, "%s: Wanted CPU %d got CPU %d\n", __func__, scfcp->scfc_cpu, smp_processor_id())) {
atomic_inc(&n_errs);
}
scf_handler(scfcp);
}
// Randomly do an smp_call_function*() invocation.
static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp)
{
bool allocfail = false;
uintptr_t cpu;
int ret = 0;
struct scf_check *scfcp = NULL;
struct scf_selector *scfsp = scf_sel_rand(trsp);
if (use_cpus_read_lock)
cpus_read_lock();
else
preempt_disable();
if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
if (!scfcp) {
WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN));
atomic_inc(&n_alloc_errs);
allocfail = true;
} else {
scfcp->scfc_cpu = -1;
scfcp->scfc_wait = scfsp->scfs_wait;
scfcp->scfc_out = false;
scfcp->scfc_rpc = false;
}
}
switch (scfsp->scfs_prim) {
case SCF_PRIM_RESCHED:
if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
cpu = torture_random(trsp) % nr_cpu_ids;
scfp->n_resched++;
resched_cpu(cpu);
this_cpu_inc(scf_invoked_count);
}
break;
case SCF_PRIM_SINGLE:
cpu = torture_random(trsp) % nr_cpu_ids;
if (scfsp->scfs_wait)
scfp->n_single_wait++;
else
scfp->n_single++;
if (scfcp) {
scfcp->scfc_cpu = cpu;
barrier(); // Prevent race-reduction compiler optimizations.
scfcp->scfc_in = true;
}
ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait);
if (ret) {
if (scfsp->scfs_wait)
scfp->n_single_wait_ofl++;
else
scfp->n_single_ofl++;
kfree(scfcp);
scfcp = NULL;
}
break;
case SCF_PRIM_SINGLE_RPC:
if (!scfcp)
break;
cpu = torture_random(trsp) % nr_cpu_ids;
scfp->n_single_rpc++;
scfcp->scfc_cpu = cpu;
scfcp->scfc_wait = true;
init_completion(&scfcp->scfc_completion);
scfcp->scfc_rpc = true;
barrier(); // Prevent race-reduction compiler optimizations.
scfcp->scfc_in = true;
ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, 0);
if (!ret) {
if (use_cpus_read_lock)
cpus_read_unlock();
else
preempt_enable();
wait_for_completion(&scfcp->scfc_completion);
if (use_cpus_read_lock)
cpus_read_lock();
else
preempt_disable();
} else {
scfp->n_single_rpc_ofl++;
kfree(scfcp);
scfcp = NULL;
}
break;
case SCF_PRIM_MANY:
if (scfsp->scfs_wait)
scfp->n_many_wait++;
else
scfp->n_many++;
if (scfcp) {
barrier(); // Prevent race-reduction compiler optimizations.
scfcp->scfc_in = true;
}
smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait);
break;
case SCF_PRIM_ALL:
if (scfsp->scfs_wait)
scfp->n_all_wait++;
else
scfp->n_all++;
if (scfcp) {
barrier(); // Prevent race-reduction compiler optimizations.
scfcp->scfc_in = true;
}
smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
break;
default:
WARN_ON_ONCE(1);
if (scfcp)
scfcp->scfc_out = true;
}
if (scfcp && scfsp->scfs_wait) {
if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) &&
!scfcp->scfc_out)) {
pr_warn("%s: Memory-ordering failure, scfs_prim: %d.\n", __func__, scfsp->scfs_prim);
atomic_inc(&n_mb_out_errs); // Leak rather than trash!
} else {
kfree(scfcp);
}
barrier(); // Prevent race-reduction compiler optimizations.
}
if (use_cpus_read_lock)
cpus_read_unlock();
else
preempt_enable();
if (allocfail)
schedule_timeout_idle((1 + longwait) * HZ); // Let no-wait handlers complete.
else if (!(torture_random(trsp) & 0xfff))
schedule_timeout_uninterruptible(1);
}
// SCF test kthread. Repeatedly does calls to members of the
// smp_call_function() family of functions.
static int scftorture_invoker(void *arg)
{
int cpu;
int curcpu;
DEFINE_TORTURE_RANDOM(rand);
struct scf_statistics *scfp = (struct scf_statistics *)arg;
bool was_offline = false;
VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
cpu = scfp->cpu % nr_cpu_ids;
WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu)));
set_user_nice(current, MAX_NICE);
if (holdoff)
schedule_timeout_interruptible(holdoff * HZ);
VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id());
// Make sure that the CPU is affinitized appropriately during testing.
curcpu = raw_smp_processor_id();
WARN_ONCE(curcpu != scfp->cpu % nr_cpu_ids,
"%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n",
__func__, scfp->cpu, curcpu, nr_cpu_ids);
if (!atomic_dec_return(&n_started))
while (atomic_read_acquire(&n_started)) {
if (torture_must_stop()) {
VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
goto end;
}
schedule_timeout_uninterruptible(1);
}
VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
do {
scftorture_invoke_one(scfp, &rand);
while (cpu_is_offline(cpu) && !torture_must_stop()) {
schedule_timeout_interruptible(HZ / 5);
was_offline = true;
}
if (was_offline) {
set_cpus_allowed_ptr(current, cpumask_of(cpu));
was_offline = false;
}
cond_resched();
stutter_wait("scftorture_invoker");
} while (!torture_must_stop());
VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
end:
torture_kthread_stopping("scftorture_invoker");
return 0;
}
static void
scftorture_print_module_parms(const char *tag)
{
pr_alert(SCFTORT_FLAG
"--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d use_cpus_read_lock=%d, weight_resched=%d, weight_single=%d, weight_single_rpc=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter, use_cpus_read_lock, weight_resched, weight_single, weight_single_rpc, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
}
static void scf_cleanup_handler(void *unused)
{
}
static void scf_torture_cleanup(void)
{
int i;
if (torture_cleanup_begin())
return;
WRITE_ONCE(scfdone, true);
if (nthreads && scf_stats_p)
for (i = 0; i < nthreads; i++)
torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
else
goto end;
smp_call_function(scf_cleanup_handler, NULL, 0);
torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
scf_torture_stats_print(); // -After- the stats thread is stopped!
kfree(scf_stats_p); // -After- the last stats print has completed!
scf_stats_p = NULL;
if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs))
scftorture_print_module_parms("End of test: FAILURE");
else if (torture_onoff_failures())
scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
else
scftorture_print_module_parms("End of test: SUCCESS");
end:
torture_cleanup_end();
}
static int __init scf_torture_init(void)
{
long i;
int firsterr = 0;
unsigned long weight_resched1 = weight_resched;
unsigned long weight_single1 = weight_single;
unsigned long weight_single_rpc1 = weight_single_rpc;
unsigned long weight_single_wait1 = weight_single_wait;
unsigned long weight_many1 = weight_many;
unsigned long weight_many_wait1 = weight_many_wait;
unsigned long weight_all1 = weight_all;
unsigned long weight_all_wait1 = weight_all_wait;
if (!torture_init_begin(SCFTORT_STRING, verbose))
return -EBUSY;
scftorture_print_module_parms("Start of test");
if (weight_resched <= 0 &&
weight_single <= 0 && weight_single_rpc <= 0 && weight_single_wait <= 0 &&
weight_many <= 0 && weight_many_wait <= 0 &&
weight_all <= 0 && weight_all_wait <= 0) {
weight_resched1 = weight_resched == 0 ? 0 : 2 * nr_cpu_ids;
weight_single1 = weight_single == 0 ? 0 : 2 * nr_cpu_ids;
weight_single_rpc1 = weight_single_rpc == 0 ? 0 : 2 * nr_cpu_ids;
weight_single_wait1 = weight_single_wait == 0 ? 0 : 2 * nr_cpu_ids;
weight_many1 = weight_many == 0 ? 0 : 2;
weight_many_wait1 = weight_many_wait == 0 ? 0 : 2;
weight_all1 = weight_all == 0 ? 0 : 1;
weight_all_wait1 = weight_all_wait == 0 ? 0 : 1;
} else {
if (weight_resched == -1)
weight_resched1 = 0;
if (weight_single == -1)
weight_single1 = 0;
if (weight_single_rpc == -1)
weight_single_rpc1 = 0;
if (weight_single_wait == -1)
weight_single_wait1 = 0;
if (weight_many == -1)
weight_many1 = 0;
if (weight_many_wait == -1)
weight_many_wait1 = 0;
if (weight_all == -1)
weight_all1 = 0;
if (weight_all_wait == -1)
weight_all_wait1 = 0;
}
if (weight_resched1 == 0 && weight_single1 == 0 && weight_single_rpc1 == 0 &&
weight_single_wait1 == 0 && weight_many1 == 0 && weight_many_wait1 == 0 &&
weight_all1 == 0 && weight_all_wait1 == 0) {
SCFTORTOUT_ERRSTRING("all zero weights makes no sense");
firsterr = -EINVAL;
goto unwind;
}
if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
else if (weight_resched1)
SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
scf_sel_add(weight_single_rpc1, SCF_PRIM_SINGLE_RPC, true);
scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true);
scf_sel_add(weight_all1, SCF_PRIM_ALL, false);
scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true);
scf_sel_dump();
if (onoff_interval > 0) {
firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
if (torture_init_error(firsterr))
goto unwind;
}
if (shutdown_secs > 0) {
firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
if (torture_init_error(firsterr))
goto unwind;
}
if (stutter > 0) {
firsterr = torture_stutter_init(stutter, stutter);
if (torture_init_error(firsterr))
goto unwind;
}
// Worker tasks invoking smp_call_function().
if (nthreads < 0)
nthreads = num_online_cpus();
scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
if (!scf_stats_p) {
SCFTORTOUT_ERRSTRING("out of memory");
firsterr = -ENOMEM;
goto unwind;
}
VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads", nthreads);
atomic_set(&n_started, nthreads);
for (i = 0; i < nthreads; i++) {
scf_stats_p[i].cpu = i;
firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
scf_stats_p[i].task);
if (torture_init_error(firsterr))
goto unwind;
}
if (stat_interval > 0) {
firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
if (torture_init_error(firsterr))
goto unwind;
}
torture_init_end();
return 0;
unwind:
torture_init_end();
scf_torture_cleanup();
if (shutdown_secs) {
WARN_ON(!IS_MODULE(CONFIG_SCF_TORTURE_TEST));
kernel_power_off();
}
return firsterr;
}
module_init(scf_torture_init);
module_exit(scf_torture_cleanup);
| linux-master | kernel/scftorture.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kdebug.h>
#include <linux/kprobes.h>
#include <linux/export.h>
#include <linux/notifier.h>
#include <linux/rcupdate.h>
#include <linux/vmalloc.h>
#include <linux/reboot.h>
#define CREATE_TRACE_POINTS
#include <trace/events/notifier.h>
/*
* Notifier list for kernel code which wants to be called
* at shutdown. This is used to stop any idling DMA operations
* and the like.
*/
BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
/*
* Notifier chain core routines. The exported routines below
* are layered on top of these, with appropriate locking added.
*/
static int notifier_chain_register(struct notifier_block **nl,
struct notifier_block *n,
bool unique_priority)
{
while ((*nl) != NULL) {
if (unlikely((*nl) == n)) {
WARN(1, "notifier callback %ps already registered",
n->notifier_call);
return -EEXIST;
}
if (n->priority > (*nl)->priority)
break;
if (n->priority == (*nl)->priority && unique_priority)
return -EBUSY;
nl = &((*nl)->next);
}
n->next = *nl;
rcu_assign_pointer(*nl, n);
trace_notifier_register((void *)n->notifier_call);
return 0;
}
static int notifier_chain_unregister(struct notifier_block **nl,
struct notifier_block *n)
{
while ((*nl) != NULL) {
if ((*nl) == n) {
rcu_assign_pointer(*nl, n->next);
trace_notifier_unregister((void *)n->notifier_call);
return 0;
}
nl = &((*nl)->next);
}
return -ENOENT;
}
/**
* notifier_call_chain - Informs the registered notifiers about an event.
* @nl: Pointer to head of the blocking notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
* @nr_to_call: Number of notifier functions to be called. Don't care
* value of this parameter is -1.
* @nr_calls: Records the number of notifications sent. Don't care
* value of this field is NULL.
* Return: notifier_call_chain returns the value returned by the
* last notifier function called.
*/
static int notifier_call_chain(struct notifier_block **nl,
unsigned long val, void *v,
int nr_to_call, int *nr_calls)
{
int ret = NOTIFY_DONE;
struct notifier_block *nb, *next_nb;
nb = rcu_dereference_raw(*nl);
while (nb && nr_to_call) {
next_nb = rcu_dereference_raw(nb->next);
#ifdef CONFIG_DEBUG_NOTIFIERS
if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) {
WARN(1, "Invalid notifier called!");
nb = next_nb;
continue;
}
#endif
trace_notifier_run((void *)nb->notifier_call);
ret = nb->notifier_call(nb, val, v);
if (nr_calls)
(*nr_calls)++;
if (ret & NOTIFY_STOP_MASK)
break;
nb = next_nb;
nr_to_call--;
}
return ret;
}
NOKPROBE_SYMBOL(notifier_call_chain);
/**
* notifier_call_chain_robust - Inform the registered notifiers about an event
* and rollback on error.
* @nl: Pointer to head of the blocking notifier chain
* @val_up: Value passed unmodified to the notifier function
* @val_down: Value passed unmodified to the notifier function when recovering
* from an error on @val_up
* @v: Pointer passed unmodified to the notifier function
*
* NOTE: It is important the @nl chain doesn't change between the two
* invocations of notifier_call_chain() such that we visit the
* exact same notifier callbacks; this rules out any RCU usage.
*
* Return: the return value of the @val_up call.
*/
static int notifier_call_chain_robust(struct notifier_block **nl,
unsigned long val_up, unsigned long val_down,
void *v)
{
int ret, nr = 0;
ret = notifier_call_chain(nl, val_up, v, -1, &nr);
if (ret & NOTIFY_STOP_MASK)
notifier_call_chain(nl, val_down, v, nr-1, NULL);
return ret;
}
/*
* Atomic notifier chain routines. Registration and unregistration
* use a spinlock, and call_chain is synchronized by RCU (no locks).
*/
/**
* atomic_notifier_chain_register - Add notifier to an atomic notifier chain
* @nh: Pointer to head of the atomic notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to an atomic notifier chain.
*
* Returns 0 on success, %-EEXIST on error.
*/
int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
struct notifier_block *n)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_register(&nh->head, n, false);
spin_unlock_irqrestore(&nh->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
/**
* atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
* @nh: Pointer to head of the atomic notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to an atomic notifier chain if there is no other
* notifier registered using the same priority.
*
* Returns 0 on success, %-EEXIST or %-EBUSY on error.
*/
int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
struct notifier_block *n)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_register(&nh->head, n, true);
spin_unlock_irqrestore(&nh->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
/**
* atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
* @nh: Pointer to head of the atomic notifier chain
* @n: Entry to remove from notifier chain
*
* Removes a notifier from an atomic notifier chain.
*
* Returns zero on success or %-ENOENT on failure.
*/
int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
struct notifier_block *n)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_unregister(&nh->head, n);
spin_unlock_irqrestore(&nh->lock, flags);
synchronize_rcu();
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister);
/**
* atomic_notifier_call_chain - Call functions in an atomic notifier chain
* @nh: Pointer to head of the atomic notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
*
* Calls each function in a notifier chain in turn. The functions
* run in an atomic context, so they must not block.
* This routine uses RCU to synchronize with changes to the chain.
*
* If the return value of the notifier can be and'ed
* with %NOTIFY_STOP_MASK then atomic_notifier_call_chain()
* will return immediately, with the return value of
* the notifier function which halted execution.
* Otherwise the return value is the return value
* of the last notifier function called.
*/
int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
unsigned long val, void *v)
{
int ret;
rcu_read_lock();
ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
NOKPROBE_SYMBOL(atomic_notifier_call_chain);
/**
* atomic_notifier_call_chain_is_empty - Check whether notifier chain is empty
* @nh: Pointer to head of the atomic notifier chain
*
* Checks whether notifier chain is empty.
*
* Returns true is notifier chain is empty, false otherwise.
*/
bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh)
{
return !rcu_access_pointer(nh->head);
}
/*
* Blocking notifier chain routines. All access to the chain is
* synchronized by an rwsem.
*/
static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
struct notifier_block *n,
bool unique_priority)
{
int ret;
/*
* This code gets used during boot-up, when task switching is
* not yet working and interrupts must remain disabled. At
* such times we must not call down_write().
*/
if (unlikely(system_state == SYSTEM_BOOTING))
return notifier_chain_register(&nh->head, n, unique_priority);
down_write(&nh->rwsem);
ret = notifier_chain_register(&nh->head, n, unique_priority);
up_write(&nh->rwsem);
return ret;
}
/**
* blocking_notifier_chain_register - Add notifier to a blocking notifier chain
* @nh: Pointer to head of the blocking notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to a blocking notifier chain.
* Must be called in process context.
*
* Returns 0 on success, %-EEXIST on error.
*/
int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
struct notifier_block *n)
{
return __blocking_notifier_chain_register(nh, n, false);
}
EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
/**
* blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
* @nh: Pointer to head of the blocking notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to an blocking notifier chain if there is no other
* notifier registered using the same priority.
*
* Returns 0 on success, %-EEXIST or %-EBUSY on error.
*/
int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
struct notifier_block *n)
{
return __blocking_notifier_chain_register(nh, n, true);
}
EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
/**
* blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
* @nh: Pointer to head of the blocking notifier chain
* @n: Entry to remove from notifier chain
*
* Removes a notifier from a blocking notifier chain.
* Must be called from process context.
*
* Returns zero on success or %-ENOENT on failure.
*/
int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
struct notifier_block *n)
{
int ret;
/*
* This code gets used during boot-up, when task switching is
* not yet working and interrupts must remain disabled. At
* such times we must not call down_write().
*/
if (unlikely(system_state == SYSTEM_BOOTING))
return notifier_chain_unregister(&nh->head, n);
down_write(&nh->rwsem);
ret = notifier_chain_unregister(&nh->head, n);
up_write(&nh->rwsem);
return ret;
}
EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister);
int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh,
unsigned long val_up, unsigned long val_down, void *v)
{
int ret = NOTIFY_DONE;
/*
* We check the head outside the lock, but if this access is
* racy then it does not matter what the result of the test
* is, we re-check the list after having taken the lock anyway:
*/
if (rcu_access_pointer(nh->head)) {
down_read(&nh->rwsem);
ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v);
up_read(&nh->rwsem);
}
return ret;
}
EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_robust);
/**
* blocking_notifier_call_chain - Call functions in a blocking notifier chain
* @nh: Pointer to head of the blocking notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
*
* Calls each function in a notifier chain in turn. The functions
* run in a process context, so they are allowed to block.
*
* If the return value of the notifier can be and'ed
* with %NOTIFY_STOP_MASK then blocking_notifier_call_chain()
* will return immediately, with the return value of
* the notifier function which halted execution.
* Otherwise the return value is the return value
* of the last notifier function called.
*/
int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
unsigned long val, void *v)
{
int ret = NOTIFY_DONE;
/*
* We check the head outside the lock, but if this access is
* racy then it does not matter what the result of the test
* is, we re-check the list after having taken the lock anyway:
*/
if (rcu_access_pointer(nh->head)) {
down_read(&nh->rwsem);
ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
up_read(&nh->rwsem);
}
return ret;
}
EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
/*
* Raw notifier chain routines. There is no protection;
* the caller must provide it. Use at your own risk!
*/
/**
* raw_notifier_chain_register - Add notifier to a raw notifier chain
* @nh: Pointer to head of the raw notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to a raw notifier chain.
* All locking must be provided by the caller.
*
* Returns 0 on success, %-EEXIST on error.
*/
int raw_notifier_chain_register(struct raw_notifier_head *nh,
struct notifier_block *n)
{
return notifier_chain_register(&nh->head, n, false);
}
EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
/**
* raw_notifier_chain_unregister - Remove notifier from a raw notifier chain
* @nh: Pointer to head of the raw notifier chain
* @n: Entry to remove from notifier chain
*
* Removes a notifier from a raw notifier chain.
* All locking must be provided by the caller.
*
* Returns zero on success or %-ENOENT on failure.
*/
int raw_notifier_chain_unregister(struct raw_notifier_head *nh,
struct notifier_block *n)
{
return notifier_chain_unregister(&nh->head, n);
}
EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister);
int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
unsigned long val_up, unsigned long val_down, void *v)
{
return notifier_call_chain_robust(&nh->head, val_up, val_down, v);
}
EXPORT_SYMBOL_GPL(raw_notifier_call_chain_robust);
/**
* raw_notifier_call_chain - Call functions in a raw notifier chain
* @nh: Pointer to head of the raw notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
*
* Calls each function in a notifier chain in turn. The functions
* run in an undefined context.
* All locking must be provided by the caller.
*
* If the return value of the notifier can be and'ed
* with %NOTIFY_STOP_MASK then raw_notifier_call_chain()
* will return immediately, with the return value of
* the notifier function which halted execution.
* Otherwise the return value is the return value
* of the last notifier function called.
*/
int raw_notifier_call_chain(struct raw_notifier_head *nh,
unsigned long val, void *v)
{
return notifier_call_chain(&nh->head, val, v, -1, NULL);
}
EXPORT_SYMBOL_GPL(raw_notifier_call_chain);
/*
* SRCU notifier chain routines. Registration and unregistration
* use a mutex, and call_chain is synchronized by SRCU (no locks).
*/
/**
* srcu_notifier_chain_register - Add notifier to an SRCU notifier chain
* @nh: Pointer to head of the SRCU notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to an SRCU notifier chain.
* Must be called in process context.
*
* Returns 0 on success, %-EEXIST on error.
*/
int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
struct notifier_block *n)
{
int ret;
/*
* This code gets used during boot-up, when task switching is
* not yet working and interrupts must remain disabled. At
* such times we must not call mutex_lock().
*/
if (unlikely(system_state == SYSTEM_BOOTING))
return notifier_chain_register(&nh->head, n, false);
mutex_lock(&nh->mutex);
ret = notifier_chain_register(&nh->head, n, false);
mutex_unlock(&nh->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(srcu_notifier_chain_register);
/**
* srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain
* @nh: Pointer to head of the SRCU notifier chain
* @n: Entry to remove from notifier chain
*
* Removes a notifier from an SRCU notifier chain.
* Must be called from process context.
*
* Returns zero on success or %-ENOENT on failure.
*/
int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh,
struct notifier_block *n)
{
int ret;
/*
* This code gets used during boot-up, when task switching is
* not yet working and interrupts must remain disabled. At
* such times we must not call mutex_lock().
*/
if (unlikely(system_state == SYSTEM_BOOTING))
return notifier_chain_unregister(&nh->head, n);
mutex_lock(&nh->mutex);
ret = notifier_chain_unregister(&nh->head, n);
mutex_unlock(&nh->mutex);
synchronize_srcu(&nh->srcu);
return ret;
}
EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister);
/**
* srcu_notifier_call_chain - Call functions in an SRCU notifier chain
* @nh: Pointer to head of the SRCU notifier chain
* @val: Value passed unmodified to notifier function
* @v: Pointer passed unmodified to notifier function
*
* Calls each function in a notifier chain in turn. The functions
* run in a process context, so they are allowed to block.
*
* If the return value of the notifier can be and'ed
* with %NOTIFY_STOP_MASK then srcu_notifier_call_chain()
* will return immediately, with the return value of
* the notifier function which halted execution.
* Otherwise the return value is the return value
* of the last notifier function called.
*/
int srcu_notifier_call_chain(struct srcu_notifier_head *nh,
unsigned long val, void *v)
{
int ret;
int idx;
idx = srcu_read_lock(&nh->srcu);
ret = notifier_call_chain(&nh->head, val, v, -1, NULL);
srcu_read_unlock(&nh->srcu, idx);
return ret;
}
EXPORT_SYMBOL_GPL(srcu_notifier_call_chain);
/**
* srcu_init_notifier_head - Initialize an SRCU notifier head
* @nh: Pointer to head of the srcu notifier chain
*
* Unlike other sorts of notifier heads, SRCU notifier heads require
* dynamic initialization. Be sure to call this routine before
* calling any of the other SRCU notifier routines for this head.
*
* If an SRCU notifier head is deallocated, it must first be cleaned
* up by calling srcu_cleanup_notifier_head(). Otherwise the head's
* per-cpu data (used by the SRCU mechanism) will leak.
*/
void srcu_init_notifier_head(struct srcu_notifier_head *nh)
{
mutex_init(&nh->mutex);
if (init_srcu_struct(&nh->srcu) < 0)
BUG();
nh->head = NULL;
}
EXPORT_SYMBOL_GPL(srcu_init_notifier_head);
static ATOMIC_NOTIFIER_HEAD(die_chain);
int notrace notify_die(enum die_val val, const char *str,
struct pt_regs *regs, long err, int trap, int sig)
{
struct die_args args = {
.regs = regs,
.str = str,
.err = err,
.trapnr = trap,
.signr = sig,
};
RCU_LOCKDEP_WARN(!rcu_is_watching(),
"notify_die called but RCU thinks we're quiescent");
return atomic_notifier_call_chain(&die_chain, val, &args);
}
NOKPROBE_SYMBOL(notify_die);
int register_die_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&die_chain, nb);
}
EXPORT_SYMBOL_GPL(register_die_notifier);
int unregister_die_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&die_chain, nb);
}
EXPORT_SYMBOL_GPL(unregister_die_notifier);
| linux-master | kernel/notifier.c |
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/user-return-notifier.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/export.h>
static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
/*
* Request a notification when the current cpu returns to userspace. Must be
* called in atomic context. The notifier will also be called in atomic
* context.
*/
void user_return_notifier_register(struct user_return_notifier *urn)
{
set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
hlist_add_head(&urn->link, this_cpu_ptr(&return_notifier_list));
}
EXPORT_SYMBOL_GPL(user_return_notifier_register);
/*
* Removes a registered user return notifier. Must be called from atomic
* context, and from the same cpu registration occurred in.
*/
void user_return_notifier_unregister(struct user_return_notifier *urn)
{
hlist_del(&urn->link);
if (hlist_empty(this_cpu_ptr(&return_notifier_list)))
clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
}
EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
/* Calls registered user return notifiers */
void fire_user_return_notifiers(void)
{
struct user_return_notifier *urn;
struct hlist_node *tmp2;
struct hlist_head *head;
head = &get_cpu_var(return_notifier_list);
hlist_for_each_entry_safe(urn, tmp2, head, link)
urn->on_user_return(urn);
put_cpu_var(return_notifier_list);
}
| linux-master | kernel/user-return-notifier.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* jump label support
*
* Copyright (C) 2009 Jason Baron <[email protected]>
* Copyright (C) 2011 Peter Zijlstra
*
*/
#include <linux/memory.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/err.h>
#include <linux/static_key.h>
#include <linux/jump_label_ratelimit.h>
#include <linux/bug.h>
#include <linux/cpu.h>
#include <asm/sections.h>
/* mutex to protect coming/going of the jump_label table */
static DEFINE_MUTEX(jump_label_mutex);
void jump_label_lock(void)
{
mutex_lock(&jump_label_mutex);
}
void jump_label_unlock(void)
{
mutex_unlock(&jump_label_mutex);
}
static int jump_label_cmp(const void *a, const void *b)
{
const struct jump_entry *jea = a;
const struct jump_entry *jeb = b;
/*
* Entrires are sorted by key.
*/
if (jump_entry_key(jea) < jump_entry_key(jeb))
return -1;
if (jump_entry_key(jea) > jump_entry_key(jeb))
return 1;
/*
* In the batching mode, entries should also be sorted by the code
* inside the already sorted list of entries, enabling a bsearch in
* the vector.
*/
if (jump_entry_code(jea) < jump_entry_code(jeb))
return -1;
if (jump_entry_code(jea) > jump_entry_code(jeb))
return 1;
return 0;
}
static void jump_label_swap(void *a, void *b, int size)
{
long delta = (unsigned long)a - (unsigned long)b;
struct jump_entry *jea = a;
struct jump_entry *jeb = b;
struct jump_entry tmp = *jea;
jea->code = jeb->code - delta;
jea->target = jeb->target - delta;
jea->key = jeb->key - delta;
jeb->code = tmp.code + delta;
jeb->target = tmp.target + delta;
jeb->key = tmp.key + delta;
}
static void
jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
{
unsigned long size;
void *swapfn = NULL;
if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE))
swapfn = jump_label_swap;
size = (((unsigned long)stop - (unsigned long)start)
/ sizeof(struct jump_entry));
sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn);
}
static void jump_label_update(struct static_key *key);
/*
* There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h.
* The use of 'atomic_read()' requires atomic.h and its problematic for some
* kernel headers such as kernel.h and others. Since static_key_count() is not
* used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok
* to have it be a function here. Similarly, for 'static_key_enable()' and
* 'static_key_disable()', which require bug.h. This should allow jump_label.h
* to be included from most/all places for CONFIG_JUMP_LABEL.
*/
int static_key_count(struct static_key *key)
{
/*
* -1 means the first static_key_slow_inc() is in progress.
* static_key_enabled() must return true, so return 1 here.
*/
int n = atomic_read(&key->enabled);
return n >= 0 ? n : 1;
}
EXPORT_SYMBOL_GPL(static_key_count);
/*
* static_key_fast_inc_not_disabled - adds a user for a static key
* @key: static key that must be already enabled
*
* The caller must make sure that the static key can't get disabled while
* in this function. It doesn't patch jump labels, only adds a user to
* an already enabled static key.
*
* Returns true if the increment was done. Unlike refcount_t the ref counter
* is not saturated, but will fail to increment on overflow.
*/
bool static_key_fast_inc_not_disabled(struct static_key *key)
{
int v;
STATIC_KEY_CHECK_USE(key);
/*
* Negative key->enabled has a special meaning: it sends
* static_key_slow_inc() down the slow path, and it is non-zero
* so it counts as "enabled" in jump_label_update(). Note that
* atomic_inc_unless_negative() checks >= 0, so roll our own.
*/
v = atomic_read(&key->enabled);
do {
if (v <= 0 || (v + 1) < 0)
return false;
} while (!likely(atomic_try_cmpxchg(&key->enabled, &v, v + 1)));
return true;
}
EXPORT_SYMBOL_GPL(static_key_fast_inc_not_disabled);
bool static_key_slow_inc_cpuslocked(struct static_key *key)
{
lockdep_assert_cpus_held();
/*
* Careful if we get concurrent static_key_slow_inc() calls;
* later calls must wait for the first one to _finish_ the
* jump_label_update() process. At the same time, however,
* the jump_label_update() call below wants to see
* static_key_enabled(&key) for jumps to be updated properly.
*/
if (static_key_fast_inc_not_disabled(key))
return true;
jump_label_lock();
if (atomic_read(&key->enabled) == 0) {
atomic_set(&key->enabled, -1);
jump_label_update(key);
/*
* Ensure that if the above cmpxchg loop observes our positive
* value, it must also observe all the text changes.
*/
atomic_set_release(&key->enabled, 1);
} else {
if (WARN_ON_ONCE(!static_key_fast_inc_not_disabled(key))) {
jump_label_unlock();
return false;
}
}
jump_label_unlock();
return true;
}
bool static_key_slow_inc(struct static_key *key)
{
bool ret;
cpus_read_lock();
ret = static_key_slow_inc_cpuslocked(key);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(static_key_slow_inc);
void static_key_enable_cpuslocked(struct static_key *key)
{
STATIC_KEY_CHECK_USE(key);
lockdep_assert_cpus_held();
if (atomic_read(&key->enabled) > 0) {
WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
return;
}
jump_label_lock();
if (atomic_read(&key->enabled) == 0) {
atomic_set(&key->enabled, -1);
jump_label_update(key);
/*
* See static_key_slow_inc().
*/
atomic_set_release(&key->enabled, 1);
}
jump_label_unlock();
}
EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
void static_key_enable(struct static_key *key)
{
cpus_read_lock();
static_key_enable_cpuslocked(key);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(static_key_enable);
void static_key_disable_cpuslocked(struct static_key *key)
{
STATIC_KEY_CHECK_USE(key);
lockdep_assert_cpus_held();
if (atomic_read(&key->enabled) != 1) {
WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
return;
}
jump_label_lock();
if (atomic_cmpxchg(&key->enabled, 1, 0))
jump_label_update(key);
jump_label_unlock();
}
EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
void static_key_disable(struct static_key *key)
{
cpus_read_lock();
static_key_disable_cpuslocked(key);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(static_key_disable);
static bool static_key_slow_try_dec(struct static_key *key)
{
int val;
val = atomic_fetch_add_unless(&key->enabled, -1, 1);
if (val == 1)
return false;
/*
* The negative count check is valid even when a negative
* key->enabled is in use by static_key_slow_inc(); a
* __static_key_slow_dec() before the first static_key_slow_inc()
* returns is unbalanced, because all other static_key_slow_inc()
* instances block while the update is in progress.
*/
WARN(val < 0, "jump label: negative count!\n");
return true;
}
static void __static_key_slow_dec_cpuslocked(struct static_key *key)
{
lockdep_assert_cpus_held();
if (static_key_slow_try_dec(key))
return;
jump_label_lock();
if (atomic_dec_and_test(&key->enabled))
jump_label_update(key);
jump_label_unlock();
}
static void __static_key_slow_dec(struct static_key *key)
{
cpus_read_lock();
__static_key_slow_dec_cpuslocked(key);
cpus_read_unlock();
}
void jump_label_update_timeout(struct work_struct *work)
{
struct static_key_deferred *key =
container_of(work, struct static_key_deferred, work.work);
__static_key_slow_dec(&key->key);
}
EXPORT_SYMBOL_GPL(jump_label_update_timeout);
void static_key_slow_dec(struct static_key *key)
{
STATIC_KEY_CHECK_USE(key);
__static_key_slow_dec(key);
}
EXPORT_SYMBOL_GPL(static_key_slow_dec);
void static_key_slow_dec_cpuslocked(struct static_key *key)
{
STATIC_KEY_CHECK_USE(key);
__static_key_slow_dec_cpuslocked(key);
}
void __static_key_slow_dec_deferred(struct static_key *key,
struct delayed_work *work,
unsigned long timeout)
{
STATIC_KEY_CHECK_USE(key);
if (static_key_slow_try_dec(key))
return;
schedule_delayed_work(work, timeout);
}
EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);
void __static_key_deferred_flush(void *key, struct delayed_work *work)
{
STATIC_KEY_CHECK_USE(key);
flush_delayed_work(work);
}
EXPORT_SYMBOL_GPL(__static_key_deferred_flush);
void jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)
{
STATIC_KEY_CHECK_USE(key);
key->timeout = rl;
INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
}
EXPORT_SYMBOL_GPL(jump_label_rate_limit);
static int addr_conflict(struct jump_entry *entry, void *start, void *end)
{
if (jump_entry_code(entry) <= (unsigned long)end &&
jump_entry_code(entry) + jump_entry_size(entry) > (unsigned long)start)
return 1;
return 0;
}
static int __jump_label_text_reserved(struct jump_entry *iter_start,
struct jump_entry *iter_stop, void *start, void *end, bool init)
{
struct jump_entry *iter;
iter = iter_start;
while (iter < iter_stop) {
if (init || !jump_entry_is_init(iter)) {
if (addr_conflict(iter, start, end))
return 1;
}
iter++;
}
return 0;
}
#ifndef arch_jump_label_transform_static
static void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
/* nothing to do on most architectures */
}
#endif
static inline struct jump_entry *static_key_entries(struct static_key *key)
{
WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
}
static inline bool static_key_type(struct static_key *key)
{
return key->type & JUMP_TYPE_TRUE;
}
static inline bool static_key_linked(struct static_key *key)
{
return key->type & JUMP_TYPE_LINKED;
}
static inline void static_key_clear_linked(struct static_key *key)
{
key->type &= ~JUMP_TYPE_LINKED;
}
static inline void static_key_set_linked(struct static_key *key)
{
key->type |= JUMP_TYPE_LINKED;
}
/***
* A 'struct static_key' uses a union such that it either points directly
* to a table of 'struct jump_entry' or to a linked list of modules which in
* turn point to 'struct jump_entry' tables.
*
* The two lower bits of the pointer are used to keep track of which pointer
* type is in use and to store the initial branch direction, we use an access
* function which preserves these bits.
*/
static void static_key_set_entries(struct static_key *key,
struct jump_entry *entries)
{
unsigned long type;
WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
type = key->type & JUMP_TYPE_MASK;
key->entries = entries;
key->type |= type;
}
static enum jump_label_type jump_label_type(struct jump_entry *entry)
{
struct static_key *key = jump_entry_key(entry);
bool enabled = static_key_enabled(key);
bool branch = jump_entry_is_branch(entry);
/* See the comment in linux/jump_label.h */
return enabled ^ branch;
}
static bool jump_label_can_update(struct jump_entry *entry, bool init)
{
/*
* Cannot update code that was in an init text area.
*/
if (!init && jump_entry_is_init(entry))
return false;
if (!kernel_text_address(jump_entry_code(entry))) {
/*
* This skips patching built-in __exit, which
* is part of init_section_contains() but is
* not part of kernel_text_address().
*
* Skipping built-in __exit is fine since it
* will never be executed.
*/
WARN_ONCE(!jump_entry_is_init(entry),
"can't patch jump_label at %pS",
(void *)jump_entry_code(entry));
return false;
}
return true;
}
#ifndef HAVE_JUMP_LABEL_BATCH
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop,
bool init)
{
for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
if (jump_label_can_update(entry, init))
arch_jump_label_transform(entry, jump_label_type(entry));
}
}
#else
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop,
bool init)
{
for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
if (!jump_label_can_update(entry, init))
continue;
if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
/*
* Queue is full: Apply the current queue and try again.
*/
arch_jump_label_transform_apply();
BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
}
}
arch_jump_label_transform_apply();
}
#endif
void __init jump_label_init(void)
{
struct jump_entry *iter_start = __start___jump_table;
struct jump_entry *iter_stop = __stop___jump_table;
struct static_key *key = NULL;
struct jump_entry *iter;
/*
* Since we are initializing the static_key.enabled field with
* with the 'raw' int values (to avoid pulling in atomic.h) in
* jump_label.h, let's make sure that is safe. There are only two
* cases to check since we initialize to 0 or 1.
*/
BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
if (static_key_initialized)
return;
cpus_read_lock();
jump_label_lock();
jump_label_sort_entries(iter_start, iter_stop);
for (iter = iter_start; iter < iter_stop; iter++) {
struct static_key *iterk;
bool in_init;
/* rewrite NOPs */
if (jump_label_type(iter) == JUMP_LABEL_NOP)
arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
in_init = init_section_contains((void *)jump_entry_code(iter), 1);
jump_entry_set_init(iter, in_init);
iterk = jump_entry_key(iter);
if (iterk == key)
continue;
key = iterk;
static_key_set_entries(key, iter);
}
static_key_initialized = true;
jump_label_unlock();
cpus_read_unlock();
}
#ifdef CONFIG_MODULES
enum jump_label_type jump_label_init_type(struct jump_entry *entry)
{
struct static_key *key = jump_entry_key(entry);
bool type = static_key_type(key);
bool branch = jump_entry_is_branch(entry);
/* See the comment in linux/jump_label.h */
return type ^ branch;
}
struct static_key_mod {
struct static_key_mod *next;
struct jump_entry *entries;
struct module *mod;
};
static inline struct static_key_mod *static_key_mod(struct static_key *key)
{
WARN_ON_ONCE(!static_key_linked(key));
return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
}
/***
* key->type and key->next are the same via union.
* This sets key->next and preserves the type bits.
*
* See additional comments above static_key_set_entries().
*/
static void static_key_set_mod(struct static_key *key,
struct static_key_mod *mod)
{
unsigned long type;
WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
type = key->type & JUMP_TYPE_MASK;
key->next = mod;
key->type |= type;
}
static int __jump_label_mod_text_reserved(void *start, void *end)
{
struct module *mod;
int ret;
preempt_disable();
mod = __module_text_address((unsigned long)start);
WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
if (!try_module_get(mod))
mod = NULL;
preempt_enable();
if (!mod)
return 0;
ret = __jump_label_text_reserved(mod->jump_entries,
mod->jump_entries + mod->num_jump_entries,
start, end, mod->state == MODULE_STATE_COMING);
module_put(mod);
return ret;
}
static void __jump_label_mod_update(struct static_key *key)
{
struct static_key_mod *mod;
for (mod = static_key_mod(key); mod; mod = mod->next) {
struct jump_entry *stop;
struct module *m;
/*
* NULL if the static_key is defined in a module
* that does not use it
*/
if (!mod->entries)
continue;
m = mod->mod;
if (!m)
stop = __stop___jump_table;
else
stop = m->jump_entries + m->num_jump_entries;
__jump_label_update(key, mod->entries, stop,
m && m->state == MODULE_STATE_COMING);
}
}
static int jump_label_add_module(struct module *mod)
{
struct jump_entry *iter_start = mod->jump_entries;
struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
struct jump_entry *iter;
struct static_key *key = NULL;
struct static_key_mod *jlm, *jlm2;
/* if the module doesn't have jump label entries, just return */
if (iter_start == iter_stop)
return 0;
jump_label_sort_entries(iter_start, iter_stop);
for (iter = iter_start; iter < iter_stop; iter++) {
struct static_key *iterk;
bool in_init;
in_init = within_module_init(jump_entry_code(iter), mod);
jump_entry_set_init(iter, in_init);
iterk = jump_entry_key(iter);
if (iterk == key)
continue;
key = iterk;
if (within_module((unsigned long)key, mod)) {
static_key_set_entries(key, iter);
continue;
}
jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
if (!jlm)
return -ENOMEM;
if (!static_key_linked(key)) {
jlm2 = kzalloc(sizeof(struct static_key_mod),
GFP_KERNEL);
if (!jlm2) {
kfree(jlm);
return -ENOMEM;
}
preempt_disable();
jlm2->mod = __module_address((unsigned long)key);
preempt_enable();
jlm2->entries = static_key_entries(key);
jlm2->next = NULL;
static_key_set_mod(key, jlm2);
static_key_set_linked(key);
}
jlm->mod = mod;
jlm->entries = iter;
jlm->next = static_key_mod(key);
static_key_set_mod(key, jlm);
static_key_set_linked(key);
/* Only update if we've changed from our initial state */
if (jump_label_type(iter) != jump_label_init_type(iter))
__jump_label_update(key, iter, iter_stop, true);
}
return 0;
}
static void jump_label_del_module(struct module *mod)
{
struct jump_entry *iter_start = mod->jump_entries;
struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
struct jump_entry *iter;
struct static_key *key = NULL;
struct static_key_mod *jlm, **prev;
for (iter = iter_start; iter < iter_stop; iter++) {
if (jump_entry_key(iter) == key)
continue;
key = jump_entry_key(iter);
if (within_module((unsigned long)key, mod))
continue;
/* No memory during module load */
if (WARN_ON(!static_key_linked(key)))
continue;
prev = &key->next;
jlm = static_key_mod(key);
while (jlm && jlm->mod != mod) {
prev = &jlm->next;
jlm = jlm->next;
}
/* No memory during module load */
if (WARN_ON(!jlm))
continue;
if (prev == &key->next)
static_key_set_mod(key, jlm->next);
else
*prev = jlm->next;
kfree(jlm);
jlm = static_key_mod(key);
/* if only one etry is left, fold it back into the static_key */
if (jlm->next == NULL) {
static_key_set_entries(key, jlm->entries);
static_key_clear_linked(key);
kfree(jlm);
}
}
}
static int
jump_label_module_notify(struct notifier_block *self, unsigned long val,
void *data)
{
struct module *mod = data;
int ret = 0;
cpus_read_lock();
jump_label_lock();
switch (val) {
case MODULE_STATE_COMING:
ret = jump_label_add_module(mod);
if (ret) {
WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
jump_label_del_module(mod);
}
break;
case MODULE_STATE_GOING:
jump_label_del_module(mod);
break;
}
jump_label_unlock();
cpus_read_unlock();
return notifier_from_errno(ret);
}
static struct notifier_block jump_label_module_nb = {
.notifier_call = jump_label_module_notify,
.priority = 1, /* higher than tracepoints */
};
static __init int jump_label_init_module(void)
{
return register_module_notifier(&jump_label_module_nb);
}
early_initcall(jump_label_init_module);
#endif /* CONFIG_MODULES */
/***
* jump_label_text_reserved - check if addr range is reserved
* @start: start text addr
* @end: end text addr
*
* checks if the text addr located between @start and @end
* overlaps with any of the jump label patch addresses. Code
* that wants to modify kernel text should first verify that
* it does not overlap with any of the jump label addresses.
* Caller must hold jump_label_mutex.
*
* returns 1 if there is an overlap, 0 otherwise
*/
int jump_label_text_reserved(void *start, void *end)
{
bool init = system_state < SYSTEM_RUNNING;
int ret = __jump_label_text_reserved(__start___jump_table,
__stop___jump_table, start, end, init);
if (ret)
return ret;
#ifdef CONFIG_MODULES
ret = __jump_label_mod_text_reserved(start, end);
#endif
return ret;
}
static void jump_label_update(struct static_key *key)
{
struct jump_entry *stop = __stop___jump_table;
bool init = system_state < SYSTEM_RUNNING;
struct jump_entry *entry;
#ifdef CONFIG_MODULES
struct module *mod;
if (static_key_linked(key)) {
__jump_label_mod_update(key);
return;
}
preempt_disable();
mod = __module_address((unsigned long)key);
if (mod) {
stop = mod->jump_entries + mod->num_jump_entries;
init = mod->state == MODULE_STATE_COMING;
}
preempt_enable();
#endif
entry = static_key_entries(key);
/* if there are no users, entry can be NULL */
if (entry)
__jump_label_update(key, entry, stop, init);
}
#ifdef CONFIG_STATIC_KEYS_SELFTEST
static DEFINE_STATIC_KEY_TRUE(sk_true);
static DEFINE_STATIC_KEY_FALSE(sk_false);
static __init int jump_label_test(void)
{
int i;
for (i = 0; i < 2; i++) {
WARN_ON(static_key_enabled(&sk_true.key) != true);
WARN_ON(static_key_enabled(&sk_false.key) != false);
WARN_ON(!static_branch_likely(&sk_true));
WARN_ON(!static_branch_unlikely(&sk_true));
WARN_ON(static_branch_likely(&sk_false));
WARN_ON(static_branch_unlikely(&sk_false));
static_branch_disable(&sk_true);
static_branch_enable(&sk_false);
WARN_ON(static_key_enabled(&sk_true.key) == true);
WARN_ON(static_key_enabled(&sk_false.key) == false);
WARN_ON(static_branch_likely(&sk_true));
WARN_ON(static_branch_unlikely(&sk_true));
WARN_ON(!static_branch_likely(&sk_false));
WARN_ON(!static_branch_unlikely(&sk_false));
static_branch_enable(&sk_true);
static_branch_disable(&sk_false);
}
return 0;
}
early_initcall(jump_label_test);
#endif /* STATIC_KEYS_SELFTEST */
| linux-master | kernel/jump_label.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra
*
* Provides a framework for enqueueing and running callbacks from hardirq
* context. The enqueueing is NMI-safe.
*/
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/irq_work.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/irqflags.h>
#include <linux/sched.h>
#include <linux/tick.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/smp.h>
#include <linux/smpboot.h>
#include <asm/processor.h>
#include <linux/kasan.h>
#include <trace/events/ipi.h>
static DEFINE_PER_CPU(struct llist_head, raised_list);
static DEFINE_PER_CPU(struct llist_head, lazy_list);
static DEFINE_PER_CPU(struct task_struct *, irq_workd);
static void wake_irq_workd(void)
{
struct task_struct *tsk = __this_cpu_read(irq_workd);
if (!llist_empty(this_cpu_ptr(&lazy_list)) && tsk)
wake_up_process(tsk);
}
#ifdef CONFIG_SMP
static void irq_work_wake(struct irq_work *entry)
{
wake_irq_workd();
}
static DEFINE_PER_CPU(struct irq_work, irq_work_wakeup) =
IRQ_WORK_INIT_HARD(irq_work_wake);
#endif
static int irq_workd_should_run(unsigned int cpu)
{
return !llist_empty(this_cpu_ptr(&lazy_list));
}
/*
* Claim the entry so that no one else will poke at it.
*/
static bool irq_work_claim(struct irq_work *work)
{
int oflags;
oflags = atomic_fetch_or(IRQ_WORK_CLAIMED | CSD_TYPE_IRQ_WORK, &work->node.a_flags);
/*
* If the work is already pending, no need to raise the IPI.
* The pairing smp_mb() in irq_work_single() makes sure
* everything we did before is visible.
*/
if (oflags & IRQ_WORK_PENDING)
return false;
return true;
}
void __weak arch_irq_work_raise(void)
{
/*
* Lame architectures will get the timer tick callback
*/
}
static __always_inline void irq_work_raise(struct irq_work *work)
{
if (trace_ipi_send_cpu_enabled() && arch_irq_work_has_interrupt())
trace_ipi_send_cpu(smp_processor_id(), _RET_IP_, work->func);
arch_irq_work_raise();
}
/* Enqueue on current CPU, work must already be claimed and preempt disabled */
static void __irq_work_queue_local(struct irq_work *work)
{
struct llist_head *list;
bool rt_lazy_work = false;
bool lazy_work = false;
int work_flags;
work_flags = atomic_read(&work->node.a_flags);
if (work_flags & IRQ_WORK_LAZY)
lazy_work = true;
else if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
!(work_flags & IRQ_WORK_HARD_IRQ))
rt_lazy_work = true;
if (lazy_work || rt_lazy_work)
list = this_cpu_ptr(&lazy_list);
else
list = this_cpu_ptr(&raised_list);
if (!llist_add(&work->node.llist, list))
return;
/* If the work is "lazy", handle it from next tick if any */
if (!lazy_work || tick_nohz_tick_stopped())
irq_work_raise(work);
}
/* Enqueue the irq work @work on the current CPU */
bool irq_work_queue(struct irq_work *work)
{
/* Only queue if not already pending */
if (!irq_work_claim(work))
return false;
/* Queue the entry and raise the IPI if needed. */
preempt_disable();
__irq_work_queue_local(work);
preempt_enable();
return true;
}
EXPORT_SYMBOL_GPL(irq_work_queue);
/*
* Enqueue the irq_work @work on @cpu unless it's already pending
* somewhere.
*
* Can be re-enqueued while the callback is still in progress.
*/
bool irq_work_queue_on(struct irq_work *work, int cpu)
{
#ifndef CONFIG_SMP
return irq_work_queue(work);
#else /* CONFIG_SMP: */
/* All work should have been flushed before going offline */
WARN_ON_ONCE(cpu_is_offline(cpu));
/* Only queue if not already pending */
if (!irq_work_claim(work))
return false;
kasan_record_aux_stack_noalloc(work);
preempt_disable();
if (cpu != smp_processor_id()) {
/* Arch remote IPI send/receive backend aren't NMI safe */
WARN_ON_ONCE(in_nmi());
/*
* On PREEMPT_RT the items which are not marked as
* IRQ_WORK_HARD_IRQ are added to the lazy list and a HARD work
* item is used on the remote CPU to wake the thread.
*/
if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
!(atomic_read(&work->node.a_flags) & IRQ_WORK_HARD_IRQ)) {
if (!llist_add(&work->node.llist, &per_cpu(lazy_list, cpu)))
goto out;
work = &per_cpu(irq_work_wakeup, cpu);
if (!irq_work_claim(work))
goto out;
}
__smp_call_single_queue(cpu, &work->node.llist);
} else {
__irq_work_queue_local(work);
}
out:
preempt_enable();
return true;
#endif /* CONFIG_SMP */
}
bool irq_work_needs_cpu(void)
{
struct llist_head *raised, *lazy;
raised = this_cpu_ptr(&raised_list);
lazy = this_cpu_ptr(&lazy_list);
if (llist_empty(raised) || arch_irq_work_has_interrupt())
if (llist_empty(lazy))
return false;
/* All work should have been flushed before going offline */
WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
return true;
}
void irq_work_single(void *arg)
{
struct irq_work *work = arg;
int flags;
/*
* Clear the PENDING bit, after this point the @work can be re-used.
* The PENDING bit acts as a lock, and we own it, so we can clear it
* without atomic ops.
*/
flags = atomic_read(&work->node.a_flags);
flags &= ~IRQ_WORK_PENDING;
atomic_set(&work->node.a_flags, flags);
/*
* See irq_work_claim().
*/
smp_mb();
lockdep_irq_work_enter(flags);
work->func(work);
lockdep_irq_work_exit(flags);
/*
* Clear the BUSY bit, if set, and return to the free state if no-one
* else claimed it meanwhile.
*/
(void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY);
if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
!arch_irq_work_has_interrupt())
rcuwait_wake_up(&work->irqwait);
}
static void irq_work_run_list(struct llist_head *list)
{
struct irq_work *work, *tmp;
struct llist_node *llnode;
/*
* On PREEMPT_RT IRQ-work which is not marked as HARD will be processed
* in a per-CPU thread in preemptible context. Only the items which are
* marked as IRQ_WORK_HARD_IRQ will be processed in hardirq context.
*/
BUG_ON(!irqs_disabled() && !IS_ENABLED(CONFIG_PREEMPT_RT));
if (llist_empty(list))
return;
llnode = llist_del_all(list);
llist_for_each_entry_safe(work, tmp, llnode, node.llist)
irq_work_single(work);
}
/*
* hotplug calls this through:
* hotplug_cfd() -> flush_smp_call_function_queue()
*/
void irq_work_run(void)
{
irq_work_run_list(this_cpu_ptr(&raised_list));
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
irq_work_run_list(this_cpu_ptr(&lazy_list));
else
wake_irq_workd();
}
EXPORT_SYMBOL_GPL(irq_work_run);
void irq_work_tick(void)
{
struct llist_head *raised = this_cpu_ptr(&raised_list);
if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
irq_work_run_list(raised);
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
irq_work_run_list(this_cpu_ptr(&lazy_list));
else
wake_irq_workd();
}
/*
* Synchronize against the irq_work @entry, ensures the entry is not
* currently in use.
*/
void irq_work_sync(struct irq_work *work)
{
lockdep_assert_irqs_enabled();
might_sleep();
if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
!arch_irq_work_has_interrupt()) {
rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
TASK_UNINTERRUPTIBLE);
return;
}
while (irq_work_is_busy(work))
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);
static void run_irq_workd(unsigned int cpu)
{
irq_work_run_list(this_cpu_ptr(&lazy_list));
}
static void irq_workd_setup(unsigned int cpu)
{
sched_set_fifo_low(current);
}
static struct smp_hotplug_thread irqwork_threads = {
.store = &irq_workd,
.setup = irq_workd_setup,
.thread_should_run = irq_workd_should_run,
.thread_fn = run_irq_workd,
.thread_comm = "irq_work/%u",
};
static __init int irq_work_init_threads(void)
{
if (IS_ENABLED(CONFIG_PREEMPT_RT))
BUG_ON(smpboot_register_percpu_thread(&irqwork_threads));
return 0;
}
early_initcall(irq_work_init_threads);
| linux-master | kernel/irq_work.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kernel/freezer.c - Function to freeze a process
*
* Originally from kernel/power/process.c
*/
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
/* total number of freezing conditions in effect */
DEFINE_STATIC_KEY_FALSE(freezer_active);
EXPORT_SYMBOL(freezer_active);
/*
* indicate whether PM freezing is in effect, protected by
* system_transition_mutex
*/
bool pm_freezing;
bool pm_nosig_freezing;
/* protects freezing and frozen transitions */
static DEFINE_SPINLOCK(freezer_lock);
/**
* freezing_slow_path - slow path for testing whether a task needs to be frozen
* @p: task to be tested
*
* This function is called by freezing() if freezer_active isn't zero
* and tests whether @p needs to enter and stay in frozen state. Can be
* called under any context. The freezers are responsible for ensuring the
* target tasks see the updated state.
*/
bool freezing_slow_path(struct task_struct *p)
{
if (p->flags & (PF_NOFREEZE | PF_SUSPEND_TASK))
return false;
if (test_tsk_thread_flag(p, TIF_MEMDIE))
return false;
if (pm_nosig_freezing || cgroup_freezing(p))
return true;
if (pm_freezing && !(p->flags & PF_KTHREAD))
return true;
return false;
}
EXPORT_SYMBOL(freezing_slow_path);
bool frozen(struct task_struct *p)
{
return READ_ONCE(p->__state) & TASK_FROZEN;
}
/* Refrigerator is place where frozen processes are stored :-). */
bool __refrigerator(bool check_kthr_stop)
{
unsigned int state = get_current_state();
bool was_frozen = false;
pr_debug("%s entered refrigerator\n", current->comm);
WARN_ON_ONCE(state && !(state & TASK_NORMAL));
for (;;) {
bool freeze;
set_current_state(TASK_FROZEN);
spin_lock_irq(&freezer_lock);
freeze = freezing(current) && !(check_kthr_stop && kthread_should_stop());
spin_unlock_irq(&freezer_lock);
if (!freeze)
break;
was_frozen = true;
schedule();
}
__set_current_state(TASK_RUNNING);
pr_debug("%s left refrigerator\n", current->comm);
return was_frozen;
}
EXPORT_SYMBOL(__refrigerator);
static void fake_signal_wake_up(struct task_struct *p)
{
unsigned long flags;
if (lock_task_sighand(p, &flags)) {
signal_wake_up(p, 0);
unlock_task_sighand(p, &flags);
}
}
static int __set_task_frozen(struct task_struct *p, void *arg)
{
unsigned int state = READ_ONCE(p->__state);
if (p->on_rq)
return 0;
if (p != current && task_curr(p))
return 0;
if (!(state & (TASK_FREEZABLE | __TASK_STOPPED | __TASK_TRACED)))
return 0;
/*
* Only TASK_NORMAL can be augmented with TASK_FREEZABLE, since they
* can suffer spurious wakeups.
*/
if (state & TASK_FREEZABLE)
WARN_ON_ONCE(!(state & TASK_NORMAL));
#ifdef CONFIG_LOCKDEP
/*
* It's dangerous to freeze with locks held; there be dragons there.
*/
if (!(state & __TASK_FREEZABLE_UNSAFE))
WARN_ON_ONCE(debug_locks && p->lockdep_depth);
#endif
WRITE_ONCE(p->__state, TASK_FROZEN);
return TASK_FROZEN;
}
static bool __freeze_task(struct task_struct *p)
{
/* TASK_FREEZABLE|TASK_STOPPED|TASK_TRACED -> TASK_FROZEN */
return task_call_func(p, __set_task_frozen, NULL);
}
/**
* freeze_task - send a freeze request to given task
* @p: task to send the request to
*
* If @p is freezing, the freeze request is sent either by sending a fake
* signal (if it's not a kernel thread) or waking it up (if it's a kernel
* thread).
*
* RETURNS:
* %false, if @p is not freezing or already frozen; %true, otherwise
*/
bool freeze_task(struct task_struct *p)
{
unsigned long flags;
spin_lock_irqsave(&freezer_lock, flags);
if (!freezing(p) || frozen(p) || __freeze_task(p)) {
spin_unlock_irqrestore(&freezer_lock, flags);
return false;
}
if (!(p->flags & PF_KTHREAD))
fake_signal_wake_up(p);
else
wake_up_state(p, TASK_NORMAL);
spin_unlock_irqrestore(&freezer_lock, flags);
return true;
}
/*
* The special task states (TASK_STOPPED, TASK_TRACED) keep their canonical
* state in p->jobctl. If either of them got a wakeup that was missed because
* TASK_FROZEN, then their canonical state reflects that and the below will
* refuse to restore the special state and instead issue the wakeup.
*/
static int __set_task_special(struct task_struct *p, void *arg)
{
unsigned int state = 0;
if (p->jobctl & JOBCTL_TRACED)
state = TASK_TRACED;
else if (p->jobctl & JOBCTL_STOPPED)
state = TASK_STOPPED;
if (state)
WRITE_ONCE(p->__state, state);
return state;
}
void __thaw_task(struct task_struct *p)
{
unsigned long flags, flags2;
spin_lock_irqsave(&freezer_lock, flags);
if (WARN_ON_ONCE(freezing(p)))
goto unlock;
if (lock_task_sighand(p, &flags2)) {
/* TASK_FROZEN -> TASK_{STOPPED,TRACED} */
bool ret = task_call_func(p, __set_task_special, NULL);
unlock_task_sighand(p, &flags2);
if (ret)
goto unlock;
}
wake_up_state(p, TASK_FROZEN);
unlock:
spin_unlock_irqrestore(&freezer_lock, flags);
}
/**
* set_freezable - make %current freezable
*
* Mark %current freezable and enter refrigerator if necessary.
*/
bool set_freezable(void)
{
might_sleep();
/*
* Modify flags while holding freezer_lock. This ensures the
* freezer notices that we aren't frozen yet or the freezing
* condition is visible to try_to_freeze() below.
*/
spin_lock_irq(&freezer_lock);
current->flags &= ~PF_NOFREEZE;
spin_unlock_irq(&freezer_lock);
return try_to_freeze();
}
EXPORT_SYMBOL(set_freezable);
| linux-master | kernel/freezer.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2007
*
* Author: Eric Biederman <[email protected]>
*/
#include <linux/export.h>
#include <linux/uts.h>
#include <linux/utsname.h>
#include <linux/random.h>
#include <linux/sysctl.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
#ifdef CONFIG_PROC_SYSCTL
static void *get_uts(struct ctl_table *table)
{
char *which = table->data;
struct uts_namespace *uts_ns;
uts_ns = current->nsproxy->uts_ns;
which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
return which;
}
/*
* Special case of dostring for the UTS structure. This has locks
* to observe. Should this be in kernel/sys.c ????
*/
static int proc_do_uts_string(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table uts_table;
int r;
char tmp_data[__NEW_UTS_LEN + 1];
memcpy(&uts_table, table, sizeof(uts_table));
uts_table.data = tmp_data;
/*
* Buffer the value in tmp_data so that proc_dostring() can be called
* without holding any locks.
* We also need to read the original value in the write==1 case to
* support partial writes.
*/
down_read(&uts_sem);
memcpy(tmp_data, get_uts(table), sizeof(tmp_data));
up_read(&uts_sem);
r = proc_dostring(&uts_table, write, buffer, lenp, ppos);
if (write) {
/*
* Write back the new value.
* Note that, since we dropped uts_sem, the result can
* theoretically be incorrect if there are two parallel writes
* at non-zero offsets to the same sysctl.
*/
add_device_randomness(tmp_data, sizeof(tmp_data));
down_write(&uts_sem);
memcpy(get_uts(table), tmp_data, sizeof(tmp_data));
up_write(&uts_sem);
proc_sys_poll_notify(table->poll);
}
return r;
}
#else
#define proc_do_uts_string NULL
#endif
static DEFINE_CTL_TABLE_POLL(hostname_poll);
static DEFINE_CTL_TABLE_POLL(domainname_poll);
// Note: update 'enum uts_proc' to match any changes to this table
static struct ctl_table uts_kern_table[] = {
{
.procname = "arch",
.data = init_uts_ns.name.machine,
.maxlen = sizeof(init_uts_ns.name.machine),
.mode = 0444,
.proc_handler = proc_do_uts_string,
},
{
.procname = "ostype",
.data = init_uts_ns.name.sysname,
.maxlen = sizeof(init_uts_ns.name.sysname),
.mode = 0444,
.proc_handler = proc_do_uts_string,
},
{
.procname = "osrelease",
.data = init_uts_ns.name.release,
.maxlen = sizeof(init_uts_ns.name.release),
.mode = 0444,
.proc_handler = proc_do_uts_string,
},
{
.procname = "version",
.data = init_uts_ns.name.version,
.maxlen = sizeof(init_uts_ns.name.version),
.mode = 0444,
.proc_handler = proc_do_uts_string,
},
{
.procname = "hostname",
.data = init_uts_ns.name.nodename,
.maxlen = sizeof(init_uts_ns.name.nodename),
.mode = 0644,
.proc_handler = proc_do_uts_string,
.poll = &hostname_poll,
},
{
.procname = "domainname",
.data = init_uts_ns.name.domainname,
.maxlen = sizeof(init_uts_ns.name.domainname),
.mode = 0644,
.proc_handler = proc_do_uts_string,
.poll = &domainname_poll,
},
{}
};
#ifdef CONFIG_PROC_SYSCTL
/*
* Notify userspace about a change in a certain entry of uts_kern_table,
* identified by the parameter proc.
*/
void uts_proc_notify(enum uts_proc proc)
{
struct ctl_table *table = &uts_kern_table[proc];
proc_sys_poll_notify(table->poll);
}
#endif
static int __init utsname_sysctl_init(void)
{
register_sysctl("kernel", uts_kern_table);
return 0;
}
device_initcall(utsname_sysctl_init);
| linux-master | kernel/utsname_sysctl.c |
// SPDX-License-Identifier: GPL-2.0-only
/* Kernel thread helper functions.
* Copyright (C) 2004 IBM Corporation, Rusty Russell.
* Copyright (C) 2009 Red Hat, Inc.
*
* Creation is done via kthreadd, so that we get a clean environment
* even if we're invoked from userspace (think modprobe, hotplug cpu,
* etc.).
*/
#include <uapi/linux/sched/types.h>
#include <linux/mm.h>
#include <linux/mmu_context.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/sched/task.h>
#include <linux/kthread.h>
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/cgroup.h>
#include <linux/cpuset.h>
#include <linux/unistd.h>
#include <linux/file.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/freezer.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <linux/numa.h>
#include <linux/sched/isolation.h>
#include <trace/events/sched.h>
static DEFINE_SPINLOCK(kthread_create_lock);
static LIST_HEAD(kthread_create_list);
struct task_struct *kthreadd_task;
struct kthread_create_info
{
/* Information passed to kthread() from kthreadd. */
char *full_name;
int (*threadfn)(void *data);
void *data;
int node;
/* Result passed back to kthread_create() from kthreadd. */
struct task_struct *result;
struct completion *done;
struct list_head list;
};
struct kthread {
unsigned long flags;
unsigned int cpu;
int result;
int (*threadfn)(void *);
void *data;
struct completion parked;
struct completion exited;
#ifdef CONFIG_BLK_CGROUP
struct cgroup_subsys_state *blkcg_css;
#endif
/* To store the full name if task comm is truncated. */
char *full_name;
};
enum KTHREAD_BITS {
KTHREAD_IS_PER_CPU = 0,
KTHREAD_SHOULD_STOP,
KTHREAD_SHOULD_PARK,
};
static inline struct kthread *to_kthread(struct task_struct *k)
{
WARN_ON(!(k->flags & PF_KTHREAD));
return k->worker_private;
}
/*
* Variant of to_kthread() that doesn't assume @p is a kthread.
*
* Per construction; when:
*
* (p->flags & PF_KTHREAD) && p->worker_private
*
* the task is both a kthread and struct kthread is persistent. However
* PF_KTHREAD on it's own is not, kernel_thread() can exec() (See umh.c and
* begin_new_exec()).
*/
static inline struct kthread *__to_kthread(struct task_struct *p)
{
void *kthread = p->worker_private;
if (kthread && !(p->flags & PF_KTHREAD))
kthread = NULL;
return kthread;
}
void get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk)
{
struct kthread *kthread = to_kthread(tsk);
if (!kthread || !kthread->full_name) {
__get_task_comm(buf, buf_size, tsk);
return;
}
strscpy_pad(buf, kthread->full_name, buf_size);
}
bool set_kthread_struct(struct task_struct *p)
{
struct kthread *kthread;
if (WARN_ON_ONCE(to_kthread(p)))
return false;
kthread = kzalloc(sizeof(*kthread), GFP_KERNEL);
if (!kthread)
return false;
init_completion(&kthread->exited);
init_completion(&kthread->parked);
p->vfork_done = &kthread->exited;
p->worker_private = kthread;
return true;
}
void free_kthread_struct(struct task_struct *k)
{
struct kthread *kthread;
/*
* Can be NULL if kmalloc() in set_kthread_struct() failed.
*/
kthread = to_kthread(k);
if (!kthread)
return;
#ifdef CONFIG_BLK_CGROUP
WARN_ON_ONCE(kthread->blkcg_css);
#endif
k->worker_private = NULL;
kfree(kthread->full_name);
kfree(kthread);
}
/**
* kthread_should_stop - should this kthread return now?
*
* When someone calls kthread_stop() on your kthread, it will be woken
* and this will return true. You should then return, and your return
* value will be passed through to kthread_stop().
*/
bool kthread_should_stop(void)
{
return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags);
}
EXPORT_SYMBOL(kthread_should_stop);
static bool __kthread_should_park(struct task_struct *k)
{
return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(k)->flags);
}
/**
* kthread_should_park - should this kthread park now?
*
* When someone calls kthread_park() on your kthread, it will be woken
* and this will return true. You should then do the necessary
* cleanup and call kthread_parkme()
*
* Similar to kthread_should_stop(), but this keeps the thread alive
* and in a park position. kthread_unpark() "restarts" the thread and
* calls the thread function again.
*/
bool kthread_should_park(void)
{
return __kthread_should_park(current);
}
EXPORT_SYMBOL_GPL(kthread_should_park);
bool kthread_should_stop_or_park(void)
{
struct kthread *kthread = __to_kthread(current);
if (!kthread)
return false;
return kthread->flags & (BIT(KTHREAD_SHOULD_STOP) | BIT(KTHREAD_SHOULD_PARK));
}
/**
* kthread_freezable_should_stop - should this freezable kthread return now?
* @was_frozen: optional out parameter, indicates whether %current was frozen
*
* kthread_should_stop() for freezable kthreads, which will enter
* refrigerator if necessary. This function is safe from kthread_stop() /
* freezer deadlock and freezable kthreads should use this function instead
* of calling try_to_freeze() directly.
*/
bool kthread_freezable_should_stop(bool *was_frozen)
{
bool frozen = false;
might_sleep();
if (unlikely(freezing(current)))
frozen = __refrigerator(true);
if (was_frozen)
*was_frozen = frozen;
return kthread_should_stop();
}
EXPORT_SYMBOL_GPL(kthread_freezable_should_stop);
/**
* kthread_func - return the function specified on kthread creation
* @task: kthread task in question
*
* Returns NULL if the task is not a kthread.
*/
void *kthread_func(struct task_struct *task)
{
struct kthread *kthread = __to_kthread(task);
if (kthread)
return kthread->threadfn;
return NULL;
}
EXPORT_SYMBOL_GPL(kthread_func);
/**
* kthread_data - return data value specified on kthread creation
* @task: kthread task in question
*
* Return the data value specified when kthread @task was created.
* The caller is responsible for ensuring the validity of @task when
* calling this function.
*/
void *kthread_data(struct task_struct *task)
{
return to_kthread(task)->data;
}
EXPORT_SYMBOL_GPL(kthread_data);
/**
* kthread_probe_data - speculative version of kthread_data()
* @task: possible kthread task in question
*
* @task could be a kthread task. Return the data value specified when it
* was created if accessible. If @task isn't a kthread task or its data is
* inaccessible for any reason, %NULL is returned. This function requires
* that @task itself is safe to dereference.
*/
void *kthread_probe_data(struct task_struct *task)
{
struct kthread *kthread = __to_kthread(task);
void *data = NULL;
if (kthread)
copy_from_kernel_nofault(&data, &kthread->data, sizeof(data));
return data;
}
static void __kthread_parkme(struct kthread *self)
{
for (;;) {
/*
* TASK_PARKED is a special state; we must serialize against
* possible pending wakeups to avoid store-store collisions on
* task->state.
*
* Such a collision might possibly result in the task state
* changin from TASK_PARKED and us failing the
* wait_task_inactive() in kthread_park().
*/
set_special_state(TASK_PARKED);
if (!test_bit(KTHREAD_SHOULD_PARK, &self->flags))
break;
/*
* Thread is going to call schedule(), do not preempt it,
* or the caller of kthread_park() may spend more time in
* wait_task_inactive().
*/
preempt_disable();
complete(&self->parked);
schedule_preempt_disabled();
preempt_enable();
}
__set_current_state(TASK_RUNNING);
}
void kthread_parkme(void)
{
__kthread_parkme(to_kthread(current));
}
EXPORT_SYMBOL_GPL(kthread_parkme);
/**
* kthread_exit - Cause the current kthread return @result to kthread_stop().
* @result: The integer value to return to kthread_stop().
*
* While kthread_exit can be called directly, it exists so that
* functions which do some additional work in non-modular code such as
* module_put_and_kthread_exit can be implemented.
*
* Does not return.
*/
void __noreturn kthread_exit(long result)
{
struct kthread *kthread = to_kthread(current);
kthread->result = result;
do_exit(0);
}
/**
* kthread_complete_and_exit - Exit the current kthread.
* @comp: Completion to complete
* @code: The integer value to return to kthread_stop().
*
* If present, complete @comp and then return code to kthread_stop().
*
* A kernel thread whose module may be removed after the completion of
* @comp can use this function to exit safely.
*
* Does not return.
*/
void __noreturn kthread_complete_and_exit(struct completion *comp, long code)
{
if (comp)
complete(comp);
kthread_exit(code);
}
EXPORT_SYMBOL(kthread_complete_and_exit);
static int kthread(void *_create)
{
static const struct sched_param param = { .sched_priority = 0 };
/* Copy data: it's on kthread's stack */
struct kthread_create_info *create = _create;
int (*threadfn)(void *data) = create->threadfn;
void *data = create->data;
struct completion *done;
struct kthread *self;
int ret;
self = to_kthread(current);
/* Release the structure when caller killed by a fatal signal. */
done = xchg(&create->done, NULL);
if (!done) {
kfree(create->full_name);
kfree(create);
kthread_exit(-EINTR);
}
self->full_name = create->full_name;
self->threadfn = threadfn;
self->data = data;
/*
* The new thread inherited kthreadd's priority and CPU mask. Reset
* back to default in case they have been changed.
*/
sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m);
set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_KTHREAD));
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_UNINTERRUPTIBLE);
create->result = current;
/*
* Thread is going to call schedule(), do not preempt it,
* or the creator may spend more time in wait_task_inactive().
*/
preempt_disable();
complete(done);
schedule_preempt_disabled();
preempt_enable();
ret = -EINTR;
if (!test_bit(KTHREAD_SHOULD_STOP, &self->flags)) {
cgroup_kthread_ready();
__kthread_parkme(self);
ret = threadfn(data);
}
kthread_exit(ret);
}
/* called from kernel_clone() to get node information for about to be created task */
int tsk_fork_get_node(struct task_struct *tsk)
{
#ifdef CONFIG_NUMA
if (tsk == kthreadd_task)
return tsk->pref_node_fork;
#endif
return NUMA_NO_NODE;
}
static void create_kthread(struct kthread_create_info *create)
{
int pid;
#ifdef CONFIG_NUMA
current->pref_node_fork = create->node;
#endif
/* We want our own signal handler (we take no signals by default). */
pid = kernel_thread(kthread, create, create->full_name,
CLONE_FS | CLONE_FILES | SIGCHLD);
if (pid < 0) {
/* Release the structure when caller killed by a fatal signal. */
struct completion *done = xchg(&create->done, NULL);
kfree(create->full_name);
if (!done) {
kfree(create);
return;
}
create->result = ERR_PTR(pid);
complete(done);
}
}
static __printf(4, 0)
struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
void *data, int node,
const char namefmt[],
va_list args)
{
DECLARE_COMPLETION_ONSTACK(done);
struct task_struct *task;
struct kthread_create_info *create = kmalloc(sizeof(*create),
GFP_KERNEL);
if (!create)
return ERR_PTR(-ENOMEM);
create->threadfn = threadfn;
create->data = data;
create->node = node;
create->done = &done;
create->full_name = kvasprintf(GFP_KERNEL, namefmt, args);
if (!create->full_name) {
task = ERR_PTR(-ENOMEM);
goto free_create;
}
spin_lock(&kthread_create_lock);
list_add_tail(&create->list, &kthread_create_list);
spin_unlock(&kthread_create_lock);
wake_up_process(kthreadd_task);
/*
* Wait for completion in killable state, for I might be chosen by
* the OOM killer while kthreadd is trying to allocate memory for
* new kernel thread.
*/
if (unlikely(wait_for_completion_killable(&done))) {
/*
* If I was killed by a fatal signal before kthreadd (or new
* kernel thread) calls complete(), leave the cleanup of this
* structure to that thread.
*/
if (xchg(&create->done, NULL))
return ERR_PTR(-EINTR);
/*
* kthreadd (or new kernel thread) will call complete()
* shortly.
*/
wait_for_completion(&done);
}
task = create->result;
free_create:
kfree(create);
return task;
}
/**
* kthread_create_on_node - create a kthread.
* @threadfn: the function to run until signal_pending(current).
* @data: data ptr for @threadfn.
* @node: task and thread structures for the thread are allocated on this node
* @namefmt: printf-style name for the thread.
*
* Description: This helper function creates and names a kernel
* thread. The thread will be stopped: use wake_up_process() to start
* it. See also kthread_run(). The new thread has SCHED_NORMAL policy and
* is affine to all CPUs.
*
* If thread is going to be bound on a particular cpu, give its node
* in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
* When woken, the thread will run @threadfn() with @data as its
* argument. @threadfn() can either return directly if it is a
* standalone thread for which no one will call kthread_stop(), or
* return when 'kthread_should_stop()' is true (which means
* kthread_stop() has been called). The return value should be zero
* or a negative error number; it will be passed to kthread_stop().
*
* Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR).
*/
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
void *data, int node,
const char namefmt[],
...)
{
struct task_struct *task;
va_list args;
va_start(args, namefmt);
task = __kthread_create_on_node(threadfn, data, node, namefmt, args);
va_end(args);
return task;
}
EXPORT_SYMBOL(kthread_create_on_node);
static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state)
{
unsigned long flags;
if (!wait_task_inactive(p, state)) {
WARN_ON(1);
return;
}
/* It's safe because the task is inactive. */
raw_spin_lock_irqsave(&p->pi_lock, flags);
do_set_cpus_allowed(p, mask);
p->flags |= PF_NO_SETAFFINITY;
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
}
static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state)
{
__kthread_bind_mask(p, cpumask_of(cpu), state);
}
void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask)
{
__kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE);
}
/**
* kthread_bind - bind a just-created kthread to a cpu.
* @p: thread created by kthread_create().
* @cpu: cpu (might not be online, must be possible) for @k to run on.
*
* Description: This function is equivalent to set_cpus_allowed(),
* except that @cpu doesn't need to be online, and the thread must be
* stopped (i.e., just returned from kthread_create()).
*/
void kthread_bind(struct task_struct *p, unsigned int cpu)
{
__kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(kthread_bind);
/**
* kthread_create_on_cpu - Create a cpu bound kthread
* @threadfn: the function to run until signal_pending(current).
* @data: data ptr for @threadfn.
* @cpu: The cpu on which the thread should be bound,
* @namefmt: printf-style name for the thread. Format is restricted
* to "name.*%u". Code fills in cpu number.
*
* Description: This helper function creates and names a kernel thread
*/
struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
void *data, unsigned int cpu,
const char *namefmt)
{
struct task_struct *p;
p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt,
cpu);
if (IS_ERR(p))
return p;
kthread_bind(p, cpu);
/* CPU hotplug need to bind once again when unparking the thread. */
to_kthread(p)->cpu = cpu;
return p;
}
EXPORT_SYMBOL(kthread_create_on_cpu);
void kthread_set_per_cpu(struct task_struct *k, int cpu)
{
struct kthread *kthread = to_kthread(k);
if (!kthread)
return;
WARN_ON_ONCE(!(k->flags & PF_NO_SETAFFINITY));
if (cpu < 0) {
clear_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
return;
}
kthread->cpu = cpu;
set_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
}
bool kthread_is_per_cpu(struct task_struct *p)
{
struct kthread *kthread = __to_kthread(p);
if (!kthread)
return false;
return test_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
}
/**
* kthread_unpark - unpark a thread created by kthread_create().
* @k: thread created by kthread_create().
*
* Sets kthread_should_park() for @k to return false, wakes it, and
* waits for it to return. If the thread is marked percpu then its
* bound to the cpu again.
*/
void kthread_unpark(struct task_struct *k)
{
struct kthread *kthread = to_kthread(k);
/*
* Newly created kthread was parked when the CPU was offline.
* The binding was lost and we need to set it again.
*/
if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
__kthread_bind(k, kthread->cpu, TASK_PARKED);
clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
/*
* __kthread_parkme() will either see !SHOULD_PARK or get the wakeup.
*/
wake_up_state(k, TASK_PARKED);
}
EXPORT_SYMBOL_GPL(kthread_unpark);
/**
* kthread_park - park a thread created by kthread_create().
* @k: thread created by kthread_create().
*
* Sets kthread_should_park() for @k to return true, wakes it, and
* waits for it to return. This can also be called after kthread_create()
* instead of calling wake_up_process(): the thread will park without
* calling threadfn().
*
* Returns 0 if the thread is parked, -ENOSYS if the thread exited.
* If called by the kthread itself just the park bit is set.
*/
int kthread_park(struct task_struct *k)
{
struct kthread *kthread = to_kthread(k);
if (WARN_ON(k->flags & PF_EXITING))
return -ENOSYS;
if (WARN_ON_ONCE(test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)))
return -EBUSY;
set_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
if (k != current) {
wake_up_process(k);
/*
* Wait for __kthread_parkme() to complete(), this means we
* _will_ have TASK_PARKED and are about to call schedule().
*/
wait_for_completion(&kthread->parked);
/*
* Now wait for that schedule() to complete and the task to
* get scheduled out.
*/
WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED));
}
return 0;
}
EXPORT_SYMBOL_GPL(kthread_park);
/**
* kthread_stop - stop a thread created by kthread_create().
* @k: thread created by kthread_create().
*
* Sets kthread_should_stop() for @k to return true, wakes it, and
* waits for it to exit. This can also be called after kthread_create()
* instead of calling wake_up_process(): the thread will exit without
* calling threadfn().
*
* If threadfn() may call kthread_exit() itself, the caller must ensure
* task_struct can't go away.
*
* Returns the result of threadfn(), or %-EINTR if wake_up_process()
* was never called.
*/
int kthread_stop(struct task_struct *k)
{
struct kthread *kthread;
int ret;
trace_sched_kthread_stop(k);
get_task_struct(k);
kthread = to_kthread(k);
set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
kthread_unpark(k);
set_tsk_thread_flag(k, TIF_NOTIFY_SIGNAL);
wake_up_process(k);
wait_for_completion(&kthread->exited);
ret = kthread->result;
put_task_struct(k);
trace_sched_kthread_stop_ret(ret);
return ret;
}
EXPORT_SYMBOL(kthread_stop);
int kthreadd(void *unused)
{
struct task_struct *tsk = current;
/* Setup a clean context for our children to inherit. */
set_task_comm(tsk, "kthreadd");
ignore_signals(tsk);
set_cpus_allowed_ptr(tsk, housekeeping_cpumask(HK_TYPE_KTHREAD));
set_mems_allowed(node_states[N_MEMORY]);
current->flags |= PF_NOFREEZE;
cgroup_init_kthreadd();
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (list_empty(&kthread_create_list))
schedule();
__set_current_state(TASK_RUNNING);
spin_lock(&kthread_create_lock);
while (!list_empty(&kthread_create_list)) {
struct kthread_create_info *create;
create = list_entry(kthread_create_list.next,
struct kthread_create_info, list);
list_del_init(&create->list);
spin_unlock(&kthread_create_lock);
create_kthread(create);
spin_lock(&kthread_create_lock);
}
spin_unlock(&kthread_create_lock);
}
return 0;
}
void __kthread_init_worker(struct kthread_worker *worker,
const char *name,
struct lock_class_key *key)
{
memset(worker, 0, sizeof(struct kthread_worker));
raw_spin_lock_init(&worker->lock);
lockdep_set_class_and_name(&worker->lock, key, name);
INIT_LIST_HEAD(&worker->work_list);
INIT_LIST_HEAD(&worker->delayed_work_list);
}
EXPORT_SYMBOL_GPL(__kthread_init_worker);
/**
* kthread_worker_fn - kthread function to process kthread_worker
* @worker_ptr: pointer to initialized kthread_worker
*
* This function implements the main cycle of kthread worker. It processes
* work_list until it is stopped with kthread_stop(). It sleeps when the queue
* is empty.
*
* The works are not allowed to keep any locks, disable preemption or interrupts
* when they finish. There is defined a safe point for freezing when one work
* finishes and before a new one is started.
*
* Also the works must not be handled by more than one worker at the same time,
* see also kthread_queue_work().
*/
int kthread_worker_fn(void *worker_ptr)
{
struct kthread_worker *worker = worker_ptr;
struct kthread_work *work;
/*
* FIXME: Update the check and remove the assignment when all kthread
* worker users are created using kthread_create_worker*() functions.
*/
WARN_ON(worker->task && worker->task != current);
worker->task = current;
if (worker->flags & KTW_FREEZABLE)
set_freezable();
repeat:
set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
raw_spin_lock_irq(&worker->lock);
worker->task = NULL;
raw_spin_unlock_irq(&worker->lock);
return 0;
}
work = NULL;
raw_spin_lock_irq(&worker->lock);
if (!list_empty(&worker->work_list)) {
work = list_first_entry(&worker->work_list,
struct kthread_work, node);
list_del_init(&work->node);
}
worker->current_work = work;
raw_spin_unlock_irq(&worker->lock);
if (work) {
kthread_work_func_t func = work->func;
__set_current_state(TASK_RUNNING);
trace_sched_kthread_work_execute_start(work);
work->func(work);
/*
* Avoid dereferencing work after this point. The trace
* event only cares about the address.
*/
trace_sched_kthread_work_execute_end(work, func);
} else if (!freezing(current))
schedule();
try_to_freeze();
cond_resched();
goto repeat;
}
EXPORT_SYMBOL_GPL(kthread_worker_fn);
static __printf(3, 0) struct kthread_worker *
__kthread_create_worker(int cpu, unsigned int flags,
const char namefmt[], va_list args)
{
struct kthread_worker *worker;
struct task_struct *task;
int node = NUMA_NO_NODE;
worker = kzalloc(sizeof(*worker), GFP_KERNEL);
if (!worker)
return ERR_PTR(-ENOMEM);
kthread_init_worker(worker);
if (cpu >= 0)
node = cpu_to_node(cpu);
task = __kthread_create_on_node(kthread_worker_fn, worker,
node, namefmt, args);
if (IS_ERR(task))
goto fail_task;
if (cpu >= 0)
kthread_bind(task, cpu);
worker->flags = flags;
worker->task = task;
wake_up_process(task);
return worker;
fail_task:
kfree(worker);
return ERR_CAST(task);
}
/**
* kthread_create_worker - create a kthread worker
* @flags: flags modifying the default behavior of the worker
* @namefmt: printf-style name for the kthread worker (task).
*
* Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM)
* when the needed structures could not get allocated, and ERR_PTR(-EINTR)
* when the caller was killed by a fatal signal.
*/
struct kthread_worker *
kthread_create_worker(unsigned int flags, const char namefmt[], ...)
{
struct kthread_worker *worker;
va_list args;
va_start(args, namefmt);
worker = __kthread_create_worker(-1, flags, namefmt, args);
va_end(args);
return worker;
}
EXPORT_SYMBOL(kthread_create_worker);
/**
* kthread_create_worker_on_cpu - create a kthread worker and bind it
* to a given CPU and the associated NUMA node.
* @cpu: CPU number
* @flags: flags modifying the default behavior of the worker
* @namefmt: printf-style name for the kthread worker (task).
*
* Use a valid CPU number if you want to bind the kthread worker
* to the given CPU and the associated NUMA node.
*
* A good practice is to add the cpu number also into the worker name.
* For example, use kthread_create_worker_on_cpu(cpu, "helper/%d", cpu).
*
* CPU hotplug:
* The kthread worker API is simple and generic. It just provides a way
* to create, use, and destroy workers.
*
* It is up to the API user how to handle CPU hotplug. They have to decide
* how to handle pending work items, prevent queuing new ones, and
* restore the functionality when the CPU goes off and on. There are a
* few catches:
*
* - CPU affinity gets lost when it is scheduled on an offline CPU.
*
* - The worker might not exist when the CPU was off when the user
* created the workers.
*
* Good practice is to implement two CPU hotplug callbacks and to
* destroy/create the worker when the CPU goes down/up.
*
* Return:
* The pointer to the allocated worker on success, ERR_PTR(-ENOMEM)
* when the needed structures could not get allocated, and ERR_PTR(-EINTR)
* when the caller was killed by a fatal signal.
*/
struct kthread_worker *
kthread_create_worker_on_cpu(int cpu, unsigned int flags,
const char namefmt[], ...)
{
struct kthread_worker *worker;
va_list args;
va_start(args, namefmt);
worker = __kthread_create_worker(cpu, flags, namefmt, args);
va_end(args);
return worker;
}
EXPORT_SYMBOL(kthread_create_worker_on_cpu);
/*
* Returns true when the work could not be queued at the moment.
* It happens when it is already pending in a worker list
* or when it is being cancelled.
*/
static inline bool queuing_blocked(struct kthread_worker *worker,
struct kthread_work *work)
{
lockdep_assert_held(&worker->lock);
return !list_empty(&work->node) || work->canceling;
}
static void kthread_insert_work_sanity_check(struct kthread_worker *worker,
struct kthread_work *work)
{
lockdep_assert_held(&worker->lock);
WARN_ON_ONCE(!list_empty(&work->node));
/* Do not use a work with >1 worker, see kthread_queue_work() */
WARN_ON_ONCE(work->worker && work->worker != worker);
}
/* insert @work before @pos in @worker */
static void kthread_insert_work(struct kthread_worker *worker,
struct kthread_work *work,
struct list_head *pos)
{
kthread_insert_work_sanity_check(worker, work);
trace_sched_kthread_work_queue_work(worker, work);
list_add_tail(&work->node, pos);
work->worker = worker;
if (!worker->current_work && likely(worker->task))
wake_up_process(worker->task);
}
/**
* kthread_queue_work - queue a kthread_work
* @worker: target kthread_worker
* @work: kthread_work to queue
*
* Queue @work to work processor @task for async execution. @task
* must have been created with kthread_worker_create(). Returns %true
* if @work was successfully queued, %false if it was already pending.
*
* Reinitialize the work if it needs to be used by another worker.
* For example, when the worker was stopped and started again.
*/
bool kthread_queue_work(struct kthread_worker *worker,
struct kthread_work *work)
{
bool ret = false;
unsigned long flags;
raw_spin_lock_irqsave(&worker->lock, flags);
if (!queuing_blocked(worker, work)) {
kthread_insert_work(worker, work, &worker->work_list);
ret = true;
}
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_queue_work);
/**
* kthread_delayed_work_timer_fn - callback that queues the associated kthread
* delayed work when the timer expires.
* @t: pointer to the expired timer
*
* The format of the function is defined by struct timer_list.
* It should have been called from irqsafe timer with irq already off.
*/
void kthread_delayed_work_timer_fn(struct timer_list *t)
{
struct kthread_delayed_work *dwork = from_timer(dwork, t, timer);
struct kthread_work *work = &dwork->work;
struct kthread_worker *worker = work->worker;
unsigned long flags;
/*
* This might happen when a pending work is reinitialized.
* It means that it is used a wrong way.
*/
if (WARN_ON_ONCE(!worker))
return;
raw_spin_lock_irqsave(&worker->lock, flags);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
/* Move the work from worker->delayed_work_list. */
WARN_ON_ONCE(list_empty(&work->node));
list_del_init(&work->node);
if (!work->canceling)
kthread_insert_work(worker, work, &worker->work_list);
raw_spin_unlock_irqrestore(&worker->lock, flags);
}
EXPORT_SYMBOL(kthread_delayed_work_timer_fn);
static void __kthread_queue_delayed_work(struct kthread_worker *worker,
struct kthread_delayed_work *dwork,
unsigned long delay)
{
struct timer_list *timer = &dwork->timer;
struct kthread_work *work = &dwork->work;
WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
/*
* If @delay is 0, queue @dwork->work immediately. This is for
* both optimization and correctness. The earliest @timer can
* expire is on the closest next tick and delayed_work users depend
* on that there's no such delay when @delay is 0.
*/
if (!delay) {
kthread_insert_work(worker, work, &worker->work_list);
return;
}
/* Be paranoid and try to detect possible races already now. */
kthread_insert_work_sanity_check(worker, work);
list_add(&work->node, &worker->delayed_work_list);
work->worker = worker;
timer->expires = jiffies + delay;
add_timer(timer);
}
/**
* kthread_queue_delayed_work - queue the associated kthread work
* after a delay.
* @worker: target kthread_worker
* @dwork: kthread_delayed_work to queue
* @delay: number of jiffies to wait before queuing
*
* If the work has not been pending it starts a timer that will queue
* the work after the given @delay. If @delay is zero, it queues the
* work immediately.
*
* Return: %false if the @work has already been pending. It means that
* either the timer was running or the work was queued. It returns %true
* otherwise.
*/
bool kthread_queue_delayed_work(struct kthread_worker *worker,
struct kthread_delayed_work *dwork,
unsigned long delay)
{
struct kthread_work *work = &dwork->work;
unsigned long flags;
bool ret = false;
raw_spin_lock_irqsave(&worker->lock, flags);
if (!queuing_blocked(worker, work)) {
__kthread_queue_delayed_work(worker, dwork, delay);
ret = true;
}
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_queue_delayed_work);
struct kthread_flush_work {
struct kthread_work work;
struct completion done;
};
static void kthread_flush_work_fn(struct kthread_work *work)
{
struct kthread_flush_work *fwork =
container_of(work, struct kthread_flush_work, work);
complete(&fwork->done);
}
/**
* kthread_flush_work - flush a kthread_work
* @work: work to flush
*
* If @work is queued or executing, wait for it to finish execution.
*/
void kthread_flush_work(struct kthread_work *work)
{
struct kthread_flush_work fwork = {
KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
COMPLETION_INITIALIZER_ONSTACK(fwork.done),
};
struct kthread_worker *worker;
bool noop = false;
worker = work->worker;
if (!worker)
return;
raw_spin_lock_irq(&worker->lock);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
if (!list_empty(&work->node))
kthread_insert_work(worker, &fwork.work, work->node.next);
else if (worker->current_work == work)
kthread_insert_work(worker, &fwork.work,
worker->work_list.next);
else
noop = true;
raw_spin_unlock_irq(&worker->lock);
if (!noop)
wait_for_completion(&fwork.done);
}
EXPORT_SYMBOL_GPL(kthread_flush_work);
/*
* Make sure that the timer is neither set nor running and could
* not manipulate the work list_head any longer.
*
* The function is called under worker->lock. The lock is temporary
* released but the timer can't be set again in the meantime.
*/
static void kthread_cancel_delayed_work_timer(struct kthread_work *work,
unsigned long *flags)
{
struct kthread_delayed_work *dwork =
container_of(work, struct kthread_delayed_work, work);
struct kthread_worker *worker = work->worker;
/*
* del_timer_sync() must be called to make sure that the timer
* callback is not running. The lock must be temporary released
* to avoid a deadlock with the callback. In the meantime,
* any queuing is blocked by setting the canceling counter.
*/
work->canceling++;
raw_spin_unlock_irqrestore(&worker->lock, *flags);
del_timer_sync(&dwork->timer);
raw_spin_lock_irqsave(&worker->lock, *flags);
work->canceling--;
}
/*
* This function removes the work from the worker queue.
*
* It is called under worker->lock. The caller must make sure that
* the timer used by delayed work is not running, e.g. by calling
* kthread_cancel_delayed_work_timer().
*
* The work might still be in use when this function finishes. See the
* current_work proceed by the worker.
*
* Return: %true if @work was pending and successfully canceled,
* %false if @work was not pending
*/
static bool __kthread_cancel_work(struct kthread_work *work)
{
/*
* Try to remove the work from a worker list. It might either
* be from worker->work_list or from worker->delayed_work_list.
*/
if (!list_empty(&work->node)) {
list_del_init(&work->node);
return true;
}
return false;
}
/**
* kthread_mod_delayed_work - modify delay of or queue a kthread delayed work
* @worker: kthread worker to use
* @dwork: kthread delayed work to queue
* @delay: number of jiffies to wait before queuing
*
* If @dwork is idle, equivalent to kthread_queue_delayed_work(). Otherwise,
* modify @dwork's timer so that it expires after @delay. If @delay is zero,
* @work is guaranteed to be queued immediately.
*
* Return: %false if @dwork was idle and queued, %true otherwise.
*
* A special case is when the work is being canceled in parallel.
* It might be caused either by the real kthread_cancel_delayed_work_sync()
* or yet another kthread_mod_delayed_work() call. We let the other command
* win and return %true here. The return value can be used for reference
* counting and the number of queued works stays the same. Anyway, the caller
* is supposed to synchronize these operations a reasonable way.
*
* This function is safe to call from any context including IRQ handler.
* See __kthread_cancel_work() and kthread_delayed_work_timer_fn()
* for details.
*/
bool kthread_mod_delayed_work(struct kthread_worker *worker,
struct kthread_delayed_work *dwork,
unsigned long delay)
{
struct kthread_work *work = &dwork->work;
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&worker->lock, flags);
/* Do not bother with canceling when never queued. */
if (!work->worker) {
ret = false;
goto fast_queue;
}
/* Work must not be used with >1 worker, see kthread_queue_work() */
WARN_ON_ONCE(work->worker != worker);
/*
* Temporary cancel the work but do not fight with another command
* that is canceling the work as well.
*
* It is a bit tricky because of possible races with another
* mod_delayed_work() and cancel_delayed_work() callers.
*
* The timer must be canceled first because worker->lock is released
* when doing so. But the work can be removed from the queue (list)
* only when it can be queued again so that the return value can
* be used for reference counting.
*/
kthread_cancel_delayed_work_timer(work, &flags);
if (work->canceling) {
/* The number of works in the queue does not change. */
ret = true;
goto out;
}
ret = __kthread_cancel_work(work);
fast_queue:
__kthread_queue_delayed_work(worker, dwork, delay);
out:
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_mod_delayed_work);
static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)
{
struct kthread_worker *worker = work->worker;
unsigned long flags;
int ret = false;
if (!worker)
goto out;
raw_spin_lock_irqsave(&worker->lock, flags);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
if (is_dwork)
kthread_cancel_delayed_work_timer(work, &flags);
ret = __kthread_cancel_work(work);
if (worker->current_work != work)
goto out_fast;
/*
* The work is in progress and we need to wait with the lock released.
* In the meantime, block any queuing by setting the canceling counter.
*/
work->canceling++;
raw_spin_unlock_irqrestore(&worker->lock, flags);
kthread_flush_work(work);
raw_spin_lock_irqsave(&worker->lock, flags);
work->canceling--;
out_fast:
raw_spin_unlock_irqrestore(&worker->lock, flags);
out:
return ret;
}
/**
* kthread_cancel_work_sync - cancel a kthread work and wait for it to finish
* @work: the kthread work to cancel
*
* Cancel @work and wait for its execution to finish. This function
* can be used even if the work re-queues itself. On return from this
* function, @work is guaranteed to be not pending or executing on any CPU.
*
* kthread_cancel_work_sync(&delayed_work->work) must not be used for
* delayed_work's. Use kthread_cancel_delayed_work_sync() instead.
*
* The caller must ensure that the worker on which @work was last
* queued can't be destroyed before this function returns.
*
* Return: %true if @work was pending, %false otherwise.
*/
bool kthread_cancel_work_sync(struct kthread_work *work)
{
return __kthread_cancel_work_sync(work, false);
}
EXPORT_SYMBOL_GPL(kthread_cancel_work_sync);
/**
* kthread_cancel_delayed_work_sync - cancel a kthread delayed work and
* wait for it to finish.
* @dwork: the kthread delayed work to cancel
*
* This is kthread_cancel_work_sync() for delayed works.
*
* Return: %true if @dwork was pending, %false otherwise.
*/
bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *dwork)
{
return __kthread_cancel_work_sync(&dwork->work, true);
}
EXPORT_SYMBOL_GPL(kthread_cancel_delayed_work_sync);
/**
* kthread_flush_worker - flush all current works on a kthread_worker
* @worker: worker to flush
*
* Wait until all currently executing or pending works on @worker are
* finished.
*/
void kthread_flush_worker(struct kthread_worker *worker)
{
struct kthread_flush_work fwork = {
KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
COMPLETION_INITIALIZER_ONSTACK(fwork.done),
};
kthread_queue_work(worker, &fwork.work);
wait_for_completion(&fwork.done);
}
EXPORT_SYMBOL_GPL(kthread_flush_worker);
/**
* kthread_destroy_worker - destroy a kthread worker
* @worker: worker to be destroyed
*
* Flush and destroy @worker. The simple flush is enough because the kthread
* worker API is used only in trivial scenarios. There are no multi-step state
* machines needed.
*
* Note that this function is not responsible for handling delayed work, so
* caller should be responsible for queuing or canceling all delayed work items
* before invoke this function.
*/
void kthread_destroy_worker(struct kthread_worker *worker)
{
struct task_struct *task;
task = worker->task;
if (WARN_ON(!task))
return;
kthread_flush_worker(worker);
kthread_stop(task);
WARN_ON(!list_empty(&worker->delayed_work_list));
WARN_ON(!list_empty(&worker->work_list));
kfree(worker);
}
EXPORT_SYMBOL(kthread_destroy_worker);
/**
* kthread_use_mm - make the calling kthread operate on an address space
* @mm: address space to operate on
*/
void kthread_use_mm(struct mm_struct *mm)
{
struct mm_struct *active_mm;
struct task_struct *tsk = current;
WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
WARN_ON_ONCE(tsk->mm);
/*
* It is possible for mm to be the same as tsk->active_mm, but
* we must still mmgrab(mm) and mmdrop_lazy_tlb(active_mm),
* because these references are not equivalent.
*/
mmgrab(mm);
task_lock(tsk);
/* Hold off tlb flush IPIs while switching mm's */
local_irq_disable();
active_mm = tsk->active_mm;
tsk->active_mm = mm;
tsk->mm = mm;
membarrier_update_current_mm(mm);
switch_mm_irqs_off(active_mm, mm, tsk);
local_irq_enable();
task_unlock(tsk);
#ifdef finish_arch_post_lock_switch
finish_arch_post_lock_switch();
#endif
/*
* When a kthread starts operating on an address space, the loop
* in membarrier_{private,global}_expedited() may not observe
* that tsk->mm, and not issue an IPI. Membarrier requires a
* memory barrier after storing to tsk->mm, before accessing
* user-space memory. A full memory barrier for membarrier
* {PRIVATE,GLOBAL}_EXPEDITED is implicitly provided by
* mmdrop_lazy_tlb().
*/
mmdrop_lazy_tlb(active_mm);
}
EXPORT_SYMBOL_GPL(kthread_use_mm);
/**
* kthread_unuse_mm - reverse the effect of kthread_use_mm()
* @mm: address space to operate on
*/
void kthread_unuse_mm(struct mm_struct *mm)
{
struct task_struct *tsk = current;
WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
WARN_ON_ONCE(!tsk->mm);
task_lock(tsk);
/*
* When a kthread stops operating on an address space, the loop
* in membarrier_{private,global}_expedited() may not observe
* that tsk->mm, and not issue an IPI. Membarrier requires a
* memory barrier after accessing user-space memory, before
* clearing tsk->mm.
*/
smp_mb__after_spinlock();
sync_mm_rss(mm);
local_irq_disable();
tsk->mm = NULL;
membarrier_update_current_mm(NULL);
mmgrab_lazy_tlb(mm);
/* active_mm is still 'mm' */
enter_lazy_tlb(mm, tsk);
local_irq_enable();
task_unlock(tsk);
mmdrop(mm);
}
EXPORT_SYMBOL_GPL(kthread_unuse_mm);
#ifdef CONFIG_BLK_CGROUP
/**
* kthread_associate_blkcg - associate blkcg to current kthread
* @css: the cgroup info
*
* Current thread must be a kthread. The thread is running jobs on behalf of
* other threads. In some cases, we expect the jobs attach cgroup info of
* original threads instead of that of current thread. This function stores
* original thread's cgroup info in current kthread context for later
* retrieval.
*/
void kthread_associate_blkcg(struct cgroup_subsys_state *css)
{
struct kthread *kthread;
if (!(current->flags & PF_KTHREAD))
return;
kthread = to_kthread(current);
if (!kthread)
return;
if (kthread->blkcg_css) {
css_put(kthread->blkcg_css);
kthread->blkcg_css = NULL;
}
if (css) {
css_get(css);
kthread->blkcg_css = css;
}
}
EXPORT_SYMBOL(kthread_associate_blkcg);
/**
* kthread_blkcg - get associated blkcg css of current kthread
*
* Current thread must be a kthread.
*/
struct cgroup_subsys_state *kthread_blkcg(void)
{
struct kthread *kthread;
if (current->flags & PF_KTHREAD) {
kthread = to_kthread(current);
if (kthread)
return kthread->blkcg_css;
}
return NULL;
}
#endif
| linux-master | kernel/kthread.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Pid namespaces
*
* Authors:
* (C) 2007 Pavel Emelyanov <[email protected]>, OpenVZ, SWsoft Inc.
* (C) 2007 Sukadev Bhattiprolu <[email protected]>, IBM
* Many thanks to Oleg Nesterov for comments and help
*
*/
#include <linux/pid.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <linux/syscalls.h>
#include <linux/cred.h>
#include <linux/err.h>
#include <linux/acct.h>
#include <linux/slab.h>
#include <linux/proc_ns.h>
#include <linux/reboot.h>
#include <linux/export.h>
#include <linux/sched/task.h>
#include <linux/sched/signal.h>
#include <linux/idr.h>
#include "pid_sysctl.h"
static DEFINE_MUTEX(pid_caches_mutex);
static struct kmem_cache *pid_ns_cachep;
/* Write once array, filled from the beginning. */
static struct kmem_cache *pid_cache[MAX_PID_NS_LEVEL];
/*
* creates the kmem cache to allocate pids from.
* @level: pid namespace level
*/
static struct kmem_cache *create_pid_cachep(unsigned int level)
{
/* Level 0 is init_pid_ns.pid_cachep */
struct kmem_cache **pkc = &pid_cache[level - 1];
struct kmem_cache *kc;
char name[4 + 10 + 1];
unsigned int len;
kc = READ_ONCE(*pkc);
if (kc)
return kc;
snprintf(name, sizeof(name), "pid_%u", level + 1);
len = struct_size_t(struct pid, numbers, level + 1);
mutex_lock(&pid_caches_mutex);
/* Name collision forces to do allocation under mutex. */
if (!*pkc)
*pkc = kmem_cache_create(name, len, 0,
SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT, NULL);
mutex_unlock(&pid_caches_mutex);
/* current can fail, but someone else can succeed. */
return READ_ONCE(*pkc);
}
static struct ucounts *inc_pid_namespaces(struct user_namespace *ns)
{
return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES);
}
static void dec_pid_namespaces(struct ucounts *ucounts)
{
dec_ucount(ucounts, UCOUNT_PID_NAMESPACES);
}
static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
struct pid_namespace *parent_pid_ns)
{
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
struct ucounts *ucounts;
int err;
err = -EINVAL;
if (!in_userns(parent_pid_ns->user_ns, user_ns))
goto out;
err = -ENOSPC;
if (level > MAX_PID_NS_LEVEL)
goto out;
ucounts = inc_pid_namespaces(user_ns);
if (!ucounts)
goto out;
err = -ENOMEM;
ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
if (ns == NULL)
goto out_dec;
idr_init(&ns->idr);
ns->pid_cachep = create_pid_cachep(level);
if (ns->pid_cachep == NULL)
goto out_free_idr;
err = ns_alloc_inum(&ns->ns);
if (err)
goto out_free_idr;
ns->ns.ops = &pidns_operations;
refcount_set(&ns->ns.count, 1);
ns->level = level;
ns->parent = get_pid_ns(parent_pid_ns);
ns->user_ns = get_user_ns(user_ns);
ns->ucounts = ucounts;
ns->pid_allocated = PIDNS_ADDING;
#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
ns->memfd_noexec_scope = pidns_memfd_noexec_scope(parent_pid_ns);
#endif
return ns;
out_free_idr:
idr_destroy(&ns->idr);
kmem_cache_free(pid_ns_cachep, ns);
out_dec:
dec_pid_namespaces(ucounts);
out:
return ERR_PTR(err);
}
static void delayed_free_pidns(struct rcu_head *p)
{
struct pid_namespace *ns = container_of(p, struct pid_namespace, rcu);
dec_pid_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
kmem_cache_free(pid_ns_cachep, ns);
}
static void destroy_pid_namespace(struct pid_namespace *ns)
{
ns_free_inum(&ns->ns);
idr_destroy(&ns->idr);
call_rcu(&ns->rcu, delayed_free_pidns);
}
struct pid_namespace *copy_pid_ns(unsigned long flags,
struct user_namespace *user_ns, struct pid_namespace *old_ns)
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
if (task_active_pid_ns(current) != old_ns)
return ERR_PTR(-EINVAL);
return create_pid_namespace(user_ns, old_ns);
}
void put_pid_ns(struct pid_namespace *ns)
{
struct pid_namespace *parent;
while (ns != &init_pid_ns) {
parent = ns->parent;
if (!refcount_dec_and_test(&ns->ns.count))
break;
destroy_pid_namespace(ns);
ns = parent;
}
}
EXPORT_SYMBOL_GPL(put_pid_ns);
void zap_pid_ns_processes(struct pid_namespace *pid_ns)
{
int nr;
int rc;
struct task_struct *task, *me = current;
int init_pids = thread_group_leader(me) ? 1 : 2;
struct pid *pid;
/* Don't allow any more processes into the pid namespace */
disable_pid_allocation(pid_ns);
/*
* Ignore SIGCHLD causing any terminated children to autoreap.
* This speeds up the namespace shutdown, plus see the comment
* below.
*/
spin_lock_irq(&me->sighand->siglock);
me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN;
spin_unlock_irq(&me->sighand->siglock);
/*
* The last thread in the cgroup-init thread group is terminating.
* Find remaining pid_ts in the namespace, signal and wait for them
* to exit.
*
* Note: This signals each threads in the namespace - even those that
* belong to the same thread group, To avoid this, we would have
* to walk the entire tasklist looking a processes in this
* namespace, but that could be unnecessarily expensive if the
* pid namespace has just a few processes. Or we need to
* maintain a tasklist for each pid namespace.
*
*/
rcu_read_lock();
read_lock(&tasklist_lock);
nr = 2;
idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
task = pid_task(pid, PIDTYPE_PID);
if (task && !__fatal_signal_pending(task))
group_send_sig_info(SIGKILL, SEND_SIG_PRIV, task, PIDTYPE_MAX);
}
read_unlock(&tasklist_lock);
rcu_read_unlock();
/*
* Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD.
* kernel_wait4() will also block until our children traced from the
* parent namespace are detached and become EXIT_DEAD.
*/
do {
clear_thread_flag(TIF_SIGPENDING);
rc = kernel_wait4(-1, NULL, __WALL, NULL);
} while (rc != -ECHILD);
/*
* kernel_wait4() misses EXIT_DEAD children, and EXIT_ZOMBIE
* process whose parents processes are outside of the pid
* namespace. Such processes are created with setns()+fork().
*
* If those EXIT_ZOMBIE processes are not reaped by their
* parents before their parents exit, they will be reparented
* to pid_ns->child_reaper. Thus pidns->child_reaper needs to
* stay valid until they all go away.
*
* The code relies on the pid_ns->child_reaper ignoring
* SIGCHILD to cause those EXIT_ZOMBIE processes to be
* autoreaped if reparented.
*
* Semantically it is also desirable to wait for EXIT_ZOMBIE
* processes before allowing the child_reaper to be reaped, as
* that gives the invariant that when the init process of a
* pid namespace is reaped all of the processes in the pid
* namespace are gone.
*
* Once all of the other tasks are gone from the pid_namespace
* free_pid() will awaken this task.
*/
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (pid_ns->pid_allocated == init_pids)
break;
/*
* Release tasks_rcu_exit_srcu to avoid following deadlock:
*
* 1) TASK A unshare(CLONE_NEWPID)
* 2) TASK A fork() twice -> TASK B (child reaper for new ns)
* and TASK C
* 3) TASK B exits, kills TASK C, waits for TASK A to reap it
* 4) TASK A calls synchronize_rcu_tasks()
* -> synchronize_srcu(tasks_rcu_exit_srcu)
* 5) *DEADLOCK*
*
* It is considered safe to release tasks_rcu_exit_srcu here
* because we assume the current task can not be concurrently
* reaped at this point.
*/
exit_tasks_rcu_stop();
schedule();
exit_tasks_rcu_start();
}
__set_current_state(TASK_RUNNING);
if (pid_ns->reboot)
current->signal->group_exit_code = pid_ns->reboot;
acct_exit_ns(pid_ns);
return;
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static int pid_ns_ctl_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct pid_namespace *pid_ns = task_active_pid_ns(current);
struct ctl_table tmp = *table;
int ret, next;
if (write && !checkpoint_restore_ns_capable(pid_ns->user_ns))
return -EPERM;
/*
* Writing directly to ns' last_pid field is OK, since this field
* is volatile in a living namespace anyway and a code writing to
* it should synchronize its usage with external means.
*/
next = idr_get_cursor(&pid_ns->idr) - 1;
tmp.data = &next;
ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
if (!ret && write)
idr_set_cursor(&pid_ns->idr, next + 1);
return ret;
}
extern int pid_max;
static struct ctl_table pid_ns_ctl_table[] = {
{
.procname = "ns_last_pid",
.maxlen = sizeof(int),
.mode = 0666, /* permissions are checked in the handler */
.proc_handler = pid_ns_ctl_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = &pid_max,
},
{ }
};
#endif /* CONFIG_CHECKPOINT_RESTORE */
int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
{
if (pid_ns == &init_pid_ns)
return 0;
switch (cmd) {
case LINUX_REBOOT_CMD_RESTART2:
case LINUX_REBOOT_CMD_RESTART:
pid_ns->reboot = SIGHUP;
break;
case LINUX_REBOOT_CMD_POWER_OFF:
case LINUX_REBOOT_CMD_HALT:
pid_ns->reboot = SIGINT;
break;
default:
return -EINVAL;
}
read_lock(&tasklist_lock);
send_sig(SIGKILL, pid_ns->child_reaper, 1);
read_unlock(&tasklist_lock);
do_exit(0);
/* Not reached */
return 0;
}
static inline struct pid_namespace *to_pid_ns(struct ns_common *ns)
{
return container_of(ns, struct pid_namespace, ns);
}
static struct ns_common *pidns_get(struct task_struct *task)
{
struct pid_namespace *ns;
rcu_read_lock();
ns = task_active_pid_ns(task);
if (ns)
get_pid_ns(ns);
rcu_read_unlock();
return ns ? &ns->ns : NULL;
}
static struct ns_common *pidns_for_children_get(struct task_struct *task)
{
struct pid_namespace *ns = NULL;
task_lock(task);
if (task->nsproxy) {
ns = task->nsproxy->pid_ns_for_children;
get_pid_ns(ns);
}
task_unlock(task);
if (ns) {
read_lock(&tasklist_lock);
if (!ns->child_reaper) {
put_pid_ns(ns);
ns = NULL;
}
read_unlock(&tasklist_lock);
}
return ns ? &ns->ns : NULL;
}
static void pidns_put(struct ns_common *ns)
{
put_pid_ns(to_pid_ns(ns));
}
static int pidns_install(struct nsset *nsset, struct ns_common *ns)
{
struct nsproxy *nsproxy = nsset->nsproxy;
struct pid_namespace *active = task_active_pid_ns(current);
struct pid_namespace *ancestor, *new = to_pid_ns(ns);
if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
* Only allow entering the current active pid namespace
* or a child of the current active pid namespace.
*
* This is required for fork to return a usable pid value and
* this maintains the property that processes and their
* children can not escape their current pid namespace.
*/
if (new->level < active->level)
return -EINVAL;
ancestor = new;
while (ancestor->level > active->level)
ancestor = ancestor->parent;
if (ancestor != active)
return -EINVAL;
put_pid_ns(nsproxy->pid_ns_for_children);
nsproxy->pid_ns_for_children = get_pid_ns(new);
return 0;
}
static struct ns_common *pidns_get_parent(struct ns_common *ns)
{
struct pid_namespace *active = task_active_pid_ns(current);
struct pid_namespace *pid_ns, *p;
/* See if the parent is in the current namespace */
pid_ns = p = to_pid_ns(ns)->parent;
for (;;) {
if (!p)
return ERR_PTR(-EPERM);
if (p == active)
break;
p = p->parent;
}
return &get_pid_ns(pid_ns)->ns;
}
static struct user_namespace *pidns_owner(struct ns_common *ns)
{
return to_pid_ns(ns)->user_ns;
}
const struct proc_ns_operations pidns_operations = {
.name = "pid",
.type = CLONE_NEWPID,
.get = pidns_get,
.put = pidns_put,
.install = pidns_install,
.owner = pidns_owner,
.get_parent = pidns_get_parent,
};
const struct proc_ns_operations pidns_for_children_operations = {
.name = "pid_for_children",
.real_ns_name = "pid",
.type = CLONE_NEWPID,
.get = pidns_for_children_get,
.put = pidns_put,
.install = pidns_install,
.owner = pidns_owner,
.get_parent = pidns_get_parent,
};
static __init int pid_namespaces_init(void)
{
pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC | SLAB_ACCOUNT);
#ifdef CONFIG_CHECKPOINT_RESTORE
register_sysctl_init("kernel", pid_ns_ctl_table);
#endif
register_pid_ns_sysctl_table_vm();
return 0;
}
__initcall(pid_namespaces_init);
| linux-master | kernel/pid_namespace.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
* are not related to any other subsystem
*
* Copyright (C) 2004 Kay Sievers <[email protected]>
*/
#include <asm/byteorder.h>
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kexec.h>
#include <linux/profile.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/capability.h>
#include <linux/compiler.h>
#include <linux/rcupdate.h> /* rcu_expedited and rcu_normal */
#if defined(__LITTLE_ENDIAN)
#define CPU_BYTEORDER_STRING "little"
#elif defined(__BIG_ENDIAN)
#define CPU_BYTEORDER_STRING "big"
#else
#error Unknown byteorder
#endif
#define KERNEL_ATTR_RO(_name) \
static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
#define KERNEL_ATTR_RW(_name) \
static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
/* current uevent sequence number */
static ssize_t uevent_seqnum_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%llu\n", (unsigned long long)uevent_seqnum);
}
KERNEL_ATTR_RO(uevent_seqnum);
/* cpu byteorder */
static ssize_t cpu_byteorder_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n", CPU_BYTEORDER_STRING);
}
KERNEL_ATTR_RO(cpu_byteorder);
/* address bits */
static ssize_t address_bits_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%zu\n", sizeof(void *) * 8 /* CHAR_BIT */);
}
KERNEL_ATTR_RO(address_bits);
#ifdef CONFIG_UEVENT_HELPER
/* uevent helper program, used during early boot */
static ssize_t uevent_helper_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%s\n", uevent_helper);
}
static ssize_t uevent_helper_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (count+1 > UEVENT_HELPER_PATH_LEN)
return -ENOENT;
memcpy(uevent_helper, buf, count);
uevent_helper[count] = '\0';
if (count && uevent_helper[count-1] == '\n')
uevent_helper[count-1] = '\0';
return count;
}
KERNEL_ATTR_RW(uevent_helper);
#endif
#ifdef CONFIG_PROFILING
static ssize_t profiling_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", prof_on);
}
static ssize_t profiling_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int ret;
if (prof_on)
return -EEXIST;
/*
* This eventually calls into get_option() which
* has a ton of callers and is not const. It is
* easiest to cast it away here.
*/
profile_setup((char *)buf);
ret = profile_init();
if (ret)
return ret;
ret = create_proc_profile();
if (ret)
return ret;
return count;
}
KERNEL_ATTR_RW(profiling);
#endif
#ifdef CONFIG_KEXEC_CORE
static ssize_t kexec_loaded_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", !!kexec_image);
}
KERNEL_ATTR_RO(kexec_loaded);
static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", kexec_crash_loaded());
}
KERNEL_ATTR_RO(kexec_crash_loaded);
static ssize_t kexec_crash_size_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
ssize_t size = crash_get_memory_size();
if (size < 0)
return size;
return sysfs_emit(buf, "%zd\n", size);
}
static ssize_t kexec_crash_size_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned long cnt;
int ret;
if (kstrtoul(buf, 0, &cnt))
return -EINVAL;
ret = crash_shrink_memory(cnt);
return ret < 0 ? ret : count;
}
KERNEL_ATTR_RW(kexec_crash_size);
#endif /* CONFIG_KEXEC_CORE */
#ifdef CONFIG_CRASH_CORE
static ssize_t vmcoreinfo_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
phys_addr_t vmcore_base = paddr_vmcoreinfo_note();
return sysfs_emit(buf, "%pa %x\n", &vmcore_base,
(unsigned int)VMCOREINFO_NOTE_SIZE);
}
KERNEL_ATTR_RO(vmcoreinfo);
#ifdef CONFIG_CRASH_HOTPLUG
static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
unsigned int sz = crash_get_elfcorehdr_size();
return sysfs_emit(buf, "%u\n", sz);
}
KERNEL_ATTR_RO(crash_elfcorehdr_size);
#endif
#endif /* CONFIG_CRASH_CORE */
/* whether file capabilities are enabled */
static ssize_t fscaps_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", file_caps_enabled);
}
KERNEL_ATTR_RO(fscaps);
#ifndef CONFIG_TINY_RCU
int rcu_expedited;
static ssize_t rcu_expedited_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_expedited));
}
static ssize_t rcu_expedited_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (kstrtoint(buf, 0, &rcu_expedited))
return -EINVAL;
return count;
}
KERNEL_ATTR_RW(rcu_expedited);
int rcu_normal;
static ssize_t rcu_normal_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", READ_ONCE(rcu_normal));
}
static ssize_t rcu_normal_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (kstrtoint(buf, 0, &rcu_normal))
return -EINVAL;
return count;
}
KERNEL_ATTR_RW(rcu_normal);
#endif /* #ifndef CONFIG_TINY_RCU */
/*
* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
*/
extern const void __start_notes __weak;
extern const void __stop_notes __weak;
#define notes_size (&__stop_notes - &__start_notes)
static ssize_t notes_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
memcpy(buf, &__start_notes + off, count);
return count;
}
static struct bin_attribute notes_attr __ro_after_init = {
.attr = {
.name = "notes",
.mode = S_IRUGO,
},
.read = ¬es_read,
};
struct kobject *kernel_kobj;
EXPORT_SYMBOL_GPL(kernel_kobj);
static struct attribute * kernel_attrs[] = {
&fscaps_attr.attr,
&uevent_seqnum_attr.attr,
&cpu_byteorder_attr.attr,
&address_bits_attr.attr,
#ifdef CONFIG_UEVENT_HELPER
&uevent_helper_attr.attr,
#endif
#ifdef CONFIG_PROFILING
&profiling_attr.attr,
#endif
#ifdef CONFIG_KEXEC_CORE
&kexec_loaded_attr.attr,
&kexec_crash_loaded_attr.attr,
&kexec_crash_size_attr.attr,
#endif
#ifdef CONFIG_CRASH_CORE
&vmcoreinfo_attr.attr,
#ifdef CONFIG_CRASH_HOTPLUG
&crash_elfcorehdr_size_attr.attr,
#endif
#endif
#ifndef CONFIG_TINY_RCU
&rcu_expedited_attr.attr,
&rcu_normal_attr.attr,
#endif
NULL
};
static const struct attribute_group kernel_attr_group = {
.attrs = kernel_attrs,
};
static int __init ksysfs_init(void)
{
int error;
kernel_kobj = kobject_create_and_add("kernel", NULL);
if (!kernel_kobj) {
error = -ENOMEM;
goto exit;
}
error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
if (error)
goto kset_exit;
if (notes_size > 0) {
notes_attr.size = notes_size;
error = sysfs_create_bin_file(kernel_kobj, ¬es_attr);
if (error)
goto group_exit;
}
return 0;
group_exit:
sysfs_remove_group(kernel_kobj, &kernel_attr_group);
kset_exit:
kobject_put(kernel_kobj);
exit:
return error;
}
core_initcall(ksysfs_init);
| linux-master | kernel/ksysfs.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kernel/stacktrace.c
*
* Stack trace management functions
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <[email protected]>
*/
#include <linux/sched/task_stack.h>
#include <linux/sched/debug.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
#include <linux/interrupt.h>
/**
* stack_trace_print - Print the entries in the stack trace
* @entries: Pointer to storage array
* @nr_entries: Number of entries in the storage array
* @spaces: Number of leading spaces to print
*/
void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
int spaces)
{
unsigned int i;
if (WARN_ON(!entries))
return;
for (i = 0; i < nr_entries; i++)
printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
}
EXPORT_SYMBOL_GPL(stack_trace_print);
/**
* stack_trace_snprint - Print the entries in the stack trace into a buffer
* @buf: Pointer to the print buffer
* @size: Size of the print buffer
* @entries: Pointer to storage array
* @nr_entries: Number of entries in the storage array
* @spaces: Number of leading spaces to print
*
* Return: Number of bytes printed.
*/
int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
unsigned int nr_entries, int spaces)
{
unsigned int generated, i, total = 0;
if (WARN_ON(!entries))
return 0;
for (i = 0; i < nr_entries && size; i++) {
generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
(void *)entries[i]);
total += generated;
if (generated >= size) {
buf += size;
size = 0;
} else {
buf += generated;
size -= generated;
}
}
return total;
}
EXPORT_SYMBOL_GPL(stack_trace_snprint);
#ifdef CONFIG_ARCH_STACKWALK
struct stacktrace_cookie {
unsigned long *store;
unsigned int size;
unsigned int skip;
unsigned int len;
};
static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
{
struct stacktrace_cookie *c = cookie;
if (c->len >= c->size)
return false;
if (c->skip > 0) {
c->skip--;
return true;
}
c->store[c->len++] = addr;
return c->len < c->size;
}
static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
{
if (in_sched_functions(addr))
return true;
return stack_trace_consume_entry(cookie, addr);
}
/**
* stack_trace_save - Save a stack trace into a storage array
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored.
*/
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
unsigned int skipnr)
{
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
struct stacktrace_cookie c = {
.store = store,
.size = size,
.skip = skipnr + 1,
};
arch_stack_walk(consume_entry, &c, current, NULL);
return c.len;
}
EXPORT_SYMBOL_GPL(stack_trace_save);
/**
* stack_trace_save_tsk - Save a task stack trace into a storage array
* @task: The task to examine
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored.
*/
unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
unsigned int size, unsigned int skipnr)
{
stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
struct stacktrace_cookie c = {
.store = store,
.size = size,
/* skip this function if they are tracing us */
.skip = skipnr + (current == tsk),
};
if (!try_get_task_stack(tsk))
return 0;
arch_stack_walk(consume_entry, &c, tsk, NULL);
put_task_stack(tsk);
return c.len;
}
/**
* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
* @regs: Pointer to pt_regs to examine
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored.
*/
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
unsigned int size, unsigned int skipnr)
{
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
struct stacktrace_cookie c = {
.store = store,
.size = size,
.skip = skipnr,
};
arch_stack_walk(consume_entry, &c, current, regs);
return c.len;
}
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
/**
* stack_trace_save_tsk_reliable - Save task stack with verification
* @tsk: Pointer to the task to examine
* @store: Pointer to storage array
* @size: Size of the storage array
*
* Return: An error if it detects any unreliable features of the
* stack. Otherwise it guarantees that the stack trace is
* reliable and returns the number of entries stored.
*
* If the task is not 'current', the caller *must* ensure the task is inactive.
*/
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
unsigned int size)
{
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
struct stacktrace_cookie c = {
.store = store,
.size = size,
};
int ret;
/*
* If the task doesn't have a stack (e.g., a zombie), the stack is
* "reliably" empty.
*/
if (!try_get_task_stack(tsk))
return 0;
ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
put_task_stack(tsk);
return ret ? ret : c.len;
}
#endif
#ifdef CONFIG_USER_STACKTRACE_SUPPORT
/**
* stack_trace_save_user - Save a user space stack trace into a storage array
* @store: Pointer to storage array
* @size: Size of the storage array
*
* Return: Number of trace entries stored.
*/
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
{
stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
struct stacktrace_cookie c = {
.store = store,
.size = size,
};
/* Trace user stack if not a kernel thread */
if (current->flags & PF_KTHREAD)
return 0;
arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
return c.len;
}
#endif
#else /* CONFIG_ARCH_STACKWALK */
/*
* Architectures that do not implement save_stack_trace_*()
* get these weak aliases and once-per-bootup warnings
* (whenever this facility is utilized - for example by procfs):
*/
__weak void
save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
}
__weak void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}
/**
* stack_trace_save - Save a stack trace into a storage array
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored
*/
unsigned int stack_trace_save(unsigned long *store, unsigned int size,
unsigned int skipnr)
{
struct stack_trace trace = {
.entries = store,
.max_entries = size,
.skip = skipnr + 1,
};
save_stack_trace(&trace);
return trace.nr_entries;
}
EXPORT_SYMBOL_GPL(stack_trace_save);
/**
* stack_trace_save_tsk - Save a task stack trace into a storage array
* @task: The task to examine
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored
*/
unsigned int stack_trace_save_tsk(struct task_struct *task,
unsigned long *store, unsigned int size,
unsigned int skipnr)
{
struct stack_trace trace = {
.entries = store,
.max_entries = size,
/* skip this function if they are tracing us */
.skip = skipnr + (current == task),
};
save_stack_trace_tsk(task, &trace);
return trace.nr_entries;
}
/**
* stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
* @regs: Pointer to pt_regs to examine
* @store: Pointer to storage array
* @size: Size of the storage array
* @skipnr: Number of entries to skip at the start of the stack trace
*
* Return: Number of trace entries stored
*/
unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
unsigned int size, unsigned int skipnr)
{
struct stack_trace trace = {
.entries = store,
.max_entries = size,
.skip = skipnr,
};
save_stack_trace_regs(regs, &trace);
return trace.nr_entries;
}
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
/**
* stack_trace_save_tsk_reliable - Save task stack with verification
* @tsk: Pointer to the task to examine
* @store: Pointer to storage array
* @size: Size of the storage array
*
* Return: An error if it detects any unreliable features of the
* stack. Otherwise it guarantees that the stack trace is
* reliable and returns the number of entries stored.
*
* If the task is not 'current', the caller *must* ensure the task is inactive.
*/
int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
unsigned int size)
{
struct stack_trace trace = {
.entries = store,
.max_entries = size,
};
int ret = save_stack_trace_tsk_reliable(tsk, &trace);
return ret ? ret : trace.nr_entries;
}
#endif
#ifdef CONFIG_USER_STACKTRACE_SUPPORT
/**
* stack_trace_save_user - Save a user space stack trace into a storage array
* @store: Pointer to storage array
* @size: Size of the storage array
*
* Return: Number of trace entries stored
*/
unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
{
struct stack_trace trace = {
.entries = store,
.max_entries = size,
};
save_stack_trace_user(&trace);
return trace.nr_entries;
}
#endif /* CONFIG_USER_STACKTRACE_SUPPORT */
#endif /* !CONFIG_ARCH_STACKWALK */
static inline bool in_irqentry_text(unsigned long ptr)
{
return (ptr >= (unsigned long)&__irqentry_text_start &&
ptr < (unsigned long)&__irqentry_text_end) ||
(ptr >= (unsigned long)&__softirqentry_text_start &&
ptr < (unsigned long)&__softirqentry_text_end);
}
/**
* filter_irq_stacks - Find first IRQ stack entry in trace
* @entries: Pointer to stack trace array
* @nr_entries: Number of entries in the storage array
*
* Return: Number of trace entries until IRQ stack starts.
*/
unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries)
{
unsigned int i;
for (i = 0; i < nr_entries; i++) {
if (in_irqentry_text(entries[i])) {
/* Include the irqentry function into the stack. */
return i + 1;
}
}
return nr_entries;
}
EXPORT_SYMBOL_GPL(filter_irq_stacks);
| linux-master | kernel/stacktrace.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/profile.c
* Simple profiling. Manages a direct-mapped profile hit count buffer,
* with configurable resolution, support for restricting the cpus on
* which profiling is done, and switching between cpu time and
* schedule() calls via kernel command line parameters passed at boot.
*
* Scheduler profiling support, Arjan van de Ven and Ingo Molnar,
* Red Hat, July 2004
* Consolidation of architecture support code for profiling,
* Nadia Yvette Chambers, Oracle, July 2004
* Amortized hit count accounting via per-cpu open-addressed hashtables
* to resolve timer interrupt livelocks, Nadia Yvette Chambers,
* Oracle, 2004
*/
#include <linux/export.h>
#include <linux/profile.h>
#include <linux/memblock.h>
#include <linux/notifier.h>
#include <linux/mm.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/highmem.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/sched/stat.h>
#include <asm/sections.h>
#include <asm/irq_regs.h>
#include <asm/ptrace.h>
struct profile_hit {
u32 pc, hits;
};
#define PROFILE_GRPSHIFT 3
#define PROFILE_GRPSZ (1 << PROFILE_GRPSHIFT)
#define NR_PROFILE_HIT (PAGE_SIZE/sizeof(struct profile_hit))
#define NR_PROFILE_GRP (NR_PROFILE_HIT/PROFILE_GRPSZ)
static atomic_t *prof_buffer;
static unsigned long prof_len;
static unsigned short int prof_shift;
int prof_on __read_mostly;
EXPORT_SYMBOL_GPL(prof_on);
static cpumask_var_t prof_cpu_mask;
#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
static DEFINE_PER_CPU(int, cpu_profile_flip);
static DEFINE_MUTEX(profile_flip_mutex);
#endif /* CONFIG_SMP */
int profile_setup(char *str)
{
static const char schedstr[] = "schedule";
static const char sleepstr[] = "sleep";
static const char kvmstr[] = "kvm";
const char *select = NULL;
int par;
if (!strncmp(str, sleepstr, strlen(sleepstr))) {
#ifdef CONFIG_SCHEDSTATS
force_schedstat_enabled();
prof_on = SLEEP_PROFILING;
select = sleepstr;
#else
pr_warn("kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
#endif /* CONFIG_SCHEDSTATS */
} else if (!strncmp(str, schedstr, strlen(schedstr))) {
prof_on = SCHED_PROFILING;
select = schedstr;
} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
prof_on = KVM_PROFILING;
select = kvmstr;
} else if (get_option(&str, &par)) {
prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
prof_on = CPU_PROFILING;
pr_info("kernel profiling enabled (shift: %u)\n",
prof_shift);
}
if (select) {
if (str[strlen(select)] == ',')
str += strlen(select) + 1;
if (get_option(&str, &par))
prof_shift = clamp(par, 0, BITS_PER_LONG - 1);
pr_info("kernel %s profiling enabled (shift: %u)\n",
select, prof_shift);
}
return 1;
}
__setup("profile=", profile_setup);
int __ref profile_init(void)
{
int buffer_bytes;
if (!prof_on)
return 0;
/* only text is profiled */
prof_len = (_etext - _stext) >> prof_shift;
if (!prof_len) {
pr_warn("profiling shift: %u too large\n", prof_shift);
prof_on = 0;
return -EINVAL;
}
buffer_bytes = prof_len*sizeof(atomic_t);
if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
return -ENOMEM;
cpumask_copy(prof_cpu_mask, cpu_possible_mask);
prof_buffer = kzalloc(buffer_bytes, GFP_KERNEL|__GFP_NOWARN);
if (prof_buffer)
return 0;
prof_buffer = alloc_pages_exact(buffer_bytes,
GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
if (prof_buffer)
return 0;
prof_buffer = vzalloc(buffer_bytes);
if (prof_buffer)
return 0;
free_cpumask_var(prof_cpu_mask);
return -ENOMEM;
}
#if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
/*
* Each cpu has a pair of open-addressed hashtables for pending
* profile hits. read_profile() IPI's all cpus to request them
* to flip buffers and flushes their contents to prof_buffer itself.
* Flip requests are serialized by the profile_flip_mutex. The sole
* use of having a second hashtable is for avoiding cacheline
* contention that would otherwise happen during flushes of pending
* profile hits required for the accuracy of reported profile hits
* and so resurrect the interrupt livelock issue.
*
* The open-addressed hashtables are indexed by profile buffer slot
* and hold the number of pending hits to that profile buffer slot on
* a cpu in an entry. When the hashtable overflows, all pending hits
* are accounted to their corresponding profile buffer slots with
* atomic_add() and the hashtable emptied. As numerous pending hits
* may be accounted to a profile buffer slot in a hashtable entry,
* this amortizes a number of atomic profile buffer increments likely
* to be far larger than the number of entries in the hashtable,
* particularly given that the number of distinct profile buffer
* positions to which hits are accounted during short intervals (e.g.
* several seconds) is usually very small. Exclusion from buffer
* flipping is provided by interrupt disablement (note that for
* SCHED_PROFILING or SLEEP_PROFILING profile_hit() may be called from
* process context).
* The hash function is meant to be lightweight as opposed to strong,
* and was vaguely inspired by ppc64 firmware-supported inverted
* pagetable hash functions, but uses a full hashtable full of finite
* collision chains, not just pairs of them.
*
* -- nyc
*/
static void __profile_flip_buffers(void *unused)
{
int cpu = smp_processor_id();
per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
}
static void profile_flip_buffers(void)
{
int i, j, cpu;
mutex_lock(&profile_flip_mutex);
j = per_cpu(cpu_profile_flip, get_cpu());
put_cpu();
on_each_cpu(__profile_flip_buffers, NULL, 1);
for_each_online_cpu(cpu) {
struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[j];
for (i = 0; i < NR_PROFILE_HIT; ++i) {
if (!hits[i].hits) {
if (hits[i].pc)
hits[i].pc = 0;
continue;
}
atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
hits[i].hits = hits[i].pc = 0;
}
}
mutex_unlock(&profile_flip_mutex);
}
static void profile_discard_flip_buffers(void)
{
int i, cpu;
mutex_lock(&profile_flip_mutex);
i = per_cpu(cpu_profile_flip, get_cpu());
put_cpu();
on_each_cpu(__profile_flip_buffers, NULL, 1);
for_each_online_cpu(cpu) {
struct profile_hit *hits = per_cpu(cpu_profile_hits, cpu)[i];
memset(hits, 0, NR_PROFILE_HIT*sizeof(struct profile_hit));
}
mutex_unlock(&profile_flip_mutex);
}
static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
{
unsigned long primary, secondary, flags, pc = (unsigned long)__pc;
int i, j, cpu;
struct profile_hit *hits;
pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
secondary = (~(pc << 1) & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
cpu = get_cpu();
hits = per_cpu(cpu_profile_hits, cpu)[per_cpu(cpu_profile_flip, cpu)];
if (!hits) {
put_cpu();
return;
}
/*
* We buffer the global profiler buffer into a per-CPU
* queue and thus reduce the number of global (and possibly
* NUMA-alien) accesses. The write-queue is self-coalescing:
*/
local_irq_save(flags);
do {
for (j = 0; j < PROFILE_GRPSZ; ++j) {
if (hits[i + j].pc == pc) {
hits[i + j].hits += nr_hits;
goto out;
} else if (!hits[i + j].hits) {
hits[i + j].pc = pc;
hits[i + j].hits = nr_hits;
goto out;
}
}
i = (i + secondary) & (NR_PROFILE_HIT - 1);
} while (i != primary);
/*
* Add the current hit(s) and flush the write-queue out
* to the global buffer:
*/
atomic_add(nr_hits, &prof_buffer[pc]);
for (i = 0; i < NR_PROFILE_HIT; ++i) {
atomic_add(hits[i].hits, &prof_buffer[hits[i].pc]);
hits[i].pc = hits[i].hits = 0;
}
out:
local_irq_restore(flags);
put_cpu();
}
static int profile_dead_cpu(unsigned int cpu)
{
struct page *page;
int i;
if (cpumask_available(prof_cpu_mask))
cpumask_clear_cpu(cpu, prof_cpu_mask);
for (i = 0; i < 2; i++) {
if (per_cpu(cpu_profile_hits, cpu)[i]) {
page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);
per_cpu(cpu_profile_hits, cpu)[i] = NULL;
__free_page(page);
}
}
return 0;
}
static int profile_prepare_cpu(unsigned int cpu)
{
int i, node = cpu_to_mem(cpu);
struct page *page;
per_cpu(cpu_profile_flip, cpu) = 0;
for (i = 0; i < 2; i++) {
if (per_cpu(cpu_profile_hits, cpu)[i])
continue;
page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
if (!page) {
profile_dead_cpu(cpu);
return -ENOMEM;
}
per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);
}
return 0;
}
static int profile_online_cpu(unsigned int cpu)
{
if (cpumask_available(prof_cpu_mask))
cpumask_set_cpu(cpu, prof_cpu_mask);
return 0;
}
#else /* !CONFIG_SMP */
#define profile_flip_buffers() do { } while (0)
#define profile_discard_flip_buffers() do { } while (0)
static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)
{
unsigned long pc;
pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
}
#endif /* !CONFIG_SMP */
void profile_hits(int type, void *__pc, unsigned int nr_hits)
{
if (prof_on != type || !prof_buffer)
return;
do_profile_hits(type, __pc, nr_hits);
}
EXPORT_SYMBOL_GPL(profile_hits);
void profile_tick(int type)
{
struct pt_regs *regs = get_irq_regs();
if (!user_mode(regs) && cpumask_available(prof_cpu_mask) &&
cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))
profile_hit(type, (void *)profile_pc(regs));
}
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
static int prof_cpu_mask_proc_show(struct seq_file *m, void *v)
{
seq_printf(m, "%*pb\n", cpumask_pr_args(prof_cpu_mask));
return 0;
}
static int prof_cpu_mask_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, prof_cpu_mask_proc_show, NULL);
}
static ssize_t prof_cpu_mask_proc_write(struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
cpumask_var_t new_value;
int err;
if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
return -ENOMEM;
err = cpumask_parse_user(buffer, count, new_value);
if (!err) {
cpumask_copy(prof_cpu_mask, new_value);
err = count;
}
free_cpumask_var(new_value);
return err;
}
static const struct proc_ops prof_cpu_mask_proc_ops = {
.proc_open = prof_cpu_mask_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
.proc_write = prof_cpu_mask_proc_write,
};
void create_prof_cpu_mask(void)
{
/* create /proc/irq/prof_cpu_mask */
proc_create("irq/prof_cpu_mask", 0600, NULL, &prof_cpu_mask_proc_ops);
}
/*
* This function accesses profiling information. The returned data is
* binary: the sampling step and the actual contents of the profile
* buffer. Use of the program readprofile is recommended in order to
* get meaningful info out of these data.
*/
static ssize_t
read_profile(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
ssize_t read;
char *pnt;
unsigned long sample_step = 1UL << prof_shift;
profile_flip_buffers();
if (p >= (prof_len+1)*sizeof(unsigned int))
return 0;
if (count > (prof_len+1)*sizeof(unsigned int) - p)
count = (prof_len+1)*sizeof(unsigned int) - p;
read = 0;
while (p < sizeof(unsigned int) && count > 0) {
if (put_user(*((char *)(&sample_step)+p), buf))
return -EFAULT;
buf++; p++; count--; read++;
}
pnt = (char *)prof_buffer + p - sizeof(atomic_t);
if (copy_to_user(buf, (void *)pnt, count))
return -EFAULT;
read += count;
*ppos += read;
return read;
}
/* default is to not implement this call */
int __weak setup_profiling_timer(unsigned mult)
{
return -EINVAL;
}
/*
* Writing to /proc/profile resets the counters
*
* Writing a 'profiling multiplier' value into it also re-sets the profiling
* interrupt frequency, on architectures that support this.
*/
static ssize_t write_profile(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
#ifdef CONFIG_SMP
if (count == sizeof(int)) {
unsigned int multiplier;
if (copy_from_user(&multiplier, buf, sizeof(int)))
return -EFAULT;
if (setup_profiling_timer(multiplier))
return -EINVAL;
}
#endif
profile_discard_flip_buffers();
memset(prof_buffer, 0, prof_len * sizeof(atomic_t));
return count;
}
static const struct proc_ops profile_proc_ops = {
.proc_read = read_profile,
.proc_write = write_profile,
.proc_lseek = default_llseek,
};
int __ref create_proc_profile(void)
{
struct proc_dir_entry *entry;
#ifdef CONFIG_SMP
enum cpuhp_state online_state;
#endif
int err = 0;
if (!prof_on)
return 0;
#ifdef CONFIG_SMP
err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",
profile_prepare_cpu, profile_dead_cpu);
if (err)
return err;
err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",
profile_online_cpu, NULL);
if (err < 0)
goto err_state_prep;
online_state = err;
err = 0;
#endif
entry = proc_create("profile", S_IWUSR | S_IRUGO,
NULL, &profile_proc_ops);
if (!entry)
goto err_state_onl;
proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));
return err;
err_state_onl:
#ifdef CONFIG_SMP
cpuhp_remove_state(online_state);
err_state_prep:
cpuhp_remove_state(CPUHP_PROFILE_PREPARE);
#endif
return err;
}
subsys_initcall(create_proc_profile);
#endif /* CONFIG_PROC_FS */
| linux-master | kernel/profile.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Test the function and performance of kallsyms
*
* Copyright (C) Huawei Technologies Co., Ltd., 2022
*
* Authors: Zhen Lei <[email protected]> Huawei
*/
#define pr_fmt(fmt) "kallsyms_selftest: " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/random.h>
#include <linux/sched/clock.h>
#include <linux/kthread.h>
#include <linux/vmalloc.h>
#include "kallsyms_internal.h"
#include "kallsyms_selftest.h"
#define MAX_NUM_OF_RECORDS 64
struct test_stat {
int min;
int max;
int save_cnt;
int real_cnt;
int perf;
u64 sum;
char *name;
unsigned long addr;
unsigned long addrs[MAX_NUM_OF_RECORDS];
};
struct test_item {
char *name;
unsigned long addr;
};
#define ITEM_FUNC(s) \
{ \
.name = #s, \
.addr = (unsigned long)s, \
}
#define ITEM_DATA(s) \
{ \
.name = #s, \
.addr = (unsigned long)&s, \
}
static int kallsyms_test_var_bss_static;
static int kallsyms_test_var_data_static = 1;
int kallsyms_test_var_bss;
int kallsyms_test_var_data = 1;
static int kallsyms_test_func_static(void)
{
kallsyms_test_var_bss_static++;
kallsyms_test_var_data_static++;
return 0;
}
int kallsyms_test_func(void)
{
return kallsyms_test_func_static();
}
__weak int kallsyms_test_func_weak(void)
{
kallsyms_test_var_bss++;
kallsyms_test_var_data++;
return 0;
}
static struct test_item test_items[] = {
ITEM_FUNC(kallsyms_test_func_static),
ITEM_FUNC(kallsyms_test_func),
ITEM_FUNC(kallsyms_test_func_weak),
ITEM_FUNC(vmalloc),
ITEM_FUNC(vfree),
#ifdef CONFIG_KALLSYMS_ALL
ITEM_DATA(kallsyms_test_var_bss_static),
ITEM_DATA(kallsyms_test_var_data_static),
ITEM_DATA(kallsyms_test_var_bss),
ITEM_DATA(kallsyms_test_var_data),
ITEM_DATA(vmap_area_list),
#endif
};
static char stub_name[KSYM_NAME_LEN];
static int stat_symbol_len(void *data, const char *name, unsigned long addr)
{
*(u32 *)data += strlen(name);
return 0;
}
static void test_kallsyms_compression_ratio(void)
{
u32 pos, off, len, num;
u32 ratio, total_size, total_len = 0;
kallsyms_on_each_symbol(stat_symbol_len, &total_len);
/*
* A symbol name cannot start with a number. This stub name helps us
* traverse the entire symbol table without finding a match. It's used
* for subsequent performance tests, and its length is the average
* length of all symbol names.
*/
memset(stub_name, '4', sizeof(stub_name));
pos = total_len / kallsyms_num_syms;
stub_name[pos] = 0;
pos = 0;
num = 0;
off = 0;
while (pos < kallsyms_num_syms) {
len = kallsyms_names[off];
num++;
off++;
pos++;
if ((len & 0x80) != 0) {
len = (len & 0x7f) | (kallsyms_names[off] << 7);
num++;
off++;
}
off += len;
}
/*
* 1. The length fields is not counted
* 2. The memory occupied by array kallsyms_token_table[] and
* kallsyms_token_index[] needs to be counted.
*/
total_size = off - num;
pos = kallsyms_token_index[0xff];
total_size += pos + strlen(&kallsyms_token_table[pos]) + 1;
total_size += 0x100 * sizeof(u16);
pr_info(" ---------------------------------------------------------\n");
pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n");
pr_info("|---------------------------------------------------------|\n");
ratio = (u32)div_u64(10000ULL * total_size, total_len);
pr_info("| %10d | %10d | %10d | %2d.%-2d |\n",
kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100);
pr_info(" ---------------------------------------------------------\n");
}
static int lookup_name(void *data, const char *name, unsigned long addr)
{
u64 t0, t1, t;
struct test_stat *stat = (struct test_stat *)data;
t0 = ktime_get_ns();
(void)kallsyms_lookup_name(name);
t1 = ktime_get_ns();
t = t1 - t0;
if (t < stat->min)
stat->min = t;
if (t > stat->max)
stat->max = t;
stat->real_cnt++;
stat->sum += t;
return 0;
}
static void test_perf_kallsyms_lookup_name(void)
{
struct test_stat stat;
memset(&stat, 0, sizeof(stat));
stat.min = INT_MAX;
kallsyms_on_each_symbol(lookup_name, &stat);
pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt);
pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n",
stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
}
static bool match_cleanup_name(const char *s, const char *name)
{
char *p;
int len;
if (!IS_ENABLED(CONFIG_LTO_CLANG))
return false;
p = strstr(s, ".llvm.");
if (!p)
return false;
len = strlen(name);
if (p - s != len)
return false;
return !strncmp(s, name, len);
}
static int find_symbol(void *data, const char *name, unsigned long addr)
{
struct test_stat *stat = (struct test_stat *)data;
if (strcmp(name, stat->name) == 0 ||
(!stat->perf && match_cleanup_name(name, stat->name))) {
stat->real_cnt++;
stat->addr = addr;
if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
stat->addrs[stat->save_cnt] = addr;
stat->save_cnt++;
}
if (stat->real_cnt == stat->max)
return 1;
}
return 0;
}
static void test_perf_kallsyms_on_each_symbol(void)
{
u64 t0, t1;
struct test_stat stat;
memset(&stat, 0, sizeof(stat));
stat.max = INT_MAX;
stat.name = stub_name;
stat.perf = 1;
t0 = ktime_get_ns();
kallsyms_on_each_symbol(find_symbol, &stat);
t1 = ktime_get_ns();
pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0);
}
static int match_symbol(void *data, unsigned long addr)
{
struct test_stat *stat = (struct test_stat *)data;
stat->real_cnt++;
stat->addr = addr;
if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
stat->addrs[stat->save_cnt] = addr;
stat->save_cnt++;
}
if (stat->real_cnt == stat->max)
return 1;
return 0;
}
static void test_perf_kallsyms_on_each_match_symbol(void)
{
u64 t0, t1;
struct test_stat stat;
memset(&stat, 0, sizeof(stat));
stat.max = INT_MAX;
stat.name = stub_name;
t0 = ktime_get_ns();
kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat);
t1 = ktime_get_ns();
pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0);
}
static int test_kallsyms_basic_function(void)
{
int i, j, ret;
int next = 0, nr_failed = 0;
char *prefix;
unsigned short rand;
unsigned long addr, lookup_addr;
char namebuf[KSYM_NAME_LEN];
struct test_stat *stat, *stat2;
stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL);
if (!stat)
return -ENOMEM;
stat2 = stat + 1;
prefix = "kallsyms_lookup_name() for";
for (i = 0; i < ARRAY_SIZE(test_items); i++) {
addr = kallsyms_lookup_name(test_items[i].name);
if (addr != test_items[i].addr) {
nr_failed++;
pr_info("%s %s failed: addr=%lx, expect %lx\n",
prefix, test_items[i].name, addr, test_items[i].addr);
}
}
prefix = "kallsyms_on_each_symbol() for";
for (i = 0; i < ARRAY_SIZE(test_items); i++) {
memset(stat, 0, sizeof(*stat));
stat->max = INT_MAX;
stat->name = test_items[i].name;
kallsyms_on_each_symbol(find_symbol, stat);
if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
nr_failed++;
pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
prefix, test_items[i].name,
stat->real_cnt, stat->addr, test_items[i].addr);
}
}
prefix = "kallsyms_on_each_match_symbol() for";
for (i = 0; i < ARRAY_SIZE(test_items); i++) {
memset(stat, 0, sizeof(*stat));
stat->max = INT_MAX;
stat->name = test_items[i].name;
kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat);
if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
nr_failed++;
pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
prefix, test_items[i].name,
stat->real_cnt, stat->addr, test_items[i].addr);
}
}
if (nr_failed) {
kfree(stat);
return -ESRCH;
}
for (i = 0; i < kallsyms_num_syms; i++) {
addr = kallsyms_sym_address(i);
if (!is_ksym_addr(addr))
continue;
ret = lookup_symbol_name(addr, namebuf);
if (unlikely(ret)) {
namebuf[0] = 0;
pr_info("%d: lookup_symbol_name(%lx) failed\n", i, addr);
goto failed;
}
lookup_addr = kallsyms_lookup_name(namebuf);
memset(stat, 0, sizeof(*stat));
stat->max = INT_MAX;
kallsyms_on_each_match_symbol(match_symbol, namebuf, stat);
/*
* kallsyms_on_each_symbol() is too slow, randomly select some
* symbols for test.
*/
if (i >= next) {
memset(stat2, 0, sizeof(*stat2));
stat2->max = INT_MAX;
stat2->name = namebuf;
kallsyms_on_each_symbol(find_symbol, stat2);
/*
* kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()
* need to get the same traversal result.
*/
if (stat->addr != stat2->addr ||
stat->real_cnt != stat2->real_cnt ||
memcmp(stat->addrs, stat2->addrs,
stat->save_cnt * sizeof(stat->addrs[0]))) {
pr_info("%s: mismatch between kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()\n",
namebuf);
goto failed;
}
/*
* The average of random increments is 128, that is, one of
* them is tested every 128 symbols.
*/
get_random_bytes(&rand, sizeof(rand));
next = i + (rand & 0xff) + 1;
}
/* Need to be found at least once */
if (!stat->real_cnt) {
pr_info("%s: Never found\n", namebuf);
goto failed;
}
/*
* kallsyms_lookup_name() returns the address of the first
* symbol found and cannot be NULL.
*/
if (!lookup_addr) {
pr_info("%s: NULL lookup_addr?!\n", namebuf);
goto failed;
}
if (lookup_addr != stat->addrs[0]) {
pr_info("%s: lookup_addr != stat->addrs[0]\n", namebuf);
goto failed;
}
/*
* If the addresses of all matching symbols are recorded, the
* target address needs to be exist.
*/
if (stat->real_cnt <= MAX_NUM_OF_RECORDS) {
for (j = 0; j < stat->save_cnt; j++) {
if (stat->addrs[j] == addr)
break;
}
if (j == stat->save_cnt) {
pr_info("%s: j == save_cnt?!\n", namebuf);
goto failed;
}
}
}
kfree(stat);
return 0;
failed:
pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr);
kfree(stat);
return -ESRCH;
}
static int test_entry(void *p)
{
int ret;
do {
schedule_timeout(5 * HZ);
} while (system_state != SYSTEM_RUNNING);
pr_info("start\n");
ret = test_kallsyms_basic_function();
if (ret) {
pr_info("abort\n");
return 0;
}
test_kallsyms_compression_ratio();
test_perf_kallsyms_lookup_name();
test_perf_kallsyms_on_each_symbol();
test_perf_kallsyms_on_each_match_symbol();
pr_info("finish\n");
return 0;
}
static int __init kallsyms_test_init(void)
{
struct task_struct *t;
t = kthread_create(test_entry, NULL, "kallsyms_test");
if (IS_ERR(t)) {
pr_info("Create kallsyms selftest task failed\n");
return PTR_ERR(t);
}
kthread_bind(t, 0);
wake_up_process(t);
return 0;
}
late_initcall(kallsyms_test_init);
| linux-master | kernel/kallsyms_selftest.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/linkage.h>
#include <linux/errno.h>
#include <asm/unistd.h>
#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */
#include <asm/syscall_wrapper.h>
#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
/* we can't #include <linux/syscalls.h> here,
but tell gcc to not warn with -Wmissing-prototypes */
asmlinkage long sys_ni_syscall(void);
/*
* Non-implemented system calls get redirected here.
*/
asmlinkage long sys_ni_syscall(void)
{
return -ENOSYS;
}
#ifndef COND_SYSCALL
#define COND_SYSCALL(name) cond_syscall(sys_##name)
#endif /* COND_SYSCALL */
#ifndef COND_SYSCALL_COMPAT
#define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name)
#endif /* COND_SYSCALL_COMPAT */
/*
* This list is kept in the same order as include/uapi/asm-generic/unistd.h.
* Architecture specific entries go below, followed by deprecated or obsolete
* system calls.
*/
COND_SYSCALL(io_setup);
COND_SYSCALL_COMPAT(io_setup);
COND_SYSCALL(io_destroy);
COND_SYSCALL(io_submit);
COND_SYSCALL_COMPAT(io_submit);
COND_SYSCALL(io_cancel);
COND_SYSCALL(io_getevents_time32);
COND_SYSCALL(io_getevents);
COND_SYSCALL(io_pgetevents_time32);
COND_SYSCALL(io_pgetevents);
COND_SYSCALL_COMPAT(io_pgetevents_time32);
COND_SYSCALL_COMPAT(io_pgetevents);
COND_SYSCALL(io_uring_setup);
COND_SYSCALL(io_uring_enter);
COND_SYSCALL(io_uring_register);
COND_SYSCALL(lookup_dcookie);
COND_SYSCALL_COMPAT(lookup_dcookie);
COND_SYSCALL(eventfd2);
COND_SYSCALL(epoll_create1);
COND_SYSCALL(epoll_ctl);
COND_SYSCALL(epoll_pwait);
COND_SYSCALL_COMPAT(epoll_pwait);
COND_SYSCALL(epoll_pwait2);
COND_SYSCALL_COMPAT(epoll_pwait2);
COND_SYSCALL(inotify_init1);
COND_SYSCALL(inotify_add_watch);
COND_SYSCALL(inotify_rm_watch);
COND_SYSCALL(ioprio_set);
COND_SYSCALL(ioprio_get);
COND_SYSCALL(flock);
COND_SYSCALL(quotactl);
COND_SYSCALL(quotactl_fd);
COND_SYSCALL(signalfd4);
COND_SYSCALL_COMPAT(signalfd4);
COND_SYSCALL(timerfd_create);
COND_SYSCALL(timerfd_settime);
COND_SYSCALL(timerfd_settime32);
COND_SYSCALL(timerfd_gettime);
COND_SYSCALL(timerfd_gettime32);
COND_SYSCALL(acct);
COND_SYSCALL(capget);
COND_SYSCALL(capset);
/* __ARCH_WANT_SYS_CLONE3 */
COND_SYSCALL(clone3);
COND_SYSCALL(futex);
COND_SYSCALL(futex_time32);
COND_SYSCALL(set_robust_list);
COND_SYSCALL_COMPAT(set_robust_list);
COND_SYSCALL(get_robust_list);
COND_SYSCALL_COMPAT(get_robust_list);
COND_SYSCALL(futex_waitv);
COND_SYSCALL(kexec_load);
COND_SYSCALL_COMPAT(kexec_load);
COND_SYSCALL(init_module);
COND_SYSCALL(delete_module);
COND_SYSCALL(syslog);
COND_SYSCALL(setregid);
COND_SYSCALL(setgid);
COND_SYSCALL(setreuid);
COND_SYSCALL(setuid);
COND_SYSCALL(setresuid);
COND_SYSCALL(getresuid);
COND_SYSCALL(setresgid);
COND_SYSCALL(getresgid);
COND_SYSCALL(setfsuid);
COND_SYSCALL(setfsgid);
COND_SYSCALL(setgroups);
COND_SYSCALL(getgroups);
COND_SYSCALL(mq_open);
COND_SYSCALL_COMPAT(mq_open);
COND_SYSCALL(mq_unlink);
COND_SYSCALL(mq_timedsend);
COND_SYSCALL(mq_timedsend_time32);
COND_SYSCALL(mq_timedreceive);
COND_SYSCALL(mq_timedreceive_time32);
COND_SYSCALL(mq_notify);
COND_SYSCALL_COMPAT(mq_notify);
COND_SYSCALL(mq_getsetattr);
COND_SYSCALL_COMPAT(mq_getsetattr);
COND_SYSCALL(msgget);
COND_SYSCALL(old_msgctl);
COND_SYSCALL(msgctl);
COND_SYSCALL_COMPAT(msgctl);
COND_SYSCALL_COMPAT(old_msgctl);
COND_SYSCALL(msgrcv);
COND_SYSCALL_COMPAT(msgrcv);
COND_SYSCALL(msgsnd);
COND_SYSCALL_COMPAT(msgsnd);
COND_SYSCALL(semget);
COND_SYSCALL(old_semctl);
COND_SYSCALL(semctl);
COND_SYSCALL_COMPAT(semctl);
COND_SYSCALL_COMPAT(old_semctl);
COND_SYSCALL(semtimedop);
COND_SYSCALL(semtimedop_time32);
COND_SYSCALL(semop);
COND_SYSCALL(shmget);
COND_SYSCALL(old_shmctl);
COND_SYSCALL(shmctl);
COND_SYSCALL_COMPAT(shmctl);
COND_SYSCALL_COMPAT(old_shmctl);
COND_SYSCALL(shmat);
COND_SYSCALL_COMPAT(shmat);
COND_SYSCALL(shmdt);
COND_SYSCALL(socket);
COND_SYSCALL(socketpair);
COND_SYSCALL(bind);
COND_SYSCALL(listen);
COND_SYSCALL(accept);
COND_SYSCALL(connect);
COND_SYSCALL(getsockname);
COND_SYSCALL(getpeername);
COND_SYSCALL(setsockopt);
COND_SYSCALL_COMPAT(setsockopt);
COND_SYSCALL(getsockopt);
COND_SYSCALL_COMPAT(getsockopt);
COND_SYSCALL(sendto);
COND_SYSCALL(shutdown);
COND_SYSCALL(recvfrom);
COND_SYSCALL_COMPAT(recvfrom);
COND_SYSCALL(sendmsg);
COND_SYSCALL_COMPAT(sendmsg);
COND_SYSCALL(recvmsg);
COND_SYSCALL_COMPAT(recvmsg);
COND_SYSCALL(mremap);
COND_SYSCALL(add_key);
COND_SYSCALL(request_key);
COND_SYSCALL(keyctl);
COND_SYSCALL_COMPAT(keyctl);
COND_SYSCALL(landlock_create_ruleset);
COND_SYSCALL(landlock_add_rule);
COND_SYSCALL(landlock_restrict_self);
COND_SYSCALL(fadvise64_64);
COND_SYSCALL_COMPAT(fadvise64_64);
/* CONFIG_MMU only */
COND_SYSCALL(swapon);
COND_SYSCALL(swapoff);
COND_SYSCALL(mprotect);
COND_SYSCALL(msync);
COND_SYSCALL(mlock);
COND_SYSCALL(munlock);
COND_SYSCALL(mlockall);
COND_SYSCALL(munlockall);
COND_SYSCALL(mincore);
COND_SYSCALL(madvise);
COND_SYSCALL(process_madvise);
COND_SYSCALL(process_mrelease);
COND_SYSCALL(remap_file_pages);
COND_SYSCALL(mbind);
COND_SYSCALL(get_mempolicy);
COND_SYSCALL(set_mempolicy);
COND_SYSCALL(migrate_pages);
COND_SYSCALL(move_pages);
COND_SYSCALL(set_mempolicy_home_node);
COND_SYSCALL(cachestat);
COND_SYSCALL(perf_event_open);
COND_SYSCALL(accept4);
COND_SYSCALL(recvmmsg);
COND_SYSCALL(recvmmsg_time32);
COND_SYSCALL_COMPAT(recvmmsg_time32);
COND_SYSCALL_COMPAT(recvmmsg_time64);
/*
* Architecture specific syscalls: see further below
*/
/* fanotify */
COND_SYSCALL(fanotify_init);
COND_SYSCALL(fanotify_mark);
/* open by handle */
COND_SYSCALL(name_to_handle_at);
COND_SYSCALL(open_by_handle_at);
COND_SYSCALL_COMPAT(open_by_handle_at);
COND_SYSCALL(sendmmsg);
COND_SYSCALL_COMPAT(sendmmsg);
COND_SYSCALL(process_vm_readv);
COND_SYSCALL_COMPAT(process_vm_readv);
COND_SYSCALL(process_vm_writev);
COND_SYSCALL_COMPAT(process_vm_writev);
/* compare kernel pointers */
COND_SYSCALL(kcmp);
COND_SYSCALL(finit_module);
/* operate on Secure Computing state */
COND_SYSCALL(seccomp);
COND_SYSCALL(memfd_create);
/* access BPF programs and maps */
COND_SYSCALL(bpf);
/* execveat */
COND_SYSCALL(execveat);
COND_SYSCALL(userfaultfd);
/* membarrier */
COND_SYSCALL(membarrier);
COND_SYSCALL(mlock2);
COND_SYSCALL(copy_file_range);
/* memory protection keys */
COND_SYSCALL(pkey_mprotect);
COND_SYSCALL(pkey_alloc);
COND_SYSCALL(pkey_free);
/* memfd_secret */
COND_SYSCALL(memfd_secret);
/*
* Architecture specific weak syscall entries.
*/
/* pciconfig: alpha, arm, arm64, ia64, sparc */
COND_SYSCALL(pciconfig_read);
COND_SYSCALL(pciconfig_write);
COND_SYSCALL(pciconfig_iobase);
/* sys_socketcall: arm, mips, x86, ... */
COND_SYSCALL(socketcall);
COND_SYSCALL_COMPAT(socketcall);
/* compat syscalls for arm64, x86, ... */
COND_SYSCALL_COMPAT(fanotify_mark);
/* x86 */
COND_SYSCALL(vm86old);
COND_SYSCALL(modify_ldt);
COND_SYSCALL(vm86);
COND_SYSCALL(kexec_file_load);
COND_SYSCALL(map_shadow_stack);
/* s390 */
COND_SYSCALL(s390_pci_mmio_read);
COND_SYSCALL(s390_pci_mmio_write);
COND_SYSCALL(s390_ipc);
COND_SYSCALL_COMPAT(s390_ipc);
/* powerpc */
COND_SYSCALL(rtas);
COND_SYSCALL(spu_run);
COND_SYSCALL(spu_create);
COND_SYSCALL(subpage_prot);
/*
* Deprecated system calls which are still defined in
* include/uapi/asm-generic/unistd.h and wanted by >= 1 arch
*/
/* __ARCH_WANT_SYSCALL_NO_FLAGS */
COND_SYSCALL(epoll_create);
COND_SYSCALL(inotify_init);
COND_SYSCALL(eventfd);
COND_SYSCALL(signalfd);
COND_SYSCALL_COMPAT(signalfd);
/* __ARCH_WANT_SYSCALL_OFF_T */
COND_SYSCALL(fadvise64);
/* __ARCH_WANT_SYSCALL_DEPRECATED */
COND_SYSCALL(epoll_wait);
COND_SYSCALL(recv);
COND_SYSCALL_COMPAT(recv);
COND_SYSCALL(send);
COND_SYSCALL(uselib);
/* optional: time32 */
COND_SYSCALL(time32);
COND_SYSCALL(stime32);
COND_SYSCALL(utime32);
COND_SYSCALL(adjtimex_time32);
COND_SYSCALL(sched_rr_get_interval_time32);
COND_SYSCALL(nanosleep_time32);
COND_SYSCALL(rt_sigtimedwait_time32);
COND_SYSCALL_COMPAT(rt_sigtimedwait_time32);
COND_SYSCALL(timer_settime32);
COND_SYSCALL(timer_gettime32);
COND_SYSCALL(clock_settime32);
COND_SYSCALL(clock_gettime32);
COND_SYSCALL(clock_getres_time32);
COND_SYSCALL(clock_nanosleep_time32);
COND_SYSCALL(utimes_time32);
COND_SYSCALL(futimesat_time32);
COND_SYSCALL(pselect6_time32);
COND_SYSCALL_COMPAT(pselect6_time32);
COND_SYSCALL(ppoll_time32);
COND_SYSCALL_COMPAT(ppoll_time32);
COND_SYSCALL(utimensat_time32);
COND_SYSCALL(clock_adjtime32);
/*
* The syscalls below are not found in include/uapi/asm-generic/unistd.h
*/
/* obsolete: SGETMASK_SYSCALL */
COND_SYSCALL(sgetmask);
COND_SYSCALL(ssetmask);
/* obsolete: SYSFS_SYSCALL */
COND_SYSCALL(sysfs);
/* obsolete: __ARCH_WANT_SYS_IPC */
COND_SYSCALL(ipc);
COND_SYSCALL_COMPAT(ipc);
/* obsolete: UID16 */
COND_SYSCALL(chown16);
COND_SYSCALL(fchown16);
COND_SYSCALL(getegid16);
COND_SYSCALL(geteuid16);
COND_SYSCALL(getgid16);
COND_SYSCALL(getgroups16);
COND_SYSCALL(getresgid16);
COND_SYSCALL(getresuid16);
COND_SYSCALL(getuid16);
COND_SYSCALL(lchown16);
COND_SYSCALL(setfsgid16);
COND_SYSCALL(setfsuid16);
COND_SYSCALL(setgid16);
COND_SYSCALL(setgroups16);
COND_SYSCALL(setregid16);
COND_SYSCALL(setresgid16);
COND_SYSCALL(setresuid16);
COND_SYSCALL(setreuid16);
COND_SYSCALL(setuid16);
/* restartable sequence */
COND_SYSCALL(rseq);
| linux-master | kernel/sys_ni.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/kernel.h>
#include <linux/nmi.h>
#include <linux/percpu-defs.h>
static cpumask_t __read_mostly watchdog_cpus;
static unsigned int watchdog_next_cpu(unsigned int cpu)
{
unsigned int next_cpu;
next_cpu = cpumask_next(cpu, &watchdog_cpus);
if (next_cpu >= nr_cpu_ids)
next_cpu = cpumask_first(&watchdog_cpus);
if (next_cpu == cpu)
return nr_cpu_ids;
return next_cpu;
}
int __init watchdog_hardlockup_probe(void)
{
return 0;
}
void watchdog_hardlockup_enable(unsigned int cpu)
{
unsigned int next_cpu;
/*
* The new CPU will be marked online before the hrtimer interrupt
* gets a chance to run on it. If another CPU tests for a
* hardlockup on the new CPU before it has run its the hrtimer
* interrupt, it will get a false positive. Touch the watchdog on
* the new CPU to delay the check for at least 3 sampling periods
* to guarantee one hrtimer has run on the new CPU.
*/
watchdog_hardlockup_touch_cpu(cpu);
/*
* We are going to check the next CPU. Our watchdog_hrtimer
* need not be zero if the CPU has already been online earlier.
* Touch the watchdog on the next CPU to avoid false positive
* if we try to check it in less then 3 interrupts.
*/
next_cpu = watchdog_next_cpu(cpu);
if (next_cpu < nr_cpu_ids)
watchdog_hardlockup_touch_cpu(next_cpu);
/*
* Makes sure that watchdog is touched on this CPU before
* other CPUs could see it in watchdog_cpus. The counter
* part is in watchdog_buddy_check_hardlockup().
*/
smp_wmb();
cpumask_set_cpu(cpu, &watchdog_cpus);
}
void watchdog_hardlockup_disable(unsigned int cpu)
{
unsigned int next_cpu = watchdog_next_cpu(cpu);
/*
* Offlining this CPU will cause the CPU before this one to start
* checking the one after this one. If this CPU just finished checking
* the next CPU and updating hrtimer_interrupts_saved, and then the
* previous CPU checks it within one sample period, it will trigger a
* false positive. Touch the watchdog on the next CPU to prevent it.
*/
if (next_cpu < nr_cpu_ids)
watchdog_hardlockup_touch_cpu(next_cpu);
/*
* Makes sure that watchdog is touched on the next CPU before
* this CPU disappear in watchdog_cpus. The counter part is in
* watchdog_buddy_check_hardlockup().
*/
smp_wmb();
cpumask_clear_cpu(cpu, &watchdog_cpus);
}
void watchdog_buddy_check_hardlockup(int hrtimer_interrupts)
{
unsigned int next_cpu;
/*
* Test for hardlockups every 3 samples. The sample period is
* watchdog_thresh * 2 / 5, so 3 samples gets us back to slightly over
* watchdog_thresh (over by 20%).
*/
if (hrtimer_interrupts % 3 != 0)
return;
/* check for a hardlockup on the next CPU */
next_cpu = watchdog_next_cpu(smp_processor_id());
if (next_cpu >= nr_cpu_ids)
return;
/*
* Make sure that the watchdog was touched on next CPU when
* watchdog_next_cpu() returned another one because of
* a change in watchdog_hardlockup_enable()/disable().
*/
smp_rmb();
watchdog_hardlockup_check(next_cpu, NULL);
}
| linux-master | kernel/watchdog_buddy.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* Helpers for initial module or kernel cmdline parsing
Copyright (C) 2001 Rusty Russell.
*/
#include <linux/kernel.h>
#include <linux/kstrtox.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/security.h>
#ifdef CONFIG_SYSFS
/* Protects all built-in parameters, modules use their own param_lock */
static DEFINE_MUTEX(param_lock);
/* Use the module's mutex, or if built-in use the built-in mutex */
#ifdef CONFIG_MODULES
#define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : ¶m_lock)
#else
#define KPARAM_MUTEX(mod) (¶m_lock)
#endif
static inline void check_kparam_locked(struct module *mod)
{
BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
}
#else
static inline void check_kparam_locked(struct module *mod)
{
}
#endif /* !CONFIG_SYSFS */
/* This just allows us to keep track of which parameters are kmalloced. */
struct kmalloced_param {
struct list_head list;
char val[];
};
static LIST_HEAD(kmalloced_params);
static DEFINE_SPINLOCK(kmalloced_params_lock);
static void *kmalloc_parameter(unsigned int size)
{
struct kmalloced_param *p;
p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
if (!p)
return NULL;
spin_lock(&kmalloced_params_lock);
list_add(&p->list, &kmalloced_params);
spin_unlock(&kmalloced_params_lock);
return p->val;
}
/* Does nothing if parameter wasn't kmalloced above. */
static void maybe_kfree_parameter(void *param)
{
struct kmalloced_param *p;
spin_lock(&kmalloced_params_lock);
list_for_each_entry(p, &kmalloced_params, list) {
if (p->val == param) {
list_del(&p->list);
kfree(p);
break;
}
}
spin_unlock(&kmalloced_params_lock);
}
static char dash2underscore(char c)
{
if (c == '-')
return '_';
return c;
}
bool parameqn(const char *a, const char *b, size_t n)
{
size_t i;
for (i = 0; i < n; i++) {
if (dash2underscore(a[i]) != dash2underscore(b[i]))
return false;
}
return true;
}
bool parameq(const char *a, const char *b)
{
return parameqn(a, b, strlen(a)+1);
}
static bool param_check_unsafe(const struct kernel_param *kp)
{
if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
return false;
if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
pr_notice("Setting dangerous option %s - tainting kernel\n",
kp->name);
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
}
return true;
}
static int parse_one(char *param,
char *val,
const char *doing,
const struct kernel_param *params,
unsigned num_params,
s16 min_level,
s16 max_level,
void *arg,
int (*handle_unknown)(char *param, char *val,
const char *doing, void *arg))
{
unsigned int i;
int err;
/* Find parameter */
for (i = 0; i < num_params; i++) {
if (parameq(param, params[i].name)) {
if (params[i].level < min_level
|| params[i].level > max_level)
return 0;
/* No one handled NULL, so do it here. */
if (!val &&
!(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
return -EINVAL;
pr_debug("handling %s with %p\n", param,
params[i].ops->set);
kernel_param_lock(params[i].mod);
if (param_check_unsafe(¶ms[i]))
err = params[i].ops->set(val, ¶ms[i]);
else
err = -EPERM;
kernel_param_unlock(params[i].mod);
return err;
}
}
if (handle_unknown) {
pr_debug("doing %s: %s='%s'\n", doing, param, val);
return handle_unknown(param, val, doing, arg);
}
pr_debug("Unknown argument '%s'\n", param);
return -ENOENT;
}
/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
char *parse_args(const char *doing,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
void *arg,
int (*unknown)(char *param, char *val,
const char *doing, void *arg))
{
char *param, *val, *err = NULL;
/* Chew leading spaces */
args = skip_spaces(args);
if (*args)
pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
while (*args) {
int ret;
int irq_was_disabled;
args = next_arg(args, ¶m, &val);
/* Stop at -- */
if (!val && strcmp(param, "--") == 0)
return err ?: args;
irq_was_disabled = irqs_disabled();
ret = parse_one(param, val, doing, params, num,
min_level, max_level, arg, unknown);
if (irq_was_disabled && !irqs_disabled())
pr_warn("%s: option '%s' enabled irq's!\n",
doing, param);
switch (ret) {
case 0:
continue;
case -ENOENT:
pr_err("%s: Unknown parameter `%s'\n", doing, param);
break;
case -ENOSPC:
pr_err("%s: `%s' too large for parameter `%s'\n",
doing, val ?: "", param);
break;
default:
pr_err("%s: `%s' invalid for parameter `%s'\n",
doing, val ?: "", param);
break;
}
err = ERR_PTR(ret);
}
return err;
}
/* Lazy bastard, eh? */
#define STANDARD_PARAM_DEF(name, type, format, strtolfn) \
int param_set_##name(const char *val, const struct kernel_param *kp) \
{ \
return strtolfn(val, 0, (type *)kp->arg); \
} \
int param_get_##name(char *buffer, const struct kernel_param *kp) \
{ \
return scnprintf(buffer, PAGE_SIZE, format "\n", \
*((type *)kp->arg)); \
} \
const struct kernel_param_ops param_ops_##name = { \
.set = param_set_##name, \
.get = param_get_##name, \
}; \
EXPORT_SYMBOL(param_set_##name); \
EXPORT_SYMBOL(param_get_##name); \
EXPORT_SYMBOL(param_ops_##name)
STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
STANDARD_PARAM_DEF(hexint, unsigned int, "%#08x", kstrtouint);
int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
unsigned int min, unsigned int max)
{
unsigned int num;
int ret;
if (!val)
return -EINVAL;
ret = kstrtouint(val, 0, &num);
if (ret)
return ret;
if (num < min || num > max)
return -EINVAL;
*((unsigned int *)kp->arg) = num;
return 0;
}
EXPORT_SYMBOL_GPL(param_set_uint_minmax);
int param_set_charp(const char *val, const struct kernel_param *kp)
{
if (strlen(val) > 1024) {
pr_err("%s: string parameter too long\n", kp->name);
return -ENOSPC;
}
maybe_kfree_parameter(*(char **)kp->arg);
/* This is a hack. We can't kmalloc in early boot, and we
* don't need to; this mangled commandline is preserved. */
if (slab_is_available()) {
*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
if (!*(char **)kp->arg)
return -ENOMEM;
strcpy(*(char **)kp->arg, val);
} else
*(const char **)kp->arg = val;
return 0;
}
EXPORT_SYMBOL(param_set_charp);
int param_get_charp(char *buffer, const struct kernel_param *kp)
{
return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
}
EXPORT_SYMBOL(param_get_charp);
void param_free_charp(void *arg)
{
maybe_kfree_parameter(*((char **)arg));
}
EXPORT_SYMBOL(param_free_charp);
const struct kernel_param_ops param_ops_charp = {
.set = param_set_charp,
.get = param_get_charp,
.free = param_free_charp,
};
EXPORT_SYMBOL(param_ops_charp);
/* Actually could be a bool or an int, for historical reasons. */
int param_set_bool(const char *val, const struct kernel_param *kp)
{
/* No equals means "set"... */
if (!val) val = "1";
/* One of =[yYnN01] */
return kstrtobool(val, kp->arg);
}
EXPORT_SYMBOL(param_set_bool);
int param_get_bool(char *buffer, const struct kernel_param *kp)
{
/* Y and N chosen as being relatively non-coder friendly */
return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
}
EXPORT_SYMBOL(param_get_bool);
const struct kernel_param_ops param_ops_bool = {
.flags = KERNEL_PARAM_OPS_FL_NOARG,
.set = param_set_bool,
.get = param_get_bool,
};
EXPORT_SYMBOL(param_ops_bool);
int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
{
int err;
bool new_value;
bool orig_value = *(bool *)kp->arg;
struct kernel_param dummy_kp = *kp;
dummy_kp.arg = &new_value;
err = param_set_bool(val, &dummy_kp);
if (err)
return err;
/* Don't let them unset it once it's set! */
if (!new_value && orig_value)
return -EROFS;
if (new_value)
err = param_set_bool(val, kp);
return err;
}
EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
const struct kernel_param_ops param_ops_bool_enable_only = {
.flags = KERNEL_PARAM_OPS_FL_NOARG,
.set = param_set_bool_enable_only,
.get = param_get_bool,
};
EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
/* This one must be bool. */
int param_set_invbool(const char *val, const struct kernel_param *kp)
{
int ret;
bool boolval;
struct kernel_param dummy;
dummy.arg = &boolval;
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(bool *)kp->arg = !boolval;
return ret;
}
EXPORT_SYMBOL(param_set_invbool);
int param_get_invbool(char *buffer, const struct kernel_param *kp)
{
return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
}
EXPORT_SYMBOL(param_get_invbool);
const struct kernel_param_ops param_ops_invbool = {
.set = param_set_invbool,
.get = param_get_invbool,
};
EXPORT_SYMBOL(param_ops_invbool);
int param_set_bint(const char *val, const struct kernel_param *kp)
{
/* Match bool exactly, by re-using it. */
struct kernel_param boolkp = *kp;
bool v;
int ret;
boolkp.arg = &v;
ret = param_set_bool(val, &boolkp);
if (ret == 0)
*(int *)kp->arg = v;
return ret;
}
EXPORT_SYMBOL(param_set_bint);
const struct kernel_param_ops param_ops_bint = {
.flags = KERNEL_PARAM_OPS_FL_NOARG,
.set = param_set_bint,
.get = param_get_int,
};
EXPORT_SYMBOL(param_ops_bint);
/* We break the rule and mangle the string. */
static int param_array(struct module *mod,
const char *name,
const char *val,
unsigned int min, unsigned int max,
void *elem, int elemsize,
int (*set)(const char *, const struct kernel_param *kp),
s16 level,
unsigned int *num)
{
int ret;
struct kernel_param kp;
char save;
/* Get the name right for errors. */
kp.name = name;
kp.arg = elem;
kp.level = level;
*num = 0;
/* We expect a comma-separated list of values. */
do {
int len;
if (*num == max) {
pr_err("%s: can only take %i arguments\n", name, max);
return -EINVAL;
}
len = strcspn(val, ",");
/* nul-terminate and parse */
save = val[len];
((char *)val)[len] = '\0';
check_kparam_locked(mod);
ret = set(val, &kp);
if (ret != 0)
return ret;
kp.arg += elemsize;
val += len+1;
(*num)++;
} while (save == ',');
if (*num < min) {
pr_err("%s: needs at least %i arguments\n", name, min);
return -EINVAL;
}
return 0;
}
static int param_array_set(const char *val, const struct kernel_param *kp)
{
const struct kparam_array *arr = kp->arr;
unsigned int temp_num;
return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
arr->elemsize, arr->ops->set, kp->level,
arr->num ?: &temp_num);
}
static int param_array_get(char *buffer, const struct kernel_param *kp)
{
int i, off, ret;
const struct kparam_array *arr = kp->arr;
struct kernel_param p = *kp;
for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
/* Replace \n with comma */
if (i)
buffer[off - 1] = ',';
p.arg = arr->elem + arr->elemsize * i;
check_kparam_locked(p.mod);
ret = arr->ops->get(buffer + off, &p);
if (ret < 0)
return ret;
off += ret;
}
buffer[off] = '\0';
return off;
}
static void param_array_free(void *arg)
{
unsigned int i;
const struct kparam_array *arr = arg;
if (arr->ops->free)
for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
arr->ops->free(arr->elem + arr->elemsize * i);
}
const struct kernel_param_ops param_array_ops = {
.set = param_array_set,
.get = param_array_get,
.free = param_array_free,
};
EXPORT_SYMBOL(param_array_ops);
int param_set_copystring(const char *val, const struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
if (strlen(val)+1 > kps->maxlen) {
pr_err("%s: string doesn't fit in %u chars.\n",
kp->name, kps->maxlen-1);
return -ENOSPC;
}
strcpy(kps->string, val);
return 0;
}
EXPORT_SYMBOL(param_set_copystring);
int param_get_string(char *buffer, const struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
}
EXPORT_SYMBOL(param_get_string);
const struct kernel_param_ops param_ops_string = {
.set = param_set_copystring,
.get = param_get_string,
};
EXPORT_SYMBOL(param_ops_string);
/* sysfs output in /sys/modules/XYZ/parameters/ */
#define to_module_attr(n) container_of(n, struct module_attribute, attr)
#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
struct param_attribute
{
struct module_attribute mattr;
const struct kernel_param *param;
};
struct module_param_attrs
{
unsigned int num;
struct attribute_group grp;
struct param_attribute attrs[];
};
#ifdef CONFIG_SYSFS
#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
static ssize_t param_attr_show(struct module_attribute *mattr,
struct module_kobject *mk, char *buf)
{
int count;
struct param_attribute *attribute = to_param_attr(mattr);
if (!attribute->param->ops->get)
return -EPERM;
kernel_param_lock(mk->mod);
count = attribute->param->ops->get(buf, attribute->param);
kernel_param_unlock(mk->mod);
return count;
}
/* sysfs always hands a nul-terminated string in buf. We rely on that. */
static ssize_t param_attr_store(struct module_attribute *mattr,
struct module_kobject *mk,
const char *buf, size_t len)
{
int err;
struct param_attribute *attribute = to_param_attr(mattr);
if (!attribute->param->ops->set)
return -EPERM;
kernel_param_lock(mk->mod);
if (param_check_unsafe(attribute->param))
err = attribute->param->ops->set(buf, attribute->param);
else
err = -EPERM;
kernel_param_unlock(mk->mod);
if (!err)
return len;
return err;
}
#endif
#ifdef CONFIG_MODULES
#define __modinit
#else
#define __modinit __init
#endif
#ifdef CONFIG_SYSFS
void kernel_param_lock(struct module *mod)
{
mutex_lock(KPARAM_MUTEX(mod));
}
void kernel_param_unlock(struct module *mod)
{
mutex_unlock(KPARAM_MUTEX(mod));
}
EXPORT_SYMBOL(kernel_param_lock);
EXPORT_SYMBOL(kernel_param_unlock);
/*
* add_sysfs_param - add a parameter to sysfs
* @mk: struct module_kobject
* @kp: the actual parameter definition to add to sysfs
* @name: name of parameter
*
* Create a kobject if for a (per-module) parameter if mp NULL, and
* create file in sysfs. Returns an error on out of memory. Always cleans up
* if there's an error.
*/
static __modinit int add_sysfs_param(struct module_kobject *mk,
const struct kernel_param *kp,
const char *name)
{
struct module_param_attrs *new_mp;
struct attribute **new_attrs;
unsigned int i;
/* We don't bother calling this with invisible parameters. */
BUG_ON(!kp->perm);
if (!mk->mp) {
/* First allocation. */
mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
if (!mk->mp)
return -ENOMEM;
mk->mp->grp.name = "parameters";
/* NULL-terminated attribute array. */
mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
GFP_KERNEL);
/* Caller will cleanup via free_module_param_attrs */
if (!mk->mp->grp.attrs)
return -ENOMEM;
}
/* Enlarge allocations. */
new_mp = krealloc(mk->mp,
sizeof(*mk->mp) +
sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
GFP_KERNEL);
if (!new_mp)
return -ENOMEM;
mk->mp = new_mp;
/* Extra pointer for NULL terminator */
new_attrs = krealloc(mk->mp->grp.attrs,
sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
GFP_KERNEL);
if (!new_attrs)
return -ENOMEM;
mk->mp->grp.attrs = new_attrs;
/* Tack new one on the end. */
memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
mk->mp->attrs[mk->mp->num].param = kp;
mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
/* Do not allow runtime DAC changes to make param writable. */
if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
else
mk->mp->attrs[mk->mp->num].mattr.store = NULL;
mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
mk->mp->num++;
/* Fix up all the pointers, since krealloc can move us */
for (i = 0; i < mk->mp->num; i++)
mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
mk->mp->grp.attrs[mk->mp->num] = NULL;
return 0;
}
#ifdef CONFIG_MODULES
static void free_module_param_attrs(struct module_kobject *mk)
{
if (mk->mp)
kfree(mk->mp->grp.attrs);
kfree(mk->mp);
mk->mp = NULL;
}
/*
* module_param_sysfs_setup - setup sysfs support for one module
* @mod: module
* @kparam: module parameters (array)
* @num_params: number of module parameters
*
* Adds sysfs entries for module parameters under
* /sys/module/[mod->name]/parameters/
*/
int module_param_sysfs_setup(struct module *mod,
const struct kernel_param *kparam,
unsigned int num_params)
{
int i, err;
bool params = false;
for (i = 0; i < num_params; i++) {
if (kparam[i].perm == 0)
continue;
err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
if (err) {
free_module_param_attrs(&mod->mkobj);
return err;
}
params = true;
}
if (!params)
return 0;
/* Create the param group. */
err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
if (err)
free_module_param_attrs(&mod->mkobj);
return err;
}
/*
* module_param_sysfs_remove - remove sysfs support for one module
* @mod: module
*
* Remove sysfs entries for module parameters and the corresponding
* kobject.
*/
void module_param_sysfs_remove(struct module *mod)
{
if (mod->mkobj.mp) {
sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
/* We are positive that no one is using any param
* attrs at this point. Deallocate immediately. */
free_module_param_attrs(&mod->mkobj);
}
}
#endif
void destroy_params(const struct kernel_param *params, unsigned num)
{
unsigned int i;
for (i = 0; i < num; i++)
if (params[i].ops->free)
params[i].ops->free(params[i].arg);
}
static struct module_kobject * __init locate_module_kobject(const char *name)
{
struct module_kobject *mk;
struct kobject *kobj;
int err;
kobj = kset_find_obj(module_kset, name);
if (kobj) {
mk = to_module_kobject(kobj);
} else {
mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
BUG_ON(!mk);
mk->mod = THIS_MODULE;
mk->kobj.kset = module_kset;
err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
"%s", name);
#ifdef CONFIG_MODULES
if (!err)
err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
#endif
if (err) {
kobject_put(&mk->kobj);
pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
name, err);
return NULL;
}
/* So that we hold reference in both cases. */
kobject_get(&mk->kobj);
}
return mk;
}
static void __init kernel_add_sysfs_param(const char *name,
const struct kernel_param *kparam,
unsigned int name_skip)
{
struct module_kobject *mk;
int err;
mk = locate_module_kobject(name);
if (!mk)
return;
/* We need to remove old parameters before adding more. */
if (mk->mp)
sysfs_remove_group(&mk->kobj, &mk->mp->grp);
/* These should not fail at boot. */
err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
BUG_ON(err);
err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
BUG_ON(err);
kobject_uevent(&mk->kobj, KOBJ_ADD);
kobject_put(&mk->kobj);
}
/*
* param_sysfs_builtin - add sysfs parameters for built-in modules
*
* Add module_parameters to sysfs for "modules" built into the kernel.
*
* The "module" name (KBUILD_MODNAME) is stored before a dot, the
* "parameter" name is stored behind a dot in kernel_param->name. So,
* extract the "module" name for all built-in kernel_param-eters,
* and for all who have the same, call kernel_add_sysfs_param.
*/
static void __init param_sysfs_builtin(void)
{
const struct kernel_param *kp;
unsigned int name_len;
char modname[MODULE_NAME_LEN];
for (kp = __start___param; kp < __stop___param; kp++) {
char *dot;
if (kp->perm == 0)
continue;
dot = strchr(kp->name, '.');
if (!dot) {
/* This happens for core_param() */
strcpy(modname, "kernel");
name_len = 0;
} else {
name_len = dot - kp->name + 1;
strscpy(modname, kp->name, name_len);
}
kernel_add_sysfs_param(modname, kp, name_len);
}
}
ssize_t __modver_version_show(struct module_attribute *mattr,
struct module_kobject *mk, char *buf)
{
struct module_version_attribute *vattr =
container_of(mattr, struct module_version_attribute, mattr);
return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
}
extern const struct module_version_attribute __start___modver[];
extern const struct module_version_attribute __stop___modver[];
static void __init version_sysfs_builtin(void)
{
const struct module_version_attribute *vattr;
struct module_kobject *mk;
int err;
for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
mk = locate_module_kobject(vattr->module_name);
if (mk) {
err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
WARN_ON_ONCE(err);
kobject_uevent(&mk->kobj, KOBJ_ADD);
kobject_put(&mk->kobj);
}
}
}
/* module-related sysfs stuff */
static ssize_t module_attr_show(struct kobject *kobj,
struct attribute *attr,
char *buf)
{
struct module_attribute *attribute;
struct module_kobject *mk;
int ret;
attribute = to_module_attr(attr);
mk = to_module_kobject(kobj);
if (!attribute->show)
return -EIO;
ret = attribute->show(attribute, mk, buf);
return ret;
}
static ssize_t module_attr_store(struct kobject *kobj,
struct attribute *attr,
const char *buf, size_t len)
{
struct module_attribute *attribute;
struct module_kobject *mk;
int ret;
attribute = to_module_attr(attr);
mk = to_module_kobject(kobj);
if (!attribute->store)
return -EIO;
ret = attribute->store(attribute, mk, buf, len);
return ret;
}
static const struct sysfs_ops module_sysfs_ops = {
.show = module_attr_show,
.store = module_attr_store,
};
static int uevent_filter(const struct kobject *kobj)
{
const struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &module_ktype)
return 1;
return 0;
}
static const struct kset_uevent_ops module_uevent_ops = {
.filter = uevent_filter,
};
struct kset *module_kset;
static void module_kobj_release(struct kobject *kobj)
{
struct module_kobject *mk = to_module_kobject(kobj);
complete(mk->kobj_completion);
}
const struct kobj_type module_ktype = {
.release = module_kobj_release,
.sysfs_ops = &module_sysfs_ops,
};
/*
* param_sysfs_init - create "module" kset
*
* This must be done before the initramfs is unpacked and
* request_module() thus becomes possible, because otherwise the
* module load would fail in mod_sysfs_init.
*/
static int __init param_sysfs_init(void)
{
module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
if (!module_kset) {
printk(KERN_WARNING "%s (%d): error creating kset\n",
__FILE__, __LINE__);
return -ENOMEM;
}
return 0;
}
subsys_initcall(param_sysfs_init);
/*
* param_sysfs_builtin_init - add sysfs version and parameter
* attributes for built-in modules
*/
static int __init param_sysfs_builtin_init(void)
{
if (!module_kset)
return -ENOMEM;
version_sysfs_builtin();
param_sysfs_builtin();
return 0;
}
late_initcall(param_sysfs_builtin_init);
#endif /* CONFIG_SYSFS */
| linux-master | kernel/params.c |
// SPDX-License-Identifier: GPL-2.0
/*
* KUnit test of proc sysctl.
*/
#include <kunit/test.h>
#include <linux/sysctl.h>
#define KUNIT_PROC_READ 0
#define KUNIT_PROC_WRITE 1
/*
* Test that proc_dointvec will not try to use a NULL .data field even when the
* length is non-zero.
*/
static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
{
struct ctl_table null_data_table = {
.procname = "foo",
/*
* Here we are testing that proc_dointvec behaves correctly when
* we give it a NULL .data field. Normally this would point to a
* piece of memory where the value would be stored.
*/
.data = NULL,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
/*
* proc_dointvec expects a buffer in user space, so we allocate one. We
* also need to cast it to __user so sparse doesn't get mad.
*/
void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
GFP_USER);
size_t len;
loff_t pos;
/*
* We don't care what the starting length is since proc_dointvec should
* not try to read because .data is NULL.
*/
len = 1234;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
KUNIT_PROC_READ, buffer, &len,
&pos));
KUNIT_EXPECT_EQ(test, 0, len);
/*
* See above.
*/
len = 1234;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
KUNIT_PROC_WRITE, buffer, &len,
&pos));
KUNIT_EXPECT_EQ(test, 0, len);
}
/*
* Similar to the previous test, we create a struct ctrl_table that has a .data
* field that proc_dointvec cannot do anything with; however, this time it is
* because we tell proc_dointvec that the size is 0.
*/
static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
{
int data = 0;
struct ctl_table data_maxlen_unset_table = {
.procname = "foo",
.data = &data,
/*
* So .data is no longer NULL, but we tell proc_dointvec its
* length is 0, so it still shouldn't try to use it.
*/
.maxlen = 0,
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
GFP_USER);
size_t len;
loff_t pos;
/*
* As before, we don't care what buffer length is because proc_dointvec
* cannot do anything because its internal .data buffer has zero length.
*/
len = 1234;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
KUNIT_PROC_READ, buffer, &len,
&pos));
KUNIT_EXPECT_EQ(test, 0, len);
/*
* See previous comment.
*/
len = 1234;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
KUNIT_PROC_WRITE, buffer, &len,
&pos));
KUNIT_EXPECT_EQ(test, 0, len);
}
/*
* Here we provide a valid struct ctl_table, but we try to read and write from
* it using a buffer of zero length, so it should still fail in a similar way as
* before.
*/
static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
{
int data = 0;
/* Good table. */
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
GFP_USER);
/*
* However, now our read/write buffer has zero length.
*/
size_t len = 0;
loff_t pos;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
&len, &pos));
KUNIT_EXPECT_EQ(test, 0, len);
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
&len, &pos));
KUNIT_EXPECT_EQ(test, 0, len);
}
/*
* Test that proc_dointvec refuses to read when the file position is non-zero.
*/
static void sysctl_test_api_dointvec_table_read_but_position_set(
struct kunit *test)
{
int data = 0;
/* Good table. */
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
GFP_USER);
/*
* We don't care about our buffer length because we start off with a
* non-zero file position.
*/
size_t len = 1234;
/*
* proc_dointvec should refuse to read into the buffer since the file
* pos is non-zero.
*/
loff_t pos = 1;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
&len, &pos));
KUNIT_EXPECT_EQ(test, 0, len);
}
/*
* Test that we can read a two digit number in a sufficiently size buffer.
* Nothing fancy.
*/
static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
{
int data = 0;
/* Good table. */
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
size_t len = 4;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
/* Store 13 in the data field. */
*((int *)table.data) = 13;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
user_buffer, &len, &pos));
KUNIT_ASSERT_EQ(test, 3, len);
buffer[len] = '\0';
/* And we read 13 back out. */
KUNIT_EXPECT_STREQ(test, "13\n", buffer);
}
/*
* Same as previous test, just now with negative numbers.
*/
static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
{
int data = 0;
/* Good table. */
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
size_t len = 5;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
*((int *)table.data) = -16;
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
user_buffer, &len, &pos));
KUNIT_ASSERT_EQ(test, 4, len);
buffer[len] = '\0';
KUNIT_EXPECT_STREQ(test, "-16\n", buffer);
}
/*
* Test that a simple positive write works.
*/
static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
{
int data = 0;
/* Good table. */
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
char input[] = "9";
size_t len = sizeof(input) - 1;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
memcpy(buffer, input, len);
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
user_buffer, &len, &pos));
KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
}
/*
* Same as previous test, but now with negative numbers.
*/
static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
{
int data = 0;
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
char input[] = "-9";
size_t len = sizeof(input) - 1;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
memcpy(buffer, input, len);
KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
user_buffer, &len, &pos));
KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
}
/*
* Test that writing a value smaller than the minimum possible value is not
* allowed.
*/
static void sysctl_test_api_dointvec_write_single_less_int_min(
struct kunit *test)
{
int data = 0;
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
size_t max_len = 32, len = max_len;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
- (INT_MAX + INT_MIN) + 1;
/*
* We use this rigmarole to create a string that contains a value one
* less than the minimum accepted value.
*/
KUNIT_ASSERT_LT(test,
(size_t)snprintf(buffer, max_len, "-%lu",
abs_of_less_than_min),
max_len);
KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
user_buffer, &len, &pos));
KUNIT_EXPECT_EQ(test, max_len, len);
KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
}
/*
* Test that writing the maximum possible value works.
*/
static void sysctl_test_api_dointvec_write_single_greater_int_max(
struct kunit *test)
{
int data = 0;
struct ctl_table table = {
.procname = "foo",
.data = &data,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE_HUNDRED,
};
size_t max_len = 32, len = max_len;
loff_t pos = 0;
char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
char __user *user_buffer = (char __user *)buffer;
unsigned long greater_than_max = (unsigned long)INT_MAX + 1;
KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
greater_than_max),
max_len);
KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
user_buffer, &len, &pos));
KUNIT_ASSERT_EQ(test, max_len, len);
KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
}
static struct kunit_case sysctl_test_cases[] = {
KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
{}
};
static struct kunit_suite sysctl_test_suite = {
.name = "sysctl_test",
.test_cases = sysctl_test_cases,
};
kunit_test_suites(&sysctl_test_suite);
MODULE_LICENSE("GPL v2");
| linux-master | kernel/sysctl-test.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
*
* 2003-06-02 Jim Houston - Concurrent Computer Corp.
* Changes to use preallocated sigqueue structures
* to allow signals to be sent reliably.
*/
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/sched/mm.h>
#include <linux/sched/user.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/cputime.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/coredump.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/signalfd.h>
#include <linux/ratelimit.h>
#include <linux/task_work.h>
#include <linux/capability.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <linux/nsproxy.h>
#include <linux/user_namespace.h>
#include <linux/uprobes.h>
#include <linux/compat.h>
#include <linux/cn_proc.h>
#include <linux/compiler.h>
#include <linux/posix-timers.h>
#include <linux/cgroup.h>
#include <linux/audit.h>
#include <linux/sysctl.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
#include <asm/param.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/siginfo.h>
#include <asm/cacheflush.h>
#include <asm/syscall.h> /* for syscall_get_* */
/*
* SLAB caches for signal bits.
*/
static struct kmem_cache *sigqueue_cachep;
int print_fatal_signals __read_mostly;
static void __user *sig_handler(struct task_struct *t, int sig)
{
return t->sighand->action[sig - 1].sa.sa_handler;
}
static inline bool sig_handler_ignored(void __user *handler, int sig)
{
/* Is it explicitly or implicitly ignored? */
return handler == SIG_IGN ||
(handler == SIG_DFL && sig_kernel_ignore(sig));
}
static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
{
void __user *handler;
handler = sig_handler(t, sig);
/* SIGKILL and SIGSTOP may not be sent to the global init */
if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
return true;
if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
handler == SIG_DFL && !(force && sig_kernel_only(sig)))
return true;
/* Only allow kernel generated signals to this kthread */
if (unlikely((t->flags & PF_KTHREAD) &&
(handler == SIG_KTHREAD_KERNEL) && !force))
return true;
return sig_handler_ignored(handler, sig);
}
static bool sig_ignored(struct task_struct *t, int sig, bool force)
{
/*
* Blocked signals are never ignored, since the
* signal handler may change by the time it is
* unblocked.
*/
if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
return false;
/*
* Tracers may want to know about even ignored signal unless it
* is SIGKILL which can't be reported anyway but can be ignored
* by SIGNAL_UNKILLABLE task.
*/
if (t->ptrace && sig != SIGKILL)
return false;
return sig_task_ignored(t, sig, force);
}
/*
* Re-calculate pending state from the set of locally pending
* signals, globally pending signals, and blocked signals.
*/
static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
{
unsigned long ready;
long i;
switch (_NSIG_WORDS) {
default:
for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
ready |= signal->sig[i] &~ blocked->sig[i];
break;
case 4: ready = signal->sig[3] &~ blocked->sig[3];
ready |= signal->sig[2] &~ blocked->sig[2];
ready |= signal->sig[1] &~ blocked->sig[1];
ready |= signal->sig[0] &~ blocked->sig[0];
break;
case 2: ready = signal->sig[1] &~ blocked->sig[1];
ready |= signal->sig[0] &~ blocked->sig[0];
break;
case 1: ready = signal->sig[0] &~ blocked->sig[0];
}
return ready != 0;
}
#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
static bool recalc_sigpending_tsk(struct task_struct *t)
{
if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
PENDING(&t->pending, &t->blocked) ||
PENDING(&t->signal->shared_pending, &t->blocked) ||
cgroup_task_frozen(t)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
return true;
}
/*
* We must never clear the flag in another thread, or in current
* when it's possible the current syscall is returning -ERESTART*.
* So we don't clear it here, and only callers who know they should do.
*/
return false;
}
/*
* After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
* This is superfluous when called on current, the wakeup is a harmless no-op.
*/
void recalc_sigpending_and_wake(struct task_struct *t)
{
if (recalc_sigpending_tsk(t))
signal_wake_up(t, 0);
}
void recalc_sigpending(void)
{
if (!recalc_sigpending_tsk(current) && !freezing(current))
clear_thread_flag(TIF_SIGPENDING);
}
EXPORT_SYMBOL(recalc_sigpending);
void calculate_sigpending(void)
{
/* Have any signals or users of TIF_SIGPENDING been delayed
* until after fork?
*/
spin_lock_irq(¤t->sighand->siglock);
set_tsk_thread_flag(current, TIF_SIGPENDING);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
}
/* Given the mask, find the first available signal that should be serviced. */
#define SYNCHRONOUS_MASK \
(sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
int next_signal(struct sigpending *pending, sigset_t *mask)
{
unsigned long i, *s, *m, x;
int sig = 0;
s = pending->signal.sig;
m = mask->sig;
/*
* Handle the first word specially: it contains the
* synchronous signals that need to be dequeued first.
*/
x = *s &~ *m;
if (x) {
if (x & SYNCHRONOUS_MASK)
x &= SYNCHRONOUS_MASK;
sig = ffz(~x) + 1;
return sig;
}
switch (_NSIG_WORDS) {
default:
for (i = 1; i < _NSIG_WORDS; ++i) {
x = *++s &~ *++m;
if (!x)
continue;
sig = ffz(~x) + i*_NSIG_BPW + 1;
break;
}
break;
case 2:
x = s[1] &~ m[1];
if (!x)
break;
sig = ffz(~x) + _NSIG_BPW + 1;
break;
case 1:
/* Nothing to do */
break;
}
return sig;
}
static inline void print_dropped_signal(int sig)
{
static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
if (!print_fatal_signals)
return;
if (!__ratelimit(&ratelimit_state))
return;
pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
current->comm, current->pid, sig);
}
/**
* task_set_jobctl_pending - set jobctl pending bits
* @task: target task
* @mask: pending bits to set
*
* Clear @mask from @task->jobctl. @mask must be subset of
* %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
* %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
* cleared. If @task is already being killed or exiting, this function
* becomes noop.
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*
* RETURNS:
* %true if @mask is set, %false if made noop because @task was dying.
*/
bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
{
BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
return false;
if (mask & JOBCTL_STOP_SIGMASK)
task->jobctl &= ~JOBCTL_STOP_SIGMASK;
task->jobctl |= mask;
return true;
}
/**
* task_clear_jobctl_trapping - clear jobctl trapping bit
* @task: target task
*
* If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
* Clear it and wake up the ptracer. Note that we don't need any further
* locking. @task->siglock guarantees that @task->parent points to the
* ptracer.
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*/
void task_clear_jobctl_trapping(struct task_struct *task)
{
if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
task->jobctl &= ~JOBCTL_TRAPPING;
smp_mb(); /* advised by wake_up_bit() */
wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
}
}
/**
* task_clear_jobctl_pending - clear jobctl pending bits
* @task: target task
* @mask: pending bits to clear
*
* Clear @mask from @task->jobctl. @mask must be subset of
* %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
* STOP bits are cleared together.
*
* If clearing of @mask leaves no stop or trap pending, this function calls
* task_clear_jobctl_trapping().
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*/
void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
{
BUG_ON(mask & ~JOBCTL_PENDING_MASK);
if (mask & JOBCTL_STOP_PENDING)
mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
task->jobctl &= ~mask;
if (!(task->jobctl & JOBCTL_PENDING_MASK))
task_clear_jobctl_trapping(task);
}
/**
* task_participate_group_stop - participate in a group stop
* @task: task participating in a group stop
*
* @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
* Group stop states are cleared and the group stop count is consumed if
* %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
* stop, the appropriate `SIGNAL_*` flags are set.
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*
* RETURNS:
* %true if group stop completion should be notified to the parent, %false
* otherwise.
*/
static bool task_participate_group_stop(struct task_struct *task)
{
struct signal_struct *sig = task->signal;
bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
if (!consume)
return false;
if (!WARN_ON_ONCE(sig->group_stop_count == 0))
sig->group_stop_count--;
/*
* Tell the caller to notify completion iff we are entering into a
* fresh group stop. Read comment in do_signal_stop() for details.
*/
if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
return true;
}
return false;
}
void task_join_group_stop(struct task_struct *task)
{
unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
struct signal_struct *sig = current->signal;
if (sig->group_stop_count) {
sig->group_stop_count++;
mask |= JOBCTL_STOP_CONSUME;
} else if (!(sig->flags & SIGNAL_STOP_STOPPED))
return;
/* Have the new thread join an on-going signal group stop */
task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
}
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
* appropriate lock must be held to stop the target task from exiting
*/
static struct sigqueue *
__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
int override_rlimit, const unsigned int sigqueue_flags)
{
struct sigqueue *q = NULL;
struct ucounts *ucounts = NULL;
long sigpending;
/*
* Protect access to @t credentials. This can go away when all
* callers hold rcu read lock.
*
* NOTE! A pending signal will hold on to the user refcount,
* and we get/put the refcount only when the sigpending count
* changes from/to zero.
*/
rcu_read_lock();
ucounts = task_ucounts(t);
sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
rcu_read_unlock();
if (!sigpending)
return NULL;
if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
} else {
print_dropped_signal(sig);
}
if (unlikely(q == NULL)) {
dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
} else {
INIT_LIST_HEAD(&q->list);
q->flags = sigqueue_flags;
q->ucounts = ucounts;
}
return q;
}
static void __sigqueue_free(struct sigqueue *q)
{
if (q->flags & SIGQUEUE_PREALLOC)
return;
if (q->ucounts) {
dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
q->ucounts = NULL;
}
kmem_cache_free(sigqueue_cachep, q);
}
void flush_sigqueue(struct sigpending *queue)
{
struct sigqueue *q;
sigemptyset(&queue->signal);
while (!list_empty(&queue->list)) {
q = list_entry(queue->list.next, struct sigqueue , list);
list_del_init(&q->list);
__sigqueue_free(q);
}
}
/*
* Flush all pending signals for this kthread.
*/
void flush_signals(struct task_struct *t)
{
unsigned long flags;
spin_lock_irqsave(&t->sighand->siglock, flags);
clear_tsk_thread_flag(t, TIF_SIGPENDING);
flush_sigqueue(&t->pending);
flush_sigqueue(&t->signal->shared_pending);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
}
EXPORT_SYMBOL(flush_signals);
#ifdef CONFIG_POSIX_TIMERS
static void __flush_itimer_signals(struct sigpending *pending)
{
sigset_t signal, retain;
struct sigqueue *q, *n;
signal = pending->signal;
sigemptyset(&retain);
list_for_each_entry_safe(q, n, &pending->list, list) {
int sig = q->info.si_signo;
if (likely(q->info.si_code != SI_TIMER)) {
sigaddset(&retain, sig);
} else {
sigdelset(&signal, sig);
list_del_init(&q->list);
__sigqueue_free(q);
}
}
sigorsets(&pending->signal, &signal, &retain);
}
void flush_itimer_signals(void)
{
struct task_struct *tsk = current;
unsigned long flags;
spin_lock_irqsave(&tsk->sighand->siglock, flags);
__flush_itimer_signals(&tsk->pending);
__flush_itimer_signals(&tsk->signal->shared_pending);
spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
}
#endif
void ignore_signals(struct task_struct *t)
{
int i;
for (i = 0; i < _NSIG; ++i)
t->sighand->action[i].sa.sa_handler = SIG_IGN;
flush_signals(t);
}
/*
* Flush all handlers for a task.
*/
void
flush_signal_handlers(struct task_struct *t, int force_default)
{
int i;
struct k_sigaction *ka = &t->sighand->action[0];
for (i = _NSIG ; i != 0 ; i--) {
if (force_default || ka->sa.sa_handler != SIG_IGN)
ka->sa.sa_handler = SIG_DFL;
ka->sa.sa_flags = 0;
#ifdef __ARCH_HAS_SA_RESTORER
ka->sa.sa_restorer = NULL;
#endif
sigemptyset(&ka->sa.sa_mask);
ka++;
}
}
bool unhandled_signal(struct task_struct *tsk, int sig)
{
void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
if (is_global_init(tsk))
return true;
if (handler != SIG_IGN && handler != SIG_DFL)
return false;
/* If dying, we handle all new signals by ignoring them */
if (fatal_signal_pending(tsk))
return false;
/* if ptraced, let the tracer determine */
return !tsk->ptrace;
}
static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
bool *resched_timer)
{
struct sigqueue *q, *first = NULL;
/*
* Collect the siginfo appropriate to this signal. Check if
* there is another siginfo for the same signal.
*/
list_for_each_entry(q, &list->list, list) {
if (q->info.si_signo == sig) {
if (first)
goto still_pending;
first = q;
}
}
sigdelset(&list->signal, sig);
if (first) {
still_pending:
list_del_init(&first->list);
copy_siginfo(info, &first->info);
*resched_timer =
(first->flags & SIGQUEUE_PREALLOC) &&
(info->si_code == SI_TIMER) &&
(info->si_sys_private);
__sigqueue_free(first);
} else {
/*
* Ok, it wasn't in the queue. This must be
* a fast-pathed signal or we must have been
* out of queue space. So zero out the info.
*/
clear_siginfo(info);
info->si_signo = sig;
info->si_errno = 0;
info->si_code = SI_USER;
info->si_pid = 0;
info->si_uid = 0;
}
}
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
kernel_siginfo_t *info, bool *resched_timer)
{
int sig = next_signal(pending, mask);
if (sig)
collect_signal(sig, pending, info, resched_timer);
return sig;
}
/*
* Dequeue a signal and return the element to the caller, which is
* expected to free it.
*
* All callers have to hold the siglock.
*/
int dequeue_signal(struct task_struct *tsk, sigset_t *mask,
kernel_siginfo_t *info, enum pid_type *type)
{
bool resched_timer = false;
int signr;
/* We only dequeue private signals from ourselves, we don't let
* signalfd steal them
*/
*type = PIDTYPE_PID;
signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
if (!signr) {
*type = PIDTYPE_TGID;
signr = __dequeue_signal(&tsk->signal->shared_pending,
mask, info, &resched_timer);
#ifdef CONFIG_POSIX_TIMERS
/*
* itimer signal ?
*
* itimers are process shared and we restart periodic
* itimers in the signal delivery path to prevent DoS
* attacks in the high resolution timer case. This is
* compliant with the old way of self-restarting
* itimers, as the SIGALRM is a legacy signal and only
* queued once. Changing the restart behaviour to
* restart the timer in the signal dequeue path is
* reducing the timer noise on heavy loaded !highres
* systems too.
*/
if (unlikely(signr == SIGALRM)) {
struct hrtimer *tmr = &tsk->signal->real_timer;
if (!hrtimer_is_queued(tmr) &&
tsk->signal->it_real_incr != 0) {
hrtimer_forward(tmr, tmr->base->get_time(),
tsk->signal->it_real_incr);
hrtimer_restart(tmr);
}
}
#endif
}
recalc_sigpending();
if (!signr)
return 0;
if (unlikely(sig_kernel_stop(signr))) {
/*
* Set a marker that we have dequeued a stop signal. Our
* caller might release the siglock and then the pending
* stop signal it is about to process is no longer in the
* pending bitmasks, but must still be cleared by a SIGCONT
* (and overruled by a SIGKILL). So those cases clear this
* shared flag after we've set it. Note that this flag may
* remain set after the signal we return is ignored or
* handled. That doesn't matter because its only purpose
* is to alert stop-signal processing code when another
* processor has come along and cleared the flag.
*/
current->jobctl |= JOBCTL_STOP_DEQUEUED;
}
#ifdef CONFIG_POSIX_TIMERS
if (resched_timer) {
/*
* Release the siglock to ensure proper locking order
* of timer locks outside of siglocks. Note, we leave
* irqs disabled here, since the posix-timers code is
* about to disable them again anyway.
*/
spin_unlock(&tsk->sighand->siglock);
posixtimer_rearm(info);
spin_lock(&tsk->sighand->siglock);
/* Don't expose the si_sys_private value to userspace */
info->si_sys_private = 0;
}
#endif
return signr;
}
EXPORT_SYMBOL_GPL(dequeue_signal);
static int dequeue_synchronous_signal(kernel_siginfo_t *info)
{
struct task_struct *tsk = current;
struct sigpending *pending = &tsk->pending;
struct sigqueue *q, *sync = NULL;
/*
* Might a synchronous signal be in the queue?
*/
if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
return 0;
/*
* Return the first synchronous signal in the queue.
*/
list_for_each_entry(q, &pending->list, list) {
/* Synchronous signals have a positive si_code */
if ((q->info.si_code > SI_USER) &&
(sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
sync = q;
goto next;
}
}
return 0;
next:
/*
* Check if there is another siginfo for the same signal.
*/
list_for_each_entry_continue(q, &pending->list, list) {
if (q->info.si_signo == sync->info.si_signo)
goto still_pending;
}
sigdelset(&pending->signal, sync->info.si_signo);
recalc_sigpending();
still_pending:
list_del_init(&sync->list);
copy_siginfo(info, &sync->info);
__sigqueue_free(sync);
return info->si_signo;
}
/*
* Tell a process that it has a new active signal..
*
* NOTE! we rely on the previous spin_lock to
* lock interrupts for us! We can only be called with
* "siglock" held, and the local interrupt must
* have been disabled when that got acquired!
*
* No need to set need_resched since signal event passing
* goes through ->blocked
*/
void signal_wake_up_state(struct task_struct *t, unsigned int state)
{
lockdep_assert_held(&t->sighand->siglock);
set_tsk_thread_flag(t, TIF_SIGPENDING);
/*
* TASK_WAKEKILL also means wake it up in the stopped/traced/killable
* case. We don't check t->state here because there is a race with it
* executing another processor and just now entering stopped state.
* By using wake_up_state, we ensure the process will wake up and
* handle its death signal.
*/
if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
kick_process(t);
}
/*
* Remove signals in mask from the pending set and queue.
* Returns 1 if any signals were found.
*
* All callers must be holding the siglock.
*/
static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
{
struct sigqueue *q, *n;
sigset_t m;
sigandsets(&m, mask, &s->signal);
if (sigisemptyset(&m))
return;
sigandnsets(&s->signal, &s->signal, mask);
list_for_each_entry_safe(q, n, &s->list, list) {
if (sigismember(mask, q->info.si_signo)) {
list_del_init(&q->list);
__sigqueue_free(q);
}
}
}
static inline int is_si_special(const struct kernel_siginfo *info)
{
return info <= SEND_SIG_PRIV;
}
static inline bool si_fromuser(const struct kernel_siginfo *info)
{
return info == SEND_SIG_NOINFO ||
(!is_si_special(info) && SI_FROMUSER(info));
}
/*
* called with RCU read lock from check_kill_permission()
*/
static bool kill_ok_by_cred(struct task_struct *t)
{
const struct cred *cred = current_cred();
const struct cred *tcred = __task_cred(t);
return uid_eq(cred->euid, tcred->suid) ||
uid_eq(cred->euid, tcred->uid) ||
uid_eq(cred->uid, tcred->suid) ||
uid_eq(cred->uid, tcred->uid) ||
ns_capable(tcred->user_ns, CAP_KILL);
}
/*
* Bad permissions for sending the signal
* - the caller must hold the RCU read lock
*/
static int check_kill_permission(int sig, struct kernel_siginfo *info,
struct task_struct *t)
{
struct pid *sid;
int error;
if (!valid_signal(sig))
return -EINVAL;
if (!si_fromuser(info))
return 0;
error = audit_signal_info(sig, t); /* Let audit system see the signal */
if (error)
return error;
if (!same_thread_group(current, t) &&
!kill_ok_by_cred(t)) {
switch (sig) {
case SIGCONT:
sid = task_session(t);
/*
* We don't return the error if sid == NULL. The
* task was unhashed, the caller must notice this.
*/
if (!sid || sid == task_session(current))
break;
fallthrough;
default:
return -EPERM;
}
}
return security_task_kill(t, info, sig, NULL);
}
/**
* ptrace_trap_notify - schedule trap to notify ptracer
* @t: tracee wanting to notify tracer
*
* This function schedules sticky ptrace trap which is cleared on the next
* TRAP_STOP to notify ptracer of an event. @t must have been seized by
* ptracer.
*
* If @t is running, STOP trap will be taken. If trapped for STOP and
* ptracer is listening for events, tracee is woken up so that it can
* re-trap for the new event. If trapped otherwise, STOP trap will be
* eventually taken without returning to userland after the existing traps
* are finished by PTRACE_CONT.
*
* CONTEXT:
* Must be called with @task->sighand->siglock held.
*/
static void ptrace_trap_notify(struct task_struct *t)
{
WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
lockdep_assert_held(&t->sighand->siglock);
task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
}
/*
* Handle magic process-wide effects of stop/continue signals. Unlike
* the signal actions, these happen immediately at signal-generation
* time regardless of blocking, ignoring, or handling. This does the
* actual continuing for SIGCONT, but not the actual stopping for stop
* signals. The process stop is done as a signal action for SIG_DFL.
*
* Returns true if the signal should be actually delivered, otherwise
* it should be dropped.
*/
static bool prepare_signal(int sig, struct task_struct *p, bool force)
{
struct signal_struct *signal = p->signal;
struct task_struct *t;
sigset_t flush;
if (signal->flags & SIGNAL_GROUP_EXIT) {
if (signal->core_state)
return sig == SIGKILL;
/*
* The process is in the middle of dying, drop the signal.
*/
return false;
} else if (sig_kernel_stop(sig)) {
/*
* This is a stop signal. Remove SIGCONT from all queues.
*/
siginitset(&flush, sigmask(SIGCONT));
flush_sigqueue_mask(&flush, &signal->shared_pending);
for_each_thread(p, t)
flush_sigqueue_mask(&flush, &t->pending);
} else if (sig == SIGCONT) {
unsigned int why;
/*
* Remove all stop signals from all queues, wake all threads.
*/
siginitset(&flush, SIG_KERNEL_STOP_MASK);
flush_sigqueue_mask(&flush, &signal->shared_pending);
for_each_thread(p, t) {
flush_sigqueue_mask(&flush, &t->pending);
task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
if (likely(!(t->ptrace & PT_SEIZED))) {
t->jobctl &= ~JOBCTL_STOPPED;
wake_up_state(t, __TASK_STOPPED);
} else
ptrace_trap_notify(t);
}
/*
* Notify the parent with CLD_CONTINUED if we were stopped.
*
* If we were in the middle of a group stop, we pretend it
* was already finished, and then continued. Since SIGCHLD
* doesn't queue we report only CLD_STOPPED, as if the next
* CLD_CONTINUED was dropped.
*/
why = 0;
if (signal->flags & SIGNAL_STOP_STOPPED)
why |= SIGNAL_CLD_CONTINUED;
else if (signal->group_stop_count)
why |= SIGNAL_CLD_STOPPED;
if (why) {
/*
* The first thread which returns from do_signal_stop()
* will take ->siglock, notice SIGNAL_CLD_MASK, and
* notify its parent. See get_signal().
*/
signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
signal->group_stop_count = 0;
signal->group_exit_code = 0;
}
}
return !sig_ignored(p, sig, force);
}
/*
* Test if P wants to take SIG. After we've checked all threads with this,
* it's equivalent to finding no threads not blocking SIG. Any threads not
* blocking SIG were ruled out because they are not running and already
* have pending signals. Such threads will dequeue from the shared queue
* as soon as they're available, so putting the signal on the shared queue
* will be equivalent to sending it to one such thread.
*/
static inline bool wants_signal(int sig, struct task_struct *p)
{
if (sigismember(&p->blocked, sig))
return false;
if (p->flags & PF_EXITING)
return false;
if (sig == SIGKILL)
return true;
if (task_is_stopped_or_traced(p))
return false;
return task_curr(p) || !task_sigpending(p);
}
static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
{
struct signal_struct *signal = p->signal;
struct task_struct *t;
/*
* Now find a thread we can wake up to take the signal off the queue.
*
* Try the suggested task first (may or may not be the main thread).
*/
if (wants_signal(sig, p))
t = p;
else if ((type == PIDTYPE_PID) || thread_group_empty(p))
/*
* There is just one thread and it does not need to be woken.
* It will dequeue unblocked signals before it runs again.
*/
return;
else {
/*
* Otherwise try to find a suitable thread.
*/
t = signal->curr_target;
while (!wants_signal(sig, t)) {
t = next_thread(t);
if (t == signal->curr_target)
/*
* No thread needs to be woken.
* Any eligible threads will see
* the signal in the queue soon.
*/
return;
}
signal->curr_target = t;
}
/*
* Found a killable thread. If the signal will be fatal,
* then start taking the whole group down immediately.
*/
if (sig_fatal(p, sig) &&
(signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
!sigismember(&t->real_blocked, sig) &&
(sig == SIGKILL || !p->ptrace)) {
/*
* This signal will be fatal to the whole group.
*/
if (!sig_kernel_coredump(sig)) {
/*
* Start a group exit and wake everybody up.
* This way we don't have other threads
* running and doing things after a slower
* thread has the fatal signal pending.
*/
signal->flags = SIGNAL_GROUP_EXIT;
signal->group_exit_code = sig;
signal->group_stop_count = 0;
t = p;
do {
task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
} while_each_thread(p, t);
return;
}
}
/*
* The signal is already in the shared-pending queue.
* Tell the chosen thread to wake up and dequeue it.
*/
signal_wake_up(t, sig == SIGKILL);
return;
}
static inline bool legacy_queue(struct sigpending *signals, int sig)
{
return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
}
static int __send_signal_locked(int sig, struct kernel_siginfo *info,
struct task_struct *t, enum pid_type type, bool force)
{
struct sigpending *pending;
struct sigqueue *q;
int override_rlimit;
int ret = 0, result;
lockdep_assert_held(&t->sighand->siglock);
result = TRACE_SIGNAL_IGNORED;
if (!prepare_signal(sig, t, force))
goto ret;
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
/*
* Short-circuit ignored signals and support queuing
* exactly one non-rt signal, so that we can get more
* detailed information about the cause of the signal.
*/
result = TRACE_SIGNAL_ALREADY_PENDING;
if (legacy_queue(pending, sig))
goto ret;
result = TRACE_SIGNAL_DELIVERED;
/*
* Skip useless siginfo allocation for SIGKILL and kernel threads.
*/
if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
goto out_set;
/*
* Real-time signals must be queued if sent by sigqueue, or
* some other real-time mechanism. It is implementation
* defined whether kill() does so. We attempt to do so, on
* the principle of least surprise, but since kill is not
* allowed to fail with EAGAIN when low on memory we just
* make sure at least one signal gets delivered and don't
* pass on the info struct.
*/
if (sig < SIGRTMIN)
override_rlimit = (is_si_special(info) || info->si_code >= 0);
else
override_rlimit = 0;
q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
if (q) {
list_add_tail(&q->list, &pending->list);
switch ((unsigned long) info) {
case (unsigned long) SEND_SIG_NOINFO:
clear_siginfo(&q->info);
q->info.si_signo = sig;
q->info.si_errno = 0;
q->info.si_code = SI_USER;
q->info.si_pid = task_tgid_nr_ns(current,
task_active_pid_ns(t));
rcu_read_lock();
q->info.si_uid =
from_kuid_munged(task_cred_xxx(t, user_ns),
current_uid());
rcu_read_unlock();
break;
case (unsigned long) SEND_SIG_PRIV:
clear_siginfo(&q->info);
q->info.si_signo = sig;
q->info.si_errno = 0;
q->info.si_code = SI_KERNEL;
q->info.si_pid = 0;
q->info.si_uid = 0;
break;
default:
copy_siginfo(&q->info, info);
break;
}
} else if (!is_si_special(info) &&
sig >= SIGRTMIN && info->si_code != SI_USER) {
/*
* Queue overflow, abort. We may abort if the
* signal was rt and sent by user using something
* other than kill().
*/
result = TRACE_SIGNAL_OVERFLOW_FAIL;
ret = -EAGAIN;
goto ret;
} else {
/*
* This is a silent loss of information. We still
* send the signal, but the *info bits are lost.
*/
result = TRACE_SIGNAL_LOSE_INFO;
}
out_set:
signalfd_notify(t, sig);
sigaddset(&pending->signal, sig);
/* Let multiprocess signals appear after on-going forks */
if (type > PIDTYPE_TGID) {
struct multiprocess_signals *delayed;
hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
sigset_t *signal = &delayed->signal;
/* Can't queue both a stop and a continue signal */
if (sig == SIGCONT)
sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
else if (sig_kernel_stop(sig))
sigdelset(signal, SIGCONT);
sigaddset(signal, sig);
}
}
complete_signal(sig, t, type);
ret:
trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
return ret;
}
static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
{
bool ret = false;
switch (siginfo_layout(info->si_signo, info->si_code)) {
case SIL_KILL:
case SIL_CHLD:
case SIL_RT:
ret = true;
break;
case SIL_TIMER:
case SIL_POLL:
case SIL_FAULT:
case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
case SIL_FAULT_PERF_EVENT:
case SIL_SYS:
ret = false;
break;
}
return ret;
}
int send_signal_locked(int sig, struct kernel_siginfo *info,
struct task_struct *t, enum pid_type type)
{
/* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
bool force = false;
if (info == SEND_SIG_NOINFO) {
/* Force if sent from an ancestor pid namespace */
force = !task_pid_nr_ns(current, task_active_pid_ns(t));
} else if (info == SEND_SIG_PRIV) {
/* Don't ignore kernel generated signals */
force = true;
} else if (has_si_pid_and_uid(info)) {
/* SIGKILL and SIGSTOP is special or has ids */
struct user_namespace *t_user_ns;
rcu_read_lock();
t_user_ns = task_cred_xxx(t, user_ns);
if (current_user_ns() != t_user_ns) {
kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
info->si_uid = from_kuid_munged(t_user_ns, uid);
}
rcu_read_unlock();
/* A kernel generated signal? */
force = (info->si_code == SI_KERNEL);
/* From an ancestor pid namespace? */
if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
info->si_pid = 0;
force = true;
}
}
return __send_signal_locked(sig, info, t, type, force);
}
static void print_fatal_signal(int signr)
{
struct pt_regs *regs = task_pt_regs(current);
struct file *exe_file;
exe_file = get_task_exe_file(current);
if (exe_file) {
pr_info("%pD: %s: potentially unexpected fatal signal %d.\n",
exe_file, current->comm, signr);
fput(exe_file);
} else {
pr_info("%s: potentially unexpected fatal signal %d.\n",
current->comm, signr);
}
#if defined(__i386__) && !defined(__arch_um__)
pr_info("code at %08lx: ", regs->ip);
{
int i;
for (i = 0; i < 16; i++) {
unsigned char insn;
if (get_user(insn, (unsigned char *)(regs->ip + i)))
break;
pr_cont("%02x ", insn);
}
}
pr_cont("\n");
#endif
preempt_disable();
show_regs(regs);
preempt_enable();
}
static int __init setup_print_fatal_signals(char *str)
{
get_option (&str, &print_fatal_signals);
return 1;
}
__setup("print-fatal-signals=", setup_print_fatal_signals);
int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
enum pid_type type)
{
unsigned long flags;
int ret = -ESRCH;
if (lock_task_sighand(p, &flags)) {
ret = send_signal_locked(sig, info, p, type);
unlock_task_sighand(p, &flags);
}
return ret;
}
enum sig_handler {
HANDLER_CURRENT, /* If reachable use the current handler */
HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
HANDLER_EXIT, /* Only visible as the process exit code */
};
/*
* Force a signal that the process can't ignore: if necessary
* we unblock the signal and change any SIG_IGN to SIG_DFL.
*
* Note: If we unblock the signal, we always reset it to SIG_DFL,
* since we do not want to have a signal handler that was blocked
* be invoked when user space had explicitly blocked it.
*
* We don't want to have recursive SIGSEGV's etc, for example,
* that is why we also clear SIGNAL_UNKILLABLE.
*/
static int
force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
enum sig_handler handler)
{
unsigned long int flags;
int ret, blocked, ignored;
struct k_sigaction *action;
int sig = info->si_signo;
spin_lock_irqsave(&t->sighand->siglock, flags);
action = &t->sighand->action[sig-1];
ignored = action->sa.sa_handler == SIG_IGN;
blocked = sigismember(&t->blocked, sig);
if (blocked || ignored || (handler != HANDLER_CURRENT)) {
action->sa.sa_handler = SIG_DFL;
if (handler == HANDLER_EXIT)
action->sa.sa_flags |= SA_IMMUTABLE;
if (blocked) {
sigdelset(&t->blocked, sig);
recalc_sigpending_and_wake(t);
}
}
/*
* Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
* debugging to leave init killable. But HANDLER_EXIT is always fatal.
*/
if (action->sa.sa_handler == SIG_DFL &&
(!t->ptrace || (handler == HANDLER_EXIT)))
t->signal->flags &= ~SIGNAL_UNKILLABLE;
ret = send_signal_locked(sig, info, t, PIDTYPE_PID);
spin_unlock_irqrestore(&t->sighand->siglock, flags);
return ret;
}
int force_sig_info(struct kernel_siginfo *info)
{
return force_sig_info_to_task(info, current, HANDLER_CURRENT);
}
/*
* Nuke all other threads in the group.
*/
int zap_other_threads(struct task_struct *p)
{
struct task_struct *t = p;
int count = 0;
p->signal->group_stop_count = 0;
while_each_thread(p, t) {
task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
/* Don't require de_thread to wait for the vhost_worker */
if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)
count++;
/* Don't bother with already dead threads */
if (t->exit_state)
continue;
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
}
return count;
}
struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
unsigned long *flags)
{
struct sighand_struct *sighand;
rcu_read_lock();
for (;;) {
sighand = rcu_dereference(tsk->sighand);
if (unlikely(sighand == NULL))
break;
/*
* This sighand can be already freed and even reused, but
* we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
* initializes ->siglock: this slab can't go away, it has
* the same object type, ->siglock can't be reinitialized.
*
* We need to ensure that tsk->sighand is still the same
* after we take the lock, we can race with de_thread() or
* __exit_signal(). In the latter case the next iteration
* must see ->sighand == NULL.
*/
spin_lock_irqsave(&sighand->siglock, *flags);
if (likely(sighand == rcu_access_pointer(tsk->sighand)))
break;
spin_unlock_irqrestore(&sighand->siglock, *flags);
}
rcu_read_unlock();
return sighand;
}
#ifdef CONFIG_LOCKDEP
void lockdep_assert_task_sighand_held(struct task_struct *task)
{
struct sighand_struct *sighand;
rcu_read_lock();
sighand = rcu_dereference(task->sighand);
if (sighand)
lockdep_assert_held(&sighand->siglock);
else
WARN_ON_ONCE(1);
rcu_read_unlock();
}
#endif
/*
* send signal info to all the members of a group
*/
int group_send_sig_info(int sig, struct kernel_siginfo *info,
struct task_struct *p, enum pid_type type)
{
int ret;
rcu_read_lock();
ret = check_kill_permission(sig, info, p);
rcu_read_unlock();
if (!ret && sig)
ret = do_send_sig_info(sig, info, p, type);
return ret;
}
/*
* __kill_pgrp_info() sends a signal to a process group: this is what the tty
* control characters do (^C, ^Z etc)
* - the caller must hold at least a readlock on tasklist_lock
*/
int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
{
struct task_struct *p = NULL;
int retval, success;
success = 0;
retval = -ESRCH;
do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
success |= !err;
retval = err;
} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
return success ? 0 : retval;
}
int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
{
int error = -ESRCH;
struct task_struct *p;
for (;;) {
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (p)
error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
rcu_read_unlock();
if (likely(!p || error != -ESRCH))
return error;
/*
* The task was unhashed in between, try again. If it
* is dead, pid_task() will return NULL, if we race with
* de_thread() it will find the new leader.
*/
}
}
static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
{
int error;
rcu_read_lock();
error = kill_pid_info(sig, info, find_vpid(pid));
rcu_read_unlock();
return error;
}
static inline bool kill_as_cred_perm(const struct cred *cred,
struct task_struct *target)
{
const struct cred *pcred = __task_cred(target);
return uid_eq(cred->euid, pcred->suid) ||
uid_eq(cred->euid, pcred->uid) ||
uid_eq(cred->uid, pcred->suid) ||
uid_eq(cred->uid, pcred->uid);
}
/*
* The usb asyncio usage of siginfo is wrong. The glibc support
* for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
* AKA after the generic fields:
* kernel_pid_t si_pid;
* kernel_uid32_t si_uid;
* sigval_t si_value;
*
* Unfortunately when usb generates SI_ASYNCIO it assumes the layout
* after the generic fields is:
* void __user *si_addr;
*
* This is a practical problem when there is a 64bit big endian kernel
* and a 32bit userspace. As the 32bit address will encoded in the low
* 32bits of the pointer. Those low 32bits will be stored at higher
* address than appear in a 32 bit pointer. So userspace will not
* see the address it was expecting for it's completions.
*
* There is nothing in the encoding that can allow
* copy_siginfo_to_user32 to detect this confusion of formats, so
* handle this by requiring the caller of kill_pid_usb_asyncio to
* notice when this situration takes place and to store the 32bit
* pointer in sival_int, instead of sival_addr of the sigval_t addr
* parameter.
*/
int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
struct pid *pid, const struct cred *cred)
{
struct kernel_siginfo info;
struct task_struct *p;
unsigned long flags;
int ret = -EINVAL;
if (!valid_signal(sig))
return ret;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = errno;
info.si_code = SI_ASYNCIO;
*((sigval_t *)&info.si_pid) = addr;
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (!p) {
ret = -ESRCH;
goto out_unlock;
}
if (!kill_as_cred_perm(cred, p)) {
ret = -EPERM;
goto out_unlock;
}
ret = security_task_kill(p, &info, sig, cred);
if (ret)
goto out_unlock;
if (sig) {
if (lock_task_sighand(p, &flags)) {
ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false);
unlock_task_sighand(p, &flags);
} else
ret = -ESRCH;
}
out_unlock:
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).
*
* POSIX specifies that kill(-1,sig) is unspecified, but what we have
* is probably wrong. Should make it like BSD or SYSV.
*/
static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
{
int ret;
if (pid > 0)
return kill_proc_info(sig, info, pid);
/* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
if (pid == INT_MIN)
return -ESRCH;
read_lock(&tasklist_lock);
if (pid != -1) {
ret = __kill_pgrp_info(sig, info,
pid ? find_vpid(-pid) : task_pgrp(current));
} else {
int retval = 0, count = 0;
struct task_struct * p;
for_each_process(p) {
if (task_pid_vnr(p) > 1 &&
!same_thread_group(p, current)) {
int err = group_send_sig_info(sig, info, p,
PIDTYPE_MAX);
++count;
if (err != -EPERM)
retval = err;
}
}
ret = count ? retval : -ESRCH;
}
read_unlock(&tasklist_lock);
return ret;
}
/*
* These are for backward compatibility with the rest of the kernel source.
*/
int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
{
/*
* Make sure legacy kernel users don't send in bad values
* (normal paths check this in check_kill_permission).
*/
if (!valid_signal(sig))
return -EINVAL;
return do_send_sig_info(sig, info, p, PIDTYPE_PID);
}
EXPORT_SYMBOL(send_sig_info);
#define __si_special(priv) \
((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
int
send_sig(int sig, struct task_struct *p, int priv)
{
return send_sig_info(sig, __si_special(priv), p);
}
EXPORT_SYMBOL(send_sig);
void force_sig(int sig)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_KERNEL;
info.si_pid = 0;
info.si_uid = 0;
force_sig_info(&info);
}
EXPORT_SYMBOL(force_sig);
void force_fatal_sig(int sig)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_KERNEL;
info.si_pid = 0;
info.si_uid = 0;
force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
}
void force_exit_sig(int sig)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_KERNEL;
info.si_pid = 0;
info.si_uid = 0;
force_sig_info_to_task(&info, current, HANDLER_EXIT);
}
/*
* When things go south during signal handling, we
* will force a SIGSEGV. And if the signal that caused
* the problem was already a SIGSEGV, we'll want to
* make sure we don't even try to deliver the signal..
*/
void force_sigsegv(int sig)
{
if (sig == SIGSEGV)
force_fatal_sig(SIGSEGV);
else
force_sig(SIGSEGV);
}
int force_sig_fault_to_task(int sig, int code, void __user *addr
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
, struct task_struct *t)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
#ifdef __ia64__
info.si_imm = imm;
info.si_flags = flags;
info.si_isr = isr;
#endif
return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
}
int force_sig_fault(int sig, int code, void __user *addr
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
{
return force_sig_fault_to_task(sig, code, addr
___ARCH_SI_IA64(imm, flags, isr), current);
}
int send_sig_fault(int sig, int code, void __user *addr
___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
, struct task_struct *t)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
#ifdef __ia64__
info.si_imm = imm;
info.si_flags = flags;
info.si_isr = isr;
#endif
return send_sig_info(info.si_signo, &info, t);
}
int force_sig_mceerr(int code, void __user *addr, short lsb)
{
struct kernel_siginfo info;
WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
clear_siginfo(&info);
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
info.si_addr_lsb = lsb;
return force_sig_info(&info);
}
int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
{
struct kernel_siginfo info;
WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
clear_siginfo(&info);
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
info.si_addr_lsb = lsb;
return send_sig_info(info.si_signo, &info, t);
}
EXPORT_SYMBOL(send_sig_mceerr);
int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = SEGV_BNDERR;
info.si_addr = addr;
info.si_lower = lower;
info.si_upper = upper;
return force_sig_info(&info);
}
#ifdef SEGV_PKUERR
int force_sig_pkuerr(void __user *addr, u32 pkey)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = SEGV_PKUERR;
info.si_addr = addr;
info.si_pkey = pkey;
return force_sig_info(&info);
}
#endif
int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_PERF;
info.si_addr = addr;
info.si_perf_data = sig_data;
info.si_perf_type = type;
/*
* Signals generated by perf events should not terminate the whole
* process if SIGTRAP is blocked, however, delivering the signal
* asynchronously is better than not delivering at all. But tell user
* space if the signal was asynchronous, so it can clearly be
* distinguished from normal synchronous ones.
*/
info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
TRAP_PERF_FLAG_ASYNC :
0;
return send_sig_info(info.si_signo, &info, current);
}
/**
* force_sig_seccomp - signals the task to allow in-process syscall emulation
* @syscall: syscall number to send to userland
* @reason: filter-supplied reason code to send to userland (via si_errno)
* @force_coredump: true to trigger a coredump
*
* Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
*/
int force_sig_seccomp(int syscall, int reason, bool force_coredump)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGSYS;
info.si_code = SYS_SECCOMP;
info.si_call_addr = (void __user *)KSTK_EIP(current);
info.si_errno = reason;
info.si_arch = syscall_get_arch(current);
info.si_syscall = syscall;
return force_sig_info_to_task(&info, current,
force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
}
/* For the crazy architectures that include trap information in
* the errno field, instead of an actual errno value.
*/
int force_sig_ptrace_errno_trap(int errno, void __user *addr)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = SIGTRAP;
info.si_errno = errno;
info.si_code = TRAP_HWBKPT;
info.si_addr = addr;
return force_sig_info(&info);
}
/* For the rare architectures that include trap information using
* si_trapno.
*/
int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
info.si_trapno = trapno;
return force_sig_info(&info);
}
/* For the rare architectures that include trap information using
* si_trapno.
*/
int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
struct task_struct *t)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info.si_addr = addr;
info.si_trapno = trapno;
return send_sig_info(info.si_signo, &info, t);
}
int kill_pgrp(struct pid *pid, int sig, int priv)
{
int ret;
read_lock(&tasklist_lock);
ret = __kill_pgrp_info(sig, __si_special(priv), pid);
read_unlock(&tasklist_lock);
return ret;
}
EXPORT_SYMBOL(kill_pgrp);
int kill_pid(struct pid *pid, int sig, int priv)
{
return kill_pid_info(sig, __si_special(priv), pid);
}
EXPORT_SYMBOL(kill_pid);
/*
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
* afford to lose notifications of asynchronous events, like timer
* expirations or I/O completions". In the case of POSIX Timers
* we allocate the sigqueue structure from the timer_create. If this
* allocation fails we are able to report the failure to the application
* with an EAGAIN error.
*/
struct sigqueue *sigqueue_alloc(void)
{
return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
}
void sigqueue_free(struct sigqueue *q)
{
unsigned long flags;
spinlock_t *lock = ¤t->sighand->siglock;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
/*
* We must hold ->siglock while testing q->list
* to serialize with collect_signal() or with
* __exit_signal()->flush_sigqueue().
*/
spin_lock_irqsave(lock, flags);
q->flags &= ~SIGQUEUE_PREALLOC;
/*
* If it is queued it will be freed when dequeued,
* like the "regular" sigqueue.
*/
if (!list_empty(&q->list))
q = NULL;
spin_unlock_irqrestore(lock, flags);
if (q)
__sigqueue_free(q);
}
int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
{
int sig = q->info.si_signo;
struct sigpending *pending;
struct task_struct *t;
unsigned long flags;
int ret, result;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
ret = -1;
rcu_read_lock();
/*
* This function is used by POSIX timers to deliver a timer signal.
* Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
* set), the signal must be delivered to the specific thread (queues
* into t->pending).
*
* Where type is not PIDTYPE_PID, signals must be delivered to the
* process. In this case, prefer to deliver to current if it is in
* the same thread group as the target process, which avoids
* unnecessarily waking up a potentially idle task.
*/
t = pid_task(pid, type);
if (!t)
goto ret;
if (type != PIDTYPE_PID && same_thread_group(t, current))
t = current;
if (!likely(lock_task_sighand(t, &flags)))
goto ret;
ret = 1; /* the signal is ignored */
result = TRACE_SIGNAL_IGNORED;
if (!prepare_signal(sig, t, false))
goto out;
ret = 0;
if (unlikely(!list_empty(&q->list))) {
/*
* If an SI_TIMER entry is already queue just increment
* the overrun count.
*/
BUG_ON(q->info.si_code != SI_TIMER);
q->info.si_overrun++;
result = TRACE_SIGNAL_ALREADY_PENDING;
goto out;
}
q->info.si_overrun = 0;
signalfd_notify(t, sig);
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
list_add_tail(&q->list, &pending->list);
sigaddset(&pending->signal, sig);
complete_signal(sig, t, type);
result = TRACE_SIGNAL_DELIVERED;
out:
trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
unlock_task_sighand(t, &flags);
ret:
rcu_read_unlock();
return ret;
}
static void do_notify_pidfd(struct task_struct *task)
{
struct pid *pid;
WARN_ON(task->exit_state == 0);
pid = task_pid(task);
wake_up_all(&pid->wait_pidfd);
}
/*
* Let a parent know about the death of a child.
* For a stopped/continued status change, use do_notify_parent_cldstop instead.
*
* Returns true if our parent ignored us and so we've switched to
* self-reaping.
*/
bool do_notify_parent(struct task_struct *tsk, int sig)
{
struct kernel_siginfo info;
unsigned long flags;
struct sighand_struct *psig;
bool autoreap = false;
u64 utime, stime;
WARN_ON_ONCE(sig == -1);
/* do_notify_parent_cldstop should have been called instead. */
WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
WARN_ON_ONCE(!tsk->ptrace &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
/* Wake up all pidfd waiters */
do_notify_pidfd(tsk);
if (sig != SIGCHLD) {
/*
* This is only possible if parent == real_parent.
* Check if it has changed security domain.
*/
if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
sig = SIGCHLD;
}
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
/*
* We are under tasklist_lock here so our parent is tied to
* us and cannot change.
*
* task_active_pid_ns will always return the same pid namespace
* until a task passes through release_task.
*
* write_lock() currently calls preempt_disable() which is the
* same as rcu_read_lock(), but according to Oleg, this is not
* correct to rely on this
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
task_uid(tsk));
rcu_read_unlock();
task_cputime(tsk, &utime, &stime);
info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
info.si_status = tsk->exit_code & 0x7f;
if (tsk->exit_code & 0x80)
info.si_code = CLD_DUMPED;
else if (tsk->exit_code & 0x7f)
info.si_code = CLD_KILLED;
else {
info.si_code = CLD_EXITED;
info.si_status = tsk->exit_code >> 8;
}
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
if (!tsk->ptrace && sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
* We are exiting and our parent doesn't care. POSIX.1
* defines special semantics for setting SIGCHLD to SIG_IGN
* or setting the SA_NOCLDWAIT flag: we should be reaped
* automatically and not left for our parent's wait4 call.
* Rather than having the parent do it as a magic kind of
* signal handler, we just set this to tell do_exit that we
* can be cleaned up without becoming a zombie. Note that
* we still call __wake_up_parent in this case, because a
* blocked sys_wait4 might now return -ECHILD.
*
* Whether we send SIGCHLD or not for SA_NOCLDWAIT
* is implementation-defined: we do (if you don't want
* it, just use SIG_IGN instead).
*/
autoreap = true;
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
sig = 0;
}
/*
* Send with __send_signal as si_pid and si_uid are in the
* parent's namespaces.
*/
if (valid_signal(sig) && sig)
__send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false);
__wake_up_parent(tsk, tsk->parent);
spin_unlock_irqrestore(&psig->siglock, flags);
return autoreap;
}
/**
* do_notify_parent_cldstop - notify parent of stopped/continued state change
* @tsk: task reporting the state change
* @for_ptracer: the notification is for ptracer
* @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
*
* Notify @tsk's parent that the stopped/continued state has changed. If
* @for_ptracer is %false, @tsk's group leader notifies to its real parent.
* If %true, @tsk reports to @tsk->parent which should be the ptracer.
*
* CONTEXT:
* Must be called with tasklist_lock at least read locked.
*/
static void do_notify_parent_cldstop(struct task_struct *tsk,
bool for_ptracer, int why)
{
struct kernel_siginfo info;
unsigned long flags;
struct task_struct *parent;
struct sighand_struct *sighand;
u64 utime, stime;
if (for_ptracer) {
parent = tsk->parent;
} else {
tsk = tsk->group_leader;
parent = tsk->real_parent;
}
clear_siginfo(&info);
info.si_signo = SIGCHLD;
info.si_errno = 0;
/*
* see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
rcu_read_unlock();
task_cputime(tsk, &utime, &stime);
info.si_utime = nsec_to_clock_t(utime);
info.si_stime = nsec_to_clock_t(stime);
info.si_code = why;
switch (why) {
case CLD_CONTINUED:
info.si_status = SIGCONT;
break;
case CLD_STOPPED:
info.si_status = tsk->signal->group_exit_code & 0x7f;
break;
case CLD_TRAPPED:
info.si_status = tsk->exit_code & 0x7f;
break;
default:
BUG();
}
sighand = parent->sighand;
spin_lock_irqsave(&sighand->siglock, flags);
if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
!(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID);
/*
* Even if SIGCHLD is not generated, we must wake up wait4 calls.
*/
__wake_up_parent(tsk, parent);
spin_unlock_irqrestore(&sighand->siglock, flags);
}
/*
* This must be called with current->sighand->siglock held.
*
* This should be the path for all ptrace stops.
* We always set current->last_siginfo while stopped here.
* That makes it a way to test a stopped process for
* being ptrace-stopped vs being job-control-stopped.
*
* Returns the signal the ptracer requested the code resume
* with. If the code did not stop because the tracer is gone,
* the stop signal remains unchanged unless clear_code.
*/
static int ptrace_stop(int exit_code, int why, unsigned long message,
kernel_siginfo_t *info)
__releases(¤t->sighand->siglock)
__acquires(¤t->sighand->siglock)
{
bool gstop_done = false;
if (arch_ptrace_stop_needed()) {
/*
* The arch code has something special to do before a
* ptrace stop. This is allowed to block, e.g. for faults
* on user stack pages. We can't keep the siglock while
* calling arch_ptrace_stop, so we must release it now.
* To preserve proper semantics, we must do this before
* any signal bookkeeping like checking group_stop_count.
*/
spin_unlock_irq(¤t->sighand->siglock);
arch_ptrace_stop();
spin_lock_irq(¤t->sighand->siglock);
}
/*
* After this point ptrace_signal_wake_up or signal_wake_up
* will clear TASK_TRACED if ptrace_unlink happens or a fatal
* signal comes in. Handle previous ptrace_unlinks and fatal
* signals here to prevent ptrace_stop sleeping in schedule.
*/
if (!current->ptrace || __fatal_signal_pending(current))
return exit_code;
set_special_state(TASK_TRACED);
current->jobctl |= JOBCTL_TRACED;
/*
* We're committing to trapping. TRACED should be visible before
* TRAPPING is cleared; otherwise, the tracer might fail do_wait().
* Also, transition to TRACED and updates to ->jobctl should be
* atomic with respect to siglock and should be done after the arch
* hook as siglock is released and regrabbed across it.
*
* TRACER TRACEE
*
* ptrace_attach()
* [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
* do_wait()
* set_current_state() smp_wmb();
* ptrace_do_wait()
* wait_task_stopped()
* task_stopped_code()
* [L] task_is_traced() [S] task_clear_jobctl_trapping();
*/
smp_wmb();
current->ptrace_message = message;
current->last_siginfo = info;
current->exit_code = exit_code;
/*
* If @why is CLD_STOPPED, we're trapping to participate in a group
* stop. Do the bookkeeping. Note that if SIGCONT was delievered
* across siglock relocks since INTERRUPT was scheduled, PENDING
* could be clear now. We act as if SIGCONT is received after
* TASK_TRACED is entered - ignore it.
*/
if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
gstop_done = task_participate_group_stop(current);
/* any trap clears pending STOP trap, STOP trap clears NOTIFY */
task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
/* entering a trap, clear TRAPPING */
task_clear_jobctl_trapping(current);
spin_unlock_irq(¤t->sighand->siglock);
read_lock(&tasklist_lock);
/*
* Notify parents of the stop.
*
* While ptraced, there are two parents - the ptracer and
* the real_parent of the group_leader. The ptracer should
* know about every stop while the real parent is only
* interested in the completion of group stop. The states
* for the two don't interact with each other. Notify
* separately unless they're gonna be duplicates.
*/
if (current->ptrace)
do_notify_parent_cldstop(current, true, why);
if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
do_notify_parent_cldstop(current, false, why);
/*
* Don't want to allow preemption here, because
* sys_ptrace() needs this task to be inactive.
*
* XXX: implement read_unlock_no_resched().
*/
preempt_disable();
read_unlock(&tasklist_lock);
cgroup_enter_frozen();
preempt_enable_no_resched();
schedule();
cgroup_leave_frozen(true);
/*
* We are back. Now reacquire the siglock before touching
* last_siginfo, so that we are sure to have synchronized with
* any signal-sending on another CPU that wants to examine it.
*/
spin_lock_irq(¤t->sighand->siglock);
exit_code = current->exit_code;
current->last_siginfo = NULL;
current->ptrace_message = 0;
current->exit_code = 0;
/* LISTENING can be set only during STOP traps, clear it */
current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
/*
* Queued signals ignored us while we were stopped for tracing.
* So check for any that we should take before resuming user mode.
* This sets TIF_SIGPENDING, but never clears it.
*/
recalc_sigpending_tsk(current);
return exit_code;
}
static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
{
kernel_siginfo_t info;
clear_siginfo(&info);
info.si_signo = signr;
info.si_code = exit_code;
info.si_pid = task_pid_vnr(current);
info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
/* Let the debugger run. */
return ptrace_stop(exit_code, why, message, &info);
}
int ptrace_notify(int exit_code, unsigned long message)
{
int signr;
BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
if (unlikely(task_work_pending(current)))
task_work_run();
spin_lock_irq(¤t->sighand->siglock);
signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
spin_unlock_irq(¤t->sighand->siglock);
return signr;
}
/**
* do_signal_stop - handle group stop for SIGSTOP and other stop signals
* @signr: signr causing group stop if initiating
*
* If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
* and participate in it. If already set, participate in the existing
* group stop. If participated in a group stop (and thus slept), %true is
* returned with siglock released.
*
* If ptraced, this function doesn't handle stop itself. Instead,
* %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
* untouched. The caller must ensure that INTERRUPT trap handling takes
* places afterwards.
*
* CONTEXT:
* Must be called with @current->sighand->siglock held, which is released
* on %true return.
*
* RETURNS:
* %false if group stop is already cancelled or ptrace trap is scheduled.
* %true if participated in group stop.
*/
static bool do_signal_stop(int signr)
__releases(¤t->sighand->siglock)
{
struct signal_struct *sig = current->signal;
if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
struct task_struct *t;
/* signr will be recorded in task->jobctl for retries */
WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
unlikely(sig->group_exec_task))
return false;
/*
* There is no group stop already in progress. We must
* initiate one now.
*
* While ptraced, a task may be resumed while group stop is
* still in effect and then receive a stop signal and
* initiate another group stop. This deviates from the
* usual behavior as two consecutive stop signals can't
* cause two group stops when !ptraced. That is why we
* also check !task_is_stopped(t) below.
*
* The condition can be distinguished by testing whether
* SIGNAL_STOP_STOPPED is already set. Don't generate
* group_exit_code in such case.
*
* This is not necessary for SIGNAL_STOP_CONTINUED because
* an intervening stop signal is required to cause two
* continued events regardless of ptrace.
*/
if (!(sig->flags & SIGNAL_STOP_STOPPED))
sig->group_exit_code = signr;
sig->group_stop_count = 0;
if (task_set_jobctl_pending(current, signr | gstop))
sig->group_stop_count++;
t = current;
while_each_thread(current, t) {
/*
* Setting state to TASK_STOPPED for a group
* stop is always done with the siglock held,
* so this check has no races.
*/
if (!task_is_stopped(t) &&
task_set_jobctl_pending(t, signr | gstop)) {
sig->group_stop_count++;
if (likely(!(t->ptrace & PT_SEIZED)))
signal_wake_up(t, 0);
else
ptrace_trap_notify(t);
}
}
}
if (likely(!current->ptrace)) {
int notify = 0;
/*
* If there are no other threads in the group, or if there
* is a group stop in progress and we are the last to stop,
* report to the parent.
*/
if (task_participate_group_stop(current))
notify = CLD_STOPPED;
current->jobctl |= JOBCTL_STOPPED;
set_special_state(TASK_STOPPED);
spin_unlock_irq(¤t->sighand->siglock);
/*
* Notify the parent of the group stop completion. Because
* we're not holding either the siglock or tasklist_lock
* here, ptracer may attach inbetween; however, this is for
* group stop and should always be delivered to the real
* parent of the group leader. The new ptracer will get
* its notification when this task transitions into
* TASK_TRACED.
*/
if (notify) {
read_lock(&tasklist_lock);
do_notify_parent_cldstop(current, false, notify);
read_unlock(&tasklist_lock);
}
/* Now we don't run again until woken by SIGCONT or SIGKILL */
cgroup_enter_frozen();
schedule();
return true;
} else {
/*
* While ptraced, group stop is handled by STOP trap.
* Schedule it and let the caller deal with it.
*/
task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
return false;
}
}
/**
* do_jobctl_trap - take care of ptrace jobctl traps
*
* When PT_SEIZED, it's used for both group stop and explicit
* SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
* accompanying siginfo. If stopped, lower eight bits of exit_code contain
* the stop signal; otherwise, %SIGTRAP.
*
* When !PT_SEIZED, it's used only for group stop trap with stop signal
* number as exit_code and no siginfo.
*
* CONTEXT:
* Must be called with @current->sighand->siglock held, which may be
* released and re-acquired before returning with intervening sleep.
*/
static void do_jobctl_trap(void)
{
struct signal_struct *signal = current->signal;
int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
if (current->ptrace & PT_SEIZED) {
if (!signal->group_stop_count &&
!(signal->flags & SIGNAL_STOP_STOPPED))
signr = SIGTRAP;
WARN_ON_ONCE(!signr);
ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
CLD_STOPPED, 0);
} else {
WARN_ON_ONCE(!signr);
ptrace_stop(signr, CLD_STOPPED, 0, NULL);
}
}
/**
* do_freezer_trap - handle the freezer jobctl trap
*
* Puts the task into frozen state, if only the task is not about to quit.
* In this case it drops JOBCTL_TRAP_FREEZE.
*
* CONTEXT:
* Must be called with @current->sighand->siglock held,
* which is always released before returning.
*/
static void do_freezer_trap(void)
__releases(¤t->sighand->siglock)
{
/*
* If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
* let's make another loop to give it a chance to be handled.
* In any case, we'll return back.
*/
if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
JOBCTL_TRAP_FREEZE) {
spin_unlock_irq(¤t->sighand->siglock);
return;
}
/*
* Now we're sure that there is no pending fatal signal and no
* pending traps. Clear TIF_SIGPENDING to not get out of schedule()
* immediately (if there is a non-fatal signal pending), and
* put the task into sleep.
*/
__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
clear_thread_flag(TIF_SIGPENDING);
spin_unlock_irq(¤t->sighand->siglock);
cgroup_enter_frozen();
schedule();
}
static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
{
/*
* We do not check sig_kernel_stop(signr) but set this marker
* unconditionally because we do not know whether debugger will
* change signr. This flag has no meaning unless we are going
* to stop after return from ptrace_stop(). In this case it will
* be checked in do_signal_stop(), we should only stop if it was
* not cleared by SIGCONT while we were sleeping. See also the
* comment in dequeue_signal().
*/
current->jobctl |= JOBCTL_STOP_DEQUEUED;
signr = ptrace_stop(signr, CLD_TRAPPED, 0, info);
/* We're back. Did the debugger cancel the sig? */
if (signr == 0)
return signr;
/*
* Update the siginfo structure if the signal has
* changed. If the debugger wanted something
* specific in the siginfo structure then it should
* have updated *info via PTRACE_SETSIGINFO.
*/
if (signr != info->si_signo) {
clear_siginfo(info);
info->si_signo = signr;
info->si_errno = 0;
info->si_code = SI_USER;
rcu_read_lock();
info->si_pid = task_pid_vnr(current->parent);
info->si_uid = from_kuid_munged(current_user_ns(),
task_uid(current->parent));
rcu_read_unlock();
}
/* If the (new) signal is now blocked, requeue it. */
if (sigismember(¤t->blocked, signr) ||
fatal_signal_pending(current)) {
send_signal_locked(signr, info, current, type);
signr = 0;
}
return signr;
}
static void hide_si_addr_tag_bits(struct ksignal *ksig)
{
switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
case SIL_FAULT:
case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
case SIL_FAULT_PERF_EVENT:
ksig->info.si_addr = arch_untagged_si_addr(
ksig->info.si_addr, ksig->sig, ksig->info.si_code);
break;
case SIL_KILL:
case SIL_TIMER:
case SIL_POLL:
case SIL_CHLD:
case SIL_RT:
case SIL_SYS:
break;
}
}
bool get_signal(struct ksignal *ksig)
{
struct sighand_struct *sighand = current->sighand;
struct signal_struct *signal = current->signal;
int signr;
clear_notify_signal();
if (unlikely(task_work_pending(current)))
task_work_run();
if (!task_sigpending(current))
return false;
if (unlikely(uprobe_deny_signal()))
return false;
/*
* Do this once, we can't return to user-mode if freezing() == T.
* do_signal_stop() and ptrace_stop() do freezable_schedule() and
* thus do not need another check after return.
*/
try_to_freeze();
relock:
spin_lock_irq(&sighand->siglock);
/*
* Every stopped thread goes here after wakeup. Check to see if
* we should notify the parent, prepare_signal(SIGCONT) encodes
* the CLD_ si_code into SIGNAL_CLD_MASK bits.
*/
if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
int why;
if (signal->flags & SIGNAL_CLD_CONTINUED)
why = CLD_CONTINUED;
else
why = CLD_STOPPED;
signal->flags &= ~SIGNAL_CLD_MASK;
spin_unlock_irq(&sighand->siglock);
/*
* Notify the parent that we're continuing. This event is
* always per-process and doesn't make whole lot of sense
* for ptracers, who shouldn't consume the state via
* wait(2) either, but, for backward compatibility, notify
* the ptracer of the group leader too unless it's gonna be
* a duplicate.
*/
read_lock(&tasklist_lock);
do_notify_parent_cldstop(current, false, why);
if (ptrace_reparented(current->group_leader))
do_notify_parent_cldstop(current->group_leader,
true, why);
read_unlock(&tasklist_lock);
goto relock;
}
for (;;) {
struct k_sigaction *ka;
enum pid_type type;
/* Has this task already been marked for death? */
if ((signal->flags & SIGNAL_GROUP_EXIT) ||
signal->group_exec_task) {
clear_siginfo(&ksig->info);
ksig->info.si_signo = signr = SIGKILL;
sigdelset(¤t->pending.signal, SIGKILL);
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
&sighand->action[SIGKILL - 1]);
recalc_sigpending();
goto fatal;
}
if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
do_signal_stop(0))
goto relock;
if (unlikely(current->jobctl &
(JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
if (current->jobctl & JOBCTL_TRAP_MASK) {
do_jobctl_trap();
spin_unlock_irq(&sighand->siglock);
} else if (current->jobctl & JOBCTL_TRAP_FREEZE)
do_freezer_trap();
goto relock;
}
/*
* If the task is leaving the frozen state, let's update
* cgroup counters and reset the frozen bit.
*/
if (unlikely(cgroup_task_frozen(current))) {
spin_unlock_irq(&sighand->siglock);
cgroup_leave_frozen(false);
goto relock;
}
/*
* Signals generated by the execution of an instruction
* need to be delivered before any other pending signals
* so that the instruction pointer in the signal stack
* frame points to the faulting instruction.
*/
type = PIDTYPE_PID;
signr = dequeue_synchronous_signal(&ksig->info);
if (!signr)
signr = dequeue_signal(current, ¤t->blocked,
&ksig->info, &type);
if (!signr)
break; /* will return 0 */
if (unlikely(current->ptrace) && (signr != SIGKILL) &&
!(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
signr = ptrace_signal(signr, &ksig->info, type);
if (!signr)
continue;
}
ka = &sighand->action[signr-1];
/* Trace actually delivered signals. */
trace_signal_deliver(signr, &ksig->info, ka);
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
if (ka->sa.sa_handler != SIG_DFL) {
/* Run the handler. */
ksig->ka = *ka;
if (ka->sa.sa_flags & SA_ONESHOT)
ka->sa.sa_handler = SIG_DFL;
break; /* will return non-zero "signr" value */
}
/*
* Now we are doing the default action for this signal.
*/
if (sig_kernel_ignore(signr)) /* Default is nothing. */
continue;
/*
* Global init gets no signals it doesn't want.
* Container-init gets no signals it doesn't want from same
* container.
*
* Note that if global/container-init sees a sig_kernel_only()
* signal here, the signal must have been generated internally
* or must have come from an ancestor namespace. In either
* case, the signal cannot be dropped.
*/
if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
!sig_kernel_only(signr))
continue;
if (sig_kernel_stop(signr)) {
/*
* The default action is to stop all threads in
* the thread group. The job control signals
* do nothing in an orphaned pgrp, but SIGSTOP
* always works. Note that siglock needs to be
* dropped during the call to is_orphaned_pgrp()
* because of lock ordering with tasklist_lock.
* This allows an intervening SIGCONT to be posted.
* We need to check for that and bail out if necessary.
*/
if (signr != SIGSTOP) {
spin_unlock_irq(&sighand->siglock);
/* signals can be posted during this window */
if (is_current_pgrp_orphaned())
goto relock;
spin_lock_irq(&sighand->siglock);
}
if (likely(do_signal_stop(ksig->info.si_signo))) {
/* It released the siglock. */
goto relock;
}
/*
* We didn't actually stop, due to a race
* with SIGCONT or something like that.
*/
continue;
}
fatal:
spin_unlock_irq(&sighand->siglock);
if (unlikely(cgroup_task_frozen(current)))
cgroup_leave_frozen(true);
/*
* Anything else is fatal, maybe with a core dump.
*/
current->flags |= PF_SIGNALED;
if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
print_fatal_signal(ksig->info.si_signo);
proc_coredump_connector(current);
/*
* If it was able to dump core, this kills all
* other threads in the group and synchronizes with
* their demise. If we lost the race with another
* thread getting here, it set group_exit_code
* first and our do_group_exit call below will use
* that value and ignore the one we pass it.
*/
do_coredump(&ksig->info);
}
/*
* PF_USER_WORKER threads will catch and exit on fatal signals
* themselves. They have cleanup that must be performed, so
* we cannot call do_exit() on their behalf.
*/
if (current->flags & PF_USER_WORKER)
goto out;
/*
* Death signals, no core dump.
*/
do_group_exit(ksig->info.si_signo);
/* NOTREACHED */
}
spin_unlock_irq(&sighand->siglock);
out:
ksig->sig = signr;
if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
hide_si_addr_tag_bits(ksig);
return ksig->sig > 0;
}
/**
* signal_delivered - called after signal delivery to update blocked signals
* @ksig: kernel signal struct
* @stepping: nonzero if debugger single-step or block-step in use
*
* This function should be called when a signal has successfully been
* delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
* is always blocked), and the signal itself is blocked unless %SA_NODEFER
* is set in @ksig->ka.sa.sa_flags. Tracing is notified.
*/
static void signal_delivered(struct ksignal *ksig, int stepping)
{
sigset_t blocked;
/* A signal was successfully delivered, and the
saved sigmask was stored on the signal frame,
and will be restored by sigreturn. So we can
simply clear the restore sigmask flag. */
clear_restore_sigmask();
sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
sigaddset(&blocked, ksig->sig);
set_current_blocked(&blocked);
if (current->sas_ss_flags & SS_AUTODISARM)
sas_ss_reset(current);
if (stepping)
ptrace_notify(SIGTRAP, 0);
}
void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
{
if (failed)
force_sigsegv(ksig->sig);
else
signal_delivered(ksig, stepping);
}
/*
* It could be that complete_signal() picked us to notify about the
* group-wide signal. Other threads should be notified now to take
* the shared signals in @which since we will not.
*/
static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
{
sigset_t retarget;
struct task_struct *t;
sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
if (sigisemptyset(&retarget))
return;
t = tsk;
while_each_thread(tsk, t) {
if (t->flags & PF_EXITING)
continue;
if (!has_pending_signals(&retarget, &t->blocked))
continue;
/* Remove the signals this thread can handle. */
sigandsets(&retarget, &retarget, &t->blocked);
if (!task_sigpending(t))
signal_wake_up(t, 0);
if (sigisemptyset(&retarget))
break;
}
}
void exit_signals(struct task_struct *tsk)
{
int group_stop = 0;
sigset_t unblocked;
/*
* @tsk is about to have PF_EXITING set - lock out users which
* expect stable threadgroup.
*/
cgroup_threadgroup_change_begin(tsk);
if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
sched_mm_cid_exit_signals(tsk);
tsk->flags |= PF_EXITING;
cgroup_threadgroup_change_end(tsk);
return;
}
spin_lock_irq(&tsk->sighand->siglock);
/*
* From now this task is not visible for group-wide signals,
* see wants_signal(), do_signal_stop().
*/
sched_mm_cid_exit_signals(tsk);
tsk->flags |= PF_EXITING;
cgroup_threadgroup_change_end(tsk);
if (!task_sigpending(tsk))
goto out;
unblocked = tsk->blocked;
signotset(&unblocked);
retarget_shared_pending(tsk, &unblocked);
if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
task_participate_group_stop(tsk))
group_stop = CLD_STOPPED;
out:
spin_unlock_irq(&tsk->sighand->siglock);
/*
* If group stop has completed, deliver the notification. This
* should always go to the real parent of the group leader.
*/
if (unlikely(group_stop)) {
read_lock(&tasklist_lock);
do_notify_parent_cldstop(tsk, false, group_stop);
read_unlock(&tasklist_lock);
}
}
/*
* System call entry points.
*/
/**
* sys_restart_syscall - restart a system call
*/
SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = ¤t->restart_block;
return restart->fn(restart);
}
long do_no_restart_syscall(struct restart_block *param)
{
return -EINTR;
}
static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
{
if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
sigset_t newblocked;
/* A set of now blocked but previously unblocked signals. */
sigandnsets(&newblocked, newset, ¤t->blocked);
retarget_shared_pending(tsk, &newblocked);
}
tsk->blocked = *newset;
recalc_sigpending();
}
/**
* set_current_blocked - change current->blocked mask
* @newset: new mask
*
* It is wrong to change ->blocked directly, this helper should be used
* to ensure the process can't miss a shared signal we are going to block.
*/
void set_current_blocked(sigset_t *newset)
{
sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
__set_current_blocked(newset);
}
void __set_current_blocked(const sigset_t *newset)
{
struct task_struct *tsk = current;
/*
* In case the signal mask hasn't changed, there is nothing we need
* to do. The current->blocked shouldn't be modified by other task.
*/
if (sigequalsets(&tsk->blocked, newset))
return;
spin_lock_irq(&tsk->sighand->siglock);
__set_task_blocked(tsk, newset);
spin_unlock_irq(&tsk->sighand->siglock);
}
/*
* This is also useful for kernel threads that want to temporarily
* (or permanently) block certain signals.
*
* NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
* interface happily blocks "unblockable" signals like SIGKILL
* and friends.
*/
int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
{
struct task_struct *tsk = current;
sigset_t newset;
/* Lockless, only current can change ->blocked, never from irq */
if (oldset)
*oldset = tsk->blocked;
switch (how) {
case SIG_BLOCK:
sigorsets(&newset, &tsk->blocked, set);
break;
case SIG_UNBLOCK:
sigandnsets(&newset, &tsk->blocked, set);
break;
case SIG_SETMASK:
newset = *set;
break;
default:
return -EINVAL;
}
__set_current_blocked(&newset);
return 0;
}
EXPORT_SYMBOL(sigprocmask);
/*
* The api helps set app-provided sigmasks.
*
* This is useful for syscalls such as ppoll, pselect, io_pgetevents and
* epoll_pwait where a new sigmask is passed from userland for the syscalls.
*
* Note that it does set_restore_sigmask() in advance, so it must be always
* paired with restore_saved_sigmask_unless() before return from syscall.
*/
int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
{
sigset_t kmask;
if (!umask)
return 0;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
return -EFAULT;
set_restore_sigmask();
current->saved_sigmask = current->blocked;
set_current_blocked(&kmask);
return 0;
}
#ifdef CONFIG_COMPAT
int set_compat_user_sigmask(const compat_sigset_t __user *umask,
size_t sigsetsize)
{
sigset_t kmask;
if (!umask)
return 0;
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (get_compat_sigset(&kmask, umask))
return -EFAULT;
set_restore_sigmask();
current->saved_sigmask = current->blocked;
set_current_blocked(&kmask);
return 0;
}
#endif
/**
* sys_rt_sigprocmask - change the list of currently blocked signals
* @how: whether to add, remove, or set signals
* @nset: stores pending signals
* @oset: previous value of signal mask if non-null
* @sigsetsize: size of sigset_t type
*/
SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
sigset_t __user *, oset, size_t, sigsetsize)
{
sigset_t old_set, new_set;
int error;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
old_set = current->blocked;
if (nset) {
if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
return -EFAULT;
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
error = sigprocmask(how, &new_set, NULL);
if (error)
return error;
}
if (oset) {
if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
return -EFAULT;
}
return 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
{
sigset_t old_set = current->blocked;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (nset) {
sigset_t new_set;
int error;
if (get_compat_sigset(&new_set, nset))
return -EFAULT;
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
error = sigprocmask(how, &new_set, NULL);
if (error)
return error;
}
return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
}
#endif
static void do_sigpending(sigset_t *set)
{
spin_lock_irq(¤t->sighand->siglock);
sigorsets(set, ¤t->pending.signal,
¤t->signal->shared_pending.signal);
spin_unlock_irq(¤t->sighand->siglock);
/* Outside the lock because only this thread touches it. */
sigandsets(set, ¤t->blocked, set);
}
/**
* sys_rt_sigpending - examine a pending signal that has been raised
* while blocked
* @uset: stores pending signals
* @sigsetsize: size of sigset_t type or larger
*/
SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
{
sigset_t set;
if (sigsetsize > sizeof(*uset))
return -EINVAL;
do_sigpending(&set);
if (copy_to_user(uset, &set, sigsetsize))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
compat_size_t, sigsetsize)
{
sigset_t set;
if (sigsetsize > sizeof(*uset))
return -EINVAL;
do_sigpending(&set);
return put_compat_sigset(uset, &set, sigsetsize);
}
#endif
static const struct {
unsigned char limit, layout;
} sig_sicodes[] = {
[SIGILL] = { NSIGILL, SIL_FAULT },
[SIGFPE] = { NSIGFPE, SIL_FAULT },
[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
[SIGBUS] = { NSIGBUS, SIL_FAULT },
[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
#if defined(SIGEMT)
[SIGEMT] = { NSIGEMT, SIL_FAULT },
#endif
[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
[SIGPOLL] = { NSIGPOLL, SIL_POLL },
[SIGSYS] = { NSIGSYS, SIL_SYS },
};
static bool known_siginfo_layout(unsigned sig, int si_code)
{
if (si_code == SI_KERNEL)
return true;
else if ((si_code > SI_USER)) {
if (sig_specific_sicodes(sig)) {
if (si_code <= sig_sicodes[sig].limit)
return true;
}
else if (si_code <= NSIGPOLL)
return true;
}
else if (si_code >= SI_DETHREAD)
return true;
else if (si_code == SI_ASYNCNL)
return true;
return false;
}
enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
{
enum siginfo_layout layout = SIL_KILL;
if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
if ((sig < ARRAY_SIZE(sig_sicodes)) &&
(si_code <= sig_sicodes[sig].limit)) {
layout = sig_sicodes[sig].layout;
/* Handle the exceptions */
if ((sig == SIGBUS) &&
(si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
layout = SIL_FAULT_MCEERR;
else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
layout = SIL_FAULT_BNDERR;
#ifdef SEGV_PKUERR
else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
layout = SIL_FAULT_PKUERR;
#endif
else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
layout = SIL_FAULT_PERF_EVENT;
else if (IS_ENABLED(CONFIG_SPARC) &&
(sig == SIGILL) && (si_code == ILL_ILLTRP))
layout = SIL_FAULT_TRAPNO;
else if (IS_ENABLED(CONFIG_ALPHA) &&
((sig == SIGFPE) ||
((sig == SIGTRAP) && (si_code == TRAP_UNK))))
layout = SIL_FAULT_TRAPNO;
}
else if (si_code <= NSIGPOLL)
layout = SIL_POLL;
} else {
if (si_code == SI_TIMER)
layout = SIL_TIMER;
else if (si_code == SI_SIGIO)
layout = SIL_POLL;
else if (si_code < 0)
layout = SIL_RT;
}
return layout;
}
static inline char __user *si_expansion(const siginfo_t __user *info)
{
return ((char __user *)info) + sizeof(struct kernel_siginfo);
}
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
{
char __user *expansion = si_expansion(to);
if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
return -EFAULT;
if (clear_user(expansion, SI_EXPANSION_SIZE))
return -EFAULT;
return 0;
}
static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
const siginfo_t __user *from)
{
if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
char __user *expansion = si_expansion(from);
char buf[SI_EXPANSION_SIZE];
int i;
/*
* An unknown si_code might need more than
* sizeof(struct kernel_siginfo) bytes. Verify all of the
* extra bytes are 0. This guarantees copy_siginfo_to_user
* will return this data to userspace exactly.
*/
if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
return -EFAULT;
for (i = 0; i < SI_EXPANSION_SIZE; i++) {
if (buf[i] != 0)
return -E2BIG;
}
}
return 0;
}
static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
const siginfo_t __user *from)
{
if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
return -EFAULT;
to->si_signo = signo;
return post_copy_siginfo_from_user(to, from);
}
int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
{
if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
return -EFAULT;
return post_copy_siginfo_from_user(to, from);
}
#ifdef CONFIG_COMPAT
/**
* copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
* @to: compat siginfo destination
* @from: kernel siginfo source
*
* Note: This function does not work properly for the SIGCHLD on x32, but
* fortunately it doesn't have to. The only valid callers for this function are
* copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
* The latter does not care because SIGCHLD will never cause a coredump.
*/
void copy_siginfo_to_external32(struct compat_siginfo *to,
const struct kernel_siginfo *from)
{
memset(to, 0, sizeof(*to));
to->si_signo = from->si_signo;
to->si_errno = from->si_errno;
to->si_code = from->si_code;
switch(siginfo_layout(from->si_signo, from->si_code)) {
case SIL_KILL:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
break;
case SIL_TIMER:
to->si_tid = from->si_tid;
to->si_overrun = from->si_overrun;
to->si_int = from->si_int;
break;
case SIL_POLL:
to->si_band = from->si_band;
to->si_fd = from->si_fd;
break;
case SIL_FAULT:
to->si_addr = ptr_to_compat(from->si_addr);
break;
case SIL_FAULT_TRAPNO:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_trapno = from->si_trapno;
break;
case SIL_FAULT_MCEERR:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_lower = ptr_to_compat(from->si_lower);
to->si_upper = ptr_to_compat(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_pkey = from->si_pkey;
break;
case SIL_FAULT_PERF_EVENT:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
to->si_perf_flags = from->si_perf_flags;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
to->si_status = from->si_status;
to->si_utime = from->si_utime;
to->si_stime = from->si_stime;
break;
case SIL_RT:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
to->si_int = from->si_int;
break;
case SIL_SYS:
to->si_call_addr = ptr_to_compat(from->si_call_addr);
to->si_syscall = from->si_syscall;
to->si_arch = from->si_arch;
break;
}
}
int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
const struct kernel_siginfo *from)
{
struct compat_siginfo new;
copy_siginfo_to_external32(&new, from);
if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
return -EFAULT;
return 0;
}
static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
const struct compat_siginfo *from)
{
clear_siginfo(to);
to->si_signo = from->si_signo;
to->si_errno = from->si_errno;
to->si_code = from->si_code;
switch(siginfo_layout(from->si_signo, from->si_code)) {
case SIL_KILL:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
break;
case SIL_TIMER:
to->si_tid = from->si_tid;
to->si_overrun = from->si_overrun;
to->si_int = from->si_int;
break;
case SIL_POLL:
to->si_band = from->si_band;
to->si_fd = from->si_fd;
break;
case SIL_FAULT:
to->si_addr = compat_ptr(from->si_addr);
break;
case SIL_FAULT_TRAPNO:
to->si_addr = compat_ptr(from->si_addr);
to->si_trapno = from->si_trapno;
break;
case SIL_FAULT_MCEERR:
to->si_addr = compat_ptr(from->si_addr);
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = compat_ptr(from->si_addr);
to->si_lower = compat_ptr(from->si_lower);
to->si_upper = compat_ptr(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = compat_ptr(from->si_addr);
to->si_pkey = from->si_pkey;
break;
case SIL_FAULT_PERF_EVENT:
to->si_addr = compat_ptr(from->si_addr);
to->si_perf_data = from->si_perf_data;
to->si_perf_type = from->si_perf_type;
to->si_perf_flags = from->si_perf_flags;
break;
case SIL_CHLD:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
to->si_status = from->si_status;
#ifdef CONFIG_X86_X32_ABI
if (in_x32_syscall()) {
to->si_utime = from->_sifields._sigchld_x32._utime;
to->si_stime = from->_sifields._sigchld_x32._stime;
} else
#endif
{
to->si_utime = from->si_utime;
to->si_stime = from->si_stime;
}
break;
case SIL_RT:
to->si_pid = from->si_pid;
to->si_uid = from->si_uid;
to->si_int = from->si_int;
break;
case SIL_SYS:
to->si_call_addr = compat_ptr(from->si_call_addr);
to->si_syscall = from->si_syscall;
to->si_arch = from->si_arch;
break;
}
return 0;
}
static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
const struct compat_siginfo __user *ufrom)
{
struct compat_siginfo from;
if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
return -EFAULT;
from.si_signo = signo;
return post_copy_siginfo_from_user32(to, &from);
}
int copy_siginfo_from_user32(struct kernel_siginfo *to,
const struct compat_siginfo __user *ufrom)
{
struct compat_siginfo from;
if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
return -EFAULT;
return post_copy_siginfo_from_user32(to, &from);
}
#endif /* CONFIG_COMPAT */
/**
* do_sigtimedwait - wait for queued signals specified in @which
* @which: queued signals to wait for
* @info: if non-null, the signal's siginfo is returned here
* @ts: upper bound on process time suspension
*/
static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
const struct timespec64 *ts)
{
ktime_t *to = NULL, timeout = KTIME_MAX;
struct task_struct *tsk = current;
sigset_t mask = *which;
enum pid_type type;
int sig, ret = 0;
if (ts) {
if (!timespec64_valid(ts))
return -EINVAL;
timeout = timespec64_to_ktime(*ts);
to = &timeout;
}
/*
* Invert the set of allowed signals to get those we want to block.
*/
sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
signotset(&mask);
spin_lock_irq(&tsk->sighand->siglock);
sig = dequeue_signal(tsk, &mask, info, &type);
if (!sig && timeout) {
/*
* None ready, temporarily unblock those we're interested
* while we are sleeping in so that we'll be awakened when
* they arrive. Unblocking is always fine, we can avoid
* set_current_blocked().
*/
tsk->real_blocked = tsk->blocked;
sigandsets(&tsk->blocked, &tsk->blocked, &mask);
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
__set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
HRTIMER_MODE_REL);
spin_lock_irq(&tsk->sighand->siglock);
__set_task_blocked(tsk, &tsk->real_blocked);
sigemptyset(&tsk->real_blocked);
sig = dequeue_signal(tsk, &mask, info, &type);
}
spin_unlock_irq(&tsk->sighand->siglock);
if (sig)
return sig;
return ret ? -EINTR : -EAGAIN;
}
/**
* sys_rt_sigtimedwait - synchronously wait for queued signals specified
* in @uthese
* @uthese: queued signals to wait for
* @uinfo: if non-null, the signal's siginfo is returned here
* @uts: upper bound on process time suspension
* @sigsetsize: size of sigset_t type
*/
SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
siginfo_t __user *, uinfo,
const struct __kernel_timespec __user *, uts,
size_t, sigsetsize)
{
sigset_t these;
struct timespec64 ts;
kernel_siginfo_t info;
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
if (uts) {
if (get_timespec64(&ts, uts))
return -EFAULT;
}
ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user(uinfo, &info))
ret = -EFAULT;
}
return ret;
}
#ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
siginfo_t __user *, uinfo,
const struct old_timespec32 __user *, uts,
size_t, sigsetsize)
{
sigset_t these;
struct timespec64 ts;
kernel_siginfo_t info;
int ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
if (uts) {
if (get_old_timespec32(&ts, uts))
return -EFAULT;
}
ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user(uinfo, &info))
ret = -EFAULT;
}
return ret;
}
#endif
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
struct compat_siginfo __user *, uinfo,
struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
{
sigset_t s;
struct timespec64 t;
kernel_siginfo_t info;
long ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (get_compat_sigset(&s, uthese))
return -EFAULT;
if (uts) {
if (get_timespec64(&t, uts))
return -EFAULT;
}
ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user32(uinfo, &info))
ret = -EFAULT;
}
return ret;
}
#ifdef CONFIG_COMPAT_32BIT_TIME
COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
struct compat_siginfo __user *, uinfo,
struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
{
sigset_t s;
struct timespec64 t;
kernel_siginfo_t info;
long ret;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (get_compat_sigset(&s, uthese))
return -EFAULT;
if (uts) {
if (get_old_timespec32(&t, uts))
return -EFAULT;
}
ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
if (ret > 0 && uinfo) {
if (copy_siginfo_to_user32(uinfo, &info))
ret = -EFAULT;
}
return ret;
}
#endif
#endif
static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
{
clear_siginfo(info);
info->si_signo = sig;
info->si_errno = 0;
info->si_code = SI_USER;
info->si_pid = task_tgid_vnr(current);
info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
}
/**
* sys_kill - send a signal to a process
* @pid: the PID of the process
* @sig: signal to be sent
*/
SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct kernel_siginfo info;
prepare_kill_siginfo(sig, &info);
return kill_something_info(sig, &info, pid);
}
/*
* Verify that the signaler and signalee either are in the same pid namespace
* or that the signaler's pid namespace is an ancestor of the signalee's pid
* namespace.
*/
static bool access_pidfd_pidns(struct pid *pid)
{
struct pid_namespace *active = task_active_pid_ns(current);
struct pid_namespace *p = ns_of_pid(pid);
for (;;) {
if (!p)
return false;
if (p == active)
break;
p = p->parent;
}
return true;
}
static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
siginfo_t __user *info)
{
#ifdef CONFIG_COMPAT
/*
* Avoid hooking up compat syscalls and instead handle necessary
* conversions here. Note, this is a stop-gap measure and should not be
* considered a generic solution.
*/
if (in_compat_syscall())
return copy_siginfo_from_user32(
kinfo, (struct compat_siginfo __user *)info);
#endif
return copy_siginfo_from_user(kinfo, info);
}
static struct pid *pidfd_to_pid(const struct file *file)
{
struct pid *pid;
pid = pidfd_pid(file);
if (!IS_ERR(pid))
return pid;
return tgid_pidfd_to_pid(file);
}
/**
* sys_pidfd_send_signal - Signal a process through a pidfd
* @pidfd: file descriptor of the process
* @sig: signal to send
* @info: signal info
* @flags: future flags
*
* The syscall currently only signals via PIDTYPE_PID which covers
* kill(<positive-pid>, <signal>. It does not signal threads or process
* groups.
* In order to extend the syscall to threads and process groups the @flags
* argument should be used. In essence, the @flags argument will determine
* what is signaled and not the file descriptor itself. Put in other words,
* grouping is a property of the flags argument not a property of the file
* descriptor.
*
* Return: 0 on success, negative errno on failure
*/
SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
siginfo_t __user *, info, unsigned int, flags)
{
int ret;
struct fd f;
struct pid *pid;
kernel_siginfo_t kinfo;
/* Enforce flags be set to 0 until we add an extension. */
if (flags)
return -EINVAL;
f = fdget(pidfd);
if (!f.file)
return -EBADF;
/* Is this a pidfd? */
pid = pidfd_to_pid(f.file);
if (IS_ERR(pid)) {
ret = PTR_ERR(pid);
goto err;
}
ret = -EINVAL;
if (!access_pidfd_pidns(pid))
goto err;
if (info) {
ret = copy_siginfo_from_user_any(&kinfo, info);
if (unlikely(ret))
goto err;
ret = -EINVAL;
if (unlikely(sig != kinfo.si_signo))
goto err;
/* Only allow sending arbitrary signals to yourself. */
ret = -EPERM;
if ((task_pid(current) != pid) &&
(kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
goto err;
} else {
prepare_kill_siginfo(sig, &kinfo);
}
ret = kill_pid_info(sig, &kinfo, pid);
err:
fdput(f);
return ret;
}
static int
do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
{
struct task_struct *p;
int error = -ESRCH;
rcu_read_lock();
p = find_task_by_vpid(pid);
if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
error = check_kill_permission(sig, info, p);
/*
* The null signal is a permissions and process existence
* probe. No signal is actually delivered.
*/
if (!error && sig) {
error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
/*
* If lock_task_sighand() failed we pretend the task
* dies after receiving the signal. The window is tiny,
* and the signal is private anyway.
*/
if (unlikely(error == -ESRCH))
error = 0;
}
}
rcu_read_unlock();
return error;
}
static int do_tkill(pid_t tgid, pid_t pid, int sig)
{
struct kernel_siginfo info;
clear_siginfo(&info);
info.si_signo = sig;
info.si_errno = 0;
info.si_code = SI_TKILL;
info.si_pid = task_tgid_vnr(current);
info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
return do_send_specific(tgid, pid, sig, &info);
}
/**
* sys_tgkill - send signal to one specific thread
* @tgid: the thread group ID of the thread
* @pid: the PID of the thread
* @sig: signal to be sent
*
* This syscall also checks the @tgid and returns -ESRCH even if the PID
* exists but it's not belonging to the target process anymore. This
* method solves the problem of threads exiting and PIDs getting reused.
*/
SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0 || tgid <= 0)
return -EINVAL;
return do_tkill(tgid, pid, sig);
}
/**
* sys_tkill - send signal to one specific task
* @pid: the PID of the task
* @sig: signal to be sent
*
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
{
/* This is only valid for single tasks */
if (pid <= 0)
return -EINVAL;
return do_tkill(0, pid, sig);
}
static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
{
/* Not even root can pretend to send signals from the kernel.
* Nor can they impersonate a kill()/tgkill(), which adds source info.
*/
if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
(task_pid_vnr(current) != pid))
return -EPERM;
/* POSIX.1b doesn't mention process groups. */
return kill_proc_info(sig, info, pid);
}
/**
* sys_rt_sigqueueinfo - send signal information to a signal
* @pid: the PID of the thread
* @sig: signal to be sent
* @uinfo: signal info to be sent
*/
SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
siginfo_t __user *, uinfo)
{
kernel_siginfo_t info;
int ret = __copy_siginfo_from_user(sig, &info, uinfo);
if (unlikely(ret))
return ret;
return do_rt_sigqueueinfo(pid, sig, &info);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
compat_pid_t, pid,
int, sig,
struct compat_siginfo __user *, uinfo)
{
kernel_siginfo_t info;
int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
if (unlikely(ret))
return ret;
return do_rt_sigqueueinfo(pid, sig, &info);
}
#endif
static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
{
/* This is only valid for single tasks */
if (pid <= 0 || tgid <= 0)
return -EINVAL;
/* Not even root can pretend to send signals from the kernel.
* Nor can they impersonate a kill()/tgkill(), which adds source info.
*/
if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
(task_pid_vnr(current) != pid))
return -EPERM;
return do_send_specific(tgid, pid, sig, info);
}
SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
siginfo_t __user *, uinfo)
{
kernel_siginfo_t info;
int ret = __copy_siginfo_from_user(sig, &info, uinfo);
if (unlikely(ret))
return ret;
return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
compat_pid_t, tgid,
compat_pid_t, pid,
int, sig,
struct compat_siginfo __user *, uinfo)
{
kernel_siginfo_t info;
int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
if (unlikely(ret))
return ret;
return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
}
#endif
/*
* For kthreads only, must not be used if cloned with CLONE_SIGHAND
*/
void kernel_sigaction(int sig, __sighandler_t action)
{
spin_lock_irq(¤t->sighand->siglock);
current->sighand->action[sig - 1].sa.sa_handler = action;
if (action == SIG_IGN) {
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, sig);
flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
flush_sigqueue_mask(&mask, ¤t->pending);
recalc_sigpending();
}
spin_unlock_irq(¤t->sighand->siglock);
}
EXPORT_SYMBOL(kernel_sigaction);
void __weak sigaction_compat_abi(struct k_sigaction *act,
struct k_sigaction *oact)
{
}
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct task_struct *p = current, *t;
struct k_sigaction *k;
sigset_t mask;
if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
return -EINVAL;
k = &p->sighand->action[sig-1];
spin_lock_irq(&p->sighand->siglock);
if (k->sa.sa_flags & SA_IMMUTABLE) {
spin_unlock_irq(&p->sighand->siglock);
return -EINVAL;
}
if (oact)
*oact = *k;
/*
* Make sure that we never accidentally claim to support SA_UNSUPPORTED,
* e.g. by having an architecture use the bit in their uapi.
*/
BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
/*
* Clear unknown flag bits in order to allow userspace to detect missing
* support for flag bits and to allow the kernel to use non-uapi bits
* internally.
*/
if (act)
act->sa.sa_flags &= UAPI_SA_FLAGS;
if (oact)
oact->sa.sa_flags &= UAPI_SA_FLAGS;
sigaction_compat_abi(act, oact);
if (act) {
sigdelsetmask(&act->sa.sa_mask,
sigmask(SIGKILL) | sigmask(SIGSTOP));
*k = *act;
/*
* POSIX 3.3.1.3:
* "Setting a signal action to SIG_IGN for a signal that is
* pending shall cause the pending signal to be discarded,
* whether or not it is blocked."
*
* "Setting a signal action to SIG_DFL for a signal that is
* pending and whose default action is to ignore the signal
* (for example, SIGCHLD), shall cause the pending signal to
* be discarded, whether or not it is blocked"
*/
if (sig_handler_ignored(sig_handler(p, sig), sig)) {
sigemptyset(&mask);
sigaddset(&mask, sig);
flush_sigqueue_mask(&mask, &p->signal->shared_pending);
for_each_thread(p, t)
flush_sigqueue_mask(&mask, &t->pending);
}
}
spin_unlock_irq(&p->sighand->siglock);
return 0;
}
#ifdef CONFIG_DYNAMIC_SIGFRAME
static inline void sigaltstack_lock(void)
__acquires(¤t->sighand->siglock)
{
spin_lock_irq(¤t->sighand->siglock);
}
static inline void sigaltstack_unlock(void)
__releases(¤t->sighand->siglock)
{
spin_unlock_irq(¤t->sighand->siglock);
}
#else
static inline void sigaltstack_lock(void) { }
static inline void sigaltstack_unlock(void) { }
#endif
static int
do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
size_t min_ss_size)
{
struct task_struct *t = current;
int ret = 0;
if (oss) {
memset(oss, 0, sizeof(stack_t));
oss->ss_sp = (void __user *) t->sas_ss_sp;
oss->ss_size = t->sas_ss_size;
oss->ss_flags = sas_ss_flags(sp) |
(current->sas_ss_flags & SS_FLAG_BITS);
}
if (ss) {
void __user *ss_sp = ss->ss_sp;
size_t ss_size = ss->ss_size;
unsigned ss_flags = ss->ss_flags;
int ss_mode;
if (unlikely(on_sig_stack(sp)))
return -EPERM;
ss_mode = ss_flags & ~SS_FLAG_BITS;
if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
ss_mode != 0))
return -EINVAL;
/*
* Return before taking any locks if no actual
* sigaltstack changes were requested.
*/
if (t->sas_ss_sp == (unsigned long)ss_sp &&
t->sas_ss_size == ss_size &&
t->sas_ss_flags == ss_flags)
return 0;
sigaltstack_lock();
if (ss_mode == SS_DISABLE) {
ss_size = 0;
ss_sp = NULL;
} else {
if (unlikely(ss_size < min_ss_size))
ret = -ENOMEM;
if (!sigaltstack_size_valid(ss_size))
ret = -ENOMEM;
}
if (!ret) {
t->sas_ss_sp = (unsigned long) ss_sp;
t->sas_ss_size = ss_size;
t->sas_ss_flags = ss_flags;
}
sigaltstack_unlock();
}
return ret;
}
SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
{
stack_t new, old;
int err;
if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
return -EFAULT;
err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
current_user_stack_pointer(),
MINSIGSTKSZ);
if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
err = -EFAULT;
return err;
}
int restore_altstack(const stack_t __user *uss)
{
stack_t new;
if (copy_from_user(&new, uss, sizeof(stack_t)))
return -EFAULT;
(void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
MINSIGSTKSZ);
/* squash all but EFAULT for now */
return 0;
}
int __save_altstack(stack_t __user *uss, unsigned long sp)
{
struct task_struct *t = current;
int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
__put_user(t->sas_ss_flags, &uss->ss_flags) |
__put_user(t->sas_ss_size, &uss->ss_size);
return err;
}
#ifdef CONFIG_COMPAT
static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
compat_stack_t __user *uoss_ptr)
{
stack_t uss, uoss;
int ret;
if (uss_ptr) {
compat_stack_t uss32;
if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
return -EFAULT;
uss.ss_sp = compat_ptr(uss32.ss_sp);
uss.ss_flags = uss32.ss_flags;
uss.ss_size = uss32.ss_size;
}
ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
compat_user_stack_pointer(),
COMPAT_MINSIGSTKSZ);
if (ret >= 0 && uoss_ptr) {
compat_stack_t old;
memset(&old, 0, sizeof(old));
old.ss_sp = ptr_to_compat(uoss.ss_sp);
old.ss_flags = uoss.ss_flags;
old.ss_size = uoss.ss_size;
if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
ret = -EFAULT;
}
return ret;
}
COMPAT_SYSCALL_DEFINE2(sigaltstack,
const compat_stack_t __user *, uss_ptr,
compat_stack_t __user *, uoss_ptr)
{
return do_compat_sigaltstack(uss_ptr, uoss_ptr);
}
int compat_restore_altstack(const compat_stack_t __user *uss)
{
int err = do_compat_sigaltstack(uss, NULL);
/* squash all but -EFAULT for now */
return err == -EFAULT ? err : 0;
}
int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
{
int err;
struct task_struct *t = current;
err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
&uss->ss_sp) |
__put_user(t->sas_ss_flags, &uss->ss_flags) |
__put_user(t->sas_ss_size, &uss->ss_size);
return err;
}
#endif
#ifdef __ARCH_WANT_SYS_SIGPENDING
/**
* sys_sigpending - examine pending signals
* @uset: where mask of pending signal is returned
*/
SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
{
sigset_t set;
if (sizeof(old_sigset_t) > sizeof(*uset))
return -EINVAL;
do_sigpending(&set);
if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
{
sigset_t set;
do_sigpending(&set);
return put_user(set.sig[0], set32);
}
#endif
#endif
#ifdef __ARCH_WANT_SYS_SIGPROCMASK
/**
* sys_sigprocmask - examine and change blocked signals
* @how: whether to add, remove, or set signals
* @nset: signals to add or remove (if non-null)
* @oset: previous value of signal mask if non-null
*
* Some platforms have their own version with special arguments;
* others support only sys_rt_sigprocmask.
*/
SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
old_sigset_t __user *, oset)
{
old_sigset_t old_set, new_set;
sigset_t new_blocked;
old_set = current->blocked.sig[0];
if (nset) {
if (copy_from_user(&new_set, nset, sizeof(*nset)))
return -EFAULT;
new_blocked = current->blocked;
switch (how) {
case SIG_BLOCK:
sigaddsetmask(&new_blocked, new_set);
break;
case SIG_UNBLOCK:
sigdelsetmask(&new_blocked, new_set);
break;
case SIG_SETMASK:
new_blocked.sig[0] = new_set;
break;
default:
return -EINVAL;
}
set_current_blocked(&new_blocked);
}
if (oset) {
if (copy_to_user(oset, &old_set, sizeof(*oset)))
return -EFAULT;
}
return 0;
}
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifndef CONFIG_ODD_RT_SIGACTION
/**
* sys_rt_sigaction - alter an action taken by a process
* @sig: signal to be sent
* @act: new sigaction
* @oact: used to save the previous sigaction
* @sigsetsize: size of sigset_t type
*/
SYSCALL_DEFINE4(rt_sigaction, int, sig,
const struct sigaction __user *, act,
struct sigaction __user *, oact,
size_t, sigsetsize)
{
struct k_sigaction new_sa, old_sa;
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
return -EFAULT;
ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
if (ret)
return ret;
if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
return -EFAULT;
return 0;
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
const struct compat_sigaction __user *, act,
struct compat_sigaction __user *, oact,
compat_size_t, sigsetsize)
{
struct k_sigaction new_ka, old_ka;
#ifdef __ARCH_HAS_SA_RESTORER
compat_uptr_t restorer;
#endif
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (act) {
compat_uptr_t handler;
ret = get_user(handler, &act->sa_handler);
new_ka.sa.sa_handler = compat_ptr(handler);
#ifdef __ARCH_HAS_SA_RESTORER
ret |= get_user(restorer, &act->sa_restorer);
new_ka.sa.sa_restorer = compat_ptr(restorer);
#endif
ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
if (ret)
return -EFAULT;
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
&oact->sa_handler);
ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
sizeof(oact->sa_mask));
ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
#ifdef __ARCH_HAS_SA_RESTORER
ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
&oact->sa_restorer);
#endif
}
return ret;
}
#endif
#endif /* !CONFIG_ODD_RT_SIGACTION */
#ifdef CONFIG_OLD_SIGACTION
SYSCALL_DEFINE3(sigaction, int, sig,
const struct old_sigaction __user *, act,
struct old_sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
if (act) {
old_sigset_t mask;
if (!access_ok(act, sizeof(*act)) ||
__get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
__get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
__get_user(mask, &act->sa_mask))
return -EFAULT;
#ifdef __ARCH_HAS_KA_RESTORER
new_ka.ka_restorer = NULL;
#endif
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(oact, sizeof(*oact)) ||
__put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
__put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
return -EFAULT;
}
return ret;
}
#endif
#ifdef CONFIG_COMPAT_OLD_SIGACTION
COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
const struct compat_old_sigaction __user *, act,
struct compat_old_sigaction __user *, oact)
{
struct k_sigaction new_ka, old_ka;
int ret;
compat_old_sigset_t mask;
compat_uptr_t handler, restorer;
if (act) {
if (!access_ok(act, sizeof(*act)) ||
__get_user(handler, &act->sa_handler) ||
__get_user(restorer, &act->sa_restorer) ||
__get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
__get_user(mask, &act->sa_mask))
return -EFAULT;
#ifdef __ARCH_HAS_KA_RESTORER
new_ka.ka_restorer = NULL;
#endif
new_ka.sa.sa_handler = compat_ptr(handler);
new_ka.sa.sa_restorer = compat_ptr(restorer);
siginitset(&new_ka.sa.sa_mask, mask);
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (!access_ok(oact, sizeof(*oact)) ||
__put_user(ptr_to_compat(old_ka.sa.sa_handler),
&oact->sa_handler) ||
__put_user(ptr_to_compat(old_ka.sa.sa_restorer),
&oact->sa_restorer) ||
__put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
return -EFAULT;
}
return ret;
}
#endif
#ifdef CONFIG_SGETMASK_SYSCALL
/*
* For backwards compatibility. Functionality superseded by sigprocmask.
*/
SYSCALL_DEFINE0(sgetmask)
{
/* SMP safe */
return current->blocked.sig[0];
}
SYSCALL_DEFINE1(ssetmask, int, newmask)
{
int old = current->blocked.sig[0];
sigset_t newset;
siginitset(&newset, newmask);
set_current_blocked(&newset);
return old;
}
#endif /* CONFIG_SGETMASK_SYSCALL */
#ifdef __ARCH_WANT_SYS_SIGNAL
/*
* For backwards compatibility. Functionality superseded by sigaction.
*/
SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
{
struct k_sigaction new_sa, old_sa;
int ret;
new_sa.sa.sa_handler = handler;
new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
sigemptyset(&new_sa.sa.sa_mask);
ret = do_sigaction(sig, &new_sa, &old_sa);
return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
}
#endif /* __ARCH_WANT_SYS_SIGNAL */
#ifdef __ARCH_WANT_SYS_PAUSE
SYSCALL_DEFINE0(pause)
{
while (!signal_pending(current)) {
__set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
return -ERESTARTNOHAND;
}
#endif
static int sigsuspend(sigset_t *set)
{
current->saved_sigmask = current->blocked;
set_current_blocked(set);
while (!signal_pending(current)) {
__set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
set_restore_sigmask();
return -ERESTARTNOHAND;
}
/**
* sys_rt_sigsuspend - replace the signal mask for a value with the
* @unewset value until a signal is received
* @unewset: new signal mask value
* @sigsetsize: size of sigset_t type
*/
SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(&newset, unewset, sizeof(newset)))
return -EFAULT;
return sigsuspend(&newset);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
{
sigset_t newset;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (get_compat_sigset(&newset, unewset))
return -EFAULT;
return sigsuspend(&newset);
}
#endif
#ifdef CONFIG_OLD_SIGSUSPEND
SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
{
sigset_t blocked;
siginitset(&blocked, mask);
return sigsuspend(&blocked);
}
#endif
#ifdef CONFIG_OLD_SIGSUSPEND3
SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
{
sigset_t blocked;
siginitset(&blocked, mask);
return sigsuspend(&blocked);
}
#endif
__weak const char *arch_vma_name(struct vm_area_struct *vma)
{
return NULL;
}
static inline void siginfo_buildtime_checks(void)
{
BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
/* Verify the offsets in the two siginfos match */
#define CHECK_OFFSET(field) \
BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
/* kill */
CHECK_OFFSET(si_pid);
CHECK_OFFSET(si_uid);
/* timer */
CHECK_OFFSET(si_tid);
CHECK_OFFSET(si_overrun);
CHECK_OFFSET(si_value);
/* rt */
CHECK_OFFSET(si_pid);
CHECK_OFFSET(si_uid);
CHECK_OFFSET(si_value);
/* sigchld */
CHECK_OFFSET(si_pid);
CHECK_OFFSET(si_uid);
CHECK_OFFSET(si_status);
CHECK_OFFSET(si_utime);
CHECK_OFFSET(si_stime);
/* sigfault */
CHECK_OFFSET(si_addr);
CHECK_OFFSET(si_trapno);
CHECK_OFFSET(si_addr_lsb);
CHECK_OFFSET(si_lower);
CHECK_OFFSET(si_upper);
CHECK_OFFSET(si_pkey);
CHECK_OFFSET(si_perf_data);
CHECK_OFFSET(si_perf_type);
CHECK_OFFSET(si_perf_flags);
/* sigpoll */
CHECK_OFFSET(si_band);
CHECK_OFFSET(si_fd);
/* sigsys */
CHECK_OFFSET(si_call_addr);
CHECK_OFFSET(si_syscall);
CHECK_OFFSET(si_arch);
#undef CHECK_OFFSET
/* usb asyncio */
BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
offsetof(struct siginfo, si_addr));
if (sizeof(int) == sizeof(void __user *)) {
BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
sizeof(void __user *));
} else {
BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
sizeof_field(struct siginfo, si_uid)) !=
sizeof(void __user *));
BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
offsetof(struct siginfo, si_uid));
}
#ifdef CONFIG_COMPAT
BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
offsetof(struct compat_siginfo, si_addr));
BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
sizeof(compat_uptr_t));
BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
sizeof_field(struct siginfo, si_pid));
#endif
}
#if defined(CONFIG_SYSCTL)
static struct ctl_table signal_debug_table[] = {
#ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
{
.procname = "exception-trace",
.data = &show_unhandled_signals,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
#endif
{ }
};
static int __init init_signal_sysctls(void)
{
register_sysctl_init("debug", signal_debug_table);
return 0;
}
early_initcall(init_signal_sysctls);
#endif /* CONFIG_SYSCTL */
void __init signals_init(void)
{
siginfo_buildtime_checks();
sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
}
#ifdef CONFIG_KGDB_KDB
#include <linux/kdb.h>
/*
* kdb_send_sig - Allows kdb to send signals without exposing
* signal internals. This function checks if the required locks are
* available before calling the main signal code, to avoid kdb
* deadlocks.
*/
void kdb_send_sig(struct task_struct *t, int sig)
{
static struct task_struct *kdb_prev_t;
int new_t, ret;
if (!spin_trylock(&t->sighand->siglock)) {
kdb_printf("Can't do kill command now.\n"
"The sigmask lock is held somewhere else in "
"kernel, try again later\n");
return;
}
new_t = kdb_prev_t != t;
kdb_prev_t = t;
if (!task_is_running(t) && new_t) {
spin_unlock(&t->sighand->siglock);
kdb_printf("Process is not RUNNING, sending a signal from "
"kdb risks deadlock\n"
"on the run queue locks. "
"The signal has _not_ been sent.\n"
"Reissue the kill command if you want to risk "
"the deadlock.\n");
return;
}
ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
spin_unlock(&t->sighand->siglock);
if (ret)
kdb_printf("Fail to deliver Signal %d to process %d.\n",
sig, t->pid);
else
kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
}
#endif /* CONFIG_KGDB_KDB */
| linux-master | kernel/signal.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kernel/workqueue.c - generic async execution with shared worker pool
*
* Copyright (C) 2002 Ingo Molnar
*
* Derived from the taskqueue/keventd code by:
* David Woodhouse <[email protected]>
* Andrew Morton
* Kai Petzke <[email protected]>
* Theodore Ts'o <[email protected]>
*
* Made to use alloc_percpu by Christoph Lameter.
*
* Copyright (C) 2010 SUSE Linux Products GmbH
* Copyright (C) 2010 Tejun Heo <[email protected]>
*
* This is the generic async execution mechanism. Work items as are
* executed in process context. The worker pool is shared and
* automatically managed. There are two worker pools for each CPU (one for
* normal work items and the other for high priority ones) and some extra
* pools for workqueues which are not bound to any specific CPU - the
* number of these backing pools is dynamic.
*
* Please read Documentation/core-api/workqueue.rst for details.
*/
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/hardirq.h>
#include <linux/mempolicy.h>
#include <linux/freezer.h>
#include <linux/debug_locks.h>
#include <linux/lockdep.h>
#include <linux/idr.h>
#include <linux/jhash.h>
#include <linux/hashtable.h>
#include <linux/rculist.h>
#include <linux/nodemask.h>
#include <linux/moduleparam.h>
#include <linux/uaccess.h>
#include <linux/sched/isolation.h>
#include <linux/sched/debug.h>
#include <linux/nmi.h>
#include <linux/kvm_para.h>
#include <linux/delay.h>
#include "workqueue_internal.h"
enum {
/*
* worker_pool flags
*
* A bound pool is either associated or disassociated with its CPU.
* While associated (!DISASSOCIATED), all workers are bound to the
* CPU and none has %WORKER_UNBOUND set and concurrency management
* is in effect.
*
* While DISASSOCIATED, the cpu may be offline and all workers have
* %WORKER_UNBOUND set and concurrency management disabled, and may
* be executing on any CPU. The pool behaves as an unbound one.
*
* Note that DISASSOCIATED should be flipped only while holding
* wq_pool_attach_mutex to avoid changing binding state while
* worker_attach_to_pool() is in progress.
*/
POOL_MANAGER_ACTIVE = 1 << 0, /* being managed */
POOL_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */
/* worker flags */
WORKER_DIE = 1 << 1, /* die die die */
WORKER_IDLE = 1 << 2, /* is idle */
WORKER_PREP = 1 << 3, /* preparing to run works */
WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */
WORKER_UNBOUND = 1 << 7, /* worker is unbound */
WORKER_REBOUND = 1 << 8, /* worker was rebound */
WORKER_NOT_RUNNING = WORKER_PREP | WORKER_CPU_INTENSIVE |
WORKER_UNBOUND | WORKER_REBOUND,
NR_STD_WORKER_POOLS = 2, /* # standard pools per cpu */
UNBOUND_POOL_HASH_ORDER = 6, /* hashed by pool->attrs */
BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2,
/* call for help after 10ms
(min two ticks) */
MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */
CREATE_COOLDOWN = HZ, /* time to breath after fail */
/*
* Rescue workers are used only on emergencies and shared by
* all cpus. Give MIN_NICE.
*/
RESCUER_NICE_LEVEL = MIN_NICE,
HIGHPRI_NICE_LEVEL = MIN_NICE,
WQ_NAME_LEN = 24,
};
/*
* Structure fields follow one of the following exclusion rules.
*
* I: Modifiable by initialization/destruction paths and read-only for
* everyone else.
*
* P: Preemption protected. Disabling preemption is enough and should
* only be modified and accessed from the local cpu.
*
* L: pool->lock protected. Access with pool->lock held.
*
* K: Only modified by worker while holding pool->lock. Can be safely read by
* self, while holding pool->lock or from IRQ context if %current is the
* kworker.
*
* S: Only modified by worker self.
*
* A: wq_pool_attach_mutex protected.
*
* PL: wq_pool_mutex protected.
*
* PR: wq_pool_mutex protected for writes. RCU protected for reads.
*
* PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads.
*
* PWR: wq_pool_mutex and wq->mutex protected for writes. Either or
* RCU for reads.
*
* WQ: wq->mutex protected.
*
* WR: wq->mutex protected for writes. RCU protected for reads.
*
* MD: wq_mayday_lock protected.
*
* WD: Used internally by the watchdog.
*/
/* struct worker is defined in workqueue_internal.h */
struct worker_pool {
raw_spinlock_t lock; /* the pool lock */
int cpu; /* I: the associated cpu */
int node; /* I: the associated node ID */
int id; /* I: pool ID */
unsigned int flags; /* L: flags */
unsigned long watchdog_ts; /* L: watchdog timestamp */
bool cpu_stall; /* WD: stalled cpu bound pool */
/*
* The counter is incremented in a process context on the associated CPU
* w/ preemption disabled, and decremented or reset in the same context
* but w/ pool->lock held. The readers grab pool->lock and are
* guaranteed to see if the counter reached zero.
*/
int nr_running;
struct list_head worklist; /* L: list of pending works */
int nr_workers; /* L: total number of workers */
int nr_idle; /* L: currently idle workers */
struct list_head idle_list; /* L: list of idle workers */
struct timer_list idle_timer; /* L: worker idle timeout */
struct work_struct idle_cull_work; /* L: worker idle cleanup */
struct timer_list mayday_timer; /* L: SOS timer for workers */
/* a workers is either on busy_hash or idle_list, or the manager */
DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
/* L: hash of busy workers */
struct worker *manager; /* L: purely informational */
struct list_head workers; /* A: attached workers */
struct list_head dying_workers; /* A: workers about to die */
struct completion *detach_completion; /* all workers detached */
struct ida worker_ida; /* worker IDs for task name */
struct workqueue_attrs *attrs; /* I: worker attributes */
struct hlist_node hash_node; /* PL: unbound_pool_hash node */
int refcnt; /* PL: refcnt for unbound pools */
/*
* Destruction of pool is RCU protected to allow dereferences
* from get_work_pool().
*/
struct rcu_head rcu;
};
/*
* Per-pool_workqueue statistics. These can be monitored using
* tools/workqueue/wq_monitor.py.
*/
enum pool_workqueue_stats {
PWQ_STAT_STARTED, /* work items started execution */
PWQ_STAT_COMPLETED, /* work items completed execution */
PWQ_STAT_CPU_TIME, /* total CPU time consumed */
PWQ_STAT_CPU_INTENSIVE, /* wq_cpu_intensive_thresh_us violations */
PWQ_STAT_CM_WAKEUP, /* concurrency-management worker wakeups */
PWQ_STAT_REPATRIATED, /* unbound workers brought back into scope */
PWQ_STAT_MAYDAY, /* maydays to rescuer */
PWQ_STAT_RESCUED, /* linked work items executed by rescuer */
PWQ_NR_STATS,
};
/*
* The per-pool workqueue. While queued, the lower WORK_STRUCT_FLAG_BITS
* of work_struct->data are used for flags and the remaining high bits
* point to the pwq; thus, pwqs need to be aligned at two's power of the
* number of flag bits.
*/
struct pool_workqueue {
struct worker_pool *pool; /* I: the associated pool */
struct workqueue_struct *wq; /* I: the owning workqueue */
int work_color; /* L: current color */
int flush_color; /* L: flushing color */
int refcnt; /* L: reference count */
int nr_in_flight[WORK_NR_COLORS];
/* L: nr of in_flight works */
/*
* nr_active management and WORK_STRUCT_INACTIVE:
*
* When pwq->nr_active >= max_active, new work item is queued to
* pwq->inactive_works instead of pool->worklist and marked with
* WORK_STRUCT_INACTIVE.
*
* All work items marked with WORK_STRUCT_INACTIVE do not participate
* in pwq->nr_active and all work items in pwq->inactive_works are
* marked with WORK_STRUCT_INACTIVE. But not all WORK_STRUCT_INACTIVE
* work items are in pwq->inactive_works. Some of them are ready to
* run in pool->worklist or worker->scheduled. Those work itmes are
* only struct wq_barrier which is used for flush_work() and should
* not participate in pwq->nr_active. For non-barrier work item, it
* is marked with WORK_STRUCT_INACTIVE iff it is in pwq->inactive_works.
*/
int nr_active; /* L: nr of active works */
int max_active; /* L: max active works */
struct list_head inactive_works; /* L: inactive works */
struct list_head pwqs_node; /* WR: node on wq->pwqs */
struct list_head mayday_node; /* MD: node on wq->maydays */
u64 stats[PWQ_NR_STATS];
/*
* Release of unbound pwq is punted to a kthread_worker. See put_pwq()
* and pwq_release_workfn() for details. pool_workqueue itself is also
* RCU protected so that the first pwq can be determined without
* grabbing wq->mutex.
*/
struct kthread_work release_work;
struct rcu_head rcu;
} __aligned(1 << WORK_STRUCT_FLAG_BITS);
/*
* Structure used to wait for workqueue flush.
*/
struct wq_flusher {
struct list_head list; /* WQ: list of flushers */
int flush_color; /* WQ: flush color waiting for */
struct completion done; /* flush completion */
};
struct wq_device;
/*
* The externally visible workqueue. It relays the issued work items to
* the appropriate worker_pool through its pool_workqueues.
*/
struct workqueue_struct {
struct list_head pwqs; /* WR: all pwqs of this wq */
struct list_head list; /* PR: list of all workqueues */
struct mutex mutex; /* protects this wq */
int work_color; /* WQ: current work color */
int flush_color; /* WQ: current flush color */
atomic_t nr_pwqs_to_flush; /* flush in progress */
struct wq_flusher *first_flusher; /* WQ: first flusher */
struct list_head flusher_queue; /* WQ: flush waiters */
struct list_head flusher_overflow; /* WQ: flush overflow list */
struct list_head maydays; /* MD: pwqs requesting rescue */
struct worker *rescuer; /* MD: rescue worker */
int nr_drainers; /* WQ: drain in progress */
int saved_max_active; /* WQ: saved pwq max_active */
struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */
struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */
#ifdef CONFIG_SYSFS
struct wq_device *wq_dev; /* I: for sysfs interface */
#endif
#ifdef CONFIG_LOCKDEP
char *lock_name;
struct lock_class_key key;
struct lockdep_map lockdep_map;
#endif
char name[WQ_NAME_LEN]; /* I: workqueue name */
/*
* Destruction of workqueue_struct is RCU protected to allow walking
* the workqueues list without grabbing wq_pool_mutex.
* This is used to dump all workqueues from sysrq.
*/
struct rcu_head rcu;
/* hot fields used during command issue, aligned to cacheline */
unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */
struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
};
static struct kmem_cache *pwq_cache;
/*
* Each pod type describes how CPUs should be grouped for unbound workqueues.
* See the comment above workqueue_attrs->affn_scope.
*/
struct wq_pod_type {
int nr_pods; /* number of pods */
cpumask_var_t *pod_cpus; /* pod -> cpus */
int *pod_node; /* pod -> node */
int *cpu_pod; /* cpu -> pod */
};
static struct wq_pod_type wq_pod_types[WQ_AFFN_NR_TYPES];
static enum wq_affn_scope wq_affn_dfl = WQ_AFFN_CACHE;
static const char *wq_affn_names[WQ_AFFN_NR_TYPES] = {
[WQ_AFFN_DFL] = "default",
[WQ_AFFN_CPU] = "cpu",
[WQ_AFFN_SMT] = "smt",
[WQ_AFFN_CACHE] = "cache",
[WQ_AFFN_NUMA] = "numa",
[WQ_AFFN_SYSTEM] = "system",
};
/*
* Per-cpu work items which run for longer than the following threshold are
* automatically considered CPU intensive and excluded from concurrency
* management to prevent them from noticeably delaying other per-cpu work items.
* ULONG_MAX indicates that the user hasn't overridden it with a boot parameter.
* The actual value is initialized in wq_cpu_intensive_thresh_init().
*/
static unsigned long wq_cpu_intensive_thresh_us = ULONG_MAX;
module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644);
/* see the comment above the definition of WQ_POWER_EFFICIENT */
static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
module_param_named(power_efficient, wq_power_efficient, bool, 0444);
static bool wq_online; /* can kworkers be created yet? */
/* buf for wq_update_unbound_pod_attrs(), protected by CPU hotplug exclusion */
static struct workqueue_attrs *wq_update_pod_attrs_buf;
static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */
static DEFINE_MUTEX(wq_pool_attach_mutex); /* protects worker attach/detach */
static DEFINE_RAW_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */
/* wait for manager to go away */
static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);
static LIST_HEAD(workqueues); /* PR: list of all workqueues */
static bool workqueue_freezing; /* PL: have wqs started freezing? */
/* PL&A: allowable cpus for unbound wqs and work items */
static cpumask_var_t wq_unbound_cpumask;
/* for further constrain wq_unbound_cpumask by cmdline parameter*/
static struct cpumask wq_cmdline_cpumask __initdata;
/* CPU where unbound work was last round robin scheduled from this CPU */
static DEFINE_PER_CPU(int, wq_rr_cpu_last);
/*
* Local execution of unbound work items is no longer guaranteed. The
* following always forces round-robin CPU selection on unbound work items
* to uncover usages which depend on it.
*/
#ifdef CONFIG_DEBUG_WQ_FORCE_RR_CPU
static bool wq_debug_force_rr_cpu = true;
#else
static bool wq_debug_force_rr_cpu = false;
#endif
module_param_named(debug_force_rr_cpu, wq_debug_force_rr_cpu, bool, 0644);
/* the per-cpu worker pools */
static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools);
static DEFINE_IDR(worker_pool_idr); /* PR: idr of all pools */
/* PL: hash of all unbound pools keyed by pool->attrs */
static DEFINE_HASHTABLE(unbound_pool_hash, UNBOUND_POOL_HASH_ORDER);
/* I: attributes used when instantiating standard unbound pools on demand */
static struct workqueue_attrs *unbound_std_wq_attrs[NR_STD_WORKER_POOLS];
/* I: attributes used when instantiating ordered pools on demand */
static struct workqueue_attrs *ordered_wq_attrs[NR_STD_WORKER_POOLS];
/*
* I: kthread_worker to release pwq's. pwq release needs to be bounced to a
* process context while holding a pool lock. Bounce to a dedicated kthread
* worker to avoid A-A deadlocks.
*/
static struct kthread_worker *pwq_release_worker;
struct workqueue_struct *system_wq __read_mostly;
EXPORT_SYMBOL(system_wq);
struct workqueue_struct *system_highpri_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_highpri_wq);
struct workqueue_struct *system_long_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_long_wq);
struct workqueue_struct *system_unbound_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_unbound_wq);
struct workqueue_struct *system_freezable_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_freezable_wq);
struct workqueue_struct *system_power_efficient_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_power_efficient_wq);
struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly;
EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq);
static int worker_thread(void *__worker);
static void workqueue_sysfs_unregister(struct workqueue_struct *wq);
static void show_pwq(struct pool_workqueue *pwq);
static void show_one_worker_pool(struct worker_pool *pool);
#define CREATE_TRACE_POINTS
#include <trace/events/workqueue.h>
#define assert_rcu_or_pool_mutex() \
RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&wq_pool_mutex), \
"RCU or wq_pool_mutex should be held")
#define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \
RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&wq->mutex) && \
!lockdep_is_held(&wq_pool_mutex), \
"RCU, wq->mutex or wq_pool_mutex should be held")
#define for_each_cpu_worker_pool(pool, cpu) \
for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \
(pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
(pool)++)
/**
* for_each_pool - iterate through all worker_pools in the system
* @pool: iteration cursor
* @pi: integer used for iteration
*
* This must be called either with wq_pool_mutex held or RCU read
* locked. If the pool needs to be used beyond the locking in effect, the
* caller is responsible for guaranteeing that the pool stays online.
*
* The if/else clause exists only for the lockdep assertion and can be
* ignored.
*/
#define for_each_pool(pool, pi) \
idr_for_each_entry(&worker_pool_idr, pool, pi) \
if (({ assert_rcu_or_pool_mutex(); false; })) { } \
else
/**
* for_each_pool_worker - iterate through all workers of a worker_pool
* @worker: iteration cursor
* @pool: worker_pool to iterate workers of
*
* This must be called with wq_pool_attach_mutex.
*
* The if/else clause exists only for the lockdep assertion and can be
* ignored.
*/
#define for_each_pool_worker(worker, pool) \
list_for_each_entry((worker), &(pool)->workers, node) \
if (({ lockdep_assert_held(&wq_pool_attach_mutex); false; })) { } \
else
/**
* for_each_pwq - iterate through all pool_workqueues of the specified workqueue
* @pwq: iteration cursor
* @wq: the target workqueue
*
* This must be called either with wq->mutex held or RCU read locked.
* If the pwq needs to be used beyond the locking in effect, the caller is
* responsible for guaranteeing that the pwq stays online.
*
* The if/else clause exists only for the lockdep assertion and can be
* ignored.
*/
#define for_each_pwq(pwq, wq) \
list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \
lockdep_is_held(&(wq->mutex)))
#ifdef CONFIG_DEBUG_OBJECTS_WORK
static const struct debug_obj_descr work_debug_descr;
static void *work_debug_hint(void *addr)
{
return ((struct work_struct *) addr)->func;
}
static bool work_is_static_object(void *addr)
{
struct work_struct *work = addr;
return test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work));
}
/*
* fixup_init is called when:
* - an active object is initialized
*/
static bool work_fixup_init(void *addr, enum debug_obj_state state)
{
struct work_struct *work = addr;
switch (state) {
case ODEBUG_STATE_ACTIVE:
cancel_work_sync(work);
debug_object_init(work, &work_debug_descr);
return true;
default:
return false;
}
}
/*
* fixup_free is called when:
* - an active object is freed
*/
static bool work_fixup_free(void *addr, enum debug_obj_state state)
{
struct work_struct *work = addr;
switch (state) {
case ODEBUG_STATE_ACTIVE:
cancel_work_sync(work);
debug_object_free(work, &work_debug_descr);
return true;
default:
return false;
}
}
static const struct debug_obj_descr work_debug_descr = {
.name = "work_struct",
.debug_hint = work_debug_hint,
.is_static_object = work_is_static_object,
.fixup_init = work_fixup_init,
.fixup_free = work_fixup_free,
};
static inline void debug_work_activate(struct work_struct *work)
{
debug_object_activate(work, &work_debug_descr);
}
static inline void debug_work_deactivate(struct work_struct *work)
{
debug_object_deactivate(work, &work_debug_descr);
}
void __init_work(struct work_struct *work, int onstack)
{
if (onstack)
debug_object_init_on_stack(work, &work_debug_descr);
else
debug_object_init(work, &work_debug_descr);
}
EXPORT_SYMBOL_GPL(__init_work);
void destroy_work_on_stack(struct work_struct *work)
{
debug_object_free(work, &work_debug_descr);
}
EXPORT_SYMBOL_GPL(destroy_work_on_stack);
void destroy_delayed_work_on_stack(struct delayed_work *work)
{
destroy_timer_on_stack(&work->timer);
debug_object_free(&work->work, &work_debug_descr);
}
EXPORT_SYMBOL_GPL(destroy_delayed_work_on_stack);
#else
static inline void debug_work_activate(struct work_struct *work) { }
static inline void debug_work_deactivate(struct work_struct *work) { }
#endif
/**
* worker_pool_assign_id - allocate ID and assign it to @pool
* @pool: the pool pointer of interest
*
* Returns 0 if ID in [0, WORK_OFFQ_POOL_NONE) is allocated and assigned
* successfully, -errno on failure.
*/
static int worker_pool_assign_id(struct worker_pool *pool)
{
int ret;
lockdep_assert_held(&wq_pool_mutex);
ret = idr_alloc(&worker_pool_idr, pool, 0, WORK_OFFQ_POOL_NONE,
GFP_KERNEL);
if (ret >= 0) {
pool->id = ret;
return 0;
}
return ret;
}
static unsigned int work_color_to_flags(int color)
{
return color << WORK_STRUCT_COLOR_SHIFT;
}
static int get_work_color(unsigned long work_data)
{
return (work_data >> WORK_STRUCT_COLOR_SHIFT) &
((1 << WORK_STRUCT_COLOR_BITS) - 1);
}
static int work_next_color(int color)
{
return (color + 1) % WORK_NR_COLORS;
}
/*
* While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
* contain the pointer to the queued pwq. Once execution starts, the flag
* is cleared and the high bits contain OFFQ flags and pool ID.
*
* set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
* and clear_work_data() can be used to set the pwq, pool or clear
* work->data. These functions should only be called while the work is
* owned - ie. while the PENDING bit is set.
*
* get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
* corresponding to a work. Pool is available once the work has been
* queued anywhere after initialization until it is sync canceled. pwq is
* available only while the work item is queued.
*
* %WORK_OFFQ_CANCELING is used to mark a work item which is being
* canceled. While being canceled, a work item may have its PENDING set
* but stay off timer and worklist for arbitrarily long and nobody should
* try to steal the PENDING bit.
*/
static inline void set_work_data(struct work_struct *work, unsigned long data,
unsigned long flags)
{
WARN_ON_ONCE(!work_pending(work));
atomic_long_set(&work->data, data | flags | work_static(work));
}
static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
unsigned long extra_flags)
{
set_work_data(work, (unsigned long)pwq,
WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
}
static void set_work_pool_and_keep_pending(struct work_struct *work,
int pool_id)
{
set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
WORK_STRUCT_PENDING);
}
static void set_work_pool_and_clear_pending(struct work_struct *work,
int pool_id)
{
/*
* The following wmb is paired with the implied mb in
* test_and_set_bit(PENDING) and ensures all updates to @work made
* here are visible to and precede any updates by the next PENDING
* owner.
*/
smp_wmb();
set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
/*
* The following mb guarantees that previous clear of a PENDING bit
* will not be reordered with any speculative LOADS or STORES from
* work->current_func, which is executed afterwards. This possible
* reordering can lead to a missed execution on attempt to queue
* the same @work. E.g. consider this case:
*
* CPU#0 CPU#1
* ---------------------------- --------------------------------
*
* 1 STORE event_indicated
* 2 queue_work_on() {
* 3 test_and_set_bit(PENDING)
* 4 } set_..._and_clear_pending() {
* 5 set_work_data() # clear bit
* 6 smp_mb()
* 7 work->current_func() {
* 8 LOAD event_indicated
* }
*
* Without an explicit full barrier speculative LOAD on line 8 can
* be executed before CPU#0 does STORE on line 1. If that happens,
* CPU#0 observes the PENDING bit is still set and new execution of
* a @work is not queued in a hope, that CPU#1 will eventually
* finish the queued @work. Meanwhile CPU#1 does not see
* event_indicated is set, because speculative LOAD was executed
* before actual STORE.
*/
smp_mb();
}
static void clear_work_data(struct work_struct *work)
{
smp_wmb(); /* see set_work_pool_and_clear_pending() */
set_work_data(work, WORK_STRUCT_NO_POOL, 0);
}
static inline struct pool_workqueue *work_struct_pwq(unsigned long data)
{
return (struct pool_workqueue *)(data & WORK_STRUCT_WQ_DATA_MASK);
}
static struct pool_workqueue *get_work_pwq(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
if (data & WORK_STRUCT_PWQ)
return work_struct_pwq(data);
else
return NULL;
}
/**
* get_work_pool - return the worker_pool a given work was associated with
* @work: the work item of interest
*
* Pools are created and destroyed under wq_pool_mutex, and allows read
* access under RCU read lock. As such, this function should be
* called under wq_pool_mutex or inside of a rcu_read_lock() region.
*
* All fields of the returned pool are accessible as long as the above
* mentioned locking is in effect. If the returned pool needs to be used
* beyond the critical section, the caller is responsible for ensuring the
* returned pool is and stays online.
*
* Return: The worker_pool @work was last associated with. %NULL if none.
*/
static struct worker_pool *get_work_pool(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
int pool_id;
assert_rcu_or_pool_mutex();
if (data & WORK_STRUCT_PWQ)
return work_struct_pwq(data)->pool;
pool_id = data >> WORK_OFFQ_POOL_SHIFT;
if (pool_id == WORK_OFFQ_POOL_NONE)
return NULL;
return idr_find(&worker_pool_idr, pool_id);
}
/**
* get_work_pool_id - return the worker pool ID a given work is associated with
* @work: the work item of interest
*
* Return: The worker_pool ID @work was last associated with.
* %WORK_OFFQ_POOL_NONE if none.
*/
static int get_work_pool_id(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
if (data & WORK_STRUCT_PWQ)
return work_struct_pwq(data)->pool->id;
return data >> WORK_OFFQ_POOL_SHIFT;
}
static void mark_work_canceling(struct work_struct *work)
{
unsigned long pool_id = get_work_pool_id(work);
pool_id <<= WORK_OFFQ_POOL_SHIFT;
set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
}
static bool work_is_canceling(struct work_struct *work)
{
unsigned long data = atomic_long_read(&work->data);
return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
}
/*
* Policy functions. These define the policies on how the global worker
* pools are managed. Unless noted otherwise, these functions assume that
* they're being called with pool->lock held.
*/
/*
* Need to wake up a worker? Called from anything but currently
* running workers.
*
* Note that, because unbound workers never contribute to nr_running, this
* function will always return %true for unbound pools as long as the
* worklist isn't empty.
*/
static bool need_more_worker(struct worker_pool *pool)
{
return !list_empty(&pool->worklist) && !pool->nr_running;
}
/* Can I start working? Called from busy but !running workers. */
static bool may_start_working(struct worker_pool *pool)
{
return pool->nr_idle;
}
/* Do I need to keep working? Called from currently running workers. */
static bool keep_working(struct worker_pool *pool)
{
return !list_empty(&pool->worklist) && (pool->nr_running <= 1);
}
/* Do we need a new worker? Called from manager. */
static bool need_to_create_worker(struct worker_pool *pool)
{
return need_more_worker(pool) && !may_start_working(pool);
}
/* Do we have too many workers and should some go away? */
static bool too_many_workers(struct worker_pool *pool)
{
bool managing = pool->flags & POOL_MANAGER_ACTIVE;
int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
int nr_busy = pool->nr_workers - nr_idle;
return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy;
}
/**
* worker_set_flags - set worker flags and adjust nr_running accordingly
* @worker: self
* @flags: flags to set
*
* Set @flags in @worker->flags and adjust nr_running accordingly.
*/
static inline void worker_set_flags(struct worker *worker, unsigned int flags)
{
struct worker_pool *pool = worker->pool;
lockdep_assert_held(&pool->lock);
/* If transitioning into NOT_RUNNING, adjust nr_running. */
if ((flags & WORKER_NOT_RUNNING) &&
!(worker->flags & WORKER_NOT_RUNNING)) {
pool->nr_running--;
}
worker->flags |= flags;
}
/**
* worker_clr_flags - clear worker flags and adjust nr_running accordingly
* @worker: self
* @flags: flags to clear
*
* Clear @flags in @worker->flags and adjust nr_running accordingly.
*/
static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
{
struct worker_pool *pool = worker->pool;
unsigned int oflags = worker->flags;
lockdep_assert_held(&pool->lock);
worker->flags &= ~flags;
/*
* If transitioning out of NOT_RUNNING, increment nr_running. Note
* that the nested NOT_RUNNING is not a noop. NOT_RUNNING is mask
* of multiple flags, not a single flag.
*/
if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
if (!(worker->flags & WORKER_NOT_RUNNING))
pool->nr_running++;
}
/* Return the first idle worker. Called with pool->lock held. */
static struct worker *first_idle_worker(struct worker_pool *pool)
{
if (unlikely(list_empty(&pool->idle_list)))
return NULL;
return list_first_entry(&pool->idle_list, struct worker, entry);
}
/**
* worker_enter_idle - enter idle state
* @worker: worker which is entering idle state
*
* @worker is entering idle state. Update stats and idle timer if
* necessary.
*
* LOCKING:
* raw_spin_lock_irq(pool->lock).
*/
static void worker_enter_idle(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
if (WARN_ON_ONCE(worker->flags & WORKER_IDLE) ||
WARN_ON_ONCE(!list_empty(&worker->entry) &&
(worker->hentry.next || worker->hentry.pprev)))
return;
/* can't use worker_set_flags(), also called from create_worker() */
worker->flags |= WORKER_IDLE;
pool->nr_idle++;
worker->last_active = jiffies;
/* idle_list is LIFO */
list_add(&worker->entry, &pool->idle_list);
if (too_many_workers(pool) && !timer_pending(&pool->idle_timer))
mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
/* Sanity check nr_running. */
WARN_ON_ONCE(pool->nr_workers == pool->nr_idle && pool->nr_running);
}
/**
* worker_leave_idle - leave idle state
* @worker: worker which is leaving idle state
*
* @worker is leaving idle state. Update stats.
*
* LOCKING:
* raw_spin_lock_irq(pool->lock).
*/
static void worker_leave_idle(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
if (WARN_ON_ONCE(!(worker->flags & WORKER_IDLE)))
return;
worker_clr_flags(worker, WORKER_IDLE);
pool->nr_idle--;
list_del_init(&worker->entry);
}
/**
* find_worker_executing_work - find worker which is executing a work
* @pool: pool of interest
* @work: work to find worker for
*
* Find a worker which is executing @work on @pool by searching
* @pool->busy_hash which is keyed by the address of @work. For a worker
* to match, its current execution should match the address of @work and
* its work function. This is to avoid unwanted dependency between
* unrelated work executions through a work item being recycled while still
* being executed.
*
* This is a bit tricky. A work item may be freed once its execution
* starts and nothing prevents the freed area from being recycled for
* another work item. If the same work item address ends up being reused
* before the original execution finishes, workqueue will identify the
* recycled work item as currently executing and make it wait until the
* current execution finishes, introducing an unwanted dependency.
*
* This function checks the work item address and work function to avoid
* false positives. Note that this isn't complete as one may construct a
* work function which can introduce dependency onto itself through a
* recycled work item. Well, if somebody wants to shoot oneself in the
* foot that badly, there's only so much we can do, and if such deadlock
* actually occurs, it should be easy to locate the culprit work function.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*
* Return:
* Pointer to worker which is executing @work if found, %NULL
* otherwise.
*/
static struct worker *find_worker_executing_work(struct worker_pool *pool,
struct work_struct *work)
{
struct worker *worker;
hash_for_each_possible(pool->busy_hash, worker, hentry,
(unsigned long)work)
if (worker->current_work == work &&
worker->current_func == work->func)
return worker;
return NULL;
}
/**
* move_linked_works - move linked works to a list
* @work: start of series of works to be scheduled
* @head: target list to append @work to
* @nextp: out parameter for nested worklist walking
*
* Schedule linked works starting from @work to @head. Work series to be
* scheduled starts at @work and includes any consecutive work with
* WORK_STRUCT_LINKED set in its predecessor. See assign_work() for details on
* @nextp.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*/
static void move_linked_works(struct work_struct *work, struct list_head *head,
struct work_struct **nextp)
{
struct work_struct *n;
/*
* Linked worklist will always end before the end of the list,
* use NULL for list head.
*/
list_for_each_entry_safe_from(work, n, NULL, entry) {
list_move_tail(&work->entry, head);
if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
break;
}
/*
* If we're already inside safe list traversal and have moved
* multiple works to the scheduled queue, the next position
* needs to be updated.
*/
if (nextp)
*nextp = n;
}
/**
* assign_work - assign a work item and its linked work items to a worker
* @work: work to assign
* @worker: worker to assign to
* @nextp: out parameter for nested worklist walking
*
* Assign @work and its linked work items to @worker. If @work is already being
* executed by another worker in the same pool, it'll be punted there.
*
* If @nextp is not NULL, it's updated to point to the next work of the last
* scheduled work. This allows assign_work() to be nested inside
* list_for_each_entry_safe().
*
* Returns %true if @work was successfully assigned to @worker. %false if @work
* was punted to another worker already executing it.
*/
static bool assign_work(struct work_struct *work, struct worker *worker,
struct work_struct **nextp)
{
struct worker_pool *pool = worker->pool;
struct worker *collision;
lockdep_assert_held(&pool->lock);
/*
* A single work shouldn't be executed concurrently by multiple workers.
* __queue_work() ensures that @work doesn't jump to a different pool
* while still running in the previous pool. Here, we should ensure that
* @work is not executed concurrently by multiple workers from the same
* pool. Check whether anyone is already processing the work. If so,
* defer the work to the currently executing one.
*/
collision = find_worker_executing_work(pool, work);
if (unlikely(collision)) {
move_linked_works(work, &collision->scheduled, nextp);
return false;
}
move_linked_works(work, &worker->scheduled, nextp);
return true;
}
/**
* kick_pool - wake up an idle worker if necessary
* @pool: pool to kick
*
* @pool may have pending work items. Wake up worker if necessary. Returns
* whether a worker was woken up.
*/
static bool kick_pool(struct worker_pool *pool)
{
struct worker *worker = first_idle_worker(pool);
struct task_struct *p;
lockdep_assert_held(&pool->lock);
if (!need_more_worker(pool) || !worker)
return false;
p = worker->task;
#ifdef CONFIG_SMP
/*
* Idle @worker is about to execute @work and waking up provides an
* opportunity to migrate @worker at a lower cost by setting the task's
* wake_cpu field. Let's see if we want to move @worker to improve
* execution locality.
*
* We're waking the worker that went idle the latest and there's some
* chance that @worker is marked idle but hasn't gone off CPU yet. If
* so, setting the wake_cpu won't do anything. As this is a best-effort
* optimization and the race window is narrow, let's leave as-is for
* now. If this becomes pronounced, we can skip over workers which are
* still on cpu when picking an idle worker.
*
* If @pool has non-strict affinity, @worker might have ended up outside
* its affinity scope. Repatriate.
*/
if (!pool->attrs->affn_strict &&
!cpumask_test_cpu(p->wake_cpu, pool->attrs->__pod_cpumask)) {
struct work_struct *work = list_first_entry(&pool->worklist,
struct work_struct, entry);
p->wake_cpu = cpumask_any_distribute(pool->attrs->__pod_cpumask);
get_work_pwq(work)->stats[PWQ_STAT_REPATRIATED]++;
}
#endif
wake_up_process(p);
return true;
}
#ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT
/*
* Concurrency-managed per-cpu work items that hog CPU for longer than
* wq_cpu_intensive_thresh_us trigger the automatic CPU_INTENSIVE mechanism,
* which prevents them from stalling other concurrency-managed work items. If a
* work function keeps triggering this mechanism, it's likely that the work item
* should be using an unbound workqueue instead.
*
* wq_cpu_intensive_report() tracks work functions which trigger such conditions
* and report them so that they can be examined and converted to use unbound
* workqueues as appropriate. To avoid flooding the console, each violating work
* function is tracked and reported with exponential backoff.
*/
#define WCI_MAX_ENTS 128
struct wci_ent {
work_func_t func;
atomic64_t cnt;
struct hlist_node hash_node;
};
static struct wci_ent wci_ents[WCI_MAX_ENTS];
static int wci_nr_ents;
static DEFINE_RAW_SPINLOCK(wci_lock);
static DEFINE_HASHTABLE(wci_hash, ilog2(WCI_MAX_ENTS));
static struct wci_ent *wci_find_ent(work_func_t func)
{
struct wci_ent *ent;
hash_for_each_possible_rcu(wci_hash, ent, hash_node,
(unsigned long)func) {
if (ent->func == func)
return ent;
}
return NULL;
}
static void wq_cpu_intensive_report(work_func_t func)
{
struct wci_ent *ent;
restart:
ent = wci_find_ent(func);
if (ent) {
u64 cnt;
/*
* Start reporting from the fourth time and back off
* exponentially.
*/
cnt = atomic64_inc_return_relaxed(&ent->cnt);
if (cnt >= 4 && is_power_of_2(cnt))
printk_deferred(KERN_WARNING "workqueue: %ps hogged CPU for >%luus %llu times, consider switching to WQ_UNBOUND\n",
ent->func, wq_cpu_intensive_thresh_us,
atomic64_read(&ent->cnt));
return;
}
/*
* @func is a new violation. Allocate a new entry for it. If wcn_ents[]
* is exhausted, something went really wrong and we probably made enough
* noise already.
*/
if (wci_nr_ents >= WCI_MAX_ENTS)
return;
raw_spin_lock(&wci_lock);
if (wci_nr_ents >= WCI_MAX_ENTS) {
raw_spin_unlock(&wci_lock);
return;
}
if (wci_find_ent(func)) {
raw_spin_unlock(&wci_lock);
goto restart;
}
ent = &wci_ents[wci_nr_ents++];
ent->func = func;
atomic64_set(&ent->cnt, 1);
hash_add_rcu(wci_hash, &ent->hash_node, (unsigned long)func);
raw_spin_unlock(&wci_lock);
}
#else /* CONFIG_WQ_CPU_INTENSIVE_REPORT */
static void wq_cpu_intensive_report(work_func_t func) {}
#endif /* CONFIG_WQ_CPU_INTENSIVE_REPORT */
/**
* wq_worker_running - a worker is running again
* @task: task waking up
*
* This function is called when a worker returns from schedule()
*/
void wq_worker_running(struct task_struct *task)
{
struct worker *worker = kthread_data(task);
if (!READ_ONCE(worker->sleeping))
return;
/*
* If preempted by unbind_workers() between the WORKER_NOT_RUNNING check
* and the nr_running increment below, we may ruin the nr_running reset
* and leave with an unexpected pool->nr_running == 1 on the newly unbound
* pool. Protect against such race.
*/
preempt_disable();
if (!(worker->flags & WORKER_NOT_RUNNING))
worker->pool->nr_running++;
preempt_enable();
/*
* CPU intensive auto-detection cares about how long a work item hogged
* CPU without sleeping. Reset the starting timestamp on wakeup.
*/
worker->current_at = worker->task->se.sum_exec_runtime;
WRITE_ONCE(worker->sleeping, 0);
}
/**
* wq_worker_sleeping - a worker is going to sleep
* @task: task going to sleep
*
* This function is called from schedule() when a busy worker is
* going to sleep.
*/
void wq_worker_sleeping(struct task_struct *task)
{
struct worker *worker = kthread_data(task);
struct worker_pool *pool;
/*
* Rescuers, which may not have all the fields set up like normal
* workers, also reach here, let's not access anything before
* checking NOT_RUNNING.
*/
if (worker->flags & WORKER_NOT_RUNNING)
return;
pool = worker->pool;
/* Return if preempted before wq_worker_running() was reached */
if (READ_ONCE(worker->sleeping))
return;
WRITE_ONCE(worker->sleeping, 1);
raw_spin_lock_irq(&pool->lock);
/*
* Recheck in case unbind_workers() preempted us. We don't
* want to decrement nr_running after the worker is unbound
* and nr_running has been reset.
*/
if (worker->flags & WORKER_NOT_RUNNING) {
raw_spin_unlock_irq(&pool->lock);
return;
}
pool->nr_running--;
if (kick_pool(pool))
worker->current_pwq->stats[PWQ_STAT_CM_WAKEUP]++;
raw_spin_unlock_irq(&pool->lock);
}
/**
* wq_worker_tick - a scheduler tick occurred while a kworker is running
* @task: task currently running
*
* Called from scheduler_tick(). We're in the IRQ context and the current
* worker's fields which follow the 'K' locking rule can be accessed safely.
*/
void wq_worker_tick(struct task_struct *task)
{
struct worker *worker = kthread_data(task);
struct pool_workqueue *pwq = worker->current_pwq;
struct worker_pool *pool = worker->pool;
if (!pwq)
return;
pwq->stats[PWQ_STAT_CPU_TIME] += TICK_USEC;
if (!wq_cpu_intensive_thresh_us)
return;
/*
* If the current worker is concurrency managed and hogged the CPU for
* longer than wq_cpu_intensive_thresh_us, it's automatically marked
* CPU_INTENSIVE to avoid stalling other concurrency-managed work items.
*
* Set @worker->sleeping means that @worker is in the process of
* switching out voluntarily and won't be contributing to
* @pool->nr_running until it wakes up. As wq_worker_sleeping() also
* decrements ->nr_running, setting CPU_INTENSIVE here can lead to
* double decrements. The task is releasing the CPU anyway. Let's skip.
* We probably want to make this prettier in the future.
*/
if ((worker->flags & WORKER_NOT_RUNNING) || READ_ONCE(worker->sleeping) ||
worker->task->se.sum_exec_runtime - worker->current_at <
wq_cpu_intensive_thresh_us * NSEC_PER_USEC)
return;
raw_spin_lock(&pool->lock);
worker_set_flags(worker, WORKER_CPU_INTENSIVE);
wq_cpu_intensive_report(worker->current_func);
pwq->stats[PWQ_STAT_CPU_INTENSIVE]++;
if (kick_pool(pool))
pwq->stats[PWQ_STAT_CM_WAKEUP]++;
raw_spin_unlock(&pool->lock);
}
/**
* wq_worker_last_func - retrieve worker's last work function
* @task: Task to retrieve last work function of.
*
* Determine the last function a worker executed. This is called from
* the scheduler to get a worker's last known identity.
*
* CONTEXT:
* raw_spin_lock_irq(rq->lock)
*
* This function is called during schedule() when a kworker is going
* to sleep. It's used by psi to identify aggregation workers during
* dequeuing, to allow periodic aggregation to shut-off when that
* worker is the last task in the system or cgroup to go to sleep.
*
* As this function doesn't involve any workqueue-related locking, it
* only returns stable values when called from inside the scheduler's
* queuing and dequeuing paths, when @task, which must be a kworker,
* is guaranteed to not be processing any works.
*
* Return:
* The last work function %current executed as a worker, NULL if it
* hasn't executed any work yet.
*/
work_func_t wq_worker_last_func(struct task_struct *task)
{
struct worker *worker = kthread_data(task);
return worker->last_func;
}
/**
* get_pwq - get an extra reference on the specified pool_workqueue
* @pwq: pool_workqueue to get
*
* Obtain an extra reference on @pwq. The caller should guarantee that
* @pwq has positive refcnt and be holding the matching pool->lock.
*/
static void get_pwq(struct pool_workqueue *pwq)
{
lockdep_assert_held(&pwq->pool->lock);
WARN_ON_ONCE(pwq->refcnt <= 0);
pwq->refcnt++;
}
/**
* put_pwq - put a pool_workqueue reference
* @pwq: pool_workqueue to put
*
* Drop a reference of @pwq. If its refcnt reaches zero, schedule its
* destruction. The caller should be holding the matching pool->lock.
*/
static void put_pwq(struct pool_workqueue *pwq)
{
lockdep_assert_held(&pwq->pool->lock);
if (likely(--pwq->refcnt))
return;
/*
* @pwq can't be released under pool->lock, bounce to a dedicated
* kthread_worker to avoid A-A deadlocks.
*/
kthread_queue_work(pwq_release_worker, &pwq->release_work);
}
/**
* put_pwq_unlocked - put_pwq() with surrounding pool lock/unlock
* @pwq: pool_workqueue to put (can be %NULL)
*
* put_pwq() with locking. This function also allows %NULL @pwq.
*/
static void put_pwq_unlocked(struct pool_workqueue *pwq)
{
if (pwq) {
/*
* As both pwqs and pools are RCU protected, the
* following lock operations are safe.
*/
raw_spin_lock_irq(&pwq->pool->lock);
put_pwq(pwq);
raw_spin_unlock_irq(&pwq->pool->lock);
}
}
static void pwq_activate_inactive_work(struct work_struct *work)
{
struct pool_workqueue *pwq = get_work_pwq(work);
trace_workqueue_activate_work(work);
if (list_empty(&pwq->pool->worklist))
pwq->pool->watchdog_ts = jiffies;
move_linked_works(work, &pwq->pool->worklist, NULL);
__clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
pwq->nr_active++;
}
static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
{
struct work_struct *work = list_first_entry(&pwq->inactive_works,
struct work_struct, entry);
pwq_activate_inactive_work(work);
}
/**
* pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
* @pwq: pwq of interest
* @work_data: work_data of work which left the queue
*
* A work either has completed or is removed from pending queue,
* decrement nr_in_flight of its pwq and handle workqueue flushing.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*/
static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, unsigned long work_data)
{
int color = get_work_color(work_data);
if (!(work_data & WORK_STRUCT_INACTIVE)) {
pwq->nr_active--;
if (!list_empty(&pwq->inactive_works)) {
/* one down, submit an inactive one */
if (pwq->nr_active < pwq->max_active)
pwq_activate_first_inactive(pwq);
}
}
pwq->nr_in_flight[color]--;
/* is flush in progress and are we at the flushing tip? */
if (likely(pwq->flush_color != color))
goto out_put;
/* are there still in-flight works? */
if (pwq->nr_in_flight[color])
goto out_put;
/* this pwq is done, clear flush_color */
pwq->flush_color = -1;
/*
* If this was the last pwq, wake up the first flusher. It
* will handle the rest.
*/
if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
complete(&pwq->wq->first_flusher->done);
out_put:
put_pwq(pwq);
}
/**
* try_to_grab_pending - steal work item from worklist and disable irq
* @work: work item to steal
* @is_dwork: @work is a delayed_work
* @flags: place to store irq state
*
* Try to grab PENDING bit of @work. This function can handle @work in any
* stable state - idle, on timer or on worklist.
*
* Return:
*
* ======== ================================================================
* 1 if @work was pending and we successfully stole PENDING
* 0 if @work was idle and we claimed PENDING
* -EAGAIN if PENDING couldn't be grabbed at the moment, safe to busy-retry
* -ENOENT if someone else is canceling @work, this state may persist
* for arbitrarily long
* ======== ================================================================
*
* Note:
* On >= 0 return, the caller owns @work's PENDING bit. To avoid getting
* interrupted while holding PENDING and @work off queue, irq must be
* disabled on entry. This, combined with delayed_work->timer being
* irqsafe, ensures that we return -EAGAIN for finite short period of time.
*
* On successful return, >= 0, irq is disabled and the caller is
* responsible for releasing it using local_irq_restore(*@flags).
*
* This function is safe to call from any context including IRQ handler.
*/
static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
unsigned long *flags)
{
struct worker_pool *pool;
struct pool_workqueue *pwq;
local_irq_save(*flags);
/* try to steal the timer if it exists */
if (is_dwork) {
struct delayed_work *dwork = to_delayed_work(work);
/*
* dwork->timer is irqsafe. If del_timer() fails, it's
* guaranteed that the timer is not queued anywhere and not
* running on the local CPU.
*/
if (likely(del_timer(&dwork->timer)))
return 1;
}
/* try to claim PENDING the normal way */
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
return 0;
rcu_read_lock();
/*
* The queueing is in progress, or it is already queued. Try to
* steal it from ->worklist without clearing WORK_STRUCT_PENDING.
*/
pool = get_work_pool(work);
if (!pool)
goto fail;
raw_spin_lock(&pool->lock);
/*
* work->data is guaranteed to point to pwq only while the work
* item is queued on pwq->wq, and both updating work->data to point
* to pwq on queueing and to pool on dequeueing are done under
* pwq->pool->lock. This in turn guarantees that, if work->data
* points to pwq which is associated with a locked pool, the work
* item is currently queued on that pool.
*/
pwq = get_work_pwq(work);
if (pwq && pwq->pool == pool) {
debug_work_deactivate(work);
/*
* A cancelable inactive work item must be in the
* pwq->inactive_works since a queued barrier can't be
* canceled (see the comments in insert_wq_barrier()).
*
* An inactive work item cannot be grabbed directly because
* it might have linked barrier work items which, if left
* on the inactive_works list, will confuse pwq->nr_active
* management later on and cause stall. Make sure the work
* item is activated before grabbing.
*/
if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
pwq_activate_inactive_work(work);
list_del_init(&work->entry);
pwq_dec_nr_in_flight(pwq, *work_data_bits(work));
/* work->data points to pwq iff queued, point to pool */
set_work_pool_and_keep_pending(work, pool->id);
raw_spin_unlock(&pool->lock);
rcu_read_unlock();
return 1;
}
raw_spin_unlock(&pool->lock);
fail:
rcu_read_unlock();
local_irq_restore(*flags);
if (work_is_canceling(work))
return -ENOENT;
cpu_relax();
return -EAGAIN;
}
/**
* insert_work - insert a work into a pool
* @pwq: pwq @work belongs to
* @work: work to insert
* @head: insertion point
* @extra_flags: extra WORK_STRUCT_* flags to set
*
* Insert @work which belongs to @pwq after @head. @extra_flags is or'd to
* work_struct flags.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*/
static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
struct list_head *head, unsigned int extra_flags)
{
debug_work_activate(work);
/* record the work call stack in order to print it in KASAN reports */
kasan_record_aux_stack_noalloc(work);
/* we own @work, set data and link */
set_work_pwq(work, pwq, extra_flags);
list_add_tail(&work->entry, head);
get_pwq(pwq);
}
/*
* Test whether @work is being queued from another work executing on the
* same workqueue.
*/
static bool is_chained_work(struct workqueue_struct *wq)
{
struct worker *worker;
worker = current_wq_worker();
/*
* Return %true iff I'm a worker executing a work item on @wq. If
* I'm @worker, it's safe to dereference it without locking.
*/
return worker && worker->current_pwq->wq == wq;
}
/*
* When queueing an unbound work item to a wq, prefer local CPU if allowed
* by wq_unbound_cpumask. Otherwise, round robin among the allowed ones to
* avoid perturbing sensitive tasks.
*/
static int wq_select_unbound_cpu(int cpu)
{
int new_cpu;
if (likely(!wq_debug_force_rr_cpu)) {
if (cpumask_test_cpu(cpu, wq_unbound_cpumask))
return cpu;
} else {
pr_warn_once("workqueue: round-robin CPU selection forced, expect performance impact\n");
}
if (cpumask_empty(wq_unbound_cpumask))
return cpu;
new_cpu = __this_cpu_read(wq_rr_cpu_last);
new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask);
if (unlikely(new_cpu >= nr_cpu_ids)) {
new_cpu = cpumask_first_and(wq_unbound_cpumask, cpu_online_mask);
if (unlikely(new_cpu >= nr_cpu_ids))
return cpu;
}
__this_cpu_write(wq_rr_cpu_last, new_cpu);
return new_cpu;
}
static void __queue_work(int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
struct pool_workqueue *pwq;
struct worker_pool *last_pool, *pool;
unsigned int work_flags;
unsigned int req_cpu = cpu;
/*
* While a work item is PENDING && off queue, a task trying to
* steal the PENDING will busy-loop waiting for it to either get
* queued or lose PENDING. Grabbing PENDING and queueing should
* happen with IRQ disabled.
*/
lockdep_assert_irqs_disabled();
/*
* For a draining wq, only works from the same workqueue are
* allowed. The __WQ_DESTROYING helps to spot the issue that
* queues a new work item to a wq after destroy_workqueue(wq).
*/
if (unlikely(wq->flags & (__WQ_DESTROYING | __WQ_DRAINING) &&
WARN_ON_ONCE(!is_chained_work(wq))))
return;
rcu_read_lock();
retry:
/* pwq which will be used unless @work is executing elsewhere */
if (req_cpu == WORK_CPU_UNBOUND) {
if (wq->flags & WQ_UNBOUND)
cpu = wq_select_unbound_cpu(raw_smp_processor_id());
else
cpu = raw_smp_processor_id();
}
pwq = rcu_dereference(*per_cpu_ptr(wq->cpu_pwq, cpu));
pool = pwq->pool;
/*
* If @work was previously on a different pool, it might still be
* running there, in which case the work needs to be queued on that
* pool to guarantee non-reentrancy.
*/
last_pool = get_work_pool(work);
if (last_pool && last_pool != pool) {
struct worker *worker;
raw_spin_lock(&last_pool->lock);
worker = find_worker_executing_work(last_pool, work);
if (worker && worker->current_pwq->wq == wq) {
pwq = worker->current_pwq;
pool = pwq->pool;
WARN_ON_ONCE(pool != last_pool);
} else {
/* meh... not running there, queue here */
raw_spin_unlock(&last_pool->lock);
raw_spin_lock(&pool->lock);
}
} else {
raw_spin_lock(&pool->lock);
}
/*
* pwq is determined and locked. For unbound pools, we could have raced
* with pwq release and it could already be dead. If its refcnt is zero,
* repeat pwq selection. Note that unbound pwqs never die without
* another pwq replacing it in cpu_pwq or while work items are executing
* on it, so the retrying is guaranteed to make forward-progress.
*/
if (unlikely(!pwq->refcnt)) {
if (wq->flags & WQ_UNBOUND) {
raw_spin_unlock(&pool->lock);
cpu_relax();
goto retry;
}
/* oops */
WARN_ONCE(true, "workqueue: per-cpu pwq for %s on cpu%d has 0 refcnt",
wq->name, cpu);
}
/* pwq determined, queue */
trace_workqueue_queue_work(req_cpu, pwq, work);
if (WARN_ON(!list_empty(&work->entry)))
goto out;
pwq->nr_in_flight[pwq->work_color]++;
work_flags = work_color_to_flags(pwq->work_color);
if (likely(pwq->nr_active < pwq->max_active)) {
if (list_empty(&pool->worklist))
pool->watchdog_ts = jiffies;
trace_workqueue_activate_work(work);
pwq->nr_active++;
insert_work(pwq, work, &pool->worklist, work_flags);
kick_pool(pool);
} else {
work_flags |= WORK_STRUCT_INACTIVE;
insert_work(pwq, work, &pwq->inactive_works, work_flags);
}
out:
raw_spin_unlock(&pool->lock);
rcu_read_unlock();
}
/**
* queue_work_on - queue work on specific cpu
* @cpu: CPU number to execute work on
* @wq: workqueue to use
* @work: work to queue
*
* We queue the work to a specific CPU, the caller must ensure it
* can't go away. Callers that fail to ensure that the specified
* CPU cannot go away will execute on a randomly chosen CPU.
* But note well that callers specifying a CPU that never has been
* online will get a splat.
*
* Return: %false if @work was already on a queue, %true otherwise.
*/
bool queue_work_on(int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
bool ret = false;
unsigned long flags;
local_irq_save(flags);
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
__queue_work(cpu, wq, work);
ret = true;
}
local_irq_restore(flags);
return ret;
}
EXPORT_SYMBOL(queue_work_on);
/**
* select_numa_node_cpu - Select a CPU based on NUMA node
* @node: NUMA node ID that we want to select a CPU from
*
* This function will attempt to find a "random" cpu available on a given
* node. If there are no CPUs available on the given node it will return
* WORK_CPU_UNBOUND indicating that we should just schedule to any
* available CPU if we need to schedule this work.
*/
static int select_numa_node_cpu(int node)
{
int cpu;
/* Delay binding to CPU if node is not valid or online */
if (node < 0 || node >= MAX_NUMNODES || !node_online(node))
return WORK_CPU_UNBOUND;
/* Use local node/cpu if we are already there */
cpu = raw_smp_processor_id();
if (node == cpu_to_node(cpu))
return cpu;
/* Use "random" otherwise know as "first" online CPU of node */
cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
/* If CPU is valid return that, otherwise just defer */
return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND;
}
/**
* queue_work_node - queue work on a "random" cpu for a given NUMA node
* @node: NUMA node that we are targeting the work for
* @wq: workqueue to use
* @work: work to queue
*
* We queue the work to a "random" CPU within a given NUMA node. The basic
* idea here is to provide a way to somehow associate work with a given
* NUMA node.
*
* This function will only make a best effort attempt at getting this onto
* the right NUMA node. If no node is requested or the requested node is
* offline then we just fall back to standard queue_work behavior.
*
* Currently the "random" CPU ends up being the first available CPU in the
* intersection of cpu_online_mask and the cpumask of the node, unless we
* are running on the node. In that case we just use the current CPU.
*
* Return: %false if @work was already on a queue, %true otherwise.
*/
bool queue_work_node(int node, struct workqueue_struct *wq,
struct work_struct *work)
{
unsigned long flags;
bool ret = false;
/*
* This current implementation is specific to unbound workqueues.
* Specifically we only return the first available CPU for a given
* node instead of cycling through individual CPUs within the node.
*
* If this is used with a per-cpu workqueue then the logic in
* workqueue_select_cpu_near would need to be updated to allow for
* some round robin type logic.
*/
WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND));
local_irq_save(flags);
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
int cpu = select_numa_node_cpu(node);
__queue_work(cpu, wq, work);
ret = true;
}
local_irq_restore(flags);
return ret;
}
EXPORT_SYMBOL_GPL(queue_work_node);
void delayed_work_timer_fn(struct timer_list *t)
{
struct delayed_work *dwork = from_timer(dwork, t, timer);
/* should have been called from irqsafe timer with irq already off */
__queue_work(dwork->cpu, dwork->wq, &dwork->work);
}
EXPORT_SYMBOL(delayed_work_timer_fn);
static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
struct delayed_work *dwork, unsigned long delay)
{
struct timer_list *timer = &dwork->timer;
struct work_struct *work = &dwork->work;
WARN_ON_ONCE(!wq);
WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
WARN_ON_ONCE(timer_pending(timer));
WARN_ON_ONCE(!list_empty(&work->entry));
/*
* If @delay is 0, queue @dwork->work immediately. This is for
* both optimization and correctness. The earliest @timer can
* expire is on the closest next tick and delayed_work users depend
* on that there's no such delay when @delay is 0.
*/
if (!delay) {
__queue_work(cpu, wq, &dwork->work);
return;
}
dwork->wq = wq;
dwork->cpu = cpu;
timer->expires = jiffies + delay;
if (unlikely(cpu != WORK_CPU_UNBOUND))
add_timer_on(timer, cpu);
else
add_timer(timer);
}
/**
* queue_delayed_work_on - queue work on specific CPU after delay
* @cpu: CPU number to execute work on
* @wq: workqueue to use
* @dwork: work to queue
* @delay: number of jiffies to wait before queueing
*
* Return: %false if @work was already on a queue, %true otherwise. If
* @delay is zero and @dwork is idle, it will be scheduled for immediate
* execution.
*/
bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
struct delayed_work *dwork, unsigned long delay)
{
struct work_struct *work = &dwork->work;
bool ret = false;
unsigned long flags;
/* read the comment in __queue_work() */
local_irq_save(flags);
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
__queue_delayed_work(cpu, wq, dwork, delay);
ret = true;
}
local_irq_restore(flags);
return ret;
}
EXPORT_SYMBOL(queue_delayed_work_on);
/**
* mod_delayed_work_on - modify delay of or queue a delayed work on specific CPU
* @cpu: CPU number to execute work on
* @wq: workqueue to use
* @dwork: work to queue
* @delay: number of jiffies to wait before queueing
*
* If @dwork is idle, equivalent to queue_delayed_work_on(); otherwise,
* modify @dwork's timer so that it expires after @delay. If @delay is
* zero, @work is guaranteed to be scheduled immediately regardless of its
* current state.
*
* Return: %false if @dwork was idle and queued, %true if @dwork was
* pending and its timer was modified.
*
* This function is safe to call from any context including IRQ handler.
* See try_to_grab_pending() for details.
*/
bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
struct delayed_work *dwork, unsigned long delay)
{
unsigned long flags;
int ret;
do {
ret = try_to_grab_pending(&dwork->work, true, &flags);
} while (unlikely(ret == -EAGAIN));
if (likely(ret >= 0)) {
__queue_delayed_work(cpu, wq, dwork, delay);
local_irq_restore(flags);
}
/* -ENOENT from try_to_grab_pending() becomes %true */
return ret;
}
EXPORT_SYMBOL_GPL(mod_delayed_work_on);
static void rcu_work_rcufn(struct rcu_head *rcu)
{
struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
/* read the comment in __queue_work() */
local_irq_disable();
__queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
local_irq_enable();
}
/**
* queue_rcu_work - queue work after a RCU grace period
* @wq: workqueue to use
* @rwork: work to queue
*
* Return: %false if @rwork was already pending, %true otherwise. Note
* that a full RCU grace period is guaranteed only after a %true return.
* While @rwork is guaranteed to be executed after a %false return, the
* execution may happen before a full RCU grace period has passed.
*/
bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
{
struct work_struct *work = &rwork->work;
if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
rwork->wq = wq;
call_rcu_hurry(&rwork->rcu, rcu_work_rcufn);
return true;
}
return false;
}
EXPORT_SYMBOL(queue_rcu_work);
static struct worker *alloc_worker(int node)
{
struct worker *worker;
worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node);
if (worker) {
INIT_LIST_HEAD(&worker->entry);
INIT_LIST_HEAD(&worker->scheduled);
INIT_LIST_HEAD(&worker->node);
/* on creation a worker is in !idle && prep state */
worker->flags = WORKER_PREP;
}
return worker;
}
static cpumask_t *pool_allowed_cpus(struct worker_pool *pool)
{
if (pool->cpu < 0 && pool->attrs->affn_strict)
return pool->attrs->__pod_cpumask;
else
return pool->attrs->cpumask;
}
/**
* worker_attach_to_pool() - attach a worker to a pool
* @worker: worker to be attached
* @pool: the target pool
*
* Attach @worker to @pool. Once attached, the %WORKER_UNBOUND flag and
* cpu-binding of @worker are kept coordinated with the pool across
* cpu-[un]hotplugs.
*/
static void worker_attach_to_pool(struct worker *worker,
struct worker_pool *pool)
{
mutex_lock(&wq_pool_attach_mutex);
/*
* The wq_pool_attach_mutex ensures %POOL_DISASSOCIATED remains
* stable across this function. See the comments above the flag
* definition for details.
*/
if (pool->flags & POOL_DISASSOCIATED)
worker->flags |= WORKER_UNBOUND;
else
kthread_set_per_cpu(worker->task, pool->cpu);
if (worker->rescue_wq)
set_cpus_allowed_ptr(worker->task, pool_allowed_cpus(pool));
list_add_tail(&worker->node, &pool->workers);
worker->pool = pool;
mutex_unlock(&wq_pool_attach_mutex);
}
/**
* worker_detach_from_pool() - detach a worker from its pool
* @worker: worker which is attached to its pool
*
* Undo the attaching which had been done in worker_attach_to_pool(). The
* caller worker shouldn't access to the pool after detached except it has
* other reference to the pool.
*/
static void worker_detach_from_pool(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
struct completion *detach_completion = NULL;
mutex_lock(&wq_pool_attach_mutex);
kthread_set_per_cpu(worker->task, -1);
list_del(&worker->node);
worker->pool = NULL;
if (list_empty(&pool->workers) && list_empty(&pool->dying_workers))
detach_completion = pool->detach_completion;
mutex_unlock(&wq_pool_attach_mutex);
/* clear leftover flags without pool->lock after it is detached */
worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);
if (detach_completion)
complete(detach_completion);
}
/**
* create_worker - create a new workqueue worker
* @pool: pool the new worker will belong to
*
* Create and start a new worker which is attached to @pool.
*
* CONTEXT:
* Might sleep. Does GFP_KERNEL allocations.
*
* Return:
* Pointer to the newly created worker.
*/
static struct worker *create_worker(struct worker_pool *pool)
{
struct worker *worker;
int id;
char id_buf[16];
/* ID is needed to determine kthread name */
id = ida_alloc(&pool->worker_ida, GFP_KERNEL);
if (id < 0) {
pr_err_once("workqueue: Failed to allocate a worker ID: %pe\n",
ERR_PTR(id));
return NULL;
}
worker = alloc_worker(pool->node);
if (!worker) {
pr_err_once("workqueue: Failed to allocate a worker\n");
goto fail;
}
worker->id = id;
if (pool->cpu >= 0)
snprintf(id_buf, sizeof(id_buf), "%d:%d%s", pool->cpu, id,
pool->attrs->nice < 0 ? "H" : "");
else
snprintf(id_buf, sizeof(id_buf), "u%d:%d", pool->id, id);
worker->task = kthread_create_on_node(worker_thread, worker, pool->node,
"kworker/%s", id_buf);
if (IS_ERR(worker->task)) {
if (PTR_ERR(worker->task) == -EINTR) {
pr_err("workqueue: Interrupted when creating a worker thread \"kworker/%s\"\n",
id_buf);
} else {
pr_err_once("workqueue: Failed to create a worker thread: %pe",
worker->task);
}
goto fail;
}
set_user_nice(worker->task, pool->attrs->nice);
kthread_bind_mask(worker->task, pool_allowed_cpus(pool));
/* successful, attach the worker to the pool */
worker_attach_to_pool(worker, pool);
/* start the newly created worker */
raw_spin_lock_irq(&pool->lock);
worker->pool->nr_workers++;
worker_enter_idle(worker);
kick_pool(pool);
/*
* @worker is waiting on a completion in kthread() and will trigger hung
* check if not woken up soon. As kick_pool() might not have waken it
* up, wake it up explicitly once more.
*/
wake_up_process(worker->task);
raw_spin_unlock_irq(&pool->lock);
return worker;
fail:
ida_free(&pool->worker_ida, id);
kfree(worker);
return NULL;
}
static void unbind_worker(struct worker *worker)
{
lockdep_assert_held(&wq_pool_attach_mutex);
kthread_set_per_cpu(worker->task, -1);
if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask))
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0);
else
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);
}
static void wake_dying_workers(struct list_head *cull_list)
{
struct worker *worker, *tmp;
list_for_each_entry_safe(worker, tmp, cull_list, entry) {
list_del_init(&worker->entry);
unbind_worker(worker);
/*
* If the worker was somehow already running, then it had to be
* in pool->idle_list when set_worker_dying() happened or we
* wouldn't have gotten here.
*
* Thus, the worker must either have observed the WORKER_DIE
* flag, or have set its state to TASK_IDLE. Either way, the
* below will be observed by the worker and is safe to do
* outside of pool->lock.
*/
wake_up_process(worker->task);
}
}
/**
* set_worker_dying - Tag a worker for destruction
* @worker: worker to be destroyed
* @list: transfer worker away from its pool->idle_list and into list
*
* Tag @worker for destruction and adjust @pool stats accordingly. The worker
* should be idle.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*/
static void set_worker_dying(struct worker *worker, struct list_head *list)
{
struct worker_pool *pool = worker->pool;
lockdep_assert_held(&pool->lock);
lockdep_assert_held(&wq_pool_attach_mutex);
/* sanity check frenzy */
if (WARN_ON(worker->current_work) ||
WARN_ON(!list_empty(&worker->scheduled)) ||
WARN_ON(!(worker->flags & WORKER_IDLE)))
return;
pool->nr_workers--;
pool->nr_idle--;
worker->flags |= WORKER_DIE;
list_move(&worker->entry, list);
list_move(&worker->node, &pool->dying_workers);
}
/**
* idle_worker_timeout - check if some idle workers can now be deleted.
* @t: The pool's idle_timer that just expired
*
* The timer is armed in worker_enter_idle(). Note that it isn't disarmed in
* worker_leave_idle(), as a worker flicking between idle and active while its
* pool is at the too_many_workers() tipping point would cause too much timer
* housekeeping overhead. Since IDLE_WORKER_TIMEOUT is long enough, we just let
* it expire and re-evaluate things from there.
*/
static void idle_worker_timeout(struct timer_list *t)
{
struct worker_pool *pool = from_timer(pool, t, idle_timer);
bool do_cull = false;
if (work_pending(&pool->idle_cull_work))
return;
raw_spin_lock_irq(&pool->lock);
if (too_many_workers(pool)) {
struct worker *worker;
unsigned long expires;
/* idle_list is kept in LIFO order, check the last one */
worker = list_entry(pool->idle_list.prev, struct worker, entry);
expires = worker->last_active + IDLE_WORKER_TIMEOUT;
do_cull = !time_before(jiffies, expires);
if (!do_cull)
mod_timer(&pool->idle_timer, expires);
}
raw_spin_unlock_irq(&pool->lock);
if (do_cull)
queue_work(system_unbound_wq, &pool->idle_cull_work);
}
/**
* idle_cull_fn - cull workers that have been idle for too long.
* @work: the pool's work for handling these idle workers
*
* This goes through a pool's idle workers and gets rid of those that have been
* idle for at least IDLE_WORKER_TIMEOUT seconds.
*
* We don't want to disturb isolated CPUs because of a pcpu kworker being
* culled, so this also resets worker affinity. This requires a sleepable
* context, hence the split between timer callback and work item.
*/
static void idle_cull_fn(struct work_struct *work)
{
struct worker_pool *pool = container_of(work, struct worker_pool, idle_cull_work);
LIST_HEAD(cull_list);
/*
* Grabbing wq_pool_attach_mutex here ensures an already-running worker
* cannot proceed beyong worker_detach_from_pool() in its self-destruct
* path. This is required as a previously-preempted worker could run after
* set_worker_dying() has happened but before wake_dying_workers() did.
*/
mutex_lock(&wq_pool_attach_mutex);
raw_spin_lock_irq(&pool->lock);
while (too_many_workers(pool)) {
struct worker *worker;
unsigned long expires;
worker = list_entry(pool->idle_list.prev, struct worker, entry);
expires = worker->last_active + IDLE_WORKER_TIMEOUT;
if (time_before(jiffies, expires)) {
mod_timer(&pool->idle_timer, expires);
break;
}
set_worker_dying(worker, &cull_list);
}
raw_spin_unlock_irq(&pool->lock);
wake_dying_workers(&cull_list);
mutex_unlock(&wq_pool_attach_mutex);
}
static void send_mayday(struct work_struct *work)
{
struct pool_workqueue *pwq = get_work_pwq(work);
struct workqueue_struct *wq = pwq->wq;
lockdep_assert_held(&wq_mayday_lock);
if (!wq->rescuer)
return;
/* mayday mayday mayday */
if (list_empty(&pwq->mayday_node)) {
/*
* If @pwq is for an unbound wq, its base ref may be put at
* any time due to an attribute change. Pin @pwq until the
* rescuer is done with it.
*/
get_pwq(pwq);
list_add_tail(&pwq->mayday_node, &wq->maydays);
wake_up_process(wq->rescuer->task);
pwq->stats[PWQ_STAT_MAYDAY]++;
}
}
static void pool_mayday_timeout(struct timer_list *t)
{
struct worker_pool *pool = from_timer(pool, t, mayday_timer);
struct work_struct *work;
raw_spin_lock_irq(&pool->lock);
raw_spin_lock(&wq_mayday_lock); /* for wq->maydays */
if (need_to_create_worker(pool)) {
/*
* We've been trying to create a new worker but
* haven't been successful. We might be hitting an
* allocation deadlock. Send distress signals to
* rescuers.
*/
list_for_each_entry(work, &pool->worklist, entry)
send_mayday(work);
}
raw_spin_unlock(&wq_mayday_lock);
raw_spin_unlock_irq(&pool->lock);
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
}
/**
* maybe_create_worker - create a new worker if necessary
* @pool: pool to create a new worker for
*
* Create a new worker for @pool if necessary. @pool is guaranteed to
* have at least one idle worker on return from this function. If
* creating a new worker takes longer than MAYDAY_INTERVAL, mayday is
* sent to all rescuers with works scheduled on @pool to resolve
* possible allocation deadlock.
*
* On return, need_to_create_worker() is guaranteed to be %false and
* may_start_working() %true.
*
* LOCKING:
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Does GFP_KERNEL allocations. Called only from
* manager.
*/
static void maybe_create_worker(struct worker_pool *pool)
__releases(&pool->lock)
__acquires(&pool->lock)
{
restart:
raw_spin_unlock_irq(&pool->lock);
/* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
while (true) {
if (create_worker(pool) || !need_to_create_worker(pool))
break;
schedule_timeout_interruptible(CREATE_COOLDOWN);
if (!need_to_create_worker(pool))
break;
}
del_timer_sync(&pool->mayday_timer);
raw_spin_lock_irq(&pool->lock);
/*
* This is necessary even after a new worker was just successfully
* created as @pool->lock was dropped and the new worker might have
* already become busy.
*/
if (need_to_create_worker(pool))
goto restart;
}
/**
* manage_workers - manage worker pool
* @worker: self
*
* Assume the manager role and manage the worker pool @worker belongs
* to. At any given time, there can be only zero or one manager per
* pool. The exclusion is handled automatically by this function.
*
* The caller can safely start processing works on false return. On
* true return, it's guaranteed that need_to_create_worker() is false
* and may_start_working() is true.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times. Does GFP_KERNEL allocations.
*
* Return:
* %false if the pool doesn't need management and the caller can safely
* start processing works, %true if management function was performed and
* the conditions that the caller verified before calling the function may
* no longer be true.
*/
static bool manage_workers(struct worker *worker)
{
struct worker_pool *pool = worker->pool;
if (pool->flags & POOL_MANAGER_ACTIVE)
return false;
pool->flags |= POOL_MANAGER_ACTIVE;
pool->manager = worker;
maybe_create_worker(pool);
pool->manager = NULL;
pool->flags &= ~POOL_MANAGER_ACTIVE;
rcuwait_wake_up(&manager_wait);
return true;
}
/**
* process_one_work - process single work
* @worker: self
* @work: work to process
*
* Process @work. This function contains all the logics necessary to
* process a single work including synchronization against and
* interaction with other workers on the same cpu, queueing and
* flushing. As long as context requirement is met, any worker can
* call this function to process a work.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock) which is released and regrabbed.
*/
static void process_one_work(struct worker *worker, struct work_struct *work)
__releases(&pool->lock)
__acquires(&pool->lock)
{
struct pool_workqueue *pwq = get_work_pwq(work);
struct worker_pool *pool = worker->pool;
unsigned long work_data;
#ifdef CONFIG_LOCKDEP
/*
* It is permissible to free the struct work_struct from
* inside the function that is called from it, this we need to
* take into account for lockdep too. To avoid bogus "held
* lock freed" warnings as well as problems when looking into
* work->lockdep_map, make a copy and use that here.
*/
struct lockdep_map lockdep_map;
lockdep_copy_map(&lockdep_map, &work->lockdep_map);
#endif
/* ensure we're on the correct CPU */
WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
raw_smp_processor_id() != pool->cpu);
/* claim and dequeue */
debug_work_deactivate(work);
hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
worker->current_work = work;
worker->current_func = work->func;
worker->current_pwq = pwq;
worker->current_at = worker->task->se.sum_exec_runtime;
work_data = *work_data_bits(work);
worker->current_color = get_work_color(work_data);
/*
* Record wq name for cmdline and debug reporting, may get
* overridden through set_worker_desc().
*/
strscpy(worker->desc, pwq->wq->name, WORKER_DESC_LEN);
list_del_init(&work->entry);
/*
* CPU intensive works don't participate in concurrency management.
* They're the scheduler's responsibility. This takes @worker out
* of concurrency management and the next code block will chain
* execution of the pending work items.
*/
if (unlikely(pwq->wq->flags & WQ_CPU_INTENSIVE))
worker_set_flags(worker, WORKER_CPU_INTENSIVE);
/*
* Kick @pool if necessary. It's always noop for per-cpu worker pools
* since nr_running would always be >= 1 at this point. This is used to
* chain execution of the pending work items for WORKER_NOT_RUNNING
* workers such as the UNBOUND and CPU_INTENSIVE ones.
*/
kick_pool(pool);
/*
* Record the last pool and clear PENDING which should be the last
* update to @work. Also, do this inside @pool->lock so that
* PENDING and queued state changes happen together while IRQ is
* disabled.
*/
set_work_pool_and_clear_pending(work, pool->id);
pwq->stats[PWQ_STAT_STARTED]++;
raw_spin_unlock_irq(&pool->lock);
lock_map_acquire(&pwq->wq->lockdep_map);
lock_map_acquire(&lockdep_map);
/*
* Strictly speaking we should mark the invariant state without holding
* any locks, that is, before these two lock_map_acquire()'s.
*
* However, that would result in:
*
* A(W1)
* WFC(C)
* A(W1)
* C(C)
*
* Which would create W1->C->W1 dependencies, even though there is no
* actual deadlock possible. There are two solutions, using a
* read-recursive acquire on the work(queue) 'locks', but this will then
* hit the lockdep limitation on recursive locks, or simply discard
* these locks.
*
* AFAICT there is no possible deadlock scenario between the
* flush_work() and complete() primitives (except for single-threaded
* workqueues), so hiding them isn't a problem.
*/
lockdep_invariant_state(true);
trace_workqueue_execute_start(work);
worker->current_func(work);
/*
* While we must be careful to not use "work" after this, the trace
* point will only record its address.
*/
trace_workqueue_execute_end(work, worker->current_func);
pwq->stats[PWQ_STAT_COMPLETED]++;
lock_map_release(&lockdep_map);
lock_map_release(&pwq->wq->lockdep_map);
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
" last function: %ps\n",
current->comm, preempt_count(), task_pid_nr(current),
worker->current_func);
debug_show_held_locks(current);
dump_stack();
}
/*
* The following prevents a kworker from hogging CPU on !PREEMPTION
* kernels, where a requeueing work item waiting for something to
* happen could deadlock with stop_machine as such work item could
* indefinitely requeue itself while all other CPUs are trapped in
* stop_machine. At the same time, report a quiescent RCU state so
* the same condition doesn't freeze RCU.
*/
cond_resched();
raw_spin_lock_irq(&pool->lock);
/*
* In addition to %WQ_CPU_INTENSIVE, @worker may also have been marked
* CPU intensive by wq_worker_tick() if @work hogged CPU longer than
* wq_cpu_intensive_thresh_us. Clear it.
*/
worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
/* tag the worker for identification in schedule() */
worker->last_func = worker->current_func;
/* we're done with it, release */
hash_del(&worker->hentry);
worker->current_work = NULL;
worker->current_func = NULL;
worker->current_pwq = NULL;
worker->current_color = INT_MAX;
pwq_dec_nr_in_flight(pwq, work_data);
}
/**
* process_scheduled_works - process scheduled works
* @worker: self
*
* Process all scheduled works. Please note that the scheduled list
* may change while processing a work, so this function repeatedly
* fetches a work from the top and executes it.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock) which may be released and regrabbed
* multiple times.
*/
static void process_scheduled_works(struct worker *worker)
{
struct work_struct *work;
bool first = true;
while ((work = list_first_entry_or_null(&worker->scheduled,
struct work_struct, entry))) {
if (first) {
worker->pool->watchdog_ts = jiffies;
first = false;
}
process_one_work(worker, work);
}
}
static void set_pf_worker(bool val)
{
mutex_lock(&wq_pool_attach_mutex);
if (val)
current->flags |= PF_WQ_WORKER;
else
current->flags &= ~PF_WQ_WORKER;
mutex_unlock(&wq_pool_attach_mutex);
}
/**
* worker_thread - the worker thread function
* @__worker: self
*
* The worker thread function. All workers belong to a worker_pool -
* either a per-cpu one or dynamic unbound one. These workers process all
* work items regardless of their specific target workqueue. The only
* exception is work items which belong to workqueues with a rescuer which
* will be explained in rescuer_thread().
*
* Return: 0
*/
static int worker_thread(void *__worker)
{
struct worker *worker = __worker;
struct worker_pool *pool = worker->pool;
/* tell the scheduler that this is a workqueue worker */
set_pf_worker(true);
woke_up:
raw_spin_lock_irq(&pool->lock);
/* am I supposed to die? */
if (unlikely(worker->flags & WORKER_DIE)) {
raw_spin_unlock_irq(&pool->lock);
set_pf_worker(false);
set_task_comm(worker->task, "kworker/dying");
ida_free(&pool->worker_ida, worker->id);
worker_detach_from_pool(worker);
WARN_ON_ONCE(!list_empty(&worker->entry));
kfree(worker);
return 0;
}
worker_leave_idle(worker);
recheck:
/* no more worker necessary? */
if (!need_more_worker(pool))
goto sleep;
/* do we need to manage? */
if (unlikely(!may_start_working(pool)) && manage_workers(worker))
goto recheck;
/*
* ->scheduled list can only be filled while a worker is
* preparing to process a work or actually processing it.
* Make sure nobody diddled with it while I was sleeping.
*/
WARN_ON_ONCE(!list_empty(&worker->scheduled));
/*
* Finish PREP stage. We're guaranteed to have at least one idle
* worker or that someone else has already assumed the manager
* role. This is where @worker starts participating in concurrency
* management if applicable and concurrency management is restored
* after being rebound. See rebind_workers() for details.
*/
worker_clr_flags(worker, WORKER_PREP | WORKER_REBOUND);
do {
struct work_struct *work =
list_first_entry(&pool->worklist,
struct work_struct, entry);
if (assign_work(work, worker, NULL))
process_scheduled_works(worker);
} while (keep_working(pool));
worker_set_flags(worker, WORKER_PREP);
sleep:
/*
* pool->lock is held and there's no work to process and no need to
* manage, sleep. Workers are woken up only while holding
* pool->lock or from local cpu, so setting the current state
* before releasing pool->lock is enough to prevent losing any
* event.
*/
worker_enter_idle(worker);
__set_current_state(TASK_IDLE);
raw_spin_unlock_irq(&pool->lock);
schedule();
goto woke_up;
}
/**
* rescuer_thread - the rescuer thread function
* @__rescuer: self
*
* Workqueue rescuer thread function. There's one rescuer for each
* workqueue which has WQ_MEM_RECLAIM set.
*
* Regular work processing on a pool may block trying to create a new
* worker which uses GFP_KERNEL allocation which has slight chance of
* developing into deadlock if some works currently on the same queue
* need to be processed to satisfy the GFP_KERNEL allocation. This is
* the problem rescuer solves.
*
* When such condition is possible, the pool summons rescuers of all
* workqueues which have works queued on the pool and let them process
* those works so that forward progress can be guaranteed.
*
* This should happen rarely.
*
* Return: 0
*/
static int rescuer_thread(void *__rescuer)
{
struct worker *rescuer = __rescuer;
struct workqueue_struct *wq = rescuer->rescue_wq;
bool should_stop;
set_user_nice(current, RESCUER_NICE_LEVEL);
/*
* Mark rescuer as worker too. As WORKER_PREP is never cleared, it
* doesn't participate in concurrency management.
*/
set_pf_worker(true);
repeat:
set_current_state(TASK_IDLE);
/*
* By the time the rescuer is requested to stop, the workqueue
* shouldn't have any work pending, but @wq->maydays may still have
* pwq(s) queued. This can happen by non-rescuer workers consuming
* all the work items before the rescuer got to them. Go through
* @wq->maydays processing before acting on should_stop so that the
* list is always empty on exit.
*/
should_stop = kthread_should_stop();
/* see whether any pwq is asking for help */
raw_spin_lock_irq(&wq_mayday_lock);
while (!list_empty(&wq->maydays)) {
struct pool_workqueue *pwq = list_first_entry(&wq->maydays,
struct pool_workqueue, mayday_node);
struct worker_pool *pool = pwq->pool;
struct work_struct *work, *n;
__set_current_state(TASK_RUNNING);
list_del_init(&pwq->mayday_node);
raw_spin_unlock_irq(&wq_mayday_lock);
worker_attach_to_pool(rescuer, pool);
raw_spin_lock_irq(&pool->lock);
/*
* Slurp in all works issued via this workqueue and
* process'em.
*/
WARN_ON_ONCE(!list_empty(&rescuer->scheduled));
list_for_each_entry_safe(work, n, &pool->worklist, entry) {
if (get_work_pwq(work) == pwq &&
assign_work(work, rescuer, &n))
pwq->stats[PWQ_STAT_RESCUED]++;
}
if (!list_empty(&rescuer->scheduled)) {
process_scheduled_works(rescuer);
/*
* The above execution of rescued work items could
* have created more to rescue through
* pwq_activate_first_inactive() or chained
* queueing. Let's put @pwq back on mayday list so
* that such back-to-back work items, which may be
* being used to relieve memory pressure, don't
* incur MAYDAY_INTERVAL delay inbetween.
*/
if (pwq->nr_active && need_to_create_worker(pool)) {
raw_spin_lock(&wq_mayday_lock);
/*
* Queue iff we aren't racing destruction
* and somebody else hasn't queued it already.
*/
if (wq->rescuer && list_empty(&pwq->mayday_node)) {
get_pwq(pwq);
list_add_tail(&pwq->mayday_node, &wq->maydays);
}
raw_spin_unlock(&wq_mayday_lock);
}
}
/*
* Put the reference grabbed by send_mayday(). @pool won't
* go away while we're still attached to it.
*/
put_pwq(pwq);
/*
* Leave this pool. Notify regular workers; otherwise, we end up
* with 0 concurrency and stalling the execution.
*/
kick_pool(pool);
raw_spin_unlock_irq(&pool->lock);
worker_detach_from_pool(rescuer);
raw_spin_lock_irq(&wq_mayday_lock);
}
raw_spin_unlock_irq(&wq_mayday_lock);
if (should_stop) {
__set_current_state(TASK_RUNNING);
set_pf_worker(false);
return 0;
}
/* rescuers should never participate in concurrency management */
WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
schedule();
goto repeat;
}
/**
* check_flush_dependency - check for flush dependency sanity
* @target_wq: workqueue being flushed
* @target_work: work item being flushed (NULL for workqueue flushes)
*
* %current is trying to flush the whole @target_wq or @target_work on it.
* If @target_wq doesn't have %WQ_MEM_RECLAIM, verify that %current is not
* reclaiming memory or running on a workqueue which doesn't have
* %WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to
* a deadlock.
*/
static void check_flush_dependency(struct workqueue_struct *target_wq,
struct work_struct *target_work)
{
work_func_t target_func = target_work ? target_work->func : NULL;
struct worker *worker;
if (target_wq->flags & WQ_MEM_RECLAIM)
return;
worker = current_wq_worker();
WARN_ONCE(current->flags & PF_MEMALLOC,
"workqueue: PF_MEMALLOC task %d(%s) is flushing !WQ_MEM_RECLAIM %s:%ps",
current->pid, current->comm, target_wq->name, target_func);
WARN_ONCE(worker && ((worker->current_pwq->wq->flags &
(WQ_MEM_RECLAIM | __WQ_LEGACY)) == WQ_MEM_RECLAIM),
"workqueue: WQ_MEM_RECLAIM %s:%ps is flushing !WQ_MEM_RECLAIM %s:%ps",
worker->current_pwq->wq->name, worker->current_func,
target_wq->name, target_func);
}
struct wq_barrier {
struct work_struct work;
struct completion done;
struct task_struct *task; /* purely informational */
};
static void wq_barrier_func(struct work_struct *work)
{
struct wq_barrier *barr = container_of(work, struct wq_barrier, work);
complete(&barr->done);
}
/**
* insert_wq_barrier - insert a barrier work
* @pwq: pwq to insert barrier into
* @barr: wq_barrier to insert
* @target: target work to attach @barr to
* @worker: worker currently executing @target, NULL if @target is not executing
*
* @barr is linked to @target such that @barr is completed only after
* @target finishes execution. Please note that the ordering
* guarantee is observed only with respect to @target and on the local
* cpu.
*
* Currently, a queued barrier can't be canceled. This is because
* try_to_grab_pending() can't determine whether the work to be
* grabbed is at the head of the queue and thus can't clear LINKED
* flag of the previous work while there must be a valid next work
* after a work with LINKED flag set.
*
* Note that when @worker is non-NULL, @target may be modified
* underneath us, so we can't reliably determine pwq from @target.
*
* CONTEXT:
* raw_spin_lock_irq(pool->lock).
*/
static void insert_wq_barrier(struct pool_workqueue *pwq,
struct wq_barrier *barr,
struct work_struct *target, struct worker *worker)
{
unsigned int work_flags = 0;
unsigned int work_color;
struct list_head *head;
/*
* debugobject calls are safe here even with pool->lock locked
* as we know for sure that this will not trigger any of the
* checks and call back into the fixup functions where we
* might deadlock.
*/
INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
init_completion_map(&barr->done, &target->lockdep_map);
barr->task = current;
/* The barrier work item does not participate in pwq->nr_active. */
work_flags |= WORK_STRUCT_INACTIVE;
/*
* If @target is currently being executed, schedule the
* barrier to the worker; otherwise, put it after @target.
*/
if (worker) {
head = worker->scheduled.next;
work_color = worker->current_color;
} else {
unsigned long *bits = work_data_bits(target);
head = target->entry.next;
/* there can already be other linked works, inherit and set */
work_flags |= *bits & WORK_STRUCT_LINKED;
work_color = get_work_color(*bits);
__set_bit(WORK_STRUCT_LINKED_BIT, bits);
}
pwq->nr_in_flight[work_color]++;
work_flags |= work_color_to_flags(work_color);
insert_work(pwq, &barr->work, head, work_flags);
}
/**
* flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
* @wq: workqueue being flushed
* @flush_color: new flush color, < 0 for no-op
* @work_color: new work color, < 0 for no-op
*
* Prepare pwqs for workqueue flushing.
*
* If @flush_color is non-negative, flush_color on all pwqs should be
* -1. If no pwq has in-flight commands at the specified color, all
* pwq->flush_color's stay at -1 and %false is returned. If any pwq
* has in flight commands, its pwq->flush_color is set to
* @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
* wakeup logic is armed and %true is returned.
*
* The caller should have initialized @wq->first_flusher prior to
* calling this function with non-negative @flush_color. If
* @flush_color is negative, no flush color update is done and %false
* is returned.
*
* If @work_color is non-negative, all pwqs should have the same
* work_color which is previous to @work_color and all will be
* advanced to @work_color.
*
* CONTEXT:
* mutex_lock(wq->mutex).
*
* Return:
* %true if @flush_color >= 0 and there's something to flush. %false
* otherwise.
*/
static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
int flush_color, int work_color)
{
bool wait = false;
struct pool_workqueue *pwq;
if (flush_color >= 0) {
WARN_ON_ONCE(atomic_read(&wq->nr_pwqs_to_flush));
atomic_set(&wq->nr_pwqs_to_flush, 1);
}
for_each_pwq(pwq, wq) {
struct worker_pool *pool = pwq->pool;
raw_spin_lock_irq(&pool->lock);
if (flush_color >= 0) {
WARN_ON_ONCE(pwq->flush_color != -1);
if (pwq->nr_in_flight[flush_color]) {
pwq->flush_color = flush_color;
atomic_inc(&wq->nr_pwqs_to_flush);
wait = true;
}
}
if (work_color >= 0) {
WARN_ON_ONCE(work_color != work_next_color(pwq->work_color));
pwq->work_color = work_color;
}
raw_spin_unlock_irq(&pool->lock);
}
if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
complete(&wq->first_flusher->done);
return wait;
}
/**
* __flush_workqueue - ensure that any scheduled work has run to completion.
* @wq: workqueue to flush
*
* This function sleeps until all work items which were queued on entry
* have finished execution, but it is not livelocked by new incoming ones.
*/
void __flush_workqueue(struct workqueue_struct *wq)
{
struct wq_flusher this_flusher = {
.list = LIST_HEAD_INIT(this_flusher.list),
.flush_color = -1,
.done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map),
};
int next_color;
if (WARN_ON(!wq_online))
return;
lock_map_acquire(&wq->lockdep_map);
lock_map_release(&wq->lockdep_map);
mutex_lock(&wq->mutex);
/*
* Start-to-wait phase
*/
next_color = work_next_color(wq->work_color);
if (next_color != wq->flush_color) {
/*
* Color space is not full. The current work_color
* becomes our flush_color and work_color is advanced
* by one.
*/
WARN_ON_ONCE(!list_empty(&wq->flusher_overflow));
this_flusher.flush_color = wq->work_color;
wq->work_color = next_color;
if (!wq->first_flusher) {
/* no flush in progress, become the first flusher */
WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
wq->first_flusher = &this_flusher;
if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
wq->work_color)) {
/* nothing to flush, done */
wq->flush_color = next_color;
wq->first_flusher = NULL;
goto out_unlock;
}
} else {
/* wait in queue */
WARN_ON_ONCE(wq->flush_color == this_flusher.flush_color);
list_add_tail(&this_flusher.list, &wq->flusher_queue);
flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
}
} else {
/*
* Oops, color space is full, wait on overflow queue.
* The next flush completion will assign us
* flush_color and transfer to flusher_queue.
*/
list_add_tail(&this_flusher.list, &wq->flusher_overflow);
}
check_flush_dependency(wq, NULL);
mutex_unlock(&wq->mutex);
wait_for_completion(&this_flusher.done);
/*
* Wake-up-and-cascade phase
*
* First flushers are responsible for cascading flushes and
* handling overflow. Non-first flushers can simply return.
*/
if (READ_ONCE(wq->first_flusher) != &this_flusher)
return;
mutex_lock(&wq->mutex);
/* we might have raced, check again with mutex held */
if (wq->first_flusher != &this_flusher)
goto out_unlock;
WRITE_ONCE(wq->first_flusher, NULL);
WARN_ON_ONCE(!list_empty(&this_flusher.list));
WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
while (true) {
struct wq_flusher *next, *tmp;
/* complete all the flushers sharing the current flush color */
list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) {
if (next->flush_color != wq->flush_color)
break;
list_del_init(&next->list);
complete(&next->done);
}
WARN_ON_ONCE(!list_empty(&wq->flusher_overflow) &&
wq->flush_color != work_next_color(wq->work_color));
/* this flush_color is finished, advance by one */
wq->flush_color = work_next_color(wq->flush_color);
/* one color has been freed, handle overflow queue */
if (!list_empty(&wq->flusher_overflow)) {
/*
* Assign the same color to all overflowed
* flushers, advance work_color and append to
* flusher_queue. This is the start-to-wait
* phase for these overflowed flushers.
*/
list_for_each_entry(tmp, &wq->flusher_overflow, list)
tmp->flush_color = wq->work_color;
wq->work_color = work_next_color(wq->work_color);
list_splice_tail_init(&wq->flusher_overflow,
&wq->flusher_queue);
flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
}
if (list_empty(&wq->flusher_queue)) {
WARN_ON_ONCE(wq->flush_color != wq->work_color);
break;
}
/*
* Need to flush more colors. Make the next flusher
* the new first flusher and arm pwqs.
*/
WARN_ON_ONCE(wq->flush_color == wq->work_color);
WARN_ON_ONCE(wq->flush_color != next->flush_color);
list_del_init(&next->list);
wq->first_flusher = next;
if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
break;
/*
* Meh... this color is already done, clear first
* flusher and repeat cascading.
*/
wq->first_flusher = NULL;
}
out_unlock:
mutex_unlock(&wq->mutex);
}
EXPORT_SYMBOL(__flush_workqueue);
/**
* drain_workqueue - drain a workqueue
* @wq: workqueue to drain
*
* Wait until the workqueue becomes empty. While draining is in progress,
* only chain queueing is allowed. IOW, only currently pending or running
* work items on @wq can queue further work items on it. @wq is flushed
* repeatedly until it becomes empty. The number of flushing is determined
* by the depth of chaining and should be relatively short. Whine if it
* takes too long.
*/
void drain_workqueue(struct workqueue_struct *wq)
{
unsigned int flush_cnt = 0;
struct pool_workqueue *pwq;
/*
* __queue_work() needs to test whether there are drainers, is much
* hotter than drain_workqueue() and already looks at @wq->flags.
* Use __WQ_DRAINING so that queue doesn't have to check nr_drainers.
*/
mutex_lock(&wq->mutex);
if (!wq->nr_drainers++)
wq->flags |= __WQ_DRAINING;
mutex_unlock(&wq->mutex);
reflush:
__flush_workqueue(wq);
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq) {
bool drained;
raw_spin_lock_irq(&pwq->pool->lock);
drained = !pwq->nr_active && list_empty(&pwq->inactive_works);
raw_spin_unlock_irq(&pwq->pool->lock);
if (drained)
continue;
if (++flush_cnt == 10 ||
(flush_cnt % 100 == 0 && flush_cnt <= 1000))
pr_warn("workqueue %s: %s() isn't complete after %u tries\n",
wq->name, __func__, flush_cnt);
mutex_unlock(&wq->mutex);
goto reflush;
}
if (!--wq->nr_drainers)
wq->flags &= ~__WQ_DRAINING;
mutex_unlock(&wq->mutex);
}
EXPORT_SYMBOL_GPL(drain_workqueue);
static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr,
bool from_cancel)
{
struct worker *worker = NULL;
struct worker_pool *pool;
struct pool_workqueue *pwq;
might_sleep();
rcu_read_lock();
pool = get_work_pool(work);
if (!pool) {
rcu_read_unlock();
return false;
}
raw_spin_lock_irq(&pool->lock);
/* see the comment in try_to_grab_pending() with the same code */
pwq = get_work_pwq(work);
if (pwq) {
if (unlikely(pwq->pool != pool))
goto already_gone;
} else {
worker = find_worker_executing_work(pool, work);
if (!worker)
goto already_gone;
pwq = worker->current_pwq;
}
check_flush_dependency(pwq->wq, work);
insert_wq_barrier(pwq, barr, work, worker);
raw_spin_unlock_irq(&pool->lock);
/*
* Force a lock recursion deadlock when using flush_work() inside a
* single-threaded or rescuer equipped workqueue.
*
* For single threaded workqueues the deadlock happens when the work
* is after the work issuing the flush_work(). For rescuer equipped
* workqueues the deadlock happens when the rescuer stalls, blocking
* forward progress.
*/
if (!from_cancel &&
(pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)) {
lock_map_acquire(&pwq->wq->lockdep_map);
lock_map_release(&pwq->wq->lockdep_map);
}
rcu_read_unlock();
return true;
already_gone:
raw_spin_unlock_irq(&pool->lock);
rcu_read_unlock();
return false;
}
static bool __flush_work(struct work_struct *work, bool from_cancel)
{
struct wq_barrier barr;
if (WARN_ON(!wq_online))
return false;
if (WARN_ON(!work->func))
return false;
lock_map_acquire(&work->lockdep_map);
lock_map_release(&work->lockdep_map);
if (start_flush_work(work, &barr, from_cancel)) {
wait_for_completion(&barr.done);
destroy_work_on_stack(&barr.work);
return true;
} else {
return false;
}
}
/**
* flush_work - wait for a work to finish executing the last queueing instance
* @work: the work to flush
*
* Wait until @work has finished execution. @work is guaranteed to be idle
* on return if it hasn't been requeued since flush started.
*
* Return:
* %true if flush_work() waited for the work to finish execution,
* %false if it was already idle.
*/
bool flush_work(struct work_struct *work)
{
return __flush_work(work, false);
}
EXPORT_SYMBOL_GPL(flush_work);
struct cwt_wait {
wait_queue_entry_t wait;
struct work_struct *work;
};
static int cwt_wakefn(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait);
if (cwait->work != key)
return 0;
return autoremove_wake_function(wait, mode, sync, key);
}
static bool __cancel_work_timer(struct work_struct *work, bool is_dwork)
{
static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq);
unsigned long flags;
int ret;
do {
ret = try_to_grab_pending(work, is_dwork, &flags);
/*
* If someone else is already canceling, wait for it to
* finish. flush_work() doesn't work for PREEMPT_NONE
* because we may get scheduled between @work's completion
* and the other canceling task resuming and clearing
* CANCELING - flush_work() will return false immediately
* as @work is no longer busy, try_to_grab_pending() will
* return -ENOENT as @work is still being canceled and the
* other canceling task won't be able to clear CANCELING as
* we're hogging the CPU.
*
* Let's wait for completion using a waitqueue. As this
* may lead to the thundering herd problem, use a custom
* wake function which matches @work along with exclusive
* wait and wakeup.
*/
if (unlikely(ret == -ENOENT)) {
struct cwt_wait cwait;
init_wait(&cwait.wait);
cwait.wait.func = cwt_wakefn;
cwait.work = work;
prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait,
TASK_UNINTERRUPTIBLE);
if (work_is_canceling(work))
schedule();
finish_wait(&cancel_waitq, &cwait.wait);
}
} while (unlikely(ret < 0));
/* tell other tasks trying to grab @work to back off */
mark_work_canceling(work);
local_irq_restore(flags);
/*
* This allows canceling during early boot. We know that @work
* isn't executing.
*/
if (wq_online)
__flush_work(work, true);
clear_work_data(work);
/*
* Paired with prepare_to_wait() above so that either
* waitqueue_active() is visible here or !work_is_canceling() is
* visible there.
*/
smp_mb();
if (waitqueue_active(&cancel_waitq))
__wake_up(&cancel_waitq, TASK_NORMAL, 1, work);
return ret;
}
/**
* cancel_work_sync - cancel a work and wait for it to finish
* @work: the work to cancel
*
* Cancel @work and wait for its execution to finish. This function
* can be used even if the work re-queues itself or migrates to
* another workqueue. On return from this function, @work is
* guaranteed to be not pending or executing on any CPU.
*
* cancel_work_sync(&delayed_work->work) must not be used for
* delayed_work's. Use cancel_delayed_work_sync() instead.
*
* The caller must ensure that the workqueue on which @work was last
* queued can't be destroyed before this function returns.
*
* Return:
* %true if @work was pending, %false otherwise.
*/
bool cancel_work_sync(struct work_struct *work)
{
return __cancel_work_timer(work, false);
}
EXPORT_SYMBOL_GPL(cancel_work_sync);
/**
* flush_delayed_work - wait for a dwork to finish executing the last queueing
* @dwork: the delayed work to flush
*
* Delayed timer is cancelled and the pending work is queued for
* immediate execution. Like flush_work(), this function only
* considers the last queueing instance of @dwork.
*
* Return:
* %true if flush_work() waited for the work to finish execution,
* %false if it was already idle.
*/
bool flush_delayed_work(struct delayed_work *dwork)
{
local_irq_disable();
if (del_timer_sync(&dwork->timer))
__queue_work(dwork->cpu, dwork->wq, &dwork->work);
local_irq_enable();
return flush_work(&dwork->work);
}
EXPORT_SYMBOL(flush_delayed_work);
/**
* flush_rcu_work - wait for a rwork to finish executing the last queueing
* @rwork: the rcu work to flush
*
* Return:
* %true if flush_rcu_work() waited for the work to finish execution,
* %false if it was already idle.
*/
bool flush_rcu_work(struct rcu_work *rwork)
{
if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
rcu_barrier();
flush_work(&rwork->work);
return true;
} else {
return flush_work(&rwork->work);
}
}
EXPORT_SYMBOL(flush_rcu_work);
static bool __cancel_work(struct work_struct *work, bool is_dwork)
{
unsigned long flags;
int ret;
do {
ret = try_to_grab_pending(work, is_dwork, &flags);
} while (unlikely(ret == -EAGAIN));
if (unlikely(ret < 0))
return false;
set_work_pool_and_clear_pending(work, get_work_pool_id(work));
local_irq_restore(flags);
return ret;
}
/*
* See cancel_delayed_work()
*/
bool cancel_work(struct work_struct *work)
{
return __cancel_work(work, false);
}
EXPORT_SYMBOL(cancel_work);
/**
* cancel_delayed_work - cancel a delayed work
* @dwork: delayed_work to cancel
*
* Kill off a pending delayed_work.
*
* Return: %true if @dwork was pending and canceled; %false if it wasn't
* pending.
*
* Note:
* The work callback function may still be running on return, unless
* it returns %true and the work doesn't re-arm itself. Explicitly flush or
* use cancel_delayed_work_sync() to wait on it.
*
* This function is safe to call from any context including IRQ handler.
*/
bool cancel_delayed_work(struct delayed_work *dwork)
{
return __cancel_work(&dwork->work, true);
}
EXPORT_SYMBOL(cancel_delayed_work);
/**
* cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
* @dwork: the delayed work cancel
*
* This is cancel_work_sync() for delayed works.
*
* Return:
* %true if @dwork was pending, %false otherwise.
*/
bool cancel_delayed_work_sync(struct delayed_work *dwork)
{
return __cancel_work_timer(&dwork->work, true);
}
EXPORT_SYMBOL(cancel_delayed_work_sync);
/**
* schedule_on_each_cpu - execute a function synchronously on each online CPU
* @func: the function to call
*
* schedule_on_each_cpu() executes @func on each online CPU using the
* system workqueue and blocks until all CPUs have completed.
* schedule_on_each_cpu() is very slow.
*
* Return:
* 0 on success, -errno on failure.
*/
int schedule_on_each_cpu(work_func_t func)
{
int cpu;
struct work_struct __percpu *works;
works = alloc_percpu(struct work_struct);
if (!works)
return -ENOMEM;
cpus_read_lock();
for_each_online_cpu(cpu) {
struct work_struct *work = per_cpu_ptr(works, cpu);
INIT_WORK(work, func);
schedule_work_on(cpu, work);
}
for_each_online_cpu(cpu)
flush_work(per_cpu_ptr(works, cpu));
cpus_read_unlock();
free_percpu(works);
return 0;
}
/**
* execute_in_process_context - reliably execute the routine with user context
* @fn: the function to execute
* @ew: guaranteed storage for the execute work structure (must
* be available when the work executes)
*
* Executes the function immediately if process context is available,
* otherwise schedules the function for delayed execution.
*
* Return: 0 - function was executed
* 1 - function was scheduled for execution
*/
int execute_in_process_context(work_func_t fn, struct execute_work *ew)
{
if (!in_interrupt()) {
fn(&ew->work);
return 0;
}
INIT_WORK(&ew->work, fn);
schedule_work(&ew->work);
return 1;
}
EXPORT_SYMBOL_GPL(execute_in_process_context);
/**
* free_workqueue_attrs - free a workqueue_attrs
* @attrs: workqueue_attrs to free
*
* Undo alloc_workqueue_attrs().
*/
void free_workqueue_attrs(struct workqueue_attrs *attrs)
{
if (attrs) {
free_cpumask_var(attrs->cpumask);
free_cpumask_var(attrs->__pod_cpumask);
kfree(attrs);
}
}
/**
* alloc_workqueue_attrs - allocate a workqueue_attrs
*
* Allocate a new workqueue_attrs, initialize with default settings and
* return it.
*
* Return: The allocated new workqueue_attr on success. %NULL on failure.
*/
struct workqueue_attrs *alloc_workqueue_attrs(void)
{
struct workqueue_attrs *attrs;
attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
if (!attrs)
goto fail;
if (!alloc_cpumask_var(&attrs->cpumask, GFP_KERNEL))
goto fail;
if (!alloc_cpumask_var(&attrs->__pod_cpumask, GFP_KERNEL))
goto fail;
cpumask_copy(attrs->cpumask, cpu_possible_mask);
attrs->affn_scope = WQ_AFFN_DFL;
return attrs;
fail:
free_workqueue_attrs(attrs);
return NULL;
}
static void copy_workqueue_attrs(struct workqueue_attrs *to,
const struct workqueue_attrs *from)
{
to->nice = from->nice;
cpumask_copy(to->cpumask, from->cpumask);
cpumask_copy(to->__pod_cpumask, from->__pod_cpumask);
to->affn_strict = from->affn_strict;
/*
* Unlike hash and equality test, copying shouldn't ignore wq-only
* fields as copying is used for both pool and wq attrs. Instead,
* get_unbound_pool() explicitly clears the fields.
*/
to->affn_scope = from->affn_scope;
to->ordered = from->ordered;
}
/*
* Some attrs fields are workqueue-only. Clear them for worker_pool's. See the
* comments in 'struct workqueue_attrs' definition.
*/
static void wqattrs_clear_for_pool(struct workqueue_attrs *attrs)
{
attrs->affn_scope = WQ_AFFN_NR_TYPES;
attrs->ordered = false;
}
/* hash value of the content of @attr */
static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
{
u32 hash = 0;
hash = jhash_1word(attrs->nice, hash);
hash = jhash(cpumask_bits(attrs->cpumask),
BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
hash = jhash(cpumask_bits(attrs->__pod_cpumask),
BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
hash = jhash_1word(attrs->affn_strict, hash);
return hash;
}
/* content equality test */
static bool wqattrs_equal(const struct workqueue_attrs *a,
const struct workqueue_attrs *b)
{
if (a->nice != b->nice)
return false;
if (!cpumask_equal(a->cpumask, b->cpumask))
return false;
if (!cpumask_equal(a->__pod_cpumask, b->__pod_cpumask))
return false;
if (a->affn_strict != b->affn_strict)
return false;
return true;
}
/* Update @attrs with actually available CPUs */
static void wqattrs_actualize_cpumask(struct workqueue_attrs *attrs,
const cpumask_t *unbound_cpumask)
{
/*
* Calculate the effective CPU mask of @attrs given @unbound_cpumask. If
* @attrs->cpumask doesn't overlap with @unbound_cpumask, we fallback to
* @unbound_cpumask.
*/
cpumask_and(attrs->cpumask, attrs->cpumask, unbound_cpumask);
if (unlikely(cpumask_empty(attrs->cpumask)))
cpumask_copy(attrs->cpumask, unbound_cpumask);
}
/* find wq_pod_type to use for @attrs */
static const struct wq_pod_type *
wqattrs_pod_type(const struct workqueue_attrs *attrs)
{
enum wq_affn_scope scope;
struct wq_pod_type *pt;
/* to synchronize access to wq_affn_dfl */
lockdep_assert_held(&wq_pool_mutex);
if (attrs->affn_scope == WQ_AFFN_DFL)
scope = wq_affn_dfl;
else
scope = attrs->affn_scope;
pt = &wq_pod_types[scope];
if (!WARN_ON_ONCE(attrs->affn_scope == WQ_AFFN_NR_TYPES) &&
likely(pt->nr_pods))
return pt;
/*
* Before workqueue_init_topology(), only SYSTEM is available which is
* initialized in workqueue_init_early().
*/
pt = &wq_pod_types[WQ_AFFN_SYSTEM];
BUG_ON(!pt->nr_pods);
return pt;
}
/**
* init_worker_pool - initialize a newly zalloc'd worker_pool
* @pool: worker_pool to initialize
*
* Initialize a newly zalloc'd @pool. It also allocates @pool->attrs.
*
* Return: 0 on success, -errno on failure. Even on failure, all fields
* inside @pool proper are initialized and put_unbound_pool() can be called
* on @pool safely to release it.
*/
static int init_worker_pool(struct worker_pool *pool)
{
raw_spin_lock_init(&pool->lock);
pool->id = -1;
pool->cpu = -1;
pool->node = NUMA_NO_NODE;
pool->flags |= POOL_DISASSOCIATED;
pool->watchdog_ts = jiffies;
INIT_LIST_HEAD(&pool->worklist);
INIT_LIST_HEAD(&pool->idle_list);
hash_init(pool->busy_hash);
timer_setup(&pool->idle_timer, idle_worker_timeout, TIMER_DEFERRABLE);
INIT_WORK(&pool->idle_cull_work, idle_cull_fn);
timer_setup(&pool->mayday_timer, pool_mayday_timeout, 0);
INIT_LIST_HEAD(&pool->workers);
INIT_LIST_HEAD(&pool->dying_workers);
ida_init(&pool->worker_ida);
INIT_HLIST_NODE(&pool->hash_node);
pool->refcnt = 1;
/* shouldn't fail above this point */
pool->attrs = alloc_workqueue_attrs();
if (!pool->attrs)
return -ENOMEM;
wqattrs_clear_for_pool(pool->attrs);
return 0;
}
#ifdef CONFIG_LOCKDEP
static void wq_init_lockdep(struct workqueue_struct *wq)
{
char *lock_name;
lockdep_register_key(&wq->key);
lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
if (!lock_name)
lock_name = wq->name;
wq->lock_name = lock_name;
lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
}
static void wq_unregister_lockdep(struct workqueue_struct *wq)
{
lockdep_unregister_key(&wq->key);
}
static void wq_free_lockdep(struct workqueue_struct *wq)
{
if (wq->lock_name != wq->name)
kfree(wq->lock_name);
}
#else
static void wq_init_lockdep(struct workqueue_struct *wq)
{
}
static void wq_unregister_lockdep(struct workqueue_struct *wq)
{
}
static void wq_free_lockdep(struct workqueue_struct *wq)
{
}
#endif
static void rcu_free_wq(struct rcu_head *rcu)
{
struct workqueue_struct *wq =
container_of(rcu, struct workqueue_struct, rcu);
wq_free_lockdep(wq);
free_percpu(wq->cpu_pwq);
free_workqueue_attrs(wq->unbound_attrs);
kfree(wq);
}
static void rcu_free_pool(struct rcu_head *rcu)
{
struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu);
ida_destroy(&pool->worker_ida);
free_workqueue_attrs(pool->attrs);
kfree(pool);
}
/**
* put_unbound_pool - put a worker_pool
* @pool: worker_pool to put
*
* Put @pool. If its refcnt reaches zero, it gets destroyed in RCU
* safe manner. get_unbound_pool() calls this function on its failure path
* and this function should be able to release pools which went through,
* successfully or not, init_worker_pool().
*
* Should be called with wq_pool_mutex held.
*/
static void put_unbound_pool(struct worker_pool *pool)
{
DECLARE_COMPLETION_ONSTACK(detach_completion);
struct worker *worker;
LIST_HEAD(cull_list);
lockdep_assert_held(&wq_pool_mutex);
if (--pool->refcnt)
return;
/* sanity checks */
if (WARN_ON(!(pool->cpu < 0)) ||
WARN_ON(!list_empty(&pool->worklist)))
return;
/* release id and unhash */
if (pool->id >= 0)
idr_remove(&worker_pool_idr, pool->id);
hash_del(&pool->hash_node);
/*
* Become the manager and destroy all workers. This prevents
* @pool's workers from blocking on attach_mutex. We're the last
* manager and @pool gets freed with the flag set.
*
* Having a concurrent manager is quite unlikely to happen as we can
* only get here with
* pwq->refcnt == pool->refcnt == 0
* which implies no work queued to the pool, which implies no worker can
* become the manager. However a worker could have taken the role of
* manager before the refcnts dropped to 0, since maybe_create_worker()
* drops pool->lock
*/
while (true) {
rcuwait_wait_event(&manager_wait,
!(pool->flags & POOL_MANAGER_ACTIVE),
TASK_UNINTERRUPTIBLE);
mutex_lock(&wq_pool_attach_mutex);
raw_spin_lock_irq(&pool->lock);
if (!(pool->flags & POOL_MANAGER_ACTIVE)) {
pool->flags |= POOL_MANAGER_ACTIVE;
break;
}
raw_spin_unlock_irq(&pool->lock);
mutex_unlock(&wq_pool_attach_mutex);
}
while ((worker = first_idle_worker(pool)))
set_worker_dying(worker, &cull_list);
WARN_ON(pool->nr_workers || pool->nr_idle);
raw_spin_unlock_irq(&pool->lock);
wake_dying_workers(&cull_list);
if (!list_empty(&pool->workers) || !list_empty(&pool->dying_workers))
pool->detach_completion = &detach_completion;
mutex_unlock(&wq_pool_attach_mutex);
if (pool->detach_completion)
wait_for_completion(pool->detach_completion);
/* shut down the timers */
del_timer_sync(&pool->idle_timer);
cancel_work_sync(&pool->idle_cull_work);
del_timer_sync(&pool->mayday_timer);
/* RCU protected to allow dereferences from get_work_pool() */
call_rcu(&pool->rcu, rcu_free_pool);
}
/**
* get_unbound_pool - get a worker_pool with the specified attributes
* @attrs: the attributes of the worker_pool to get
*
* Obtain a worker_pool which has the same attributes as @attrs, bump the
* reference count and return it. If there already is a matching
* worker_pool, it will be used; otherwise, this function attempts to
* create a new one.
*
* Should be called with wq_pool_mutex held.
*
* Return: On success, a worker_pool with the same attributes as @attrs.
* On failure, %NULL.
*/
static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
{
struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_NUMA];
u32 hash = wqattrs_hash(attrs);
struct worker_pool *pool;
int pod, node = NUMA_NO_NODE;
lockdep_assert_held(&wq_pool_mutex);
/* do we already have a matching pool? */
hash_for_each_possible(unbound_pool_hash, pool, hash_node, hash) {
if (wqattrs_equal(pool->attrs, attrs)) {
pool->refcnt++;
return pool;
}
}
/* If __pod_cpumask is contained inside a NUMA pod, that's our node */
for (pod = 0; pod < pt->nr_pods; pod++) {
if (cpumask_subset(attrs->__pod_cpumask, pt->pod_cpus[pod])) {
node = pt->pod_node[pod];
break;
}
}
/* nope, create a new one */
pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, node);
if (!pool || init_worker_pool(pool) < 0)
goto fail;
pool->node = node;
copy_workqueue_attrs(pool->attrs, attrs);
wqattrs_clear_for_pool(pool->attrs);
if (worker_pool_assign_id(pool) < 0)
goto fail;
/* create and start the initial worker */
if (wq_online && !create_worker(pool))
goto fail;
/* install */
hash_add(unbound_pool_hash, &pool->hash_node, hash);
return pool;
fail:
if (pool)
put_unbound_pool(pool);
return NULL;
}
static void rcu_free_pwq(struct rcu_head *rcu)
{
kmem_cache_free(pwq_cache,
container_of(rcu, struct pool_workqueue, rcu));
}
/*
* Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero
* refcnt and needs to be destroyed.
*/
static void pwq_release_workfn(struct kthread_work *work)
{
struct pool_workqueue *pwq = container_of(work, struct pool_workqueue,
release_work);
struct workqueue_struct *wq = pwq->wq;
struct worker_pool *pool = pwq->pool;
bool is_last = false;
/*
* When @pwq is not linked, it doesn't hold any reference to the
* @wq, and @wq is invalid to access.
*/
if (!list_empty(&pwq->pwqs_node)) {
mutex_lock(&wq->mutex);
list_del_rcu(&pwq->pwqs_node);
is_last = list_empty(&wq->pwqs);
mutex_unlock(&wq->mutex);
}
if (wq->flags & WQ_UNBOUND) {
mutex_lock(&wq_pool_mutex);
put_unbound_pool(pool);
mutex_unlock(&wq_pool_mutex);
}
call_rcu(&pwq->rcu, rcu_free_pwq);
/*
* If we're the last pwq going away, @wq is already dead and no one
* is gonna access it anymore. Schedule RCU free.
*/
if (is_last) {
wq_unregister_lockdep(wq);
call_rcu(&wq->rcu, rcu_free_wq);
}
}
/**
* pwq_adjust_max_active - update a pwq's max_active to the current setting
* @pwq: target pool_workqueue
*
* If @pwq isn't freezing, set @pwq->max_active to the associated
* workqueue's saved_max_active and activate inactive work items
* accordingly. If @pwq is freezing, clear @pwq->max_active to zero.
*/
static void pwq_adjust_max_active(struct pool_workqueue *pwq)
{
struct workqueue_struct *wq = pwq->wq;
bool freezable = wq->flags & WQ_FREEZABLE;
unsigned long flags;
/* for @wq->saved_max_active */
lockdep_assert_held(&wq->mutex);
/* fast exit for non-freezable wqs */
if (!freezable && pwq->max_active == wq->saved_max_active)
return;
/* this function can be called during early boot w/ irq disabled */
raw_spin_lock_irqsave(&pwq->pool->lock, flags);
/*
* During [un]freezing, the caller is responsible for ensuring that
* this function is called at least once after @workqueue_freezing
* is updated and visible.
*/
if (!freezable || !workqueue_freezing) {
pwq->max_active = wq->saved_max_active;
while (!list_empty(&pwq->inactive_works) &&
pwq->nr_active < pwq->max_active)
pwq_activate_first_inactive(pwq);
kick_pool(pwq->pool);
} else {
pwq->max_active = 0;
}
raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
}
/* initialize newly allocated @pwq which is associated with @wq and @pool */
static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
struct worker_pool *pool)
{
BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);
memset(pwq, 0, sizeof(*pwq));
pwq->pool = pool;
pwq->wq = wq;
pwq->flush_color = -1;
pwq->refcnt = 1;
INIT_LIST_HEAD(&pwq->inactive_works);
INIT_LIST_HEAD(&pwq->pwqs_node);
INIT_LIST_HEAD(&pwq->mayday_node);
kthread_init_work(&pwq->release_work, pwq_release_workfn);
}
/* sync @pwq with the current state of its associated wq and link it */
static void link_pwq(struct pool_workqueue *pwq)
{
struct workqueue_struct *wq = pwq->wq;
lockdep_assert_held(&wq->mutex);
/* may be called multiple times, ignore if already linked */
if (!list_empty(&pwq->pwqs_node))
return;
/* set the matching work_color */
pwq->work_color = wq->work_color;
/* sync max_active to the current setting */
pwq_adjust_max_active(pwq);
/* link in @pwq */
list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
}
/* obtain a pool matching @attr and create a pwq associating the pool and @wq */
static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
const struct workqueue_attrs *attrs)
{
struct worker_pool *pool;
struct pool_workqueue *pwq;
lockdep_assert_held(&wq_pool_mutex);
pool = get_unbound_pool(attrs);
if (!pool)
return NULL;
pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node);
if (!pwq) {
put_unbound_pool(pool);
return NULL;
}
init_pwq(pwq, wq, pool);
return pwq;
}
/**
* wq_calc_pod_cpumask - calculate a wq_attrs' cpumask for a pod
* @attrs: the wq_attrs of the default pwq of the target workqueue
* @cpu: the target CPU
* @cpu_going_down: if >= 0, the CPU to consider as offline
*
* Calculate the cpumask a workqueue with @attrs should use on @pod. If
* @cpu_going_down is >= 0, that cpu is considered offline during calculation.
* The result is stored in @attrs->__pod_cpumask.
*
* If pod affinity is not enabled, @attrs->cpumask is always used. If enabled
* and @pod has online CPUs requested by @attrs, the returned cpumask is the
* intersection of the possible CPUs of @pod and @attrs->cpumask.
*
* The caller is responsible for ensuring that the cpumask of @pod stays stable.
*/
static void wq_calc_pod_cpumask(struct workqueue_attrs *attrs, int cpu,
int cpu_going_down)
{
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
int pod = pt->cpu_pod[cpu];
/* does @pod have any online CPUs @attrs wants? */
cpumask_and(attrs->__pod_cpumask, pt->pod_cpus[pod], attrs->cpumask);
cpumask_and(attrs->__pod_cpumask, attrs->__pod_cpumask, cpu_online_mask);
if (cpu_going_down >= 0)
cpumask_clear_cpu(cpu_going_down, attrs->__pod_cpumask);
if (cpumask_empty(attrs->__pod_cpumask)) {
cpumask_copy(attrs->__pod_cpumask, attrs->cpumask);
return;
}
/* yeap, return possible CPUs in @pod that @attrs wants */
cpumask_and(attrs->__pod_cpumask, attrs->cpumask, pt->pod_cpus[pod]);
if (cpumask_empty(attrs->__pod_cpumask))
pr_warn_once("WARNING: workqueue cpumask: online intersect > "
"possible intersect\n");
}
/* install @pwq into @wq's cpu_pwq and return the old pwq */
static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
int cpu, struct pool_workqueue *pwq)
{
struct pool_workqueue *old_pwq;
lockdep_assert_held(&wq_pool_mutex);
lockdep_assert_held(&wq->mutex);
/* link_pwq() can handle duplicate calls */
link_pwq(pwq);
old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq);
return old_pwq;
}
/* context to store the prepared attrs & pwqs before applying */
struct apply_wqattrs_ctx {
struct workqueue_struct *wq; /* target workqueue */
struct workqueue_attrs *attrs; /* attrs to apply */
struct list_head list; /* queued for batching commit */
struct pool_workqueue *dfl_pwq;
struct pool_workqueue *pwq_tbl[];
};
/* free the resources after success or abort */
static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
{
if (ctx) {
int cpu;
for_each_possible_cpu(cpu)
put_pwq_unlocked(ctx->pwq_tbl[cpu]);
put_pwq_unlocked(ctx->dfl_pwq);
free_workqueue_attrs(ctx->attrs);
kfree(ctx);
}
}
/* allocate the attrs and pwqs for later installation */
static struct apply_wqattrs_ctx *
apply_wqattrs_prepare(struct workqueue_struct *wq,
const struct workqueue_attrs *attrs,
const cpumask_var_t unbound_cpumask)
{
struct apply_wqattrs_ctx *ctx;
struct workqueue_attrs *new_attrs;
int cpu;
lockdep_assert_held(&wq_pool_mutex);
if (WARN_ON(attrs->affn_scope < 0 ||
attrs->affn_scope >= WQ_AFFN_NR_TYPES))
return ERR_PTR(-EINVAL);
ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_cpu_ids), GFP_KERNEL);
new_attrs = alloc_workqueue_attrs();
if (!ctx || !new_attrs)
goto out_free;
/*
* If something goes wrong during CPU up/down, we'll fall back to
* the default pwq covering whole @attrs->cpumask. Always create
* it even if we don't use it immediately.
*/
copy_workqueue_attrs(new_attrs, attrs);
wqattrs_actualize_cpumask(new_attrs, unbound_cpumask);
cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask);
ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs);
if (!ctx->dfl_pwq)
goto out_free;
for_each_possible_cpu(cpu) {
if (new_attrs->ordered) {
ctx->dfl_pwq->refcnt++;
ctx->pwq_tbl[cpu] = ctx->dfl_pwq;
} else {
wq_calc_pod_cpumask(new_attrs, cpu, -1);
ctx->pwq_tbl[cpu] = alloc_unbound_pwq(wq, new_attrs);
if (!ctx->pwq_tbl[cpu])
goto out_free;
}
}
/* save the user configured attrs and sanitize it. */
copy_workqueue_attrs(new_attrs, attrs);
cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask);
cpumask_copy(new_attrs->__pod_cpumask, new_attrs->cpumask);
ctx->attrs = new_attrs;
ctx->wq = wq;
return ctx;
out_free:
free_workqueue_attrs(new_attrs);
apply_wqattrs_cleanup(ctx);
return ERR_PTR(-ENOMEM);
}
/* set attrs and install prepared pwqs, @ctx points to old pwqs on return */
static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
{
int cpu;
/* all pwqs have been created successfully, let's install'em */
mutex_lock(&ctx->wq->mutex);
copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
/* save the previous pwq and install the new one */
for_each_possible_cpu(cpu)
ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
ctx->pwq_tbl[cpu]);
/* @dfl_pwq might not have been used, ensure it's linked */
link_pwq(ctx->dfl_pwq);
swap(ctx->wq->dfl_pwq, ctx->dfl_pwq);
mutex_unlock(&ctx->wq->mutex);
}
static void apply_wqattrs_lock(void)
{
/* CPUs should stay stable across pwq creations and installations */
cpus_read_lock();
mutex_lock(&wq_pool_mutex);
}
static void apply_wqattrs_unlock(void)
{
mutex_unlock(&wq_pool_mutex);
cpus_read_unlock();
}
static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
const struct workqueue_attrs *attrs)
{
struct apply_wqattrs_ctx *ctx;
/* only unbound workqueues can change attributes */
if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
return -EINVAL;
/* creating multiple pwqs breaks ordering guarantee */
if (!list_empty(&wq->pwqs)) {
if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return -EINVAL;
wq->flags &= ~__WQ_ORDERED;
}
ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
/* the ctx has been prepared successfully, let's commit it */
apply_wqattrs_commit(ctx);
apply_wqattrs_cleanup(ctx);
return 0;
}
/**
* apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
* @wq: the target workqueue
* @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
*
* Apply @attrs to an unbound workqueue @wq. Unless disabled, this function maps
* a separate pwq to each CPU pod with possibles CPUs in @attrs->cpumask so that
* work items are affine to the pod it was issued on. Older pwqs are released as
* in-flight work items finish. Note that a work item which repeatedly requeues
* itself back-to-back will stay on its current pwq.
*
* Performs GFP_KERNEL allocations.
*
* Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock().
*
* Return: 0 on success and -errno on failure.
*/
int apply_workqueue_attrs(struct workqueue_struct *wq,
const struct workqueue_attrs *attrs)
{
int ret;
lockdep_assert_cpus_held();
mutex_lock(&wq_pool_mutex);
ret = apply_workqueue_attrs_locked(wq, attrs);
mutex_unlock(&wq_pool_mutex);
return ret;
}
/**
* wq_update_pod - update pod affinity of a wq for CPU hot[un]plug
* @wq: the target workqueue
* @cpu: the CPU to update pool association for
* @hotplug_cpu: the CPU coming up or going down
* @online: whether @cpu is coming up or going down
*
* This function is to be called from %CPU_DOWN_PREPARE, %CPU_ONLINE and
* %CPU_DOWN_FAILED. @cpu is being hot[un]plugged, update pod affinity of
* @wq accordingly.
*
*
* If pod affinity can't be adjusted due to memory allocation failure, it falls
* back to @wq->dfl_pwq which may not be optimal but is always correct.
*
* Note that when the last allowed CPU of a pod goes offline for a workqueue
* with a cpumask spanning multiple pods, the workers which were already
* executing the work items for the workqueue will lose their CPU affinity and
* may execute on any CPU. This is similar to how per-cpu workqueues behave on
* CPU_DOWN. If a workqueue user wants strict affinity, it's the user's
* responsibility to flush the work item from CPU_DOWN_PREPARE.
*/
static void wq_update_pod(struct workqueue_struct *wq, int cpu,
int hotplug_cpu, bool online)
{
int off_cpu = online ? -1 : hotplug_cpu;
struct pool_workqueue *old_pwq = NULL, *pwq;
struct workqueue_attrs *target_attrs;
lockdep_assert_held(&wq_pool_mutex);
if (!(wq->flags & WQ_UNBOUND) || wq->unbound_attrs->ordered)
return;
/*
* We don't wanna alloc/free wq_attrs for each wq for each CPU.
* Let's use a preallocated one. The following buf is protected by
* CPU hotplug exclusion.
*/
target_attrs = wq_update_pod_attrs_buf;
copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
wqattrs_actualize_cpumask(target_attrs, wq_unbound_cpumask);
/* nothing to do if the target cpumask matches the current pwq */
wq_calc_pod_cpumask(target_attrs, cpu, off_cpu);
pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu),
lockdep_is_held(&wq_pool_mutex));
if (wqattrs_equal(target_attrs, pwq->pool->attrs))
return;
/* create a new pwq */
pwq = alloc_unbound_pwq(wq, target_attrs);
if (!pwq) {
pr_warn("workqueue: allocation failed while updating CPU pod affinity of \"%s\"\n",
wq->name);
goto use_dfl_pwq;
}
/* Install the new pwq. */
mutex_lock(&wq->mutex);
old_pwq = install_unbound_pwq(wq, cpu, pwq);
goto out_unlock;
use_dfl_pwq:
mutex_lock(&wq->mutex);
raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
get_pwq(wq->dfl_pwq);
raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq);
out_unlock:
mutex_unlock(&wq->mutex);
put_pwq_unlocked(old_pwq);
}
static int alloc_and_link_pwqs(struct workqueue_struct *wq)
{
bool highpri = wq->flags & WQ_HIGHPRI;
int cpu, ret;
wq->cpu_pwq = alloc_percpu(struct pool_workqueue *);
if (!wq->cpu_pwq)
goto enomem;
if (!(wq->flags & WQ_UNBOUND)) {
for_each_possible_cpu(cpu) {
struct pool_workqueue **pwq_p =
per_cpu_ptr(wq->cpu_pwq, cpu);
struct worker_pool *pool =
&(per_cpu_ptr(cpu_worker_pools, cpu)[highpri]);
*pwq_p = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL,
pool->node);
if (!*pwq_p)
goto enomem;
init_pwq(*pwq_p, wq, pool);
mutex_lock(&wq->mutex);
link_pwq(*pwq_p);
mutex_unlock(&wq->mutex);
}
return 0;
}
cpus_read_lock();
if (wq->flags & __WQ_ORDERED) {
ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]);
/* there should only be single pwq for ordering guarantee */
WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node ||
wq->pwqs.prev != &wq->dfl_pwq->pwqs_node),
"ordering guarantee broken for workqueue %s\n", wq->name);
} else {
ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]);
}
cpus_read_unlock();
return ret;
enomem:
if (wq->cpu_pwq) {
for_each_possible_cpu(cpu)
kfree(*per_cpu_ptr(wq->cpu_pwq, cpu));
free_percpu(wq->cpu_pwq);
wq->cpu_pwq = NULL;
}
return -ENOMEM;
}
static int wq_clamp_max_active(int max_active, unsigned int flags,
const char *name)
{
if (max_active < 1 || max_active > WQ_MAX_ACTIVE)
pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
max_active, name, 1, WQ_MAX_ACTIVE);
return clamp_val(max_active, 1, WQ_MAX_ACTIVE);
}
/*
* Workqueues which may be used during memory reclaim should have a rescuer
* to guarantee forward progress.
*/
static int init_rescuer(struct workqueue_struct *wq)
{
struct worker *rescuer;
int ret;
if (!(wq->flags & WQ_MEM_RECLAIM))
return 0;
rescuer = alloc_worker(NUMA_NO_NODE);
if (!rescuer) {
pr_err("workqueue: Failed to allocate a rescuer for wq \"%s\"\n",
wq->name);
return -ENOMEM;
}
rescuer->rescue_wq = wq;
rescuer->task = kthread_create(rescuer_thread, rescuer, "kworker/R-%s", wq->name);
if (IS_ERR(rescuer->task)) {
ret = PTR_ERR(rescuer->task);
pr_err("workqueue: Failed to create a rescuer kthread for wq \"%s\": %pe",
wq->name, ERR_PTR(ret));
kfree(rescuer);
return ret;
}
wq->rescuer = rescuer;
kthread_bind_mask(rescuer->task, cpu_possible_mask);
wake_up_process(rescuer->task);
return 0;
}
__printf(1, 4)
struct workqueue_struct *alloc_workqueue(const char *fmt,
unsigned int flags,
int max_active, ...)
{
va_list args;
struct workqueue_struct *wq;
struct pool_workqueue *pwq;
/*
* Unbound && max_active == 1 used to imply ordered, which is no longer
* the case on many machines due to per-pod pools. While
* alloc_ordered_workqueue() is the right way to create an ordered
* workqueue, keep the previous behavior to avoid subtle breakages.
*/
if ((flags & WQ_UNBOUND) && max_active == 1)
flags |= __WQ_ORDERED;
/* see the comment above the definition of WQ_POWER_EFFICIENT */
if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
flags |= WQ_UNBOUND;
/* allocate wq and format name */
wq = kzalloc(sizeof(*wq), GFP_KERNEL);
if (!wq)
return NULL;
if (flags & WQ_UNBOUND) {
wq->unbound_attrs = alloc_workqueue_attrs();
if (!wq->unbound_attrs)
goto err_free_wq;
}
va_start(args, max_active);
vsnprintf(wq->name, sizeof(wq->name), fmt, args);
va_end(args);
max_active = max_active ?: WQ_DFL_ACTIVE;
max_active = wq_clamp_max_active(max_active, flags, wq->name);
/* init wq */
wq->flags = flags;
wq->saved_max_active = max_active;
mutex_init(&wq->mutex);
atomic_set(&wq->nr_pwqs_to_flush, 0);
INIT_LIST_HEAD(&wq->pwqs);
INIT_LIST_HEAD(&wq->flusher_queue);
INIT_LIST_HEAD(&wq->flusher_overflow);
INIT_LIST_HEAD(&wq->maydays);
wq_init_lockdep(wq);
INIT_LIST_HEAD(&wq->list);
if (alloc_and_link_pwqs(wq) < 0)
goto err_unreg_lockdep;
if (wq_online && init_rescuer(wq) < 0)
goto err_destroy;
if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
goto err_destroy;
/*
* wq_pool_mutex protects global freeze state and workqueues list.
* Grab it, adjust max_active and add the new @wq to workqueues
* list.
*/
mutex_lock(&wq_pool_mutex);
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq)
pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
list_add_tail_rcu(&wq->list, &workqueues);
mutex_unlock(&wq_pool_mutex);
return wq;
err_unreg_lockdep:
wq_unregister_lockdep(wq);
wq_free_lockdep(wq);
err_free_wq:
free_workqueue_attrs(wq->unbound_attrs);
kfree(wq);
return NULL;
err_destroy:
destroy_workqueue(wq);
return NULL;
}
EXPORT_SYMBOL_GPL(alloc_workqueue);
static bool pwq_busy(struct pool_workqueue *pwq)
{
int i;
for (i = 0; i < WORK_NR_COLORS; i++)
if (pwq->nr_in_flight[i])
return true;
if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1))
return true;
if (pwq->nr_active || !list_empty(&pwq->inactive_works))
return true;
return false;
}
/**
* destroy_workqueue - safely terminate a workqueue
* @wq: target workqueue
*
* Safely destroy a workqueue. All work currently pending will be done first.
*/
void destroy_workqueue(struct workqueue_struct *wq)
{
struct pool_workqueue *pwq;
int cpu;
/*
* Remove it from sysfs first so that sanity check failure doesn't
* lead to sysfs name conflicts.
*/
workqueue_sysfs_unregister(wq);
/* mark the workqueue destruction is in progress */
mutex_lock(&wq->mutex);
wq->flags |= __WQ_DESTROYING;
mutex_unlock(&wq->mutex);
/* drain it before proceeding with destruction */
drain_workqueue(wq);
/* kill rescuer, if sanity checks fail, leave it w/o rescuer */
if (wq->rescuer) {
struct worker *rescuer = wq->rescuer;
/* this prevents new queueing */
raw_spin_lock_irq(&wq_mayday_lock);
wq->rescuer = NULL;
raw_spin_unlock_irq(&wq_mayday_lock);
/* rescuer will empty maydays list before exiting */
kthread_stop(rescuer->task);
kfree(rescuer);
}
/*
* Sanity checks - grab all the locks so that we wait for all
* in-flight operations which may do put_pwq().
*/
mutex_lock(&wq_pool_mutex);
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq) {
raw_spin_lock_irq(&pwq->pool->lock);
if (WARN_ON(pwq_busy(pwq))) {
pr_warn("%s: %s has the following busy pwq\n",
__func__, wq->name);
show_pwq(pwq);
raw_spin_unlock_irq(&pwq->pool->lock);
mutex_unlock(&wq->mutex);
mutex_unlock(&wq_pool_mutex);
show_one_workqueue(wq);
return;
}
raw_spin_unlock_irq(&pwq->pool->lock);
}
mutex_unlock(&wq->mutex);
/*
* wq list is used to freeze wq, remove from list after
* flushing is complete in case freeze races us.
*/
list_del_rcu(&wq->list);
mutex_unlock(&wq_pool_mutex);
/*
* We're the sole accessor of @wq. Directly access cpu_pwq and dfl_pwq
* to put the base refs. @wq will be auto-destroyed from the last
* pwq_put. RCU read lock prevents @wq from going away from under us.
*/
rcu_read_lock();
for_each_possible_cpu(cpu) {
pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL);
put_pwq_unlocked(pwq);
}
put_pwq_unlocked(wq->dfl_pwq);
wq->dfl_pwq = NULL;
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(destroy_workqueue);
/**
* workqueue_set_max_active - adjust max_active of a workqueue
* @wq: target workqueue
* @max_active: new max_active value.
*
* Set max_active of @wq to @max_active.
*
* CONTEXT:
* Don't call from IRQ context.
*/
void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
{
struct pool_workqueue *pwq;
/* disallow meddling with max_active for ordered workqueues */
if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return;
max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
mutex_lock(&wq->mutex);
wq->flags &= ~__WQ_ORDERED;
wq->saved_max_active = max_active;
for_each_pwq(pwq, wq)
pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
EXPORT_SYMBOL_GPL(workqueue_set_max_active);
/**
* current_work - retrieve %current task's work struct
*
* Determine if %current task is a workqueue worker and what it's working on.
* Useful to find out the context that the %current task is running in.
*
* Return: work struct if %current task is a workqueue worker, %NULL otherwise.
*/
struct work_struct *current_work(void)
{
struct worker *worker = current_wq_worker();
return worker ? worker->current_work : NULL;
}
EXPORT_SYMBOL(current_work);
/**
* current_is_workqueue_rescuer - is %current workqueue rescuer?
*
* Determine whether %current is a workqueue rescuer. Can be used from
* work functions to determine whether it's being run off the rescuer task.
*
* Return: %true if %current is a workqueue rescuer. %false otherwise.
*/
bool current_is_workqueue_rescuer(void)
{
struct worker *worker = current_wq_worker();
return worker && worker->rescue_wq;
}
/**
* workqueue_congested - test whether a workqueue is congested
* @cpu: CPU in question
* @wq: target workqueue
*
* Test whether @wq's cpu workqueue for @cpu is congested. There is
* no synchronization around this function and the test result is
* unreliable and only useful as advisory hints or for debugging.
*
* If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
*
* With the exception of ordered workqueues, all workqueues have per-cpu
* pool_workqueues, each with its own congested state. A workqueue being
* congested on one CPU doesn't mean that the workqueue is contested on any
* other CPUs.
*
* Return:
* %true if congested, %false otherwise.
*/
bool workqueue_congested(int cpu, struct workqueue_struct *wq)
{
struct pool_workqueue *pwq;
bool ret;
rcu_read_lock();
preempt_disable();
if (cpu == WORK_CPU_UNBOUND)
cpu = smp_processor_id();
pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
ret = !list_empty(&pwq->inactive_works);
preempt_enable();
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(workqueue_congested);
/**
* work_busy - test whether a work is currently pending or running
* @work: the work to be tested
*
* Test whether @work is currently pending or running. There is no
* synchronization around this function and the test result is
* unreliable and only useful as advisory hints or for debugging.
*
* Return:
* OR'd bitmask of WORK_BUSY_* bits.
*/
unsigned int work_busy(struct work_struct *work)
{
struct worker_pool *pool;
unsigned long flags;
unsigned int ret = 0;
if (work_pending(work))
ret |= WORK_BUSY_PENDING;
rcu_read_lock();
pool = get_work_pool(work);
if (pool) {
raw_spin_lock_irqsave(&pool->lock, flags);
if (find_worker_executing_work(pool, work))
ret |= WORK_BUSY_RUNNING;
raw_spin_unlock_irqrestore(&pool->lock, flags);
}
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(work_busy);
/**
* set_worker_desc - set description for the current work item
* @fmt: printf-style format string
* @...: arguments for the format string
*
* This function can be called by a running work function to describe what
* the work item is about. If the worker task gets dumped, this
* information will be printed out together to help debugging. The
* description can be at most WORKER_DESC_LEN including the trailing '\0'.
*/
void set_worker_desc(const char *fmt, ...)
{
struct worker *worker = current_wq_worker();
va_list args;
if (worker) {
va_start(args, fmt);
vsnprintf(worker->desc, sizeof(worker->desc), fmt, args);
va_end(args);
}
}
EXPORT_SYMBOL_GPL(set_worker_desc);
/**
* print_worker_info - print out worker information and description
* @log_lvl: the log level to use when printing
* @task: target task
*
* If @task is a worker and currently executing a work item, print out the
* name of the workqueue being serviced and worker description set with
* set_worker_desc() by the currently executing work item.
*
* This function can be safely called on any task as long as the
* task_struct itself is accessible. While safe, this function isn't
* synchronized and may print out mixups or garbages of limited length.
*/
void print_worker_info(const char *log_lvl, struct task_struct *task)
{
work_func_t *fn = NULL;
char name[WQ_NAME_LEN] = { };
char desc[WORKER_DESC_LEN] = { };
struct pool_workqueue *pwq = NULL;
struct workqueue_struct *wq = NULL;
struct worker *worker;
if (!(task->flags & PF_WQ_WORKER))
return;
/*
* This function is called without any synchronization and @task
* could be in any state. Be careful with dereferences.
*/
worker = kthread_probe_data(task);
/*
* Carefully copy the associated workqueue's workfn, name and desc.
* Keep the original last '\0' in case the original is garbage.
*/
copy_from_kernel_nofault(&fn, &worker->current_func, sizeof(fn));
copy_from_kernel_nofault(&pwq, &worker->current_pwq, sizeof(pwq));
copy_from_kernel_nofault(&wq, &pwq->wq, sizeof(wq));
copy_from_kernel_nofault(name, wq->name, sizeof(name) - 1);
copy_from_kernel_nofault(desc, worker->desc, sizeof(desc) - 1);
if (fn || name[0] || desc[0]) {
printk("%sWorkqueue: %s %ps", log_lvl, name, fn);
if (strcmp(name, desc))
pr_cont(" (%s)", desc);
pr_cont("\n");
}
}
static void pr_cont_pool_info(struct worker_pool *pool)
{
pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask);
if (pool->node != NUMA_NO_NODE)
pr_cont(" node=%d", pool->node);
pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice);
}
struct pr_cont_work_struct {
bool comma;
work_func_t func;
long ctr;
};
static void pr_cont_work_flush(bool comma, work_func_t func, struct pr_cont_work_struct *pcwsp)
{
if (!pcwsp->ctr)
goto out_record;
if (func == pcwsp->func) {
pcwsp->ctr++;
return;
}
if (pcwsp->ctr == 1)
pr_cont("%s %ps", pcwsp->comma ? "," : "", pcwsp->func);
else
pr_cont("%s %ld*%ps", pcwsp->comma ? "," : "", pcwsp->ctr, pcwsp->func);
pcwsp->ctr = 0;
out_record:
if ((long)func == -1L)
return;
pcwsp->comma = comma;
pcwsp->func = func;
pcwsp->ctr = 1;
}
static void pr_cont_work(bool comma, struct work_struct *work, struct pr_cont_work_struct *pcwsp)
{
if (work->func == wq_barrier_func) {
struct wq_barrier *barr;
barr = container_of(work, struct wq_barrier, work);
pr_cont_work_flush(comma, (work_func_t)-1, pcwsp);
pr_cont("%s BAR(%d)", comma ? "," : "",
task_pid_nr(barr->task));
} else {
if (!comma)
pr_cont_work_flush(comma, (work_func_t)-1, pcwsp);
pr_cont_work_flush(comma, work->func, pcwsp);
}
}
static void show_pwq(struct pool_workqueue *pwq)
{
struct pr_cont_work_struct pcws = { .ctr = 0, };
struct worker_pool *pool = pwq->pool;
struct work_struct *work;
struct worker *worker;
bool has_in_flight = false, has_pending = false;
int bkt;
pr_info(" pwq %d:", pool->id);
pr_cont_pool_info(pool);
pr_cont(" active=%d/%d refcnt=%d%s\n",
pwq->nr_active, pwq->max_active, pwq->refcnt,
!list_empty(&pwq->mayday_node) ? " MAYDAY" : "");
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
if (worker->current_pwq == pwq) {
has_in_flight = true;
break;
}
}
if (has_in_flight) {
bool comma = false;
pr_info(" in-flight:");
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
if (worker->current_pwq != pwq)
continue;
pr_cont("%s %d%s:%ps", comma ? "," : "",
task_pid_nr(worker->task),
worker->rescue_wq ? "(RESCUER)" : "",
worker->current_func);
list_for_each_entry(work, &worker->scheduled, entry)
pr_cont_work(false, work, &pcws);
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
comma = true;
}
pr_cont("\n");
}
list_for_each_entry(work, &pool->worklist, entry) {
if (get_work_pwq(work) == pwq) {
has_pending = true;
break;
}
}
if (has_pending) {
bool comma = false;
pr_info(" pending:");
list_for_each_entry(work, &pool->worklist, entry) {
if (get_work_pwq(work) != pwq)
continue;
pr_cont_work(comma, work, &pcws);
comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
}
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
pr_cont("\n");
}
if (!list_empty(&pwq->inactive_works)) {
bool comma = false;
pr_info(" inactive:");
list_for_each_entry(work, &pwq->inactive_works, entry) {
pr_cont_work(comma, work, &pcws);
comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED);
}
pr_cont_work_flush(comma, (work_func_t)-1L, &pcws);
pr_cont("\n");
}
}
/**
* show_one_workqueue - dump state of specified workqueue
* @wq: workqueue whose state will be printed
*/
void show_one_workqueue(struct workqueue_struct *wq)
{
struct pool_workqueue *pwq;
bool idle = true;
unsigned long flags;
for_each_pwq(pwq, wq) {
if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
idle = false;
break;
}
}
if (idle) /* Nothing to print for idle workqueue */
return;
pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags);
for_each_pwq(pwq, wq) {
raw_spin_lock_irqsave(&pwq->pool->lock, flags);
if (pwq->nr_active || !list_empty(&pwq->inactive_works)) {
/*
* Defer printing to avoid deadlocks in console
* drivers that queue work while holding locks
* also taken in their write paths.
*/
printk_deferred_enter();
show_pwq(pwq);
printk_deferred_exit();
}
raw_spin_unlock_irqrestore(&pwq->pool->lock, flags);
/*
* We could be printing a lot from atomic context, e.g.
* sysrq-t -> show_all_workqueues(). Avoid triggering
* hard lockup.
*/
touch_nmi_watchdog();
}
}
/**
* show_one_worker_pool - dump state of specified worker pool
* @pool: worker pool whose state will be printed
*/
static void show_one_worker_pool(struct worker_pool *pool)
{
struct worker *worker;
bool first = true;
unsigned long flags;
unsigned long hung = 0;
raw_spin_lock_irqsave(&pool->lock, flags);
if (pool->nr_workers == pool->nr_idle)
goto next_pool;
/* How long the first pending work is waiting for a worker. */
if (!list_empty(&pool->worklist))
hung = jiffies_to_msecs(jiffies - pool->watchdog_ts) / 1000;
/*
* Defer printing to avoid deadlocks in console drivers that
* queue work while holding locks also taken in their write
* paths.
*/
printk_deferred_enter();
pr_info("pool %d:", pool->id);
pr_cont_pool_info(pool);
pr_cont(" hung=%lus workers=%d", hung, pool->nr_workers);
if (pool->manager)
pr_cont(" manager: %d",
task_pid_nr(pool->manager->task));
list_for_each_entry(worker, &pool->idle_list, entry) {
pr_cont(" %s%d", first ? "idle: " : "",
task_pid_nr(worker->task));
first = false;
}
pr_cont("\n");
printk_deferred_exit();
next_pool:
raw_spin_unlock_irqrestore(&pool->lock, flags);
/*
* We could be printing a lot from atomic context, e.g.
* sysrq-t -> show_all_workqueues(). Avoid triggering
* hard lockup.
*/
touch_nmi_watchdog();
}
/**
* show_all_workqueues - dump workqueue state
*
* Called from a sysrq handler and prints out all busy workqueues and pools.
*/
void show_all_workqueues(void)
{
struct workqueue_struct *wq;
struct worker_pool *pool;
int pi;
rcu_read_lock();
pr_info("Showing busy workqueues and worker pools:\n");
list_for_each_entry_rcu(wq, &workqueues, list)
show_one_workqueue(wq);
for_each_pool(pool, pi)
show_one_worker_pool(pool);
rcu_read_unlock();
}
/**
* show_freezable_workqueues - dump freezable workqueue state
*
* Called from try_to_freeze_tasks() and prints out all freezable workqueues
* still busy.
*/
void show_freezable_workqueues(void)
{
struct workqueue_struct *wq;
rcu_read_lock();
pr_info("Showing freezable workqueues that are still busy:\n");
list_for_each_entry_rcu(wq, &workqueues, list) {
if (!(wq->flags & WQ_FREEZABLE))
continue;
show_one_workqueue(wq);
}
rcu_read_unlock();
}
/* used to show worker information through /proc/PID/{comm,stat,status} */
void wq_worker_comm(char *buf, size_t size, struct task_struct *task)
{
int off;
/* always show the actual comm */
off = strscpy(buf, task->comm, size);
if (off < 0)
return;
/* stabilize PF_WQ_WORKER and worker pool association */
mutex_lock(&wq_pool_attach_mutex);
if (task->flags & PF_WQ_WORKER) {
struct worker *worker = kthread_data(task);
struct worker_pool *pool = worker->pool;
if (pool) {
raw_spin_lock_irq(&pool->lock);
/*
* ->desc tracks information (wq name or
* set_worker_desc()) for the latest execution. If
* current, prepend '+', otherwise '-'.
*/
if (worker->desc[0] != '\0') {
if (worker->current_work)
scnprintf(buf + off, size - off, "+%s",
worker->desc);
else
scnprintf(buf + off, size - off, "-%s",
worker->desc);
}
raw_spin_unlock_irq(&pool->lock);
}
}
mutex_unlock(&wq_pool_attach_mutex);
}
#ifdef CONFIG_SMP
/*
* CPU hotplug.
*
* There are two challenges in supporting CPU hotplug. Firstly, there
* are a lot of assumptions on strong associations among work, pwq and
* pool which make migrating pending and scheduled works very
* difficult to implement without impacting hot paths. Secondly,
* worker pools serve mix of short, long and very long running works making
* blocked draining impractical.
*
* This is solved by allowing the pools to be disassociated from the CPU
* running as an unbound one and allowing it to be reattached later if the
* cpu comes back online.
*/
static void unbind_workers(int cpu)
{
struct worker_pool *pool;
struct worker *worker;
for_each_cpu_worker_pool(pool, cpu) {
mutex_lock(&wq_pool_attach_mutex);
raw_spin_lock_irq(&pool->lock);
/*
* We've blocked all attach/detach operations. Make all workers
* unbound and set DISASSOCIATED. Before this, all workers
* must be on the cpu. After this, they may become diasporas.
* And the preemption disabled section in their sched callbacks
* are guaranteed to see WORKER_UNBOUND since the code here
* is on the same cpu.
*/
for_each_pool_worker(worker, pool)
worker->flags |= WORKER_UNBOUND;
pool->flags |= POOL_DISASSOCIATED;
/*
* The handling of nr_running in sched callbacks are disabled
* now. Zap nr_running. After this, nr_running stays zero and
* need_more_worker() and keep_working() are always true as
* long as the worklist is not empty. This pool now behaves as
* an unbound (in terms of concurrency management) pool which
* are served by workers tied to the pool.
*/
pool->nr_running = 0;
/*
* With concurrency management just turned off, a busy
* worker blocking could lead to lengthy stalls. Kick off
* unbound chain execution of currently pending work items.
*/
kick_pool(pool);
raw_spin_unlock_irq(&pool->lock);
for_each_pool_worker(worker, pool)
unbind_worker(worker);
mutex_unlock(&wq_pool_attach_mutex);
}
}
/**
* rebind_workers - rebind all workers of a pool to the associated CPU
* @pool: pool of interest
*
* @pool->cpu is coming online. Rebind all workers to the CPU.
*/
static void rebind_workers(struct worker_pool *pool)
{
struct worker *worker;
lockdep_assert_held(&wq_pool_attach_mutex);
/*
* Restore CPU affinity of all workers. As all idle workers should
* be on the run-queue of the associated CPU before any local
* wake-ups for concurrency management happen, restore CPU affinity
* of all workers first and then clear UNBOUND. As we're called
* from CPU_ONLINE, the following shouldn't fail.
*/
for_each_pool_worker(worker, pool) {
kthread_set_per_cpu(worker->task, pool->cpu);
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
pool_allowed_cpus(pool)) < 0);
}
raw_spin_lock_irq(&pool->lock);
pool->flags &= ~POOL_DISASSOCIATED;
for_each_pool_worker(worker, pool) {
unsigned int worker_flags = worker->flags;
/*
* We want to clear UNBOUND but can't directly call
* worker_clr_flags() or adjust nr_running. Atomically
* replace UNBOUND with another NOT_RUNNING flag REBOUND.
* @worker will clear REBOUND using worker_clr_flags() when
* it initiates the next execution cycle thus restoring
* concurrency management. Note that when or whether
* @worker clears REBOUND doesn't affect correctness.
*
* WRITE_ONCE() is necessary because @worker->flags may be
* tested without holding any lock in
* wq_worker_running(). Without it, NOT_RUNNING test may
* fail incorrectly leading to premature concurrency
* management operations.
*/
WARN_ON_ONCE(!(worker_flags & WORKER_UNBOUND));
worker_flags |= WORKER_REBOUND;
worker_flags &= ~WORKER_UNBOUND;
WRITE_ONCE(worker->flags, worker_flags);
}
raw_spin_unlock_irq(&pool->lock);
}
/**
* restore_unbound_workers_cpumask - restore cpumask of unbound workers
* @pool: unbound pool of interest
* @cpu: the CPU which is coming up
*
* An unbound pool may end up with a cpumask which doesn't have any online
* CPUs. When a worker of such pool get scheduled, the scheduler resets
* its cpus_allowed. If @cpu is in @pool's cpumask which didn't have any
* online CPU before, cpus_allowed of all its workers should be restored.
*/
static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
{
static cpumask_t cpumask;
struct worker *worker;
lockdep_assert_held(&wq_pool_attach_mutex);
/* is @cpu allowed for @pool? */
if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
return;
cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
/* as we're called from CPU_ONLINE, the following shouldn't fail */
for_each_pool_worker(worker, pool)
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
}
int workqueue_prepare_cpu(unsigned int cpu)
{
struct worker_pool *pool;
for_each_cpu_worker_pool(pool, cpu) {
if (pool->nr_workers)
continue;
if (!create_worker(pool))
return -ENOMEM;
}
return 0;
}
int workqueue_online_cpu(unsigned int cpu)
{
struct worker_pool *pool;
struct workqueue_struct *wq;
int pi;
mutex_lock(&wq_pool_mutex);
for_each_pool(pool, pi) {
mutex_lock(&wq_pool_attach_mutex);
if (pool->cpu == cpu)
rebind_workers(pool);
else if (pool->cpu < 0)
restore_unbound_workers_cpumask(pool, cpu);
mutex_unlock(&wq_pool_attach_mutex);
}
/* update pod affinity of unbound workqueues */
list_for_each_entry(wq, &workqueues, list) {
struct workqueue_attrs *attrs = wq->unbound_attrs;
if (attrs) {
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
int tcpu;
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
wq_update_pod(wq, tcpu, cpu, true);
}
}
mutex_unlock(&wq_pool_mutex);
return 0;
}
int workqueue_offline_cpu(unsigned int cpu)
{
struct workqueue_struct *wq;
/* unbinding per-cpu workers should happen on the local CPU */
if (WARN_ON(cpu != smp_processor_id()))
return -1;
unbind_workers(cpu);
/* update pod affinity of unbound workqueues */
mutex_lock(&wq_pool_mutex);
list_for_each_entry(wq, &workqueues, list) {
struct workqueue_attrs *attrs = wq->unbound_attrs;
if (attrs) {
const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
int tcpu;
for_each_cpu(tcpu, pt->pod_cpus[pt->cpu_pod[cpu]])
wq_update_pod(wq, tcpu, cpu, false);
}
}
mutex_unlock(&wq_pool_mutex);
return 0;
}
struct work_for_cpu {
struct work_struct work;
long (*fn)(void *);
void *arg;
long ret;
};
static void work_for_cpu_fn(struct work_struct *work)
{
struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);
wfc->ret = wfc->fn(wfc->arg);
}
/**
* work_on_cpu - run a function in thread context on a particular cpu
* @cpu: the cpu to run on
* @fn: the function to run
* @arg: the function arg
*
* It is up to the caller to ensure that the cpu doesn't go offline.
* The caller must not hold any locks which would prevent @fn from completing.
*
* Return: The value @fn returns.
*/
long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
{
struct work_for_cpu wfc = { .fn = fn, .arg = arg };
INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
schedule_work_on(cpu, &wfc.work);
flush_work(&wfc.work);
destroy_work_on_stack(&wfc.work);
return wfc.ret;
}
EXPORT_SYMBOL_GPL(work_on_cpu);
/**
* work_on_cpu_safe - run a function in thread context on a particular cpu
* @cpu: the cpu to run on
* @fn: the function to run
* @arg: the function argument
*
* Disables CPU hotplug and calls work_on_cpu(). The caller must not hold
* any locks which would prevent @fn from completing.
*
* Return: The value @fn returns.
*/
long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
{
long ret = -ENODEV;
cpus_read_lock();
if (cpu_online(cpu))
ret = work_on_cpu(cpu, fn, arg);
cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(work_on_cpu_safe);
#endif /* CONFIG_SMP */
#ifdef CONFIG_FREEZER
/**
* freeze_workqueues_begin - begin freezing workqueues
*
* Start freezing workqueues. After this function returns, all freezable
* workqueues will queue new works to their inactive_works list instead of
* pool->worklist.
*
* CONTEXT:
* Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
*/
void freeze_workqueues_begin(void)
{
struct workqueue_struct *wq;
struct pool_workqueue *pwq;
mutex_lock(&wq_pool_mutex);
WARN_ON_ONCE(workqueue_freezing);
workqueue_freezing = true;
list_for_each_entry(wq, &workqueues, list) {
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq)
pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
mutex_unlock(&wq_pool_mutex);
}
/**
* freeze_workqueues_busy - are freezable workqueues still busy?
*
* Check whether freezing is complete. This function must be called
* between freeze_workqueues_begin() and thaw_workqueues().
*
* CONTEXT:
* Grabs and releases wq_pool_mutex.
*
* Return:
* %true if some freezable workqueues are still busy. %false if freezing
* is complete.
*/
bool freeze_workqueues_busy(void)
{
bool busy = false;
struct workqueue_struct *wq;
struct pool_workqueue *pwq;
mutex_lock(&wq_pool_mutex);
WARN_ON_ONCE(!workqueue_freezing);
list_for_each_entry(wq, &workqueues, list) {
if (!(wq->flags & WQ_FREEZABLE))
continue;
/*
* nr_active is monotonically decreasing. It's safe
* to peek without lock.
*/
rcu_read_lock();
for_each_pwq(pwq, wq) {
WARN_ON_ONCE(pwq->nr_active < 0);
if (pwq->nr_active) {
busy = true;
rcu_read_unlock();
goto out_unlock;
}
}
rcu_read_unlock();
}
out_unlock:
mutex_unlock(&wq_pool_mutex);
return busy;
}
/**
* thaw_workqueues - thaw workqueues
*
* Thaw workqueues. Normal queueing is restored and all collected
* frozen works are transferred to their respective pool worklists.
*
* CONTEXT:
* Grabs and releases wq_pool_mutex, wq->mutex and pool->lock's.
*/
void thaw_workqueues(void)
{
struct workqueue_struct *wq;
struct pool_workqueue *pwq;
mutex_lock(&wq_pool_mutex);
if (!workqueue_freezing)
goto out_unlock;
workqueue_freezing = false;
/* restore max_active and repopulate worklist */
list_for_each_entry(wq, &workqueues, list) {
mutex_lock(&wq->mutex);
for_each_pwq(pwq, wq)
pwq_adjust_max_active(pwq);
mutex_unlock(&wq->mutex);
}
out_unlock:
mutex_unlock(&wq_pool_mutex);
}
#endif /* CONFIG_FREEZER */
static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
{
LIST_HEAD(ctxs);
int ret = 0;
struct workqueue_struct *wq;
struct apply_wqattrs_ctx *ctx, *n;
lockdep_assert_held(&wq_pool_mutex);
list_for_each_entry(wq, &workqueues, list) {
if (!(wq->flags & WQ_UNBOUND))
continue;
/* creating multiple pwqs breaks ordering guarantee */
if (wq->flags & __WQ_ORDERED)
continue;
ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
if (IS_ERR(ctx)) {
ret = PTR_ERR(ctx);
break;
}
list_add_tail(&ctx->list, &ctxs);
}
list_for_each_entry_safe(ctx, n, &ctxs, list) {
if (!ret)
apply_wqattrs_commit(ctx);
apply_wqattrs_cleanup(ctx);
}
if (!ret) {
mutex_lock(&wq_pool_attach_mutex);
cpumask_copy(wq_unbound_cpumask, unbound_cpumask);
mutex_unlock(&wq_pool_attach_mutex);
}
return ret;
}
/**
* workqueue_set_unbound_cpumask - Set the low-level unbound cpumask
* @cpumask: the cpumask to set
*
* The low-level workqueues cpumask is a global cpumask that limits
* the affinity of all unbound workqueues. This function check the @cpumask
* and apply it to all unbound workqueues and updates all pwqs of them.
*
* Return: 0 - Success
* -EINVAL - Invalid @cpumask
* -ENOMEM - Failed to allocate memory for attrs or pwqs.
*/
int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
{
int ret = -EINVAL;
/*
* Not excluding isolated cpus on purpose.
* If the user wishes to include them, we allow that.
*/
cpumask_and(cpumask, cpumask, cpu_possible_mask);
if (!cpumask_empty(cpumask)) {
apply_wqattrs_lock();
if (cpumask_equal(cpumask, wq_unbound_cpumask)) {
ret = 0;
goto out_unlock;
}
ret = workqueue_apply_unbound_cpumask(cpumask);
out_unlock:
apply_wqattrs_unlock();
}
return ret;
}
static int parse_affn_scope(const char *val)
{
int i;
for (i = 0; i < ARRAY_SIZE(wq_affn_names); i++) {
if (!strncasecmp(val, wq_affn_names[i], strlen(wq_affn_names[i])))
return i;
}
return -EINVAL;
}
static int wq_affn_dfl_set(const char *val, const struct kernel_param *kp)
{
struct workqueue_struct *wq;
int affn, cpu;
affn = parse_affn_scope(val);
if (affn < 0)
return affn;
if (affn == WQ_AFFN_DFL)
return -EINVAL;
cpus_read_lock();
mutex_lock(&wq_pool_mutex);
wq_affn_dfl = affn;
list_for_each_entry(wq, &workqueues, list) {
for_each_online_cpu(cpu) {
wq_update_pod(wq, cpu, cpu, true);
}
}
mutex_unlock(&wq_pool_mutex);
cpus_read_unlock();
return 0;
}
static int wq_affn_dfl_get(char *buffer, const struct kernel_param *kp)
{
return scnprintf(buffer, PAGE_SIZE, "%s\n", wq_affn_names[wq_affn_dfl]);
}
static const struct kernel_param_ops wq_affn_dfl_ops = {
.set = wq_affn_dfl_set,
.get = wq_affn_dfl_get,
};
module_param_cb(default_affinity_scope, &wq_affn_dfl_ops, NULL, 0644);
#ifdef CONFIG_SYSFS
/*
* Workqueues with WQ_SYSFS flag set is visible to userland via
* /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the
* following attributes.
*
* per_cpu RO bool : whether the workqueue is per-cpu or unbound
* max_active RW int : maximum number of in-flight work items
*
* Unbound workqueues have the following extra attributes.
*
* nice RW int : nice value of the workers
* cpumask RW mask : bitmask of allowed CPUs for the workers
* affinity_scope RW str : worker CPU affinity scope (cache, numa, none)
* affinity_strict RW bool : worker CPU affinity is strict
*/
struct wq_device {
struct workqueue_struct *wq;
struct device dev;
};
static struct workqueue_struct *dev_to_wq(struct device *dev)
{
struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
return wq_dev->wq;
}
static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND));
}
static DEVICE_ATTR_RO(per_cpu);
static ssize_t max_active_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active);
}
static ssize_t max_active_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
int val;
if (sscanf(buf, "%d", &val) != 1 || val <= 0)
return -EINVAL;
workqueue_set_max_active(wq, val);
return count;
}
static DEVICE_ATTR_RW(max_active);
static struct attribute *wq_sysfs_attrs[] = {
&dev_attr_per_cpu.attr,
&dev_attr_max_active.attr,
NULL,
};
ATTRIBUTE_GROUPS(wq_sysfs);
static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
int written;
mutex_lock(&wq->mutex);
written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice);
mutex_unlock(&wq->mutex);
return written;
}
/* prepare workqueue_attrs for sysfs store operations */
static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq)
{
struct workqueue_attrs *attrs;
lockdep_assert_held(&wq_pool_mutex);
attrs = alloc_workqueue_attrs();
if (!attrs)
return NULL;
copy_workqueue_attrs(attrs, wq->unbound_attrs);
return attrs;
}
static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
int ret = -ENOMEM;
apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
goto out_unlock;
if (sscanf(buf, "%d", &attrs->nice) == 1 &&
attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
ret = apply_workqueue_attrs_locked(wq, attrs);
else
ret = -EINVAL;
out_unlock:
apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
static ssize_t wq_cpumask_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
int written;
mutex_lock(&wq->mutex);
written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
cpumask_pr_args(wq->unbound_attrs->cpumask));
mutex_unlock(&wq->mutex);
return written;
}
static ssize_t wq_cpumask_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
int ret = -ENOMEM;
apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
goto out_unlock;
ret = cpumask_parse(buf, attrs->cpumask);
if (!ret)
ret = apply_workqueue_attrs_locked(wq, attrs);
out_unlock:
apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
static ssize_t wq_affn_scope_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
int written;
mutex_lock(&wq->mutex);
if (wq->unbound_attrs->affn_scope == WQ_AFFN_DFL)
written = scnprintf(buf, PAGE_SIZE, "%s (%s)\n",
wq_affn_names[WQ_AFFN_DFL],
wq_affn_names[wq_affn_dfl]);
else
written = scnprintf(buf, PAGE_SIZE, "%s\n",
wq_affn_names[wq->unbound_attrs->affn_scope]);
mutex_unlock(&wq->mutex);
return written;
}
static ssize_t wq_affn_scope_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
int affn, ret = -ENOMEM;
affn = parse_affn_scope(buf);
if (affn < 0)
return affn;
apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (attrs) {
attrs->affn_scope = affn;
ret = apply_workqueue_attrs_locked(wq, attrs);
}
apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
static ssize_t wq_affinity_strict_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n",
wq->unbound_attrs->affn_strict);
}
static ssize_t wq_affinity_strict_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
int v, ret = -ENOMEM;
if (sscanf(buf, "%d", &v) != 1)
return -EINVAL;
apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (attrs) {
attrs->affn_strict = (bool)v;
ret = apply_workqueue_attrs_locked(wq, attrs);
}
apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
static struct device_attribute wq_sysfs_unbound_attrs[] = {
__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
__ATTR(affinity_scope, 0644, wq_affn_scope_show, wq_affn_scope_store),
__ATTR(affinity_strict, 0644, wq_affinity_strict_show, wq_affinity_strict_store),
__ATTR_NULL,
};
static struct bus_type wq_subsys = {
.name = "workqueue",
.dev_groups = wq_sysfs_groups,
};
static ssize_t wq_unbound_cpumask_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int written;
mutex_lock(&wq_pool_mutex);
written = scnprintf(buf, PAGE_SIZE, "%*pb\n",
cpumask_pr_args(wq_unbound_cpumask));
mutex_unlock(&wq_pool_mutex);
return written;
}
static ssize_t wq_unbound_cpumask_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
cpumask_var_t cpumask;
int ret;
if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
return -ENOMEM;
ret = cpumask_parse(buf, cpumask);
if (!ret)
ret = workqueue_set_unbound_cpumask(cpumask);
free_cpumask_var(cpumask);
return ret ? ret : count;
}
static struct device_attribute wq_sysfs_cpumask_attr =
__ATTR(cpumask, 0644, wq_unbound_cpumask_show,
wq_unbound_cpumask_store);
static int __init wq_sysfs_init(void)
{
struct device *dev_root;
int err;
err = subsys_virtual_register(&wq_subsys, NULL);
if (err)
return err;
dev_root = bus_get_dev_root(&wq_subsys);
if (dev_root) {
err = device_create_file(dev_root, &wq_sysfs_cpumask_attr);
put_device(dev_root);
}
return err;
}
core_initcall(wq_sysfs_init);
static void wq_device_release(struct device *dev)
{
struct wq_device *wq_dev = container_of(dev, struct wq_device, dev);
kfree(wq_dev);
}
/**
* workqueue_sysfs_register - make a workqueue visible in sysfs
* @wq: the workqueue to register
*
* Expose @wq in sysfs under /sys/bus/workqueue/devices.
* alloc_workqueue*() automatically calls this function if WQ_SYSFS is set
* which is the preferred method.
*
* Workqueue user should use this function directly iff it wants to apply
* workqueue_attrs before making the workqueue visible in sysfs; otherwise,
* apply_workqueue_attrs() may race against userland updating the
* attributes.
*
* Return: 0 on success, -errno on failure.
*/
int workqueue_sysfs_register(struct workqueue_struct *wq)
{
struct wq_device *wq_dev;
int ret;
/*
* Adjusting max_active or creating new pwqs by applying
* attributes breaks ordering guarantee. Disallow exposing ordered
* workqueues.
*/
if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return -EINVAL;
wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
if (!wq_dev)
return -ENOMEM;
wq_dev->wq = wq;
wq_dev->dev.bus = &wq_subsys;
wq_dev->dev.release = wq_device_release;
dev_set_name(&wq_dev->dev, "%s", wq->name);
/*
* unbound_attrs are created separately. Suppress uevent until
* everything is ready.
*/
dev_set_uevent_suppress(&wq_dev->dev, true);
ret = device_register(&wq_dev->dev);
if (ret) {
put_device(&wq_dev->dev);
wq->wq_dev = NULL;
return ret;
}
if (wq->flags & WQ_UNBOUND) {
struct device_attribute *attr;
for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) {
ret = device_create_file(&wq_dev->dev, attr);
if (ret) {
device_unregister(&wq_dev->dev);
wq->wq_dev = NULL;
return ret;
}
}
}
dev_set_uevent_suppress(&wq_dev->dev, false);
kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
return 0;
}
/**
* workqueue_sysfs_unregister - undo workqueue_sysfs_register()
* @wq: the workqueue to unregister
*
* If @wq is registered to sysfs by workqueue_sysfs_register(), unregister.
*/
static void workqueue_sysfs_unregister(struct workqueue_struct *wq)
{
struct wq_device *wq_dev = wq->wq_dev;
if (!wq->wq_dev)
return;
wq->wq_dev = NULL;
device_unregister(&wq_dev->dev);
}
#else /* CONFIG_SYSFS */
static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { }
#endif /* CONFIG_SYSFS */
/*
* Workqueue watchdog.
*
* Stall may be caused by various bugs - missing WQ_MEM_RECLAIM, illegal
* flush dependency, a concurrency managed work item which stays RUNNING
* indefinitely. Workqueue stalls can be very difficult to debug as the
* usual warning mechanisms don't trigger and internal workqueue state is
* largely opaque.
*
* Workqueue watchdog monitors all worker pools periodically and dumps
* state if some pools failed to make forward progress for a while where
* forward progress is defined as the first item on ->worklist changing.
*
* This mechanism is controlled through the kernel parameter
* "workqueue.watchdog_thresh" which can be updated at runtime through the
* corresponding sysfs parameter file.
*/
#ifdef CONFIG_WQ_WATCHDOG
static unsigned long wq_watchdog_thresh = 30;
static struct timer_list wq_watchdog_timer;
static unsigned long wq_watchdog_touched = INITIAL_JIFFIES;
static DEFINE_PER_CPU(unsigned long, wq_watchdog_touched_cpu) = INITIAL_JIFFIES;
/*
* Show workers that might prevent the processing of pending work items.
* The only candidates are CPU-bound workers in the running state.
* Pending work items should be handled by another idle worker
* in all other situations.
*/
static void show_cpu_pool_hog(struct worker_pool *pool)
{
struct worker *worker;
unsigned long flags;
int bkt;
raw_spin_lock_irqsave(&pool->lock, flags);
hash_for_each(pool->busy_hash, bkt, worker, hentry) {
if (task_is_running(worker->task)) {
/*
* Defer printing to avoid deadlocks in console
* drivers that queue work while holding locks
* also taken in their write paths.
*/
printk_deferred_enter();
pr_info("pool %d:\n", pool->id);
sched_show_task(worker->task);
printk_deferred_exit();
}
}
raw_spin_unlock_irqrestore(&pool->lock, flags);
}
static void show_cpu_pools_hogs(void)
{
struct worker_pool *pool;
int pi;
pr_info("Showing backtraces of running workers in stalled CPU-bound worker pools:\n");
rcu_read_lock();
for_each_pool(pool, pi) {
if (pool->cpu_stall)
show_cpu_pool_hog(pool);
}
rcu_read_unlock();
}
static void wq_watchdog_reset_touched(void)
{
int cpu;
wq_watchdog_touched = jiffies;
for_each_possible_cpu(cpu)
per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
}
static void wq_watchdog_timer_fn(struct timer_list *unused)
{
unsigned long thresh = READ_ONCE(wq_watchdog_thresh) * HZ;
bool lockup_detected = false;
bool cpu_pool_stall = false;
unsigned long now = jiffies;
struct worker_pool *pool;
int pi;
if (!thresh)
return;
rcu_read_lock();
for_each_pool(pool, pi) {
unsigned long pool_ts, touched, ts;
pool->cpu_stall = false;
if (list_empty(&pool->worklist))
continue;
/*
* If a virtual machine is stopped by the host it can look to
* the watchdog like a stall.
*/
kvm_check_and_clear_guest_paused();
/* get the latest of pool and touched timestamps */
if (pool->cpu >= 0)
touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu));
else
touched = READ_ONCE(wq_watchdog_touched);
pool_ts = READ_ONCE(pool->watchdog_ts);
if (time_after(pool_ts, touched))
ts = pool_ts;
else
ts = touched;
/* did we stall? */
if (time_after(now, ts + thresh)) {
lockup_detected = true;
if (pool->cpu >= 0) {
pool->cpu_stall = true;
cpu_pool_stall = true;
}
pr_emerg("BUG: workqueue lockup - pool");
pr_cont_pool_info(pool);
pr_cont(" stuck for %us!\n",
jiffies_to_msecs(now - pool_ts) / 1000);
}
}
rcu_read_unlock();
if (lockup_detected)
show_all_workqueues();
if (cpu_pool_stall)
show_cpu_pools_hogs();
wq_watchdog_reset_touched();
mod_timer(&wq_watchdog_timer, jiffies + thresh);
}
notrace void wq_watchdog_touch(int cpu)
{
if (cpu >= 0)
per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies;
wq_watchdog_touched = jiffies;
}
static void wq_watchdog_set_thresh(unsigned long thresh)
{
wq_watchdog_thresh = 0;
del_timer_sync(&wq_watchdog_timer);
if (thresh) {
wq_watchdog_thresh = thresh;
wq_watchdog_reset_touched();
mod_timer(&wq_watchdog_timer, jiffies + thresh * HZ);
}
}
static int wq_watchdog_param_set_thresh(const char *val,
const struct kernel_param *kp)
{
unsigned long thresh;
int ret;
ret = kstrtoul(val, 0, &thresh);
if (ret)
return ret;
if (system_wq)
wq_watchdog_set_thresh(thresh);
else
wq_watchdog_thresh = thresh;
return 0;
}
static const struct kernel_param_ops wq_watchdog_thresh_ops = {
.set = wq_watchdog_param_set_thresh,
.get = param_get_ulong,
};
module_param_cb(watchdog_thresh, &wq_watchdog_thresh_ops, &wq_watchdog_thresh,
0644);
static void wq_watchdog_init(void)
{
timer_setup(&wq_watchdog_timer, wq_watchdog_timer_fn, TIMER_DEFERRABLE);
wq_watchdog_set_thresh(wq_watchdog_thresh);
}
#else /* CONFIG_WQ_WATCHDOG */
static inline void wq_watchdog_init(void) { }
#endif /* CONFIG_WQ_WATCHDOG */
/**
* workqueue_init_early - early init for workqueue subsystem
*
* This is the first step of three-staged workqueue subsystem initialization and
* invoked as soon as the bare basics - memory allocation, cpumasks and idr are
* up. It sets up all the data structures and system workqueues and allows early
* boot code to create workqueues and queue/cancel work items. Actual work item
* execution starts only after kthreads can be created and scheduled right
* before early initcalls.
*/
void __init workqueue_init_early(void)
{
struct wq_pod_type *pt = &wq_pod_types[WQ_AFFN_SYSTEM];
int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
int i, cpu;
BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ));
cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));
if (!cpumask_empty(&wq_cmdline_cpumask))
cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, &wq_cmdline_cpumask);
pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
wq_update_pod_attrs_buf = alloc_workqueue_attrs();
BUG_ON(!wq_update_pod_attrs_buf);
/* initialize WQ_AFFN_SYSTEM pods */
pt->pod_cpus = kcalloc(1, sizeof(pt->pod_cpus[0]), GFP_KERNEL);
pt->pod_node = kcalloc(1, sizeof(pt->pod_node[0]), GFP_KERNEL);
pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL);
BUG_ON(!pt->pod_cpus || !pt->pod_node || !pt->cpu_pod);
BUG_ON(!zalloc_cpumask_var_node(&pt->pod_cpus[0], GFP_KERNEL, NUMA_NO_NODE));
wq_update_pod_attrs_buf = alloc_workqueue_attrs();
BUG_ON(!wq_update_pod_attrs_buf);
pt->nr_pods = 1;
cpumask_copy(pt->pod_cpus[0], cpu_possible_mask);
pt->pod_node[0] = NUMA_NO_NODE;
pt->cpu_pod[0] = 0;
/* initialize CPU pools */
for_each_possible_cpu(cpu) {
struct worker_pool *pool;
i = 0;
for_each_cpu_worker_pool(pool, cpu) {
BUG_ON(init_worker_pool(pool));
pool->cpu = cpu;
cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu));
cpumask_copy(pool->attrs->__pod_cpumask, cpumask_of(cpu));
pool->attrs->nice = std_nice[i++];
pool->attrs->affn_strict = true;
pool->node = cpu_to_node(cpu);
/* alloc pool ID */
mutex_lock(&wq_pool_mutex);
BUG_ON(worker_pool_assign_id(pool));
mutex_unlock(&wq_pool_mutex);
}
}
/* create default unbound and ordered wq attrs */
for (i = 0; i < NR_STD_WORKER_POOLS; i++) {
struct workqueue_attrs *attrs;
BUG_ON(!(attrs = alloc_workqueue_attrs()));
attrs->nice = std_nice[i];
unbound_std_wq_attrs[i] = attrs;
/*
* An ordered wq should have only one pwq as ordering is
* guaranteed by max_active which is enforced by pwqs.
*/
BUG_ON(!(attrs = alloc_workqueue_attrs()));
attrs->nice = std_nice[i];
attrs->ordered = true;
ordered_wq_attrs[i] = attrs;
}
system_wq = alloc_workqueue("events", 0, 0);
system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
system_long_wq = alloc_workqueue("events_long", 0, 0);
system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
WQ_MAX_ACTIVE);
system_freezable_wq = alloc_workqueue("events_freezable",
WQ_FREEZABLE, 0);
system_power_efficient_wq = alloc_workqueue("events_power_efficient",
WQ_POWER_EFFICIENT, 0);
system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient",
WQ_FREEZABLE | WQ_POWER_EFFICIENT,
0);
BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq ||
!system_unbound_wq || !system_freezable_wq ||
!system_power_efficient_wq ||
!system_freezable_power_efficient_wq);
}
static void __init wq_cpu_intensive_thresh_init(void)
{
unsigned long thresh;
unsigned long bogo;
/* if the user set it to a specific value, keep it */
if (wq_cpu_intensive_thresh_us != ULONG_MAX)
return;
pwq_release_worker = kthread_create_worker(0, "pool_workqueue_release");
BUG_ON(IS_ERR(pwq_release_worker));
/*
* The default of 10ms is derived from the fact that most modern (as of
* 2023) processors can do a lot in 10ms and that it's just below what
* most consider human-perceivable. However, the kernel also runs on a
* lot slower CPUs including microcontrollers where the threshold is way
* too low.
*
* Let's scale up the threshold upto 1 second if BogoMips is below 4000.
* This is by no means accurate but it doesn't have to be. The mechanism
* is still useful even when the threshold is fully scaled up. Also, as
* the reports would usually be applicable to everyone, some machines
* operating on longer thresholds won't significantly diminish their
* usefulness.
*/
thresh = 10 * USEC_PER_MSEC;
/* see init/calibrate.c for lpj -> BogoMIPS calculation */
bogo = max_t(unsigned long, loops_per_jiffy / 500000 * HZ, 1);
if (bogo < 4000)
thresh = min_t(unsigned long, thresh * 4000 / bogo, USEC_PER_SEC);
pr_debug("wq_cpu_intensive_thresh: lpj=%lu BogoMIPS=%lu thresh_us=%lu\n",
loops_per_jiffy, bogo, thresh);
wq_cpu_intensive_thresh_us = thresh;
}
/**
* workqueue_init - bring workqueue subsystem fully online
*
* This is the second step of three-staged workqueue subsystem initialization
* and invoked as soon as kthreads can be created and scheduled. Workqueues have
* been created and work items queued on them, but there are no kworkers
* executing the work items yet. Populate the worker pools with the initial
* workers and enable future kworker creations.
*/
void __init workqueue_init(void)
{
struct workqueue_struct *wq;
struct worker_pool *pool;
int cpu, bkt;
wq_cpu_intensive_thresh_init();
mutex_lock(&wq_pool_mutex);
/*
* Per-cpu pools created earlier could be missing node hint. Fix them
* up. Also, create a rescuer for workqueues that requested it.
*/
for_each_possible_cpu(cpu) {
for_each_cpu_worker_pool(pool, cpu) {
pool->node = cpu_to_node(cpu);
}
}
list_for_each_entry(wq, &workqueues, list) {
WARN(init_rescuer(wq),
"workqueue: failed to create early rescuer for %s",
wq->name);
}
mutex_unlock(&wq_pool_mutex);
/* create the initial workers */
for_each_online_cpu(cpu) {
for_each_cpu_worker_pool(pool, cpu) {
pool->flags &= ~POOL_DISASSOCIATED;
BUG_ON(!create_worker(pool));
}
}
hash_for_each(unbound_pool_hash, bkt, pool, hash_node)
BUG_ON(!create_worker(pool));
wq_online = true;
wq_watchdog_init();
}
/*
* Initialize @pt by first initializing @pt->cpu_pod[] with pod IDs according to
* @cpu_shares_pod(). Each subset of CPUs that share a pod is assigned a unique
* and consecutive pod ID. The rest of @pt is initialized accordingly.
*/
static void __init init_pod_type(struct wq_pod_type *pt,
bool (*cpus_share_pod)(int, int))
{
int cur, pre, cpu, pod;
pt->nr_pods = 0;
/* init @pt->cpu_pod[] according to @cpus_share_pod() */
pt->cpu_pod = kcalloc(nr_cpu_ids, sizeof(pt->cpu_pod[0]), GFP_KERNEL);
BUG_ON(!pt->cpu_pod);
for_each_possible_cpu(cur) {
for_each_possible_cpu(pre) {
if (pre >= cur) {
pt->cpu_pod[cur] = pt->nr_pods++;
break;
}
if (cpus_share_pod(cur, pre)) {
pt->cpu_pod[cur] = pt->cpu_pod[pre];
break;
}
}
}
/* init the rest to match @pt->cpu_pod[] */
pt->pod_cpus = kcalloc(pt->nr_pods, sizeof(pt->pod_cpus[0]), GFP_KERNEL);
pt->pod_node = kcalloc(pt->nr_pods, sizeof(pt->pod_node[0]), GFP_KERNEL);
BUG_ON(!pt->pod_cpus || !pt->pod_node);
for (pod = 0; pod < pt->nr_pods; pod++)
BUG_ON(!zalloc_cpumask_var(&pt->pod_cpus[pod], GFP_KERNEL));
for_each_possible_cpu(cpu) {
cpumask_set_cpu(cpu, pt->pod_cpus[pt->cpu_pod[cpu]]);
pt->pod_node[pt->cpu_pod[cpu]] = cpu_to_node(cpu);
}
}
static bool __init cpus_dont_share(int cpu0, int cpu1)
{
return false;
}
static bool __init cpus_share_smt(int cpu0, int cpu1)
{
#ifdef CONFIG_SCHED_SMT
return cpumask_test_cpu(cpu0, cpu_smt_mask(cpu1));
#else
return false;
#endif
}
static bool __init cpus_share_numa(int cpu0, int cpu1)
{
return cpu_to_node(cpu0) == cpu_to_node(cpu1);
}
/**
* workqueue_init_topology - initialize CPU pods for unbound workqueues
*
* This is the third step of there-staged workqueue subsystem initialization and
* invoked after SMP and topology information are fully initialized. It
* initializes the unbound CPU pods accordingly.
*/
void __init workqueue_init_topology(void)
{
struct workqueue_struct *wq;
int cpu;
init_pod_type(&wq_pod_types[WQ_AFFN_CPU], cpus_dont_share);
init_pod_type(&wq_pod_types[WQ_AFFN_SMT], cpus_share_smt);
init_pod_type(&wq_pod_types[WQ_AFFN_CACHE], cpus_share_cache);
init_pod_type(&wq_pod_types[WQ_AFFN_NUMA], cpus_share_numa);
mutex_lock(&wq_pool_mutex);
/*
* Workqueues allocated earlier would have all CPUs sharing the default
* worker pool. Explicitly call wq_update_pod() on all workqueue and CPU
* combinations to apply per-pod sharing.
*/
list_for_each_entry(wq, &workqueues, list) {
for_each_online_cpu(cpu) {
wq_update_pod(wq, cpu, cpu, true);
}
}
mutex_unlock(&wq_pool_mutex);
}
void __warn_flushing_systemwide_wq(void)
{
pr_warn("WARNING: Flushing system-wide workqueues will be prohibited in near future.\n");
dump_stack();
}
EXPORT_SYMBOL(__warn_flushing_systemwide_wq);
static int __init workqueue_unbound_cpus_setup(char *str)
{
if (cpulist_parse(str, &wq_cmdline_cpumask) < 0) {
cpumask_clear(&wq_cmdline_cpumask);
pr_warn("workqueue.unbound_cpus: incorrect CPU range, using default\n");
}
return 1;
}
__setup("workqueue.unbound_cpus=", workqueue_unbound_cpus_setup);
| linux-master | kernel/workqueue.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2006 IBM Corporation
*
* Author: Serge Hallyn <[email protected]>
*
* Jun 2006 - namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <[email protected]>
*/
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/nsproxy.h>
#include <linux/init_task.h>
#include <linux/mnt_namespace.h>
#include <linux/utsname.h>
#include <linux/pid_namespace.h>
#include <net/net_namespace.h>
#include <linux/ipc_namespace.h>
#include <linux/time_namespace.h>
#include <linux/fs_struct.h>
#include <linux/proc_fs.h>
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
#include <linux/cgroup.h>
#include <linux/perf_event.h>
static struct kmem_cache *nsproxy_cachep;
struct nsproxy init_nsproxy = {
.count = REFCOUNT_INIT(1),
.uts_ns = &init_uts_ns,
#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
.ipc_ns = &init_ipc_ns,
#endif
.mnt_ns = NULL,
.pid_ns_for_children = &init_pid_ns,
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
#ifdef CONFIG_CGROUPS
.cgroup_ns = &init_cgroup_ns,
#endif
#ifdef CONFIG_TIME_NS
.time_ns = &init_time_ns,
.time_ns_for_children = &init_time_ns,
#endif
};
static inline struct nsproxy *create_nsproxy(void)
{
struct nsproxy *nsproxy;
nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
if (nsproxy)
refcount_set(&nsproxy->count, 1);
return nsproxy;
}
/*
* Create new nsproxy and all of its the associated namespaces.
* Return the newly created nsproxy. Do not attach this to the task,
* leave it to the caller to do proper locking and attach it to task.
*/
static struct nsproxy *create_new_namespaces(unsigned long flags,
struct task_struct *tsk, struct user_namespace *user_ns,
struct fs_struct *new_fs)
{
struct nsproxy *new_nsp;
int err;
new_nsp = create_nsproxy();
if (!new_nsp)
return ERR_PTR(-ENOMEM);
new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
if (IS_ERR(new_nsp->mnt_ns)) {
err = PTR_ERR(new_nsp->mnt_ns);
goto out_ns;
}
new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns);
if (IS_ERR(new_nsp->uts_ns)) {
err = PTR_ERR(new_nsp->uts_ns);
goto out_uts;
}
new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns);
if (IS_ERR(new_nsp->ipc_ns)) {
err = PTR_ERR(new_nsp->ipc_ns);
goto out_ipc;
}
new_nsp->pid_ns_for_children =
copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns_for_children);
if (IS_ERR(new_nsp->pid_ns_for_children)) {
err = PTR_ERR(new_nsp->pid_ns_for_children);
goto out_pid;
}
new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
tsk->nsproxy->cgroup_ns);
if (IS_ERR(new_nsp->cgroup_ns)) {
err = PTR_ERR(new_nsp->cgroup_ns);
goto out_cgroup;
}
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
goto out_net;
}
new_nsp->time_ns_for_children = copy_time_ns(flags, user_ns,
tsk->nsproxy->time_ns_for_children);
if (IS_ERR(new_nsp->time_ns_for_children)) {
err = PTR_ERR(new_nsp->time_ns_for_children);
goto out_time;
}
new_nsp->time_ns = get_time_ns(tsk->nsproxy->time_ns);
return new_nsp;
out_time:
put_net(new_nsp->net_ns);
out_net:
put_cgroup_ns(new_nsp->cgroup_ns);
out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
if (new_nsp->ipc_ns)
put_ipc_ns(new_nsp->ipc_ns);
out_ipc:
if (new_nsp->uts_ns)
put_uts_ns(new_nsp->uts_ns);
out_uts:
if (new_nsp->mnt_ns)
put_mnt_ns(new_nsp->mnt_ns);
out_ns:
kmem_cache_free(nsproxy_cachep, new_nsp);
return ERR_PTR(err);
}
/*
* called from clone. This now handles copy for nsproxy and all
* namespaces therein.
*/
int copy_namespaces(unsigned long flags, struct task_struct *tsk)
{
struct nsproxy *old_ns = tsk->nsproxy;
struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
CLONE_NEWPID | CLONE_NEWNET |
CLONE_NEWCGROUP | CLONE_NEWTIME)))) {
if ((flags & CLONE_VM) ||
likely(old_ns->time_ns_for_children == old_ns->time_ns)) {
get_nsproxy(old_ns);
return 0;
}
} else if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
* CLONE_NEWIPC must detach from the undolist: after switching
* to a new ipc namespace, the semaphore arrays from the old
* namespace are unreachable. In clone parlance, CLONE_SYSVSEM
* means share undolist with parent, so we must forbid using
* it along with CLONE_NEWIPC.
*/
if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) ==
(CLONE_NEWIPC | CLONE_SYSVSEM))
return -EINVAL;
new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs);
if (IS_ERR(new_ns))
return PTR_ERR(new_ns);
if ((flags & CLONE_VM) == 0)
timens_on_fork(new_ns, tsk);
tsk->nsproxy = new_ns;
return 0;
}
void free_nsproxy(struct nsproxy *ns)
{
if (ns->mnt_ns)
put_mnt_ns(ns->mnt_ns);
if (ns->uts_ns)
put_uts_ns(ns->uts_ns);
if (ns->ipc_ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
if (ns->time_ns)
put_time_ns(ns->time_ns);
if (ns->time_ns_for_children)
put_time_ns(ns->time_ns_for_children);
put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
/*
* Called from unshare. Unshare all the namespaces part of nsproxy.
* On success, returns the new nsproxy.
*/
int unshare_nsproxy_namespaces(unsigned long unshare_flags,
struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs)
{
struct user_namespace *user_ns;
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP |
CLONE_NEWTIME)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
new_fs ? new_fs : current->fs);
if (IS_ERR(*new_nsp)) {
err = PTR_ERR(*new_nsp);
goto out;
}
out:
return err;
}
void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
{
struct nsproxy *ns;
might_sleep();
task_lock(p);
ns = p->nsproxy;
p->nsproxy = new;
task_unlock(p);
if (ns)
put_nsproxy(ns);
}
void exit_task_namespaces(struct task_struct *p)
{
switch_task_namespaces(p, NULL);
}
int exec_task_namespaces(void)
{
struct task_struct *tsk = current;
struct nsproxy *new;
if (tsk->nsproxy->time_ns_for_children == tsk->nsproxy->time_ns)
return 0;
new = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
if (IS_ERR(new))
return PTR_ERR(new);
timens_on_fork(new, tsk);
switch_task_namespaces(tsk, new);
return 0;
}
static int check_setns_flags(unsigned long flags)
{
if (!flags || (flags & ~(CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
CLONE_NEWNET | CLONE_NEWTIME | CLONE_NEWUSER |
CLONE_NEWPID | CLONE_NEWCGROUP)))
return -EINVAL;
#ifndef CONFIG_USER_NS
if (flags & CLONE_NEWUSER)
return -EINVAL;
#endif
#ifndef CONFIG_PID_NS
if (flags & CLONE_NEWPID)
return -EINVAL;
#endif
#ifndef CONFIG_UTS_NS
if (flags & CLONE_NEWUTS)
return -EINVAL;
#endif
#ifndef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC)
return -EINVAL;
#endif
#ifndef CONFIG_CGROUPS
if (flags & CLONE_NEWCGROUP)
return -EINVAL;
#endif
#ifndef CONFIG_NET_NS
if (flags & CLONE_NEWNET)
return -EINVAL;
#endif
#ifndef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME)
return -EINVAL;
#endif
return 0;
}
static void put_nsset(struct nsset *nsset)
{
unsigned flags = nsset->flags;
if (flags & CLONE_NEWUSER)
put_cred(nsset_cred(nsset));
/*
* We only created a temporary copy if we attached to more than just
* the mount namespace.
*/
if (nsset->fs && (flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS))
free_fs_struct(nsset->fs);
if (nsset->nsproxy)
free_nsproxy(nsset->nsproxy);
}
static int prepare_nsset(unsigned flags, struct nsset *nsset)
{
struct task_struct *me = current;
nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs);
if (IS_ERR(nsset->nsproxy))
return PTR_ERR(nsset->nsproxy);
if (flags & CLONE_NEWUSER)
nsset->cred = prepare_creds();
else
nsset->cred = current_cred();
if (!nsset->cred)
goto out;
/* Only create a temporary copy of fs_struct if we really need to. */
if (flags == CLONE_NEWNS) {
nsset->fs = me->fs;
} else if (flags & CLONE_NEWNS) {
nsset->fs = copy_fs_struct(me->fs);
if (!nsset->fs)
goto out;
}
nsset->flags = flags;
return 0;
out:
put_nsset(nsset);
return -ENOMEM;
}
static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
{
return ns->ops->install(nsset, ns);
}
/*
* This is the inverse operation to unshare().
* Ordering is equivalent to the standard ordering used everywhere else
* during unshare and process creation. The switch to the new set of
* namespaces occurs at the point of no return after installation of
* all requested namespaces was successful in commit_nsset().
*/
static int validate_nsset(struct nsset *nsset, struct pid *pid)
{
int ret = 0;
unsigned flags = nsset->flags;
struct user_namespace *user_ns = NULL;
struct pid_namespace *pid_ns = NULL;
struct nsproxy *nsp;
struct task_struct *tsk;
/* Take a "snapshot" of the target task's namespaces. */
rcu_read_lock();
tsk = pid_task(pid, PIDTYPE_PID);
if (!tsk) {
rcu_read_unlock();
return -ESRCH;
}
if (!ptrace_may_access(tsk, PTRACE_MODE_READ_REALCREDS)) {
rcu_read_unlock();
return -EPERM;
}
task_lock(tsk);
nsp = tsk->nsproxy;
if (nsp)
get_nsproxy(nsp);
task_unlock(tsk);
if (!nsp) {
rcu_read_unlock();
return -ESRCH;
}
#ifdef CONFIG_PID_NS
if (flags & CLONE_NEWPID) {
pid_ns = task_active_pid_ns(tsk);
if (unlikely(!pid_ns)) {
rcu_read_unlock();
ret = -ESRCH;
goto out;
}
get_pid_ns(pid_ns);
}
#endif
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER)
user_ns = get_user_ns(__task_cred(tsk)->user_ns);
#endif
rcu_read_unlock();
/*
* Install requested namespaces. The caller will have
* verified earlier that the requested namespaces are
* supported on this kernel. We don't report errors here
* if a namespace is requested that isn't supported.
*/
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER) {
ret = validate_ns(nsset, &user_ns->ns);
if (ret)
goto out;
}
#endif
if (flags & CLONE_NEWNS) {
ret = validate_ns(nsset, from_mnt_ns(nsp->mnt_ns));
if (ret)
goto out;
}
#ifdef CONFIG_UTS_NS
if (flags & CLONE_NEWUTS) {
ret = validate_ns(nsset, &nsp->uts_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC) {
ret = validate_ns(nsset, &nsp->ipc_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_PID_NS
if (flags & CLONE_NEWPID) {
ret = validate_ns(nsset, &pid_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_CGROUPS
if (flags & CLONE_NEWCGROUP) {
ret = validate_ns(nsset, &nsp->cgroup_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_NET_NS
if (flags & CLONE_NEWNET) {
ret = validate_ns(nsset, &nsp->net_ns->ns);
if (ret)
goto out;
}
#endif
#ifdef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME) {
ret = validate_ns(nsset, &nsp->time_ns->ns);
if (ret)
goto out;
}
#endif
out:
if (pid_ns)
put_pid_ns(pid_ns);
if (nsp)
put_nsproxy(nsp);
put_user_ns(user_ns);
return ret;
}
/*
* This is the point of no return. There are just a few namespaces
* that do some actual work here and it's sufficiently minimal that
* a separate ns_common operation seems unnecessary for now.
* Unshare is doing the same thing. If we'll end up needing to do
* more in a given namespace or a helper here is ultimately not
* exported anymore a simple commit handler for each namespace
* should be added to ns_common.
*/
static void commit_nsset(struct nsset *nsset)
{
unsigned flags = nsset->flags;
struct task_struct *me = current;
#ifdef CONFIG_USER_NS
if (flags & CLONE_NEWUSER) {
/* transfer ownership */
commit_creds(nsset_cred(nsset));
nsset->cred = NULL;
}
#endif
/* We only need to commit if we have used a temporary fs_struct. */
if ((flags & CLONE_NEWNS) && (flags & ~CLONE_NEWNS)) {
set_fs_root(me->fs, &nsset->fs->root);
set_fs_pwd(me->fs, &nsset->fs->pwd);
}
#ifdef CONFIG_IPC_NS
if (flags & CLONE_NEWIPC)
exit_sem(me);
#endif
#ifdef CONFIG_TIME_NS
if (flags & CLONE_NEWTIME)
timens_commit(me, nsset->nsproxy->time_ns);
#endif
/* transfer ownership */
switch_task_namespaces(me, nsset->nsproxy);
nsset->nsproxy = NULL;
}
SYSCALL_DEFINE2(setns, int, fd, int, flags)
{
struct fd f = fdget(fd);
struct ns_common *ns = NULL;
struct nsset nsset = {};
int err = 0;
if (!f.file)
return -EBADF;
if (proc_ns_file(f.file)) {
ns = get_proc_ns(file_inode(f.file));
if (flags && (ns->ops->type != flags))
err = -EINVAL;
flags = ns->ops->type;
} else if (!IS_ERR(pidfd_pid(f.file))) {
err = check_setns_flags(flags);
} else {
err = -EINVAL;
}
if (err)
goto out;
err = prepare_nsset(flags, &nsset);
if (err)
goto out;
if (proc_ns_file(f.file))
err = validate_ns(&nsset, ns);
else
err = validate_nsset(&nsset, f.file->private_data);
if (!err) {
commit_nsset(&nsset);
perf_event_namespaces(current);
}
put_nsset(&nsset);
out:
fdput(f);
return err;
}
int __init nsproxy_cache_init(void)
{
nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC|SLAB_ACCOUNT);
return 0;
}
| linux-master | kernel/nsproxy.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Google, Inc.
*
* Author:
* Colin Cross <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/cpu_pm.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/syscore_ops.h>
/*
* atomic_notifiers use a spinlock_t, which can block under PREEMPT_RT.
* Notifications for cpu_pm will be issued by the idle task itself, which can
* never block, IOW it requires using a raw_spinlock_t.
*/
static struct {
struct raw_notifier_head chain;
raw_spinlock_t lock;
} cpu_pm_notifier = {
.chain = RAW_NOTIFIER_INIT(cpu_pm_notifier.chain),
.lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock),
};
static int cpu_pm_notify(enum cpu_pm_event event)
{
int ret;
rcu_read_lock();
ret = raw_notifier_call_chain(&cpu_pm_notifier.chain, event, NULL);
rcu_read_unlock();
return notifier_to_errno(ret);
}
static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_call_chain_robust(&cpu_pm_notifier.chain, event_up, event_down, NULL);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return notifier_to_errno(ret);
}
/**
* cpu_pm_register_notifier - register a driver with cpu_pm
* @nb: notifier block to register
*
* Add a driver to a list of drivers that are notified about
* CPU and CPU cluster low power entry and exit.
*
* This function has the same return conditions as raw_notifier_chain_register.
*/
int cpu_pm_register_notifier(struct notifier_block *nb)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_chain_register(&cpu_pm_notifier.chain, nb);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(cpu_pm_register_notifier);
/**
* cpu_pm_unregister_notifier - unregister a driver with cpu_pm
* @nb: notifier block to be unregistered
*
* Remove a driver from the CPU PM notifier list.
*
* This function has the same return conditions as raw_notifier_chain_unregister.
*/
int cpu_pm_unregister_notifier(struct notifier_block *nb)
{
unsigned long flags;
int ret;
raw_spin_lock_irqsave(&cpu_pm_notifier.lock, flags);
ret = raw_notifier_chain_unregister(&cpu_pm_notifier.chain, nb);
raw_spin_unlock_irqrestore(&cpu_pm_notifier.lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier);
/**
* cpu_pm_enter - CPU low power entry notifier
*
* Notifies listeners that a single CPU is entering a low power state that may
* cause some blocks in the same power domain as the cpu to reset.
*
* Must be called on the affected CPU with interrupts disabled. Platform is
* responsible for ensuring that cpu_pm_enter is not called twice on the same
* CPU before cpu_pm_exit is called. Notified drivers can include VFP
* co-processor, interrupt controller and its PM extensions, local CPU
* timers context save/restore which shouldn't be interrupted. Hence it
* must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_pm_enter(void)
{
return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED);
}
EXPORT_SYMBOL_GPL(cpu_pm_enter);
/**
* cpu_pm_exit - CPU low power exit notifier
*
* Notifies listeners that a single CPU is exiting a low power state that may
* have caused some blocks in the same power domain as the cpu to reset.
*
* Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_pm_exit(void)
{
return cpu_pm_notify(CPU_PM_EXIT);
}
EXPORT_SYMBOL_GPL(cpu_pm_exit);
/**
* cpu_cluster_pm_enter - CPU cluster low power entry notifier
*
* Notifies listeners that all cpus in a power domain are entering a low power
* state that may cause some blocks in the same power domain to reset.
*
* Must be called after cpu_pm_enter has been called on all cpus in the power
* domain, and before cpu_pm_exit has been called on any cpu in the power
* domain. Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_cluster_pm_enter(void)
{
return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED);
}
EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter);
/**
* cpu_cluster_pm_exit - CPU cluster low power exit notifier
*
* Notifies listeners that all cpus in a power domain are exiting form a
* low power state that may have caused some blocks in the same power domain
* to reset.
*
* Must be called after cpu_cluster_pm_enter has been called for the power
* domain, and before cpu_pm_exit has been called on any cpu in the power
* domain. Notified drivers can include VFP co-processor, interrupt controller
* and its PM extensions, local CPU timers context save/restore which
* shouldn't be interrupted. Hence it must be called with interrupts disabled.
*
* Return conditions are same as __raw_notifier_call_chain.
*/
int cpu_cluster_pm_exit(void)
{
return cpu_pm_notify(CPU_CLUSTER_PM_EXIT);
}
EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit);
#ifdef CONFIG_PM
static int cpu_pm_suspend(void)
{
int ret;
ret = cpu_pm_enter();
if (ret)
return ret;
ret = cpu_cluster_pm_enter();
return ret;
}
static void cpu_pm_resume(void)
{
cpu_cluster_pm_exit();
cpu_pm_exit();
}
static struct syscore_ops cpu_pm_syscore_ops = {
.suspend = cpu_pm_suspend,
.resume = cpu_pm_resume,
};
static int cpu_pm_init(void)
{
register_syscore_ops(&cpu_pm_syscore_ops);
return 0;
}
core_initcall(cpu_pm_init);
#endif
| linux-master | kernel/cpu_pm.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* audit_fsnotify.c -- tracking inodes
*
* Copyright 2003-2009,2014-2015 Red Hat, Inc.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright 2005 IBM Corporation
*/
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
#include "audit.h"
/*
* this mark lives on the parent directory of the inode in question.
* but dev, ino, and path are about the child
*/
struct audit_fsnotify_mark {
dev_t dev; /* associated superblock device */
unsigned long ino; /* associated inode number */
char *path; /* insertion path */
struct fsnotify_mark mark; /* fsnotify mark on the inode */
struct audit_krule *rule;
};
/* fsnotify handle. */
static struct fsnotify_group *audit_fsnotify_group;
/* fsnotify events we care about. */
#define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
FS_MOVE_SELF)
static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark)
{
kfree(audit_mark->path);
kfree(audit_mark);
}
static void audit_fsnotify_free_mark(struct fsnotify_mark *mark)
{
struct audit_fsnotify_mark *audit_mark;
audit_mark = container_of(mark, struct audit_fsnotify_mark, mark);
audit_fsnotify_mark_free(audit_mark);
}
char *audit_mark_path(struct audit_fsnotify_mark *mark)
{
return mark->path;
}
int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev)
{
if (mark->ino == AUDIT_INO_UNSET)
return 0;
return (mark->ino == ino) && (mark->dev == dev);
}
static void audit_update_mark(struct audit_fsnotify_mark *audit_mark,
const struct inode *inode)
{
audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET;
audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET;
}
struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len)
{
struct audit_fsnotify_mark *audit_mark;
struct path path;
struct dentry *dentry;
struct inode *inode;
int ret;
if (pathname[0] != '/' || pathname[len-1] == '/')
return ERR_PTR(-EINVAL);
dentry = kern_path_locked(pathname, &path);
if (IS_ERR(dentry))
return ERR_CAST(dentry); /* returning an error */
inode = path.dentry->d_inode;
inode_unlock(inode);
audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL);
if (unlikely(!audit_mark)) {
audit_mark = ERR_PTR(-ENOMEM);
goto out;
}
fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group);
audit_mark->mark.mask = AUDIT_FS_EVENTS;
audit_mark->path = pathname;
audit_update_mark(audit_mark, dentry->d_inode);
audit_mark->rule = krule;
ret = fsnotify_add_inode_mark(&audit_mark->mark, inode, 0);
if (ret < 0) {
audit_mark->path = NULL;
fsnotify_put_mark(&audit_mark->mark);
audit_mark = ERR_PTR(ret);
}
out:
dput(dentry);
path_put(&path);
return audit_mark;
}
static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op)
{
struct audit_buffer *ab;
struct audit_krule *rule = audit_mark->rule;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return;
audit_log_session_info(ab);
audit_log_format(ab, " op=%s path=", op);
audit_log_untrustedstring(ab, audit_mark->path);
audit_log_key(ab, rule->filterkey);
audit_log_format(ab, " list=%d res=1", rule->listnr);
audit_log_end(ab);
}
void audit_remove_mark(struct audit_fsnotify_mark *audit_mark)
{
fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group);
fsnotify_put_mark(&audit_mark->mark);
}
void audit_remove_mark_rule(struct audit_krule *krule)
{
struct audit_fsnotify_mark *mark = krule->exe;
audit_remove_mark(mark);
}
static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark)
{
struct audit_krule *rule = audit_mark->rule;
struct audit_entry *entry = container_of(rule, struct audit_entry, rule);
audit_mark_log_rule_change(audit_mark, "autoremove_rule");
audit_del_rule(entry);
}
/* Update mark data in audit rules based on fsnotify events. */
static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
struct inode *inode, struct inode *dir,
const struct qstr *dname, u32 cookie)
{
struct audit_fsnotify_mark *audit_mark;
audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark);
if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group))
return 0;
if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) {
if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL))
return 0;
audit_update_mark(audit_mark, inode);
} else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) {
audit_autoremove_mark_rule(audit_mark);
}
return 0;
}
static const struct fsnotify_ops audit_mark_fsnotify_ops = {
.handle_inode_event = audit_mark_handle_event,
.free_mark = audit_fsnotify_free_mark,
};
static int __init audit_fsnotify_init(void)
{
audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops,
FSNOTIFY_GROUP_DUPS);
if (IS_ERR(audit_fsnotify_group)) {
audit_fsnotify_group = NULL;
audit_panic("cannot create audit fsnotify group");
}
return 0;
}
device_initcall(audit_fsnotify_init);
| linux-master | kernel/audit_fsnotify.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
*
* Rewritten and vastly simplified by Rusty Russell for in-kernel
* module loader:
* Copyright 2002 Rusty Russell <[email protected]> IBM Corporation
*
* ChangeLog:
*
* (25/Aug/2004) Paulo Marques <[email protected]>
* Changed the compression method from stem compression to "table lookup"
* compression (see scripts/kallsyms.c for a more complete description)
*/
#include <linux/kallsyms.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/kdb.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
#include <linux/sched.h> /* for cond_resched */
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/filter.h>
#include <linux/ftrace.h>
#include <linux/kprobes.h>
#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bsearch.h>
#include <linux/btf_ids.h>
#include "kallsyms_internal.h"
/*
* Expand a compressed symbol data into the resulting uncompressed string,
* if uncompressed string is too long (>= maxlen), it will be truncated,
* given the offset to where the symbol is in the compressed stream.
*/
static unsigned int kallsyms_expand_symbol(unsigned int off,
char *result, size_t maxlen)
{
int len, skipped_first = 0;
const char *tptr;
const u8 *data;
/* Get the compressed symbol length from the first symbol byte. */
data = &kallsyms_names[off];
len = *data;
data++;
off++;
/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
if ((len & 0x80) != 0) {
len = (len & 0x7F) | (*data << 7);
data++;
off++;
}
/*
* Update the offset to return the offset for the next symbol on
* the compressed stream.
*/
off += len;
/*
* For every byte on the compressed symbol data, copy the table
* entry for that byte.
*/
while (len) {
tptr = &kallsyms_token_table[kallsyms_token_index[*data]];
data++;
len--;
while (*tptr) {
if (skipped_first) {
if (maxlen <= 1)
goto tail;
*result = *tptr;
result++;
maxlen--;
} else
skipped_first = 1;
tptr++;
}
}
tail:
if (maxlen)
*result = '\0';
/* Return to offset to the next symbol. */
return off;
}
/*
* Get symbol type information. This is encoded as a single char at the
* beginning of the symbol name.
*/
static char kallsyms_get_symbol_type(unsigned int off)
{
/*
* Get just the first code, look it up in the token table,
* and return the first char from this token.
*/
return kallsyms_token_table[kallsyms_token_index[kallsyms_names[off + 1]]];
}
/*
* Find the offset on the compressed stream given and index in the
* kallsyms array.
*/
static unsigned int get_symbol_offset(unsigned long pos)
{
const u8 *name;
int i, len;
/*
* Use the closest marker we have. We have markers every 256 positions,
* so that should be close enough.
*/
name = &kallsyms_names[kallsyms_markers[pos >> 8]];
/*
* Sequentially scan all the symbols up to the point we're searching
* for. Every symbol is stored in a [<len>][<len> bytes of data] format,
* so we just need to add the len to the current pointer for every
* symbol we wish to skip.
*/
for (i = 0; i < (pos & 0xFF); i++) {
len = *name;
/*
* If MSB is 1, it is a "big" symbol, so we need to look into
* the next byte (and skip it, too).
*/
if ((len & 0x80) != 0)
len = ((len & 0x7F) | (name[1] << 7)) + 1;
name = name + len + 1;
}
return name - kallsyms_names;
}
unsigned long kallsyms_sym_address(int idx)
{
if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
return kallsyms_addresses[idx];
/* values are unsigned offsets if --absolute-percpu is not in effect */
if (!IS_ENABLED(CONFIG_KALLSYMS_ABSOLUTE_PERCPU))
return kallsyms_relative_base + (u32)kallsyms_offsets[idx];
/* ...otherwise, positive offsets are absolute values */
if (kallsyms_offsets[idx] >= 0)
return kallsyms_offsets[idx];
/* ...and negative offsets are relative to kallsyms_relative_base - 1 */
return kallsyms_relative_base - 1 - kallsyms_offsets[idx];
}
static void cleanup_symbol_name(char *s)
{
char *res;
if (!IS_ENABLED(CONFIG_LTO_CLANG))
return;
/*
* LLVM appends various suffixes for local functions and variables that
* must be promoted to global scope as part of LTO. This can break
* hooking of static functions with kprobes. '.' is not a valid
* character in an identifier in C. Suffixes only in LLVM LTO observed:
* - foo.llvm.[0-9a-f]+
*/
res = strstr(s, ".llvm.");
if (res)
*res = '\0';
return;
}
static int compare_symbol_name(const char *name, char *namebuf)
{
/* The kallsyms_seqs_of_names is sorted based on names after
* cleanup_symbol_name() (see scripts/kallsyms.c) if clang lto is enabled.
* To ensure correct bisection in kallsyms_lookup_names(), do
* cleanup_symbol_name(namebuf) before comparing name and namebuf.
*/
cleanup_symbol_name(namebuf);
return strcmp(name, namebuf);
}
static unsigned int get_symbol_seq(int index)
{
unsigned int i, seq = 0;
for (i = 0; i < 3; i++)
seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];
return seq;
}
static int kallsyms_lookup_names(const char *name,
unsigned int *start,
unsigned int *end)
{
int ret;
int low, mid, high;
unsigned int seq, off;
char namebuf[KSYM_NAME_LEN];
low = 0;
high = kallsyms_num_syms - 1;
while (low <= high) {
mid = low + (high - low) / 2;
seq = get_symbol_seq(mid);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
ret = compare_symbol_name(name, namebuf);
if (ret > 0)
low = mid + 1;
else if (ret < 0)
high = mid - 1;
else
break;
}
if (low > high)
return -ESRCH;
low = mid;
while (low) {
seq = get_symbol_seq(low - 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
break;
low--;
}
*start = low;
if (end) {
high = mid;
while (high < kallsyms_num_syms - 1) {
seq = get_symbol_seq(high + 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
if (compare_symbol_name(name, namebuf))
break;
high++;
}
*end = high;
}
return 0;
}
/* Lookup the address for this symbol. Returns 0 if not found. */
unsigned long kallsyms_lookup_name(const char *name)
{
int ret;
unsigned int i;
/* Skip the search for empty string. */
if (!*name)
return 0;
ret = kallsyms_lookup_names(name, &i, NULL);
if (!ret)
return kallsyms_sym_address(get_symbol_seq(i));
return module_kallsyms_lookup_name(name);
}
/*
* Iterate over all symbols in vmlinux. For symbols from modules use
* module_kallsyms_on_each_symbol instead.
*/
int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long),
void *data)
{
char namebuf[KSYM_NAME_LEN];
unsigned long i;
unsigned int off;
int ret;
for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
ret = fn(data, namebuf, kallsyms_sym_address(i));
if (ret != 0)
return ret;
cond_resched();
}
return 0;
}
int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
const char *name, void *data)
{
int ret;
unsigned int i, start, end;
ret = kallsyms_lookup_names(name, &start, &end);
if (ret)
return 0;
for (i = start; !ret && i <= end; i++) {
ret = fn(data, kallsyms_sym_address(get_symbol_seq(i)));
cond_resched();
}
return ret;
}
static unsigned long get_symbol_pos(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset)
{
unsigned long symbol_start = 0, symbol_end = 0;
unsigned long i, low, high, mid;
/* This kernel should never had been booted. */
if (!IS_ENABLED(CONFIG_KALLSYMS_BASE_RELATIVE))
BUG_ON(!kallsyms_addresses);
else
BUG_ON(!kallsyms_offsets);
/* Do a binary search on the sorted kallsyms_addresses array. */
low = 0;
high = kallsyms_num_syms;
while (high - low > 1) {
mid = low + (high - low) / 2;
if (kallsyms_sym_address(mid) <= addr)
low = mid;
else
high = mid;
}
/*
* Search for the first aliased symbol. Aliased
* symbols are symbols with the same address.
*/
while (low && kallsyms_sym_address(low-1) == kallsyms_sym_address(low))
--low;
symbol_start = kallsyms_sym_address(low);
/* Search for next non-aliased symbol. */
for (i = low + 1; i < kallsyms_num_syms; i++) {
if (kallsyms_sym_address(i) > symbol_start) {
symbol_end = kallsyms_sym_address(i);
break;
}
}
/* If we found no next symbol, we use the end of the section. */
if (!symbol_end) {
if (is_kernel_inittext(addr))
symbol_end = (unsigned long)_einittext;
else if (IS_ENABLED(CONFIG_KALLSYMS_ALL))
symbol_end = (unsigned long)_end;
else
symbol_end = (unsigned long)_etext;
}
if (symbolsize)
*symbolsize = symbol_end - symbol_start;
if (offset)
*offset = addr - symbol_start;
return low;
}
/*
* Lookup an address but don't bother to find any names.
*/
int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
unsigned long *offset)
{
char namebuf[KSYM_NAME_LEN];
if (is_ksym_addr(addr)) {
get_symbol_pos(addr, symbolsize, offset);
return 1;
}
return !!module_address_lookup(addr, symbolsize, offset, NULL, NULL, namebuf) ||
!!__bpf_address_lookup(addr, symbolsize, offset, namebuf);
}
static const char *kallsyms_lookup_buildid(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset, char **modname,
const unsigned char **modbuildid, char *namebuf)
{
const char *ret;
namebuf[KSYM_NAME_LEN - 1] = 0;
namebuf[0] = 0;
if (is_ksym_addr(addr)) {
unsigned long pos;
pos = get_symbol_pos(addr, symbolsize, offset);
/* Grab name */
kallsyms_expand_symbol(get_symbol_offset(pos),
namebuf, KSYM_NAME_LEN);
if (modname)
*modname = NULL;
if (modbuildid)
*modbuildid = NULL;
ret = namebuf;
goto found;
}
/* See if it's in a module or a BPF JITed image. */
ret = module_address_lookup(addr, symbolsize, offset,
modname, modbuildid, namebuf);
if (!ret)
ret = bpf_address_lookup(addr, symbolsize,
offset, modname, namebuf);
if (!ret)
ret = ftrace_mod_address_lookup(addr, symbolsize,
offset, modname, namebuf);
found:
cleanup_symbol_name(namebuf);
return ret;
}
/*
* Lookup an address
* - modname is set to NULL if it's in the kernel.
* - We guarantee that the returned name is valid until we reschedule even if.
* It resides in a module.
* - We also guarantee that modname will be valid until rescheduled.
*/
const char *kallsyms_lookup(unsigned long addr,
unsigned long *symbolsize,
unsigned long *offset,
char **modname, char *namebuf)
{
return kallsyms_lookup_buildid(addr, symbolsize, offset, modname,
NULL, namebuf);
}
int lookup_symbol_name(unsigned long addr, char *symname)
{
int res;
symname[0] = '\0';
symname[KSYM_NAME_LEN - 1] = '\0';
if (is_ksym_addr(addr)) {
unsigned long pos;
pos = get_symbol_pos(addr, NULL, NULL);
/* Grab name */
kallsyms_expand_symbol(get_symbol_offset(pos),
symname, KSYM_NAME_LEN);
goto found;
}
/* See if it's in a module. */
res = lookup_module_symbol_name(addr, symname);
if (res)
return res;
found:
cleanup_symbol_name(symname);
return 0;
}
/* Look up a kernel symbol and return it in a text buffer. */
static int __sprint_symbol(char *buffer, unsigned long address,
int symbol_offset, int add_offset, int add_buildid)
{
char *modname;
const unsigned char *buildid;
const char *name;
unsigned long offset, size;
int len;
address += symbol_offset;
name = kallsyms_lookup_buildid(address, &size, &offset, &modname, &buildid,
buffer);
if (!name)
return sprintf(buffer, "0x%lx", address - symbol_offset);
if (name != buffer)
strcpy(buffer, name);
len = strlen(buffer);
offset -= symbol_offset;
if (add_offset)
len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
if (modname) {
len += sprintf(buffer + len, " [%s", modname);
#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
if (add_buildid && buildid) {
/* build ID should match length of sprintf */
#if IS_ENABLED(CONFIG_MODULES)
static_assert(sizeof(typeof_member(struct module, build_id)) == 20);
#endif
len += sprintf(buffer + len, " %20phN", buildid);
}
#endif
len += sprintf(buffer + len, "]");
}
return len;
}
/**
* sprint_symbol - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name,
* offset, size and module name to @buffer if possible. If no symbol was found,
* just saves its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 1, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol);
/**
* sprint_symbol_build_id - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name,
* offset, size, module name and module build ID to @buffer if possible. If no
* symbol was found, just saves its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol_build_id(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 1, 1);
}
EXPORT_SYMBOL_GPL(sprint_symbol_build_id);
/**
* sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function looks up a kernel symbol with @address and stores its name
* and module name to @buffer if possible. If no symbol was found, just saves
* its @address as is.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_symbol_no_offset(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, 0, 0, 0);
}
EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
/**
* sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function is for stack backtrace and does the same thing as
* sprint_symbol() but with modified/decreased @address. If there is a
* tail-call to the function marked "noreturn", gcc optimized out code after
* the call so that the stack-saved return address could point outside of the
* caller. This function ensures that kallsyms will find the original caller
* by decreasing @address.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_backtrace(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, -1, 1, 0);
}
/**
* sprint_backtrace_build_id - Look up a backtrace symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
*
* This function is for stack backtrace and does the same thing as
* sprint_symbol() but with modified/decreased @address. If there is a
* tail-call to the function marked "noreturn", gcc optimized out code after
* the call so that the stack-saved return address could point outside of the
* caller. This function ensures that kallsyms will find the original caller
* by decreasing @address. This function also appends the module build ID to
* the @buffer if @address is within a kernel module.
*
* This function returns the number of bytes stored in @buffer.
*/
int sprint_backtrace_build_id(char *buffer, unsigned long address)
{
return __sprint_symbol(buffer, address, -1, 1, 1);
}
/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
struct kallsym_iter {
loff_t pos;
loff_t pos_mod_end;
loff_t pos_ftrace_mod_end;
loff_t pos_bpf_end;
unsigned long value;
unsigned int nameoff; /* If iterating in core kernel symbols. */
char type;
char name[KSYM_NAME_LEN];
char module_name[MODULE_NAME_LEN];
int exported;
int show_value;
};
static int get_ksymbol_mod(struct kallsym_iter *iter)
{
int ret = module_get_kallsym(iter->pos - kallsyms_num_syms,
&iter->value, &iter->type,
iter->name, iter->module_name,
&iter->exported);
if (ret < 0) {
iter->pos_mod_end = iter->pos;
return 0;
}
return 1;
}
/*
* ftrace_mod_get_kallsym() may also get symbols for pages allocated for ftrace
* purposes. In that case "__builtin__ftrace" is used as a module name, even
* though "__builtin__ftrace" is not a module.
*/
static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter)
{
int ret = ftrace_mod_get_kallsym(iter->pos - iter->pos_mod_end,
&iter->value, &iter->type,
iter->name, iter->module_name,
&iter->exported);
if (ret < 0) {
iter->pos_ftrace_mod_end = iter->pos;
return 0;
}
return 1;
}
static int get_ksymbol_bpf(struct kallsym_iter *iter)
{
int ret;
strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);
iter->exported = 0;
ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
&iter->value, &iter->type,
iter->name);
if (ret < 0) {
iter->pos_bpf_end = iter->pos;
return 0;
}
return 1;
}
/*
* This uses "__builtin__kprobes" as a module name for symbols for pages
* allocated for kprobes' purposes, even though "__builtin__kprobes" is not a
* module.
*/
static int get_ksymbol_kprobe(struct kallsym_iter *iter)
{
strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
iter->exported = 0;
return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
&iter->value, &iter->type,
iter->name) < 0 ? 0 : 1;
}
/* Returns space to next name. */
static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
{
unsigned off = iter->nameoff;
iter->module_name[0] = '\0';
iter->value = kallsyms_sym_address(iter->pos);
iter->type = kallsyms_get_symbol_type(off);
off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name));
return off - iter->nameoff;
}
static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
{
iter->name[0] = '\0';
iter->nameoff = get_symbol_offset(new_pos);
iter->pos = new_pos;
if (new_pos == 0) {
iter->pos_mod_end = 0;
iter->pos_ftrace_mod_end = 0;
iter->pos_bpf_end = 0;
}
}
/*
* The end position (last + 1) of each additional kallsyms section is recorded
* in iter->pos_..._end as each section is added, and so can be used to
* determine which get_ksymbol_...() function to call next.
*/
static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
{
iter->pos = pos;
if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
get_ksymbol_mod(iter))
return 1;
if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
get_ksymbol_ftrace_mod(iter))
return 1;
if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) &&
get_ksymbol_bpf(iter))
return 1;
return get_ksymbol_kprobe(iter);
}
/* Returns false if pos at or past end of file. */
static int update_iter(struct kallsym_iter *iter, loff_t pos)
{
/* Module symbols can be accessed randomly. */
if (pos >= kallsyms_num_syms)
return update_iter_mod(iter, pos);
/* If we're not on the desired position, reset to new position. */
if (pos != iter->pos)
reset_iter(iter, pos);
iter->nameoff += get_ksymbol_core(iter);
iter->pos++;
return 1;
}
static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
(*pos)++;
if (!update_iter(m->private, *pos))
return NULL;
return p;
}
static void *s_start(struct seq_file *m, loff_t *pos)
{
if (!update_iter(m->private, *pos))
return NULL;
return m->private;
}
static void s_stop(struct seq_file *m, void *p)
{
}
static int s_show(struct seq_file *m, void *p)
{
void *value;
struct kallsym_iter *iter = m->private;
/* Some debugging symbols have no name. Ignore them. */
if (!iter->name[0])
return 0;
value = iter->show_value ? (void *)iter->value : NULL;
if (iter->module_name[0]) {
char type;
/*
* Label it "global" if it is exported,
* "local" if not exported.
*/
type = iter->exported ? toupper(iter->type) :
tolower(iter->type);
seq_printf(m, "%px %c %s\t[%s]\n", value,
type, iter->name, iter->module_name);
} else
seq_printf(m, "%px %c %s\n", value,
iter->type, iter->name);
return 0;
}
static const struct seq_operations kallsyms_op = {
.start = s_start,
.next = s_next,
.stop = s_stop,
.show = s_show
};
#ifdef CONFIG_BPF_SYSCALL
struct bpf_iter__ksym {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct kallsym_iter *, ksym);
};
static int ksym_prog_seq_show(struct seq_file *m, bool in_stop)
{
struct bpf_iter__ksym ctx;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
meta.seq = m;
prog = bpf_iter_get_info(&meta, in_stop);
if (!prog)
return 0;
ctx.meta = &meta;
ctx.ksym = m ? m->private : NULL;
return bpf_iter_run_prog(prog, &ctx);
}
static int bpf_iter_ksym_seq_show(struct seq_file *m, void *p)
{
return ksym_prog_seq_show(m, false);
}
static void bpf_iter_ksym_seq_stop(struct seq_file *m, void *p)
{
if (!p)
(void) ksym_prog_seq_show(m, true);
else
s_stop(m, p);
}
static const struct seq_operations bpf_iter_ksym_ops = {
.start = s_start,
.next = s_next,
.stop = bpf_iter_ksym_seq_stop,
.show = bpf_iter_ksym_seq_show,
};
static int bpf_iter_ksym_init(void *priv_data, struct bpf_iter_aux_info *aux)
{
struct kallsym_iter *iter = priv_data;
reset_iter(iter, 0);
/* cache here as in kallsyms_open() case; use current process
* credentials to tell BPF iterators if values should be shown.
*/
iter->show_value = kallsyms_show_value(current_cred());
return 0;
}
DEFINE_BPF_ITER_FUNC(ksym, struct bpf_iter_meta *meta, struct kallsym_iter *ksym)
static const struct bpf_iter_seq_info ksym_iter_seq_info = {
.seq_ops = &bpf_iter_ksym_ops,
.init_seq_private = bpf_iter_ksym_init,
.fini_seq_private = NULL,
.seq_priv_size = sizeof(struct kallsym_iter),
};
static struct bpf_iter_reg ksym_iter_reg_info = {
.target = "ksym",
.feature = BPF_ITER_RESCHED,
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__ksym, ksym),
PTR_TO_BTF_ID_OR_NULL },
},
.seq_info = &ksym_iter_seq_info,
};
BTF_ID_LIST(btf_ksym_iter_id)
BTF_ID(struct, kallsym_iter)
static int __init bpf_ksym_iter_register(void)
{
ksym_iter_reg_info.ctx_arg_info[0].btf_id = *btf_ksym_iter_id;
return bpf_iter_reg_target(&ksym_iter_reg_info);
}
late_initcall(bpf_ksym_iter_register);
#endif /* CONFIG_BPF_SYSCALL */
static int kallsyms_open(struct inode *inode, struct file *file)
{
/*
* We keep iterator in m->private, since normal case is to
* s_start from where we left off, so we avoid doing
* using get_symbol_offset for every symbol.
*/
struct kallsym_iter *iter;
iter = __seq_open_private(file, &kallsyms_op, sizeof(*iter));
if (!iter)
return -ENOMEM;
reset_iter(iter, 0);
/*
* Instead of checking this on every s_show() call, cache
* the result here at open time.
*/
iter->show_value = kallsyms_show_value(file->f_cred);
return 0;
}
#ifdef CONFIG_KGDB_KDB
const char *kdb_walk_kallsyms(loff_t *pos)
{
static struct kallsym_iter kdb_walk_kallsyms_iter;
if (*pos == 0) {
memset(&kdb_walk_kallsyms_iter, 0,
sizeof(kdb_walk_kallsyms_iter));
reset_iter(&kdb_walk_kallsyms_iter, 0);
}
while (1) {
if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
return NULL;
++*pos;
/* Some debugging symbols have no name. Ignore them. */
if (kdb_walk_kallsyms_iter.name[0])
return kdb_walk_kallsyms_iter.name;
}
}
#endif /* CONFIG_KGDB_KDB */
static const struct proc_ops kallsyms_proc_ops = {
.proc_open = kallsyms_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = seq_release_private,
};
static int __init kallsyms_init(void)
{
proc_create("kallsyms", 0444, NULL, &kallsyms_proc_ops);
return 0;
}
device_initcall(kallsyms_init);
| linux-master | kernel/kallsyms.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Detect hard lockups on a system using perf
*
* started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
*
* Note: Most of this code is borrowed heavily from the original softlockup
* detector, so thanks to Ingo for the initial implementation.
* Some chunks also taken from the old x86-specific nmi watchdog code, thanks
* to those contributors as well.
*/
#define pr_fmt(fmt) "NMI watchdog: " fmt
#include <linux/nmi.h>
#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/sched/debug.h>
#include <asm/irq_regs.h>
#include <linux/perf_event.h>
static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
static DEFINE_PER_CPU(struct perf_event *, dead_event);
static struct cpumask dead_events_mask;
static atomic_t watchdog_cpus = ATOMIC_INIT(0);
#ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP
static DEFINE_PER_CPU(ktime_t, last_timestamp);
static DEFINE_PER_CPU(unsigned int, nmi_rearmed);
static ktime_t watchdog_hrtimer_sample_threshold __read_mostly;
void watchdog_update_hrtimer_threshold(u64 period)
{
/*
* The hrtimer runs with a period of (watchdog_threshold * 2) / 5
*
* So it runs effectively with 2.5 times the rate of the NMI
* watchdog. That means the hrtimer should fire 2-3 times before
* the NMI watchdog expires. The NMI watchdog on x86 is based on
* unhalted CPU cycles, so if Turbo-Mode is enabled the CPU cycles
* might run way faster than expected and the NMI fires in a
* smaller period than the one deduced from the nominal CPU
* frequency. Depending on the Turbo-Mode factor this might be fast
* enough to get the NMI period smaller than the hrtimer watchdog
* period and trigger false positives.
*
* The sample threshold is used to check in the NMI handler whether
* the minimum time between two NMI samples has elapsed. That
* prevents false positives.
*
* Set this to 4/5 of the actual watchdog threshold period so the
* hrtimer is guaranteed to fire at least once within the real
* watchdog threshold.
*/
watchdog_hrtimer_sample_threshold = period * 2;
}
static bool watchdog_check_timestamp(void)
{
ktime_t delta, now = ktime_get_mono_fast_ns();
delta = now - __this_cpu_read(last_timestamp);
if (delta < watchdog_hrtimer_sample_threshold) {
/*
* If ktime is jiffies based, a stalled timer would prevent
* jiffies from being incremented and the filter would look
* at a stale timestamp and never trigger.
*/
if (__this_cpu_inc_return(nmi_rearmed) < 10)
return false;
}
__this_cpu_write(nmi_rearmed, 0);
__this_cpu_write(last_timestamp, now);
return true;
}
#else
static inline bool watchdog_check_timestamp(void)
{
return true;
}
#endif
static struct perf_event_attr wd_hw_attr = {
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
.size = sizeof(struct perf_event_attr),
.pinned = 1,
.disabled = 1,
};
/* Callback function for perf event subsystem */
static void watchdog_overflow_callback(struct perf_event *event,
struct perf_sample_data *data,
struct pt_regs *regs)
{
/* Ensure the watchdog never gets throttled */
event->hw.interrupts = 0;
if (!watchdog_check_timestamp())
return;
watchdog_hardlockup_check(smp_processor_id(), regs);
}
static int hardlockup_detector_event_create(void)
{
unsigned int cpu;
struct perf_event_attr *wd_attr;
struct perf_event *evt;
/*
* Preemption is not disabled because memory will be allocated.
* Ensure CPU-locality by calling this in per-CPU kthread.
*/
WARN_ON(!is_percpu_thread());
cpu = raw_smp_processor_id();
wd_attr = &wd_hw_attr;
wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
/* Try to register using hardware perf events */
evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
watchdog_overflow_callback, NULL);
if (IS_ERR(evt)) {
pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
PTR_ERR(evt));
return PTR_ERR(evt);
}
this_cpu_write(watchdog_ev, evt);
return 0;
}
/**
* watchdog_hardlockup_enable - Enable the local event
*
* @cpu: The CPU to enable hard lockup on.
*/
void watchdog_hardlockup_enable(unsigned int cpu)
{
WARN_ON_ONCE(cpu != smp_processor_id());
if (hardlockup_detector_event_create())
return;
/* use original value for check */
if (!atomic_fetch_inc(&watchdog_cpus))
pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");
perf_event_enable(this_cpu_read(watchdog_ev));
}
/**
* watchdog_hardlockup_disable - Disable the local event
*
* @cpu: The CPU to enable hard lockup on.
*/
void watchdog_hardlockup_disable(unsigned int cpu)
{
struct perf_event *event = this_cpu_read(watchdog_ev);
WARN_ON_ONCE(cpu != smp_processor_id());
if (event) {
perf_event_disable(event);
this_cpu_write(watchdog_ev, NULL);
this_cpu_write(dead_event, event);
cpumask_set_cpu(smp_processor_id(), &dead_events_mask);
atomic_dec(&watchdog_cpus);
}
}
/**
* hardlockup_detector_perf_cleanup - Cleanup disabled events and destroy them
*
* Called from lockup_detector_cleanup(). Serialized by the caller.
*/
void hardlockup_detector_perf_cleanup(void)
{
int cpu;
for_each_cpu(cpu, &dead_events_mask) {
struct perf_event *event = per_cpu(dead_event, cpu);
/*
* Required because for_each_cpu() reports unconditionally
* CPU0 as set on UP kernels. Sigh.
*/
if (event)
perf_event_release_kernel(event);
per_cpu(dead_event, cpu) = NULL;
}
cpumask_clear(&dead_events_mask);
}
/**
* hardlockup_detector_perf_stop - Globally stop watchdog events
*
* Special interface for x86 to handle the perf HT bug.
*/
void __init hardlockup_detector_perf_stop(void)
{
int cpu;
lockdep_assert_cpus_held();
for_each_online_cpu(cpu) {
struct perf_event *event = per_cpu(watchdog_ev, cpu);
if (event)
perf_event_disable(event);
}
}
/**
* hardlockup_detector_perf_restart - Globally restart watchdog events
*
* Special interface for x86 to handle the perf HT bug.
*/
void __init hardlockup_detector_perf_restart(void)
{
int cpu;
lockdep_assert_cpus_held();
if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED))
return;
for_each_online_cpu(cpu) {
struct perf_event *event = per_cpu(watchdog_ev, cpu);
if (event)
perf_event_enable(event);
}
}
bool __weak __init arch_perf_nmi_is_available(void)
{
return true;
}
/**
* watchdog_hardlockup_probe - Probe whether NMI event is available at all
*/
int __init watchdog_hardlockup_probe(void)
{
int ret;
if (!arch_perf_nmi_is_available())
return -ENODEV;
ret = hardlockup_detector_event_create();
if (ret) {
pr_info("Perf NMI watchdog permanently disabled\n");
} else {
perf_event_release_kernel(this_cpu_read(watchdog_ev));
this_cpu_write(watchdog_ev, NULL);
}
return ret;
}
| linux-master | kernel/watchdog_perf.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Kernel Probes (KProbes)
*
* Copyright (C) IBM Corporation, 2002, 2004
*
* 2002-Oct Created by Vamsi Krishna S <[email protected]> Kernel
* Probes initial implementation (includes suggestions from
* Rusty Russell).
* 2004-Aug Updated by Prasanna S Panchamukhi <[email protected]> with
* hlists and exceptions notifier as suggested by Andi Kleen.
* 2004-July Suparna Bhattacharya <[email protected]> added jumper probes
* interface to access function arguments.
* 2004-Sep Prasanna S Panchamukhi <[email protected]> Changed Kprobes
* exceptions notifier to be first on the priority list.
* 2005-May Hien Nguyen <[email protected]>, Jim Keniston
* <[email protected]> and Prasanna S Panchamukhi
* <[email protected]> added function-return probes.
*/
#define pr_fmt(fmt) "kprobes: " fmt
#include <linux/kprobes.h>
#include <linux/hash.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/stddef.h>
#include <linux/export.h>
#include <linux/moduleloader.h>
#include <linux/kallsyms.h>
#include <linux/freezer.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/sysctl.h>
#include <linux/kdebug.h>
#include <linux/memory.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/jump_label.h>
#include <linux/static_call.h>
#include <linux/perf_event.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
#include <asm/errno.h>
#include <linux/uaccess.h>
#define KPROBE_HASH_BITS 6
#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
#if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL)
#define kprobe_sysctls_init() do { } while (0)
#endif
static int kprobes_initialized;
/* kprobe_table can be accessed by
* - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held.
* Or
* - RCU hlist traversal under disabling preempt (breakpoint handlers)
*/
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
/* NOTE: change this value only with 'kprobe_mutex' held */
static bool kprobes_all_disarmed;
/* This protects 'kprobe_table' and 'optimizing_list' */
static DEFINE_MUTEX(kprobe_mutex);
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);
kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
unsigned int __unused)
{
return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
}
/*
* Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where
* kprobes can not probe.
*/
static LIST_HEAD(kprobe_blacklist);
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* 'kprobe::ainsn.insn' points to the copy of the instruction to be
* single-stepped. x86_64, POWER4 and above have no-exec support and
* stepping on the instruction on a vmalloced/kmalloced/data page
* is a recipe for disaster
*/
struct kprobe_insn_page {
struct list_head list;
kprobe_opcode_t *insns; /* Page of instruction slots */
struct kprobe_insn_cache *cache;
int nused;
int ngarbage;
char slot_used[];
};
#define KPROBE_INSN_PAGE_SIZE(slots) \
(offsetof(struct kprobe_insn_page, slot_used) + \
(sizeof(char) * (slots)))
static int slots_per_page(struct kprobe_insn_cache *c)
{
return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
}
enum kprobe_slot_state {
SLOT_CLEAN = 0,
SLOT_DIRTY = 1,
SLOT_USED = 2,
};
void __weak *alloc_insn_page(void)
{
/*
* Use module_alloc() so this page is within +/- 2GB of where the
* kernel image and loaded module images reside. This is required
* for most of the architectures.
* (e.g. x86-64 needs this to handle the %rip-relative fixups.)
*/
return module_alloc(PAGE_SIZE);
}
static void free_insn_page(void *page)
{
module_memfree(page);
}
struct kprobe_insn_cache kprobe_insn_slots = {
.mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
.alloc = alloc_insn_page,
.free = free_insn_page,
.sym = KPROBE_INSN_PAGE_SYM,
.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
.insn_size = MAX_INSN_SIZE,
.nr_garbage = 0,
};
static int collect_garbage_slots(struct kprobe_insn_cache *c);
/**
* __get_insn_slot() - Find a slot on an executable page for an instruction.
* We allocate an executable page if there's no room on existing ones.
*/
kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
{
struct kprobe_insn_page *kip;
kprobe_opcode_t *slot = NULL;
/* Since the slot array is not protected by rcu, we need a mutex */
mutex_lock(&c->mutex);
retry:
rcu_read_lock();
list_for_each_entry_rcu(kip, &c->pages, list) {
if (kip->nused < slots_per_page(c)) {
int i;
for (i = 0; i < slots_per_page(c); i++) {
if (kip->slot_used[i] == SLOT_CLEAN) {
kip->slot_used[i] = SLOT_USED;
kip->nused++;
slot = kip->insns + (i * c->insn_size);
rcu_read_unlock();
goto out;
}
}
/* kip->nused is broken. Fix it. */
kip->nused = slots_per_page(c);
WARN_ON(1);
}
}
rcu_read_unlock();
/* If there are any garbage slots, collect it and try again. */
if (c->nr_garbage && collect_garbage_slots(c) == 0)
goto retry;
/* All out of space. Need to allocate a new page. */
kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
if (!kip)
goto out;
kip->insns = c->alloc();
if (!kip->insns) {
kfree(kip);
goto out;
}
INIT_LIST_HEAD(&kip->list);
memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
kip->slot_used[0] = SLOT_USED;
kip->nused = 1;
kip->ngarbage = 0;
kip->cache = c;
list_add_rcu(&kip->list, &c->pages);
slot = kip->insns;
/* Record the perf ksymbol register event after adding the page */
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns,
PAGE_SIZE, false, c->sym);
out:
mutex_unlock(&c->mutex);
return slot;
}
/* Return true if all garbages are collected, otherwise false. */
static bool collect_one_slot(struct kprobe_insn_page *kip, int idx)
{
kip->slot_used[idx] = SLOT_CLEAN;
kip->nused--;
if (kip->nused == 0) {
/*
* Page is no longer in use. Free it unless
* it's the last one. We keep the last one
* so as not to have to set it up again the
* next time somebody inserts a probe.
*/
if (!list_is_singular(&kip->list)) {
/*
* Record perf ksymbol unregister event before removing
* the page.
*/
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
(unsigned long)kip->insns, PAGE_SIZE, true,
kip->cache->sym);
list_del_rcu(&kip->list);
synchronize_rcu();
kip->cache->free(kip->insns);
kfree(kip);
}
return true;
}
return false;
}
static int collect_garbage_slots(struct kprobe_insn_cache *c)
{
struct kprobe_insn_page *kip, *next;
/* Ensure no-one is interrupted on the garbages */
synchronize_rcu();
list_for_each_entry_safe(kip, next, &c->pages, list) {
int i;
if (kip->ngarbage == 0)
continue;
kip->ngarbage = 0; /* we will collect all garbages */
for (i = 0; i < slots_per_page(c); i++) {
if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, i))
break;
}
}
c->nr_garbage = 0;
return 0;
}
void __free_insn_slot(struct kprobe_insn_cache *c,
kprobe_opcode_t *slot, int dirty)
{
struct kprobe_insn_page *kip;
long idx;
mutex_lock(&c->mutex);
rcu_read_lock();
list_for_each_entry_rcu(kip, &c->pages, list) {
idx = ((long)slot - (long)kip->insns) /
(c->insn_size * sizeof(kprobe_opcode_t));
if (idx >= 0 && idx < slots_per_page(c))
goto out;
}
/* Could not find this slot. */
WARN_ON(1);
kip = NULL;
out:
rcu_read_unlock();
/* Mark and sweep: this may sleep */
if (kip) {
/* Check double free */
WARN_ON(kip->slot_used[idx] != SLOT_USED);
if (dirty) {
kip->slot_used[idx] = SLOT_DIRTY;
kip->ngarbage++;
if (++c->nr_garbage > slots_per_page(c))
collect_garbage_slots(c);
} else {
collect_one_slot(kip, idx);
}
}
mutex_unlock(&c->mutex);
}
/*
* Check given address is on the page of kprobe instruction slots.
* This will be used for checking whether the address on a stack
* is on a text area or not.
*/
bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
{
struct kprobe_insn_page *kip;
bool ret = false;
rcu_read_lock();
list_for_each_entry_rcu(kip, &c->pages, list) {
if (addr >= (unsigned long)kip->insns &&
addr < (unsigned long)kip->insns + PAGE_SIZE) {
ret = true;
break;
}
}
rcu_read_unlock();
return ret;
}
int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
unsigned long *value, char *type, char *sym)
{
struct kprobe_insn_page *kip;
int ret = -ERANGE;
rcu_read_lock();
list_for_each_entry_rcu(kip, &c->pages, list) {
if ((*symnum)--)
continue;
strscpy(sym, c->sym, KSYM_NAME_LEN);
*type = 't';
*value = (unsigned long)kip->insns;
ret = 0;
break;
}
rcu_read_unlock();
return ret;
}
#ifdef CONFIG_OPTPROBES
void __weak *alloc_optinsn_page(void)
{
return alloc_insn_page();
}
void __weak free_optinsn_page(void *page)
{
free_insn_page(page);
}
/* For optimized_kprobe buffer */
struct kprobe_insn_cache kprobe_optinsn_slots = {
.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
.alloc = alloc_optinsn_page,
.free = free_optinsn_page,
.sym = KPROBE_OPTINSN_PAGE_SYM,
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
/* .insn_size is initialized later */
.nr_garbage = 0,
};
#endif
#endif
/* We have preemption disabled.. so it is safe to use __ versions */
static inline void set_kprobe_instance(struct kprobe *kp)
{
__this_cpu_write(kprobe_instance, kp);
}
static inline void reset_kprobe_instance(void)
{
__this_cpu_write(kprobe_instance, NULL);
}
/*
* This routine is called either:
* - under the 'kprobe_mutex' - during kprobe_[un]register().
* OR
* - with preemption disabled - from architecture specific code.
*/
struct kprobe *get_kprobe(void *addr)
{
struct hlist_head *head;
struct kprobe *p;
head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
hlist_for_each_entry_rcu(p, head, hlist,
lockdep_is_held(&kprobe_mutex)) {
if (p->addr == addr)
return p;
}
return NULL;
}
NOKPROBE_SYMBOL(get_kprobe);
static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
/* Return true if 'p' is an aggregator */
static inline bool kprobe_aggrprobe(struct kprobe *p)
{
return p->pre_handler == aggr_pre_handler;
}
/* Return true if 'p' is unused */
static inline bool kprobe_unused(struct kprobe *p)
{
return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
list_empty(&p->list);
}
/* Keep all fields in the kprobe consistent. */
static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
{
memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
}
#ifdef CONFIG_OPTPROBES
/* NOTE: This is protected by 'kprobe_mutex'. */
static bool kprobes_allow_optimization;
/*
* Call all 'kprobe::pre_handler' on the list, but ignores its return value.
* This must be called from arch-dep optimized caller.
*/
void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
set_kprobe_instance(kp);
kp->pre_handler(kp, regs);
}
reset_kprobe_instance();
}
}
NOKPROBE_SYMBOL(opt_pre_handler);
/* Free optimized instructions and optimized_kprobe */
static void free_aggr_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
arch_remove_optimized_kprobe(op);
arch_remove_kprobe(p);
kfree(op);
}
/* Return true if the kprobe is ready for optimization. */
static inline int kprobe_optready(struct kprobe *p)
{
struct optimized_kprobe *op;
if (kprobe_aggrprobe(p)) {
op = container_of(p, struct optimized_kprobe, kp);
return arch_prepared_optinsn(&op->optinsn);
}
return 0;
}
/* Return true if the kprobe is disarmed. Note: p must be on hash list */
bool kprobe_disarmed(struct kprobe *p)
{
struct optimized_kprobe *op;
/* If kprobe is not aggr/opt probe, just return kprobe is disabled */
if (!kprobe_aggrprobe(p))
return kprobe_disabled(p);
op = container_of(p, struct optimized_kprobe, kp);
return kprobe_disabled(p) && list_empty(&op->list);
}
/* Return true if the probe is queued on (un)optimizing lists */
static bool kprobe_queued(struct kprobe *p)
{
struct optimized_kprobe *op;
if (kprobe_aggrprobe(p)) {
op = container_of(p, struct optimized_kprobe, kp);
if (!list_empty(&op->list))
return true;
}
return false;
}
/*
* Return an optimized kprobe whose optimizing code replaces
* instructions including 'addr' (exclude breakpoint).
*/
static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr)
{
int i;
struct kprobe *p = NULL;
struct optimized_kprobe *op;
/* Don't check i == 0, since that is a breakpoint case. */
for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++)
p = get_kprobe(addr - i);
if (p && kprobe_optready(p)) {
op = container_of(p, struct optimized_kprobe, kp);
if (arch_within_optimized_kprobe(op, addr))
return p;
}
return NULL;
}
/* Optimization staging list, protected by 'kprobe_mutex' */
static LIST_HEAD(optimizing_list);
static LIST_HEAD(unoptimizing_list);
static LIST_HEAD(freeing_list);
static void kprobe_optimizer(struct work_struct *work);
static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
#define OPTIMIZE_DELAY 5
/*
* Optimize (replace a breakpoint with a jump) kprobes listed on
* 'optimizing_list'.
*/
static void do_optimize_kprobes(void)
{
lockdep_assert_held(&text_mutex);
/*
* The optimization/unoptimization refers 'online_cpus' via
* stop_machine() and cpu-hotplug modifies the 'online_cpus'.
* And same time, 'text_mutex' will be held in cpu-hotplug and here.
* This combination can cause a deadlock (cpu-hotplug tries to lock
* 'text_mutex' but stop_machine() can not be done because
* the 'online_cpus' has been changed)
* To avoid this deadlock, caller must have locked cpu-hotplug
* for preventing cpu-hotplug outside of 'text_mutex' locking.
*/
lockdep_assert_cpus_held();
/* Optimization never be done when disarmed */
if (kprobes_all_disarmed || !kprobes_allow_optimization ||
list_empty(&optimizing_list))
return;
arch_optimize_kprobes(&optimizing_list);
}
/*
* Unoptimize (replace a jump with a breakpoint and remove the breakpoint
* if need) kprobes listed on 'unoptimizing_list'.
*/
static void do_unoptimize_kprobes(void)
{
struct optimized_kprobe *op, *tmp;
lockdep_assert_held(&text_mutex);
/* See comment in do_optimize_kprobes() */
lockdep_assert_cpus_held();
if (!list_empty(&unoptimizing_list))
arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list);
/* Loop on 'freeing_list' for disarming and removing from kprobe hash list */
list_for_each_entry_safe(op, tmp, &freeing_list, list) {
/* Switching from detour code to origin */
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
/* Disarm probes if marked disabled and not gone */
if (kprobe_disabled(&op->kp) && !kprobe_gone(&op->kp))
arch_disarm_kprobe(&op->kp);
if (kprobe_unused(&op->kp)) {
/*
* Remove unused probes from hash list. After waiting
* for synchronization, these probes are reclaimed.
* (reclaiming is done by do_free_cleaned_kprobes().)
*/
hlist_del_rcu(&op->kp.hlist);
} else
list_del_init(&op->list);
}
}
/* Reclaim all kprobes on the 'freeing_list' */
static void do_free_cleaned_kprobes(void)
{
struct optimized_kprobe *op, *tmp;
list_for_each_entry_safe(op, tmp, &freeing_list, list) {
list_del_init(&op->list);
if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
/*
* This must not happen, but if there is a kprobe
* still in use, keep it on kprobes hash list.
*/
continue;
}
free_aggr_kprobe(&op->kp);
}
}
/* Start optimizer after OPTIMIZE_DELAY passed */
static void kick_kprobe_optimizer(void)
{
schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
}
/* Kprobe jump optimizer */
static void kprobe_optimizer(struct work_struct *work)
{
mutex_lock(&kprobe_mutex);
cpus_read_lock();
mutex_lock(&text_mutex);
/*
* Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
* kprobes before waiting for quiesence period.
*/
do_unoptimize_kprobes();
/*
* Step 2: Wait for quiesence period to ensure all potentially
* preempted tasks to have normally scheduled. Because optprobe
* may modify multiple instructions, there is a chance that Nth
* instruction is preempted. In that case, such tasks can return
* to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
* Note that on non-preemptive kernel, this is transparently converted
* to synchronoze_sched() to wait for all interrupts to have completed.
*/
synchronize_rcu_tasks();
/* Step 3: Optimize kprobes after quiesence period */
do_optimize_kprobes();
/* Step 4: Free cleaned kprobes after quiesence period */
do_free_cleaned_kprobes();
mutex_unlock(&text_mutex);
cpus_read_unlock();
/* Step 5: Kick optimizer again if needed */
if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
kick_kprobe_optimizer();
mutex_unlock(&kprobe_mutex);
}
/* Wait for completing optimization and unoptimization */
void wait_for_kprobe_optimizer(void)
{
mutex_lock(&kprobe_mutex);
while (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) {
mutex_unlock(&kprobe_mutex);
/* This will also make 'optimizing_work' execute immmediately */
flush_delayed_work(&optimizing_work);
/* 'optimizing_work' might not have been queued yet, relax */
cpu_relax();
mutex_lock(&kprobe_mutex);
}
mutex_unlock(&kprobe_mutex);
}
bool optprobe_queued_unopt(struct optimized_kprobe *op)
{
struct optimized_kprobe *_op;
list_for_each_entry(_op, &unoptimizing_list, list) {
if (op == _op)
return true;
}
return false;
}
/* Optimize kprobe if p is ready to be optimized */
static void optimize_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
/* Check if the kprobe is disabled or not ready for optimization. */
if (!kprobe_optready(p) || !kprobes_allow_optimization ||
(kprobe_disabled(p) || kprobes_all_disarmed))
return;
/* kprobes with 'post_handler' can not be optimized */
if (p->post_handler)
return;
op = container_of(p, struct optimized_kprobe, kp);
/* Check there is no other kprobes at the optimized instructions */
if (arch_check_optimized_kprobe(op) < 0)
return;
/* Check if it is already optimized. */
if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) {
if (optprobe_queued_unopt(op)) {
/* This is under unoptimizing. Just dequeue the probe */
list_del_init(&op->list);
}
return;
}
op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
/*
* On the 'unoptimizing_list' and 'optimizing_list',
* 'op' must have OPTIMIZED flag
*/
if (WARN_ON_ONCE(!list_empty(&op->list)))
return;
list_add(&op->list, &optimizing_list);
kick_kprobe_optimizer();
}
/* Short cut to direct unoptimizing */
static void force_unoptimize_kprobe(struct optimized_kprobe *op)
{
lockdep_assert_cpus_held();
arch_unoptimize_kprobe(op);
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
}
/* Unoptimize a kprobe if p is optimized */
static void unoptimize_kprobe(struct kprobe *p, bool force)
{
struct optimized_kprobe *op;
if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
return; /* This is not an optprobe nor optimized */
op = container_of(p, struct optimized_kprobe, kp);
if (!kprobe_optimized(p))
return;
if (!list_empty(&op->list)) {
if (optprobe_queued_unopt(op)) {
/* Queued in unoptimizing queue */
if (force) {
/*
* Forcibly unoptimize the kprobe here, and queue it
* in the freeing list for release afterwards.
*/
force_unoptimize_kprobe(op);
list_move(&op->list, &freeing_list);
}
} else {
/* Dequeue from the optimizing queue */
list_del_init(&op->list);
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
}
return;
}
/* Optimized kprobe case */
if (force) {
/* Forcibly update the code: this is a special case */
force_unoptimize_kprobe(op);
} else {
list_add(&op->list, &unoptimizing_list);
kick_kprobe_optimizer();
}
}
/* Cancel unoptimizing for reusing */
static int reuse_unused_kprobe(struct kprobe *ap)
{
struct optimized_kprobe *op;
/*
* Unused kprobe MUST be on the way of delayed unoptimizing (means
* there is still a relative jump) and disabled.
*/
op = container_of(ap, struct optimized_kprobe, kp);
WARN_ON_ONCE(list_empty(&op->list));
/* Enable the probe again */
ap->flags &= ~KPROBE_FLAG_DISABLED;
/* Optimize it again. (remove from 'op->list') */
if (!kprobe_optready(ap))
return -EINVAL;
optimize_kprobe(ap);
return 0;
}
/* Remove optimized instructions */
static void kill_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
if (!list_empty(&op->list))
/* Dequeue from the (un)optimization queue */
list_del_init(&op->list);
op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
if (kprobe_unused(p)) {
/*
* Unused kprobe is on unoptimizing or freeing list. We move it
* to freeing_list and let the kprobe_optimizer() remove it from
* the kprobe hash list and free it.
*/
if (optprobe_queued_unopt(op))
list_move(&op->list, &freeing_list);
}
/* Don't touch the code, because it is already freed. */
arch_remove_optimized_kprobe(op);
}
static inline
void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
{
if (!kprobe_ftrace(p))
arch_prepare_optimized_kprobe(op, p);
}
/* Try to prepare optimized instructions */
static void prepare_optimized_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = container_of(p, struct optimized_kprobe, kp);
__prepare_optimized_kprobe(op, p);
}
/* Allocate new optimized_kprobe and try to prepare optimized instructions. */
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
struct optimized_kprobe *op;
op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
if (!op)
return NULL;
INIT_LIST_HEAD(&op->list);
op->kp.addr = p->addr;
__prepare_optimized_kprobe(op, p);
return &op->kp;
}
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
/*
* Prepare an optimized_kprobe and optimize it.
* NOTE: 'p' must be a normal registered kprobe.
*/
static void try_to_optimize_kprobe(struct kprobe *p)
{
struct kprobe *ap;
struct optimized_kprobe *op;
/* Impossible to optimize ftrace-based kprobe. */
if (kprobe_ftrace(p))
return;
/* For preparing optimization, jump_label_text_reserved() is called. */
cpus_read_lock();
jump_label_lock();
mutex_lock(&text_mutex);
ap = alloc_aggr_kprobe(p);
if (!ap)
goto out;
op = container_of(ap, struct optimized_kprobe, kp);
if (!arch_prepared_optinsn(&op->optinsn)) {
/* If failed to setup optimizing, fallback to kprobe. */
arch_remove_optimized_kprobe(op);
kfree(op);
goto out;
}
init_aggr_kprobe(ap, p);
optimize_kprobe(ap); /* This just kicks optimizer thread. */
out:
mutex_unlock(&text_mutex);
jump_label_unlock();
cpus_read_unlock();
}
static void optimize_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
unsigned int i;
mutex_lock(&kprobe_mutex);
/* If optimization is already allowed, just return. */
if (kprobes_allow_optimization)
goto out;
cpus_read_lock();
kprobes_allow_optimization = true;
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry(p, head, hlist)
if (!kprobe_disabled(p))
optimize_kprobe(p);
}
cpus_read_unlock();
pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n");
out:
mutex_unlock(&kprobe_mutex);
}
#ifdef CONFIG_SYSCTL
static void unoptimize_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
unsigned int i;
mutex_lock(&kprobe_mutex);
/* If optimization is already prohibited, just return. */
if (!kprobes_allow_optimization) {
mutex_unlock(&kprobe_mutex);
return;
}
cpus_read_lock();
kprobes_allow_optimization = false;
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry(p, head, hlist) {
if (!kprobe_disabled(p))
unoptimize_kprobe(p, false);
}
}
cpus_read_unlock();
mutex_unlock(&kprobe_mutex);
/* Wait for unoptimizing completion. */
wait_for_kprobe_optimizer();
pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n");
}
static DEFINE_MUTEX(kprobe_sysctl_mutex);
static int sysctl_kprobes_optimization;
static int proc_kprobes_optimization_handler(struct ctl_table *table,
int write, void *buffer,
size_t *length, loff_t *ppos)
{
int ret;
mutex_lock(&kprobe_sysctl_mutex);
sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (sysctl_kprobes_optimization)
optimize_all_kprobes();
else
unoptimize_all_kprobes();
mutex_unlock(&kprobe_sysctl_mutex);
return ret;
}
static struct ctl_table kprobe_sysctls[] = {
{
.procname = "kprobes-optimization",
.data = &sysctl_kprobes_optimization,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_kprobes_optimization_handler,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{}
};
static void __init kprobe_sysctls_init(void)
{
register_sysctl_init("debug", kprobe_sysctls);
}
#endif /* CONFIG_SYSCTL */
/* Put a breakpoint for a probe. */
static void __arm_kprobe(struct kprobe *p)
{
struct kprobe *_p;
lockdep_assert_held(&text_mutex);
/* Find the overlapping optimized kprobes. */
_p = get_optimized_kprobe(p->addr);
if (unlikely(_p))
/* Fallback to unoptimized kprobe */
unoptimize_kprobe(_p, true);
arch_arm_kprobe(p);
optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
}
/* Remove the breakpoint of a probe. */
static void __disarm_kprobe(struct kprobe *p, bool reopt)
{
struct kprobe *_p;
lockdep_assert_held(&text_mutex);
/* Try to unoptimize */
unoptimize_kprobe(p, kprobes_all_disarmed);
if (!kprobe_queued(p)) {
arch_disarm_kprobe(p);
/* If another kprobe was blocked, re-optimize it. */
_p = get_optimized_kprobe(p->addr);
if (unlikely(_p) && reopt)
optimize_kprobe(_p);
}
/*
* TODO: Since unoptimization and real disarming will be done by
* the worker thread, we can not check whether another probe are
* unoptimized because of this probe here. It should be re-optimized
* by the worker thread.
*/
}
#else /* !CONFIG_OPTPROBES */
#define optimize_kprobe(p) do {} while (0)
#define unoptimize_kprobe(p, f) do {} while (0)
#define kill_optimized_kprobe(p) do {} while (0)
#define prepare_optimized_kprobe(p) do {} while (0)
#define try_to_optimize_kprobe(p) do {} while (0)
#define __arm_kprobe(p) arch_arm_kprobe(p)
#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
#define kprobe_disarmed(p) kprobe_disabled(p)
#define wait_for_kprobe_optimizer() do {} while (0)
static int reuse_unused_kprobe(struct kprobe *ap)
{
/*
* If the optimized kprobe is NOT supported, the aggr kprobe is
* released at the same time that the last aggregated kprobe is
* unregistered.
* Thus there should be no chance to reuse unused kprobe.
*/
WARN_ON_ONCE(1);
return -EINVAL;
}
static void free_aggr_kprobe(struct kprobe *p)
{
arch_remove_kprobe(p);
kfree(p);
}
static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
{
return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
}
#endif /* CONFIG_OPTPROBES */
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS,
};
static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
};
static int kprobe_ipmodify_enabled;
static int kprobe_ftrace_enabled;
static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
int ret;
lockdep_assert_held(&kprobe_mutex);
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 0, 0);
if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
return ret;
if (*cnt == 0) {
ret = register_ftrace_function(ops);
if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret))
goto err_ftrace;
}
(*cnt)++;
return ret;
err_ftrace:
/*
* At this point, sinec ops is not registered, we should be sefe from
* registering empty filter.
*/
ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
return ret;
}
static int arm_kprobe_ftrace(struct kprobe *p)
{
bool ipmodify = (p->post_handler != NULL);
return __arm_kprobe_ftrace(p,
ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
int *cnt)
{
int ret;
lockdep_assert_held(&kprobe_mutex);
if (*cnt == 1) {
ret = unregister_ftrace_function(ops);
if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret))
return ret;
}
(*cnt)--;
ret = ftrace_set_filter_ip(ops, (unsigned long)p->addr, 1, 0);
WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n",
p->addr, ret);
return ret;
}
static int disarm_kprobe_ftrace(struct kprobe *p)
{
bool ipmodify = (p->post_handler != NULL);
return __disarm_kprobe_ftrace(p,
ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
}
#else /* !CONFIG_KPROBES_ON_FTRACE */
static inline int arm_kprobe_ftrace(struct kprobe *p)
{
return -ENODEV;
}
static inline int disarm_kprobe_ftrace(struct kprobe *p)
{
return -ENODEV;
}
#endif
static int prepare_kprobe(struct kprobe *p)
{
/* Must ensure p->addr is really on ftrace */
if (kprobe_ftrace(p))
return arch_prepare_kprobe_ftrace(p);
return arch_prepare_kprobe(p);
}
static int arm_kprobe(struct kprobe *kp)
{
if (unlikely(kprobe_ftrace(kp)))
return arm_kprobe_ftrace(kp);
cpus_read_lock();
mutex_lock(&text_mutex);
__arm_kprobe(kp);
mutex_unlock(&text_mutex);
cpus_read_unlock();
return 0;
}
static int disarm_kprobe(struct kprobe *kp, bool reopt)
{
if (unlikely(kprobe_ftrace(kp)))
return disarm_kprobe_ftrace(kp);
cpus_read_lock();
mutex_lock(&text_mutex);
__disarm_kprobe(kp, reopt);
mutex_unlock(&text_mutex);
cpus_read_unlock();
return 0;
}
/*
* Aggregate handlers for multiple kprobes support - these handlers
* take care of invoking the individual kprobe handlers on p->list
*/
static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
set_kprobe_instance(kp);
if (kp->pre_handler(kp, regs))
return 1;
}
reset_kprobe_instance();
}
return 0;
}
NOKPROBE_SYMBOL(aggr_pre_handler);
static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
struct kprobe *kp;
list_for_each_entry_rcu(kp, &p->list, list) {
if (kp->post_handler && likely(!kprobe_disabled(kp))) {
set_kprobe_instance(kp);
kp->post_handler(kp, regs, flags);
reset_kprobe_instance();
}
}
}
NOKPROBE_SYMBOL(aggr_post_handler);
/* Walks the list and increments 'nmissed' if 'p' has child probes. */
void kprobes_inc_nmissed_count(struct kprobe *p)
{
struct kprobe *kp;
if (!kprobe_aggrprobe(p)) {
p->nmissed++;
} else {
list_for_each_entry_rcu(kp, &p->list, list)
kp->nmissed++;
}
}
NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
static struct kprobe kprobe_busy = {
.addr = (void *) get_kprobe,
};
void kprobe_busy_begin(void)
{
struct kprobe_ctlblk *kcb;
preempt_disable();
__this_cpu_write(current_kprobe, &kprobe_busy);
kcb = get_kprobe_ctlblk();
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
}
void kprobe_busy_end(void)
{
__this_cpu_write(current_kprobe, NULL);
preempt_enable();
}
/* Add the new probe to 'ap->list'. */
static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
{
if (p->post_handler)
unoptimize_kprobe(ap, true); /* Fall back to normal kprobe */
list_add_rcu(&p->list, &ap->list);
if (p->post_handler && !ap->post_handler)
ap->post_handler = aggr_post_handler;
return 0;
}
/*
* Fill in the required fields of the aggregator kprobe. Replace the
* earlier kprobe in the hlist with the aggregator kprobe.
*/
static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
{
/* Copy the insn slot of 'p' to 'ap'. */
copy_kprobe(p, ap);
flush_insn_slot(ap);
ap->addr = p->addr;
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
ap->pre_handler = aggr_pre_handler;
/* We don't care the kprobe which has gone. */
if (p->post_handler && !kprobe_gone(p))
ap->post_handler = aggr_post_handler;
INIT_LIST_HEAD(&ap->list);
INIT_HLIST_NODE(&ap->hlist);
list_add_rcu(&p->list, &ap->list);
hlist_replace_rcu(&p->hlist, &ap->hlist);
}
/*
* This registers the second or subsequent kprobe at the same address.
*/
static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
{
int ret = 0;
struct kprobe *ap = orig_p;
cpus_read_lock();
/* For preparing optimization, jump_label_text_reserved() is called */
jump_label_lock();
mutex_lock(&text_mutex);
if (!kprobe_aggrprobe(orig_p)) {
/* If 'orig_p' is not an 'aggr_kprobe', create new one. */
ap = alloc_aggr_kprobe(orig_p);
if (!ap) {
ret = -ENOMEM;
goto out;
}
init_aggr_kprobe(ap, orig_p);
} else if (kprobe_unused(ap)) {
/* This probe is going to die. Rescue it */
ret = reuse_unused_kprobe(ap);
if (ret)
goto out;
}
if (kprobe_gone(ap)) {
/*
* Attempting to insert new probe at the same location that
* had a probe in the module vaddr area which already
* freed. So, the instruction slot has already been
* released. We need a new slot for the new probe.
*/
ret = arch_prepare_kprobe(ap);
if (ret)
/*
* Even if fail to allocate new slot, don't need to
* free the 'ap'. It will be used next time, or
* freed by unregister_kprobe().
*/
goto out;
/* Prepare optimized instructions if possible. */
prepare_optimized_kprobe(ap);
/*
* Clear gone flag to prevent allocating new slot again, and
* set disabled flag because it is not armed yet.
*/
ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
| KPROBE_FLAG_DISABLED;
}
/* Copy the insn slot of 'p' to 'ap'. */
copy_kprobe(ap, p);
ret = add_new_kprobe(ap, p);
out:
mutex_unlock(&text_mutex);
jump_label_unlock();
cpus_read_unlock();
if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
ap->flags &= ~KPROBE_FLAG_DISABLED;
if (!kprobes_all_disarmed) {
/* Arm the breakpoint again. */
ret = arm_kprobe(ap);
if (ret) {
ap->flags |= KPROBE_FLAG_DISABLED;
list_del_rcu(&p->list);
synchronize_rcu();
}
}
}
return ret;
}
bool __weak arch_within_kprobe_blacklist(unsigned long addr)
{
/* The '__kprobes' functions and entry code must not be probed. */
return addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end;
}
static bool __within_kprobe_blacklist(unsigned long addr)
{
struct kprobe_blacklist_entry *ent;
if (arch_within_kprobe_blacklist(addr))
return true;
/*
* If 'kprobe_blacklist' is defined, check the address and
* reject any probe registration in the prohibited area.
*/
list_for_each_entry(ent, &kprobe_blacklist, list) {
if (addr >= ent->start_addr && addr < ent->end_addr)
return true;
}
return false;
}
bool within_kprobe_blacklist(unsigned long addr)
{
char symname[KSYM_NAME_LEN], *p;
if (__within_kprobe_blacklist(addr))
return true;
/* Check if the address is on a suffixed-symbol */
if (!lookup_symbol_name(addr, symname)) {
p = strchr(symname, '.');
if (!p)
return false;
*p = '\0';
addr = (unsigned long)kprobe_lookup_name(symname, 0);
if (addr)
return __within_kprobe_blacklist(addr);
}
return false;
}
/*
* arch_adjust_kprobe_addr - adjust the address
* @addr: symbol base address
* @offset: offset within the symbol
* @on_func_entry: was this @addr+@offset on the function entry
*
* Typically returns @addr + @offset, except for special cases where the
* function might be prefixed by a CFI landing pad, in that case any offset
* inside the landing pad is mapped to the first 'real' instruction of the
* symbol.
*
* Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C
* instruction at +0.
*/
kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr,
unsigned long offset,
bool *on_func_entry)
{
*on_func_entry = !offset;
return (kprobe_opcode_t *)(addr + offset);
}
/*
* If 'symbol_name' is specified, look it up and add the 'offset'
* to it. This way, we can specify a relative address to a symbol.
* This returns encoded errors if it fails to look up symbol or invalid
* combination of parameters.
*/
static kprobe_opcode_t *
_kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name,
unsigned long offset, bool *on_func_entry)
{
if ((symbol_name && addr) || (!symbol_name && !addr))
goto invalid;
if (symbol_name) {
/*
* Input: @sym + @offset
* Output: @addr + @offset
*
* NOTE: kprobe_lookup_name() does *NOT* fold the offset
* argument into it's output!
*/
addr = kprobe_lookup_name(symbol_name, offset);
if (!addr)
return ERR_PTR(-ENOENT);
}
/*
* So here we have @addr + @offset, displace it into a new
* @addr' + @offset' where @addr' is the symbol start address.
*/
addr = (void *)addr + offset;
if (!kallsyms_lookup_size_offset((unsigned long)addr, NULL, &offset))
return ERR_PTR(-ENOENT);
addr = (void *)addr - offset;
/*
* Then ask the architecture to re-combine them, taking care of
* magical function entry details while telling us if this was indeed
* at the start of the function.
*/
addr = arch_adjust_kprobe_addr((unsigned long)addr, offset, on_func_entry);
if (addr)
return addr;
invalid:
return ERR_PTR(-EINVAL);
}
static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
{
bool on_func_entry;
return _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
}
/*
* Check the 'p' is valid and return the aggregator kprobe
* at the same address.
*/
static struct kprobe *__get_valid_kprobe(struct kprobe *p)
{
struct kprobe *ap, *list_p;
lockdep_assert_held(&kprobe_mutex);
ap = get_kprobe(p->addr);
if (unlikely(!ap))
return NULL;
if (p != ap) {
list_for_each_entry(list_p, &ap->list, list)
if (list_p == p)
/* kprobe p is a valid probe */
goto valid;
return NULL;
}
valid:
return ap;
}
/*
* Warn and return error if the kprobe is being re-registered since
* there must be a software bug.
*/
static inline int warn_kprobe_rereg(struct kprobe *p)
{
int ret = 0;
mutex_lock(&kprobe_mutex);
if (WARN_ON_ONCE(__get_valid_kprobe(p)))
ret = -EINVAL;
mutex_unlock(&kprobe_mutex);
return ret;
}
static int check_ftrace_location(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
if (ftrace_location(addr) == addr) {
#ifdef CONFIG_KPROBES_ON_FTRACE
p->flags |= KPROBE_FLAG_FTRACE;
#else /* !CONFIG_KPROBES_ON_FTRACE */
return -EINVAL;
#endif
}
return 0;
}
static bool is_cfi_preamble_symbol(unsigned long addr)
{
char symbuf[KSYM_NAME_LEN];
if (lookup_symbol_name(addr, symbuf))
return false;
return str_has_prefix("__cfi_", symbuf) ||
str_has_prefix("__pfx_", symbuf);
}
static int check_kprobe_address_safe(struct kprobe *p,
struct module **probed_mod)
{
int ret;
ret = check_ftrace_location(p);
if (ret)
return ret;
jump_label_lock();
preempt_disable();
/* Ensure it is not in reserved area nor out of text */
if (!(core_kernel_text((unsigned long) p->addr) ||
is_module_text_address((unsigned long) p->addr)) ||
in_gate_area_no_mm((unsigned long) p->addr) ||
within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr) ||
static_call_text_reserved(p->addr, p->addr) ||
find_bug((unsigned long)p->addr) ||
is_cfi_preamble_symbol((unsigned long)p->addr)) {
ret = -EINVAL;
goto out;
}
/* Check if 'p' is probing a module. */
*probed_mod = __module_text_address((unsigned long) p->addr);
if (*probed_mod) {
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
if (unlikely(!try_module_get(*probed_mod))) {
ret = -ENOENT;
goto out;
}
/*
* If the module freed '.init.text', we couldn't insert
* kprobes in there.
*/
if (within_module_init((unsigned long)p->addr, *probed_mod) &&
(*probed_mod)->state != MODULE_STATE_COMING) {
module_put(*probed_mod);
*probed_mod = NULL;
ret = -ENOENT;
}
}
out:
preempt_enable();
jump_label_unlock();
return ret;
}
int register_kprobe(struct kprobe *p)
{
int ret;
struct kprobe *old_p;
struct module *probed_mod;
kprobe_opcode_t *addr;
bool on_func_entry;
/* Adjust probe address from symbol */
addr = _kprobe_addr(p->addr, p->symbol_name, p->offset, &on_func_entry);
if (IS_ERR(addr))
return PTR_ERR(addr);
p->addr = addr;
ret = warn_kprobe_rereg(p);
if (ret)
return ret;
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
p->flags &= KPROBE_FLAG_DISABLED;
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
ret = check_kprobe_address_safe(p, &probed_mod);
if (ret)
return ret;
mutex_lock(&kprobe_mutex);
if (on_func_entry)
p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY;
old_p = get_kprobe(p->addr);
if (old_p) {
/* Since this may unoptimize 'old_p', locking 'text_mutex'. */
ret = register_aggr_kprobe(old_p, p);
goto out;
}
cpus_read_lock();
/* Prevent text modification */
mutex_lock(&text_mutex);
ret = prepare_kprobe(p);
mutex_unlock(&text_mutex);
cpus_read_unlock();
if (ret)
goto out;
INIT_HLIST_NODE(&p->hlist);
hlist_add_head_rcu(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
ret = arm_kprobe(p);
if (ret) {
hlist_del_rcu(&p->hlist);
synchronize_rcu();
goto out;
}
}
/* Try to optimize kprobe */
try_to_optimize_kprobe(p);
out:
mutex_unlock(&kprobe_mutex);
if (probed_mod)
module_put(probed_mod);
return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);
/* Check if all probes on the 'ap' are disabled. */
static bool aggr_kprobe_disabled(struct kprobe *ap)
{
struct kprobe *kp;
lockdep_assert_held(&kprobe_mutex);
list_for_each_entry(kp, &ap->list, list)
if (!kprobe_disabled(kp))
/*
* Since there is an active probe on the list,
* we can't disable this 'ap'.
*/
return false;
return true;
}
static struct kprobe *__disable_kprobe(struct kprobe *p)
{
struct kprobe *orig_p;
int ret;
lockdep_assert_held(&kprobe_mutex);
/* Get an original kprobe for return */
orig_p = __get_valid_kprobe(p);
if (unlikely(orig_p == NULL))
return ERR_PTR(-EINVAL);
if (!kprobe_disabled(p)) {
/* Disable probe if it is a child probe */
if (p != orig_p)
p->flags |= KPROBE_FLAG_DISABLED;
/* Try to disarm and disable this/parent probe */
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
/*
* Don't be lazy here. Even if 'kprobes_all_disarmed'
* is false, 'orig_p' might not have been armed yet.
* Note arm_all_kprobes() __tries__ to arm all kprobes
* on the best effort basis.
*/
if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) {
ret = disarm_kprobe(orig_p, true);
if (ret) {
p->flags &= ~KPROBE_FLAG_DISABLED;
return ERR_PTR(ret);
}
}
orig_p->flags |= KPROBE_FLAG_DISABLED;
}
}
return orig_p;
}
/*
* Unregister a kprobe without a scheduler synchronization.
*/
static int __unregister_kprobe_top(struct kprobe *p)
{
struct kprobe *ap, *list_p;
/* Disable kprobe. This will disarm it if needed. */
ap = __disable_kprobe(p);
if (IS_ERR(ap))
return PTR_ERR(ap);
if (ap == p)
/*
* This probe is an independent(and non-optimized) kprobe
* (not an aggrprobe). Remove from the hash list.
*/
goto disarmed;
/* Following process expects this probe is an aggrprobe */
WARN_ON(!kprobe_aggrprobe(ap));
if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
/*
* !disarmed could be happen if the probe is under delayed
* unoptimizing.
*/
goto disarmed;
else {
/* If disabling probe has special handlers, update aggrprobe */
if (p->post_handler && !kprobe_gone(p)) {
list_for_each_entry(list_p, &ap->list, list) {
if ((list_p != p) && (list_p->post_handler))
goto noclean;
}
/*
* For the kprobe-on-ftrace case, we keep the
* post_handler setting to identify this aggrprobe
* armed with kprobe_ipmodify_ops.
*/
if (!kprobe_ftrace(ap))
ap->post_handler = NULL;
}
noclean:
/*
* Remove from the aggrprobe: this path will do nothing in
* __unregister_kprobe_bottom().
*/
list_del_rcu(&p->list);
if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
/*
* Try to optimize this probe again, because post
* handler may have been changed.
*/
optimize_kprobe(ap);
}
return 0;
disarmed:
hlist_del_rcu(&ap->hlist);
return 0;
}
static void __unregister_kprobe_bottom(struct kprobe *p)
{
struct kprobe *ap;
if (list_empty(&p->list))
/* This is an independent kprobe */
arch_remove_kprobe(p);
else if (list_is_singular(&p->list)) {
/* This is the last child of an aggrprobe */
ap = list_entry(p->list.next, struct kprobe, list);
list_del(&p->list);
free_aggr_kprobe(ap);
}
/* Otherwise, do nothing. */
}
int register_kprobes(struct kprobe **kps, int num)
{
int i, ret = 0;
if (num <= 0)
return -EINVAL;
for (i = 0; i < num; i++) {
ret = register_kprobe(kps[i]);
if (ret < 0) {
if (i > 0)
unregister_kprobes(kps, i);
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(register_kprobes);
void unregister_kprobe(struct kprobe *p)
{
unregister_kprobes(&p, 1);
}
EXPORT_SYMBOL_GPL(unregister_kprobe);
void unregister_kprobes(struct kprobe **kps, int num)
{
int i;
if (num <= 0)
return;
mutex_lock(&kprobe_mutex);
for (i = 0; i < num; i++)
if (__unregister_kprobe_top(kps[i]) < 0)
kps[i]->addr = NULL;
mutex_unlock(&kprobe_mutex);
synchronize_rcu();
for (i = 0; i < num; i++)
if (kps[i]->addr)
__unregister_kprobe_bottom(kps[i]);
}
EXPORT_SYMBOL_GPL(unregister_kprobes);
int __weak kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return NOTIFY_DONE;
}
NOKPROBE_SYMBOL(kprobe_exceptions_notify);
static struct notifier_block kprobe_exceptions_nb = {
.notifier_call = kprobe_exceptions_notify,
.priority = 0x7fffffff /* we need to be notified first */
};
#ifdef CONFIG_KRETPROBES
#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
static void free_rp_inst_rcu(struct rcu_head *head)
{
struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
if (refcount_dec_and_test(&ri->rph->ref))
kfree(ri->rph);
kfree(ri);
}
NOKPROBE_SYMBOL(free_rp_inst_rcu);
static void recycle_rp_inst(struct kretprobe_instance *ri)
{
struct kretprobe *rp = get_kretprobe(ri);
if (likely(rp))
freelist_add(&ri->freelist, &rp->freelist);
else
call_rcu(&ri->rcu, free_rp_inst_rcu);
}
NOKPROBE_SYMBOL(recycle_rp_inst);
/*
* This function is called from delayed_put_task_struct() when a task is
* dead and cleaned up to recycle any kretprobe instances associated with
* this task. These left over instances represent probed functions that
* have been called but will never return.
*/
void kprobe_flush_task(struct task_struct *tk)
{
struct kretprobe_instance *ri;
struct llist_node *node;
/* Early boot, not yet initialized. */
if (unlikely(!kprobes_initialized))
return;
kprobe_busy_begin();
node = __llist_del_all(&tk->kretprobe_instances);
while (node) {
ri = container_of(node, struct kretprobe_instance, llist);
node = node->next;
recycle_rp_inst(ri);
}
kprobe_busy_end();
}
NOKPROBE_SYMBOL(kprobe_flush_task);
static inline void free_rp_inst(struct kretprobe *rp)
{
struct kretprobe_instance *ri;
struct freelist_node *node;
int count = 0;
node = rp->freelist.head;
while (node) {
ri = container_of(node, struct kretprobe_instance, freelist);
node = node->next;
kfree(ri);
count++;
}
if (refcount_sub_and_test(count, &rp->rph->ref)) {
kfree(rp->rph);
rp->rph = NULL;
}
}
/* This assumes the 'tsk' is the current task or the is not running. */
static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk,
struct llist_node **cur)
{
struct kretprobe_instance *ri = NULL;
struct llist_node *node = *cur;
if (!node)
node = tsk->kretprobe_instances.first;
else
node = node->next;
while (node) {
ri = container_of(node, struct kretprobe_instance, llist);
if (ri->ret_addr != kretprobe_trampoline_addr()) {
*cur = node;
return ri->ret_addr;
}
node = node->next;
}
return NULL;
}
NOKPROBE_SYMBOL(__kretprobe_find_ret_addr);
/**
* kretprobe_find_ret_addr -- Find correct return address modified by kretprobe
* @tsk: Target task
* @fp: A frame pointer
* @cur: a storage of the loop cursor llist_node pointer for next call
*
* Find the correct return address modified by a kretprobe on @tsk in unsigned
* long type. If it finds the return address, this returns that address value,
* or this returns 0.
* The @tsk must be 'current' or a task which is not running. @fp is a hint
* to get the currect return address - which is compared with the
* kretprobe_instance::fp field. The @cur is a loop cursor for searching the
* kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the
* first call, but '@cur' itself must NOT NULL.
*/
unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
struct llist_node **cur)
{
struct kretprobe_instance *ri = NULL;
kprobe_opcode_t *ret;
if (WARN_ON_ONCE(!cur))
return 0;
do {
ret = __kretprobe_find_ret_addr(tsk, cur);
if (!ret)
break;
ri = container_of(*cur, struct kretprobe_instance, llist);
} while (ri->fp != fp);
return (unsigned long)ret;
}
NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
void __weak arch_kretprobe_fixup_return(struct pt_regs *regs,
kprobe_opcode_t *correct_ret_addr)
{
/*
* Do nothing by default. Please fill this to update the fake return
* address on the stack with the correct one on each arch if possible.
*/
}
unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
void *frame_pointer)
{
struct kretprobe_instance *ri = NULL;
struct llist_node *first, *node = NULL;
kprobe_opcode_t *correct_ret_addr;
struct kretprobe *rp;
/* Find correct address and all nodes for this frame. */
correct_ret_addr = __kretprobe_find_ret_addr(current, &node);
if (!correct_ret_addr) {
pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n");
BUG_ON(1);
}
/*
* Set the return address as the instruction pointer, because if the
* user handler calls stack_trace_save_regs() with this 'regs',
* the stack trace will start from the instruction pointer.
*/
instruction_pointer_set(regs, (unsigned long)correct_ret_addr);
/* Run the user handler of the nodes. */
first = current->kretprobe_instances.first;
while (first) {
ri = container_of(first, struct kretprobe_instance, llist);
if (WARN_ON_ONCE(ri->fp != frame_pointer))
break;
rp = get_kretprobe(ri);
if (rp && rp->handler) {
struct kprobe *prev = kprobe_running();
__this_cpu_write(current_kprobe, &rp->kp);
ri->ret_addr = correct_ret_addr;
rp->handler(ri, regs);
__this_cpu_write(current_kprobe, prev);
}
if (first == node)
break;
first = first->next;
}
arch_kretprobe_fixup_return(regs, correct_ret_addr);
/* Unlink all nodes for this frame. */
first = current->kretprobe_instances.first;
current->kretprobe_instances.first = node->next;
node->next = NULL;
/* Recycle free instances. */
while (first) {
ri = container_of(first, struct kretprobe_instance, llist);
first = first->next;
recycle_rp_inst(ri);
}
return (unsigned long)correct_ret_addr;
}
NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)
/*
* This kprobe pre_handler is registered with every kretprobe. When probe
* hits it will set up the return probe.
*/
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
struct kretprobe_instance *ri;
struct freelist_node *fn;
fn = freelist_try_get(&rp->freelist);
if (!fn) {
rp->nmissed++;
return 0;
}
ri = container_of(fn, struct kretprobe_instance, freelist);
if (rp->entry_handler && rp->entry_handler(ri, regs)) {
freelist_add(&ri->freelist, &rp->freelist);
return 0;
}
arch_prepare_kretprobe(ri, regs);
__llist_add(&ri->llist, ¤t->kretprobe_instances);
return 0;
}
NOKPROBE_SYMBOL(pre_handler_kretprobe);
#else /* CONFIG_KRETPROBE_ON_RETHOOK */
/*
* This kprobe pre_handler is registered with every kretprobe. When probe
* hits it will set up the return probe.
*/
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe *rp = container_of(p, struct kretprobe, kp);
struct kretprobe_instance *ri;
struct rethook_node *rhn;
rhn = rethook_try_get(rp->rh);
if (!rhn) {
rp->nmissed++;
return 0;
}
ri = container_of(rhn, struct kretprobe_instance, node);
if (rp->entry_handler && rp->entry_handler(ri, regs))
rethook_recycle(rhn);
else
rethook_hook(rhn, regs, kprobe_ftrace(p));
return 0;
}
NOKPROBE_SYMBOL(pre_handler_kretprobe);
static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
unsigned long ret_addr,
struct pt_regs *regs)
{
struct kretprobe *rp = (struct kretprobe *)data;
struct kretprobe_instance *ri;
struct kprobe_ctlblk *kcb;
/* The data must NOT be null. This means rethook data structure is broken. */
if (WARN_ON_ONCE(!data) || !rp->handler)
return;
__this_cpu_write(current_kprobe, &rp->kp);
kcb = get_kprobe_ctlblk();
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
ri = container_of(rh, struct kretprobe_instance, node);
rp->handler(ri, regs);
__this_cpu_write(current_kprobe, NULL);
}
NOKPROBE_SYMBOL(kretprobe_rethook_handler);
#endif /* !CONFIG_KRETPROBE_ON_RETHOOK */
/**
* kprobe_on_func_entry() -- check whether given address is function entry
* @addr: Target address
* @sym: Target symbol name
* @offset: The offset from the symbol or the address
*
* This checks whether the given @addr+@offset or @sym+@offset is on the
* function entry address or not.
* This returns 0 if it is the function entry, or -EINVAL if it is not.
* And also it returns -ENOENT if it fails the symbol or address lookup.
* Caller must pass @addr or @sym (either one must be NULL), or this
* returns -EINVAL.
*/
int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
{
bool on_func_entry;
kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset, &on_func_entry);
if (IS_ERR(kp_addr))
return PTR_ERR(kp_addr);
if (!on_func_entry)
return -EINVAL;
return 0;
}
int register_kretprobe(struct kretprobe *rp)
{
int ret;
struct kretprobe_instance *inst;
int i;
void *addr;
ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset);
if (ret)
return ret;
/* If only 'rp->kp.addr' is specified, check reregistering kprobes */
if (rp->kp.addr && warn_kprobe_rereg(&rp->kp))
return -EINVAL;
if (kretprobe_blacklist_size) {
addr = kprobe_addr(&rp->kp);
if (IS_ERR(addr))
return PTR_ERR(addr);
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
if (kretprobe_blacklist[i].addr == addr)
return -EINVAL;
}
}
if (rp->data_size > KRETPROBE_MAX_DATA_SIZE)
return -E2BIG;
rp->kp.pre_handler = pre_handler_kretprobe;
rp->kp.post_handler = NULL;
/* Pre-allocate memory for max kretprobe instances */
if (rp->maxactive <= 0)
rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
rp->rh = rethook_alloc((void *)rp, kretprobe_rethook_handler);
if (!rp->rh)
return -ENOMEM;
for (i = 0; i < rp->maxactive; i++) {
inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
if (inst == NULL) {
rethook_free(rp->rh);
rp->rh = NULL;
return -ENOMEM;
}
rethook_add_node(rp->rh, &inst->node);
}
rp->nmissed = 0;
/* Establish function entry probe point */
ret = register_kprobe(&rp->kp);
if (ret != 0) {
rethook_free(rp->rh);
rp->rh = NULL;
}
#else /* !CONFIG_KRETPROBE_ON_RETHOOK */
rp->freelist.head = NULL;
rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
if (!rp->rph)
return -ENOMEM;
rp->rph->rp = rp;
for (i = 0; i < rp->maxactive; i++) {
inst = kzalloc(struct_size(inst, data, rp->data_size), GFP_KERNEL);
if (inst == NULL) {
refcount_set(&rp->rph->ref, i);
free_rp_inst(rp);
return -ENOMEM;
}
inst->rph = rp->rph;
freelist_add(&inst->freelist, &rp->freelist);
}
refcount_set(&rp->rph->ref, i);
rp->nmissed = 0;
/* Establish function entry probe point */
ret = register_kprobe(&rp->kp);
if (ret != 0)
free_rp_inst(rp);
#endif
return ret;
}
EXPORT_SYMBOL_GPL(register_kretprobe);
int register_kretprobes(struct kretprobe **rps, int num)
{
int ret = 0, i;
if (num <= 0)
return -EINVAL;
for (i = 0; i < num; i++) {
ret = register_kretprobe(rps[i]);
if (ret < 0) {
if (i > 0)
unregister_kretprobes(rps, i);
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(register_kretprobes);
void unregister_kretprobe(struct kretprobe *rp)
{
unregister_kretprobes(&rp, 1);
}
EXPORT_SYMBOL_GPL(unregister_kretprobe);
void unregister_kretprobes(struct kretprobe **rps, int num)
{
int i;
if (num <= 0)
return;
mutex_lock(&kprobe_mutex);
for (i = 0; i < num; i++) {
if (__unregister_kprobe_top(&rps[i]->kp) < 0)
rps[i]->kp.addr = NULL;
#ifdef CONFIG_KRETPROBE_ON_RETHOOK
rethook_free(rps[i]->rh);
#else
rps[i]->rph->rp = NULL;
#endif
}
mutex_unlock(&kprobe_mutex);
synchronize_rcu();
for (i = 0; i < num; i++) {
if (rps[i]->kp.addr) {
__unregister_kprobe_bottom(&rps[i]->kp);
#ifndef CONFIG_KRETPROBE_ON_RETHOOK
free_rp_inst(rps[i]);
#endif
}
}
}
EXPORT_SYMBOL_GPL(unregister_kretprobes);
#else /* CONFIG_KRETPROBES */
int register_kretprobe(struct kretprobe *rp)
{
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(register_kretprobe);
int register_kretprobes(struct kretprobe **rps, int num)
{
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(register_kretprobes);
void unregister_kretprobe(struct kretprobe *rp)
{
}
EXPORT_SYMBOL_GPL(unregister_kretprobe);
void unregister_kretprobes(struct kretprobe **rps, int num)
{
}
EXPORT_SYMBOL_GPL(unregister_kretprobes);
static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
{
return 0;
}
NOKPROBE_SYMBOL(pre_handler_kretprobe);
#endif /* CONFIG_KRETPROBES */
/* Set the kprobe gone and remove its instruction buffer. */
static void kill_kprobe(struct kprobe *p)
{
struct kprobe *kp;
lockdep_assert_held(&kprobe_mutex);
/*
* The module is going away. We should disarm the kprobe which
* is using ftrace, because ftrace framework is still available at
* 'MODULE_STATE_GOING' notification.
*/
if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
disarm_kprobe_ftrace(p);
p->flags |= KPROBE_FLAG_GONE;
if (kprobe_aggrprobe(p)) {
/*
* If this is an aggr_kprobe, we have to list all the
* chained probes and mark them GONE.
*/
list_for_each_entry(kp, &p->list, list)
kp->flags |= KPROBE_FLAG_GONE;
p->post_handler = NULL;
kill_optimized_kprobe(p);
}
/*
* Here, we can remove insn_slot safely, because no thread calls
* the original probed function (which will be freed soon) any more.
*/
arch_remove_kprobe(p);
}
/* Disable one kprobe */
int disable_kprobe(struct kprobe *kp)
{
int ret = 0;
struct kprobe *p;
mutex_lock(&kprobe_mutex);
/* Disable this kprobe */
p = __disable_kprobe(kp);
if (IS_ERR(p))
ret = PTR_ERR(p);
mutex_unlock(&kprobe_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(disable_kprobe);
/* Enable one kprobe */
int enable_kprobe(struct kprobe *kp)
{
int ret = 0;
struct kprobe *p;
mutex_lock(&kprobe_mutex);
/* Check whether specified probe is valid. */
p = __get_valid_kprobe(kp);
if (unlikely(p == NULL)) {
ret = -EINVAL;
goto out;
}
if (kprobe_gone(kp)) {
/* This kprobe has gone, we couldn't enable it. */
ret = -EINVAL;
goto out;
}
if (p != kp)
kp->flags &= ~KPROBE_FLAG_DISABLED;
if (!kprobes_all_disarmed && kprobe_disabled(p)) {
p->flags &= ~KPROBE_FLAG_DISABLED;
ret = arm_kprobe(p);
if (ret) {
p->flags |= KPROBE_FLAG_DISABLED;
if (p != kp)
kp->flags |= KPROBE_FLAG_DISABLED;
}
}
out:
mutex_unlock(&kprobe_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(enable_kprobe);
/* Caller must NOT call this in usual path. This is only for critical case */
void dump_kprobe(struct kprobe *kp)
{
pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n",
kp->symbol_name, kp->offset, kp->addr);
}
NOKPROBE_SYMBOL(dump_kprobe);
int kprobe_add_ksym_blacklist(unsigned long entry)
{
struct kprobe_blacklist_entry *ent;
unsigned long offset = 0, size = 0;
if (!kernel_text_address(entry) ||
!kallsyms_lookup_size_offset(entry, &size, &offset))
return -EINVAL;
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)
return -ENOMEM;
ent->start_addr = entry;
ent->end_addr = entry + size;
INIT_LIST_HEAD(&ent->list);
list_add_tail(&ent->list, &kprobe_blacklist);
return (int)size;
}
/* Add all symbols in given area into kprobe blacklist */
int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
{
unsigned long entry;
int ret = 0;
for (entry = start; entry < end; entry += ret) {
ret = kprobe_add_ksym_blacklist(entry);
if (ret < 0)
return ret;
if (ret == 0) /* In case of alias symbol */
ret = 1;
}
return 0;
}
/* Remove all symbols in given area from kprobe blacklist */
static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
{
struct kprobe_blacklist_entry *ent, *n;
list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
if (ent->start_addr < start || ent->start_addr >= end)
continue;
list_del(&ent->list);
kfree(ent);
}
}
static void kprobe_remove_ksym_blacklist(unsigned long entry)
{
kprobe_remove_area_blacklist(entry, entry + 1);
}
int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
char *type, char *sym)
{
return -ERANGE;
}
int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
char *sym)
{
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym))
return 0;
#ifdef CONFIG_OPTPROBES
if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym))
return 0;
#endif
#endif
if (!arch_kprobe_get_kallsym(&symnum, value, type, sym))
return 0;
return -ERANGE;
}
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
}
/*
* Lookup and populate the kprobe_blacklist.
*
* Unlike the kretprobe blacklist, we'll need to determine
* the range of addresses that belong to the said functions,
* since a kprobe need not necessarily be at the beginning
* of a function.
*/
static int __init populate_kprobe_blacklist(unsigned long *start,
unsigned long *end)
{
unsigned long entry;
unsigned long *iter;
int ret;
for (iter = start; iter < end; iter++) {
entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
ret = kprobe_add_ksym_blacklist(entry);
if (ret == -EINVAL)
continue;
if (ret < 0)
return ret;
}
/* Symbols in '__kprobes_text' are blacklisted */
ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
(unsigned long)__kprobes_text_end);
if (ret)
return ret;
/* Symbols in 'noinstr' section are blacklisted */
ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
(unsigned long)__noinstr_text_end);
return ret ? : arch_populate_kprobe_blacklist();
}
static void add_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
int i;
if (mod->kprobe_blacklist) {
for (i = 0; i < mod->num_kprobe_blacklist; i++)
kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
}
start = (unsigned long)mod->kprobes_text_start;
if (start) {
end = start + mod->kprobes_text_size;
kprobe_add_area_blacklist(start, end);
}
start = (unsigned long)mod->noinstr_text_start;
if (start) {
end = start + mod->noinstr_text_size;
kprobe_add_area_blacklist(start, end);
}
}
static void remove_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
int i;
if (mod->kprobe_blacklist) {
for (i = 0; i < mod->num_kprobe_blacklist; i++)
kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
}
start = (unsigned long)mod->kprobes_text_start;
if (start) {
end = start + mod->kprobes_text_size;
kprobe_remove_area_blacklist(start, end);
}
start = (unsigned long)mod->noinstr_text_start;
if (start) {
end = start + mod->noinstr_text_size;
kprobe_remove_area_blacklist(start, end);
}
}
/* Module notifier call back, checking kprobes on the module */
static int kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
{
struct module *mod = data;
struct hlist_head *head;
struct kprobe *p;
unsigned int i;
int checkcore = (val == MODULE_STATE_GOING);
if (val == MODULE_STATE_COMING) {
mutex_lock(&kprobe_mutex);
add_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex);
}
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE;
/*
* When 'MODULE_STATE_GOING' was notified, both of module '.text' and
* '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was
* notified, only '.init.text' section would be freed. We need to
* disable kprobes which have been inserted in the sections.
*/
mutex_lock(&kprobe_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry(p, head, hlist)
if (within_module_init((unsigned long)p->addr, mod) ||
(checkcore &&
within_module_core((unsigned long)p->addr, mod))) {
/*
* The vaddr this probe is installed will soon
* be vfreed buy not synced to disk. Hence,
* disarming the breakpoint isn't needed.
*
* Note, this will also move any optimized probes
* that are pending to be removed from their
* corresponding lists to the 'freeing_list' and
* will not be touched by the delayed
* kprobe_optimizer() work handler.
*/
kill_kprobe(p);
}
}
if (val == MODULE_STATE_GOING)
remove_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex);
return NOTIFY_DONE;
}
static struct notifier_block kprobe_module_nb = {
.notifier_call = kprobes_module_callback,
.priority = 0
};
void kprobe_free_init_mem(void)
{
void *start = (void *)(&__init_begin);
void *end = (void *)(&__init_end);
struct hlist_head *head;
struct kprobe *p;
int i;
mutex_lock(&kprobe_mutex);
/* Kill all kprobes on initmem because the target code has been freed. */
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry(p, head, hlist) {
if (start <= (void *)p->addr && (void *)p->addr < end)
kill_kprobe(p);
}
}
mutex_unlock(&kprobe_mutex);
}
static int __init init_kprobes(void)
{
int i, err;
/* FIXME allocate the probe table, currently defined statically */
/* initialize all list heads */
for (i = 0; i < KPROBE_TABLE_SIZE; i++)
INIT_HLIST_HEAD(&kprobe_table[i]);
err = populate_kprobe_blacklist(__start_kprobe_blacklist,
__stop_kprobe_blacklist);
if (err)
pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err);
if (kretprobe_blacklist_size) {
/* lookup the function address from its name */
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
kretprobe_blacklist[i].addr =
kprobe_lookup_name(kretprobe_blacklist[i].name, 0);
if (!kretprobe_blacklist[i].addr)
pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n",
kretprobe_blacklist[i].name);
}
}
/* By default, kprobes are armed */
kprobes_all_disarmed = false;
#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
/* Init 'kprobe_optinsn_slots' for allocation */
kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
#endif
err = arch_init_kprobes();
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
if (!err)
err = register_module_notifier(&kprobe_module_nb);
kprobes_initialized = (err == 0);
kprobe_sysctls_init();
return err;
}
early_initcall(init_kprobes);
#if defined(CONFIG_OPTPROBES)
static int __init init_optprobes(void)
{
/*
* Enable kprobe optimization - this kicks the optimizer which
* depends on synchronize_rcu_tasks() and ksoftirqd, that is
* not spawned in early initcall. So delay the optimization.
*/
optimize_all_kprobes();
return 0;
}
subsys_initcall(init_optprobes);
#endif
#ifdef CONFIG_DEBUG_FS
static void report_probe(struct seq_file *pi, struct kprobe *p,
const char *sym, int offset, char *modname, struct kprobe *pp)
{
char *kprobe_type;
void *addr = p->addr;
if (p->pre_handler == pre_handler_kretprobe)
kprobe_type = "r";
else
kprobe_type = "k";
if (!kallsyms_show_value(pi->file->f_cred))
addr = NULL;
if (sym)
seq_printf(pi, "%px %s %s+0x%x %s ",
addr, kprobe_type, sym, offset,
(modname ? modname : " "));
else /* try to use %pS */
seq_printf(pi, "%px %s %pS ",
addr, kprobe_type, p->addr);
if (!pp)
pp = p;
seq_printf(pi, "%s%s%s%s\n",
(kprobe_gone(p) ? "[GONE]" : ""),
((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""),
(kprobe_ftrace(pp) ? "[FTRACE]" : ""));
}
static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
{
return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
}
static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= KPROBE_TABLE_SIZE)
return NULL;
return pos;
}
static void kprobe_seq_stop(struct seq_file *f, void *v)
{
/* Nothing to do */
}
static int show_kprobe_addr(struct seq_file *pi, void *v)
{
struct hlist_head *head;
struct kprobe *p, *kp;
const char *sym = NULL;
unsigned int i = *(loff_t *) v;
unsigned long offset = 0;
char *modname, namebuf[KSYM_NAME_LEN];
head = &kprobe_table[i];
preempt_disable();
hlist_for_each_entry_rcu(p, head, hlist) {
sym = kallsyms_lookup((unsigned long)p->addr, NULL,
&offset, &modname, namebuf);
if (kprobe_aggrprobe(p)) {
list_for_each_entry_rcu(kp, &p->list, list)
report_probe(pi, kp, sym, offset, modname, p);
} else
report_probe(pi, p, sym, offset, modname, NULL);
}
preempt_enable();
return 0;
}
static const struct seq_operations kprobes_sops = {
.start = kprobe_seq_start,
.next = kprobe_seq_next,
.stop = kprobe_seq_stop,
.show = show_kprobe_addr
};
DEFINE_SEQ_ATTRIBUTE(kprobes);
/* kprobes/blacklist -- shows which functions can not be probed */
static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&kprobe_mutex);
return seq_list_start(&kprobe_blacklist, *pos);
}
static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
return seq_list_next(v, &kprobe_blacklist, pos);
}
static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
{
struct kprobe_blacklist_entry *ent =
list_entry(v, struct kprobe_blacklist_entry, list);
/*
* If '/proc/kallsyms' is not showing kernel address, we won't
* show them here either.
*/
if (!kallsyms_show_value(m->file->f_cred))
seq_printf(m, "0x%px-0x%px\t%ps\n", NULL, NULL,
(void *)ent->start_addr);
else
seq_printf(m, "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
(void *)ent->end_addr, (void *)ent->start_addr);
return 0;
}
static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
{
mutex_unlock(&kprobe_mutex);
}
static const struct seq_operations kprobe_blacklist_sops = {
.start = kprobe_blacklist_seq_start,
.next = kprobe_blacklist_seq_next,
.stop = kprobe_blacklist_seq_stop,
.show = kprobe_blacklist_seq_show,
};
DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist);
static int arm_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
unsigned int i, total = 0, errors = 0;
int err, ret = 0;
mutex_lock(&kprobe_mutex);
/* If kprobes are armed, just return */
if (!kprobes_all_disarmed)
goto already_enabled;
/*
* optimize_kprobe() called by arm_kprobe() checks
* kprobes_all_disarmed, so set kprobes_all_disarmed before
* arm_kprobe.
*/
kprobes_all_disarmed = false;
/* Arming kprobes doesn't optimize kprobe itself */
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
/* Arm all kprobes on a best-effort basis */
hlist_for_each_entry(p, head, hlist) {
if (!kprobe_disabled(p)) {
err = arm_kprobe(p);
if (err) {
errors++;
ret = err;
}
total++;
}
}
}
if (errors)
pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n",
errors, total);
else
pr_info("Kprobes globally enabled\n");
already_enabled:
mutex_unlock(&kprobe_mutex);
return ret;
}
static int disarm_all_kprobes(void)
{
struct hlist_head *head;
struct kprobe *p;
unsigned int i, total = 0, errors = 0;
int err, ret = 0;
mutex_lock(&kprobe_mutex);
/* If kprobes are already disarmed, just return */
if (kprobes_all_disarmed) {
mutex_unlock(&kprobe_mutex);
return 0;
}
kprobes_all_disarmed = true;
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
/* Disarm all kprobes on a best-effort basis */
hlist_for_each_entry(p, head, hlist) {
if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
err = disarm_kprobe(p, false);
if (err) {
errors++;
ret = err;
}
total++;
}
}
}
if (errors)
pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n",
errors, total);
else
pr_info("Kprobes globally disabled\n");
mutex_unlock(&kprobe_mutex);
/* Wait for disarming all kprobes by optimizer */
wait_for_kprobe_optimizer();
return ret;
}
/*
* XXX: The debugfs bool file interface doesn't allow for callbacks
* when the bool state is switched. We can reuse that facility when
* available
*/
static ssize_t read_enabled_file_bool(struct file *file,
char __user *user_buf, size_t count, loff_t *ppos)
{
char buf[3];
if (!kprobes_all_disarmed)
buf[0] = '1';
else
buf[0] = '0';
buf[1] = '\n';
buf[2] = 0x00;
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
static ssize_t write_enabled_file_bool(struct file *file,
const char __user *user_buf, size_t count, loff_t *ppos)
{
bool enable;
int ret;
ret = kstrtobool_from_user(user_buf, count, &enable);
if (ret)
return ret;
ret = enable ? arm_all_kprobes() : disarm_all_kprobes();
if (ret)
return ret;
return count;
}
static const struct file_operations fops_kp = {
.read = read_enabled_file_bool,
.write = write_enabled_file_bool,
.llseek = default_llseek,
};
static int __init debugfs_kprobe_init(void)
{
struct dentry *dir;
dir = debugfs_create_dir("kprobes", NULL);
debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops);
debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp);
debugfs_create_file("blacklist", 0400, dir, NULL,
&kprobe_blacklist_fops);
return 0;
}
late_initcall(debugfs_kprobe_init);
#endif /* CONFIG_DEBUG_FS */
| linux-master | kernel/kprobes.c |
// SPDX-License-Identifier: GPL-2.0+
/*
* Common functions for in-kernel torture tests.
*
* Copyright (C) IBM Corporation, 2014
*
* Author: Paul E. McKenney <[email protected]>
* Based on kernel/rcu/torture.c.
*/
#define pr_fmt(fmt) fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/freezer.h>
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
#include <linux/ktime.h>
#include <asm/byteorder.h>
#include <linux/torture.h>
#include <linux/sched/rt.h>
#include "rcu/rcu.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <[email protected]>");
static bool disable_onoff_at_boot;
module_param(disable_onoff_at_boot, bool, 0444);
static bool ftrace_dump_at_shutdown;
module_param(ftrace_dump_at_shutdown, bool, 0444);
static int verbose_sleep_frequency;
module_param(verbose_sleep_frequency, int, 0444);
static int verbose_sleep_duration = 1;
module_param(verbose_sleep_duration, int, 0444);
static int random_shuffle;
module_param(random_shuffle, int, 0444);
static char *torture_type;
static int verbose;
/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
#define FULLSTOP_SHUTDOWN 1 /* System shutdown with torture running. */
#define FULLSTOP_RMMOD 2 /* Normal rmmod of torture. */
static int fullstop = FULLSTOP_RMMOD;
static DEFINE_MUTEX(fullstop_mutex);
static atomic_t verbose_sleep_counter;
/*
* Sleep if needed from VERBOSE_TOROUT*().
*/
void verbose_torout_sleep(void)
{
if (verbose_sleep_frequency > 0 &&
verbose_sleep_duration > 0 &&
!(atomic_inc_return(&verbose_sleep_counter) % verbose_sleep_frequency))
schedule_timeout_uninterruptible(verbose_sleep_duration);
}
EXPORT_SYMBOL_GPL(verbose_torout_sleep);
/*
* Schedule a high-resolution-timer sleep in nanoseconds, with a 32-bit
* nanosecond random fuzz. This function and its friends desynchronize
* testing from the timer wheel.
*/
int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, struct torture_random_state *trsp)
{
ktime_t hto = baset_ns;
if (trsp)
hto += torture_random(trsp) % fuzzt_ns;
set_current_state(TASK_IDLE);
return schedule_hrtimeout(&hto, HRTIMER_MODE_REL);
}
EXPORT_SYMBOL_GPL(torture_hrtimeout_ns);
/*
* Schedule a high-resolution-timer sleep in microseconds, with a 32-bit
* nanosecond (not microsecond!) random fuzz.
*/
int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp)
{
ktime_t baset_ns = baset_us * NSEC_PER_USEC;
return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
}
EXPORT_SYMBOL_GPL(torture_hrtimeout_us);
/*
* Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
* microsecond (not millisecond!) random fuzz.
*/
int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp)
{
ktime_t baset_ns = baset_ms * NSEC_PER_MSEC;
u32 fuzzt_ns;
if ((u32)~0U / NSEC_PER_USEC < fuzzt_us)
fuzzt_ns = (u32)~0U;
else
fuzzt_ns = fuzzt_us * NSEC_PER_USEC;
return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
}
EXPORT_SYMBOL_GPL(torture_hrtimeout_ms);
/*
* Schedule a high-resolution-timer sleep in jiffies, with an
* implied one-jiffy random fuzz. This is intended to replace calls to
* schedule_timeout_interruptible() and friends.
*/
int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp)
{
ktime_t baset_ns = jiffies_to_nsecs(baset_j);
return torture_hrtimeout_ns(baset_ns, jiffies_to_nsecs(1), trsp);
}
EXPORT_SYMBOL_GPL(torture_hrtimeout_jiffies);
/*
* Schedule a high-resolution-timer sleep in milliseconds, with a 32-bit
* millisecond (not second!) random fuzz.
*/
int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp)
{
ktime_t baset_ns = baset_s * NSEC_PER_SEC;
u32 fuzzt_ns;
if ((u32)~0U / NSEC_PER_MSEC < fuzzt_ms)
fuzzt_ns = (u32)~0U;
else
fuzzt_ns = fuzzt_ms * NSEC_PER_MSEC;
return torture_hrtimeout_ns(baset_ns, fuzzt_ns, trsp);
}
EXPORT_SYMBOL_GPL(torture_hrtimeout_s);
#ifdef CONFIG_HOTPLUG_CPU
/*
* Variables for online-offline handling. Only present if CPU hotplug
* is enabled, otherwise does nothing.
*/
static struct task_struct *onoff_task;
static long onoff_holdoff;
static long onoff_interval;
static torture_ofl_func *onoff_f;
static long n_offline_attempts;
static long n_offline_successes;
static unsigned long sum_offline;
static int min_offline = -1;
static int max_offline;
static long n_online_attempts;
static long n_online_successes;
static unsigned long sum_online;
static int min_online = -1;
static int max_online;
static int torture_online_cpus = NR_CPUS;
/*
* Some torture testing leverages confusion as to the number of online
* CPUs. This function returns the torture-testing view of this number,
* which allows torture tests to load-balance appropriately.
*/
int torture_num_online_cpus(void)
{
return READ_ONCE(torture_online_cpus);
}
EXPORT_SYMBOL_GPL(torture_num_online_cpus);
/*
* Attempt to take a CPU offline. Return false if the CPU is already
* offline or if it is not subject to CPU-hotplug operations. The
* caller can detect other failures by looking at the statistics.
*/
bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
unsigned long *sum_offl, int *min_offl, int *max_offl)
{
unsigned long delta;
int ret;
char *s;
unsigned long starttime;
if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
if (num_online_cpus() <= 1)
return false; /* Can't offline the last CPU. */
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: offlining %d\n",
torture_type, cpu);
starttime = jiffies;
(*n_offl_attempts)++;
ret = remove_cpu(cpu);
if (ret) {
s = "";
if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
// PCI probe frequently disables hotplug during boot.
(*n_offl_attempts)--;
s = " (-EBUSY forgiven during boot)";
}
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: offline %d failed%s: errno %d\n",
torture_type, cpu, s, ret);
} else {
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: offlined %d\n",
torture_type, cpu);
if (onoff_f)
onoff_f();
(*n_offl_successes)++;
delta = jiffies - starttime;
*sum_offl += delta;
if (*min_offl < 0) {
*min_offl = delta;
*max_offl = delta;
}
if (*min_offl > delta)
*min_offl = delta;
if (*max_offl < delta)
*max_offl = delta;
WRITE_ONCE(torture_online_cpus, torture_online_cpus - 1);
WARN_ON_ONCE(torture_online_cpus <= 0);
}
return true;
}
EXPORT_SYMBOL_GPL(torture_offline);
/*
* Attempt to bring a CPU online. Return false if the CPU is already
* online or if it is not subject to CPU-hotplug operations. The
* caller can detect other failures by looking at the statistics.
*/
bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
unsigned long *sum_onl, int *min_onl, int *max_onl)
{
unsigned long delta;
int ret;
char *s;
unsigned long starttime;
if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: onlining %d\n",
torture_type, cpu);
starttime = jiffies;
(*n_onl_attempts)++;
ret = add_cpu(cpu);
if (ret) {
s = "";
if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {
// PCI probe frequently disables hotplug during boot.
(*n_onl_attempts)--;
s = " (-EBUSY forgiven during boot)";
}
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: online %d failed%s: errno %d\n",
torture_type, cpu, s, ret);
} else {
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
"torture_onoff task: onlined %d\n",
torture_type, cpu);
(*n_onl_successes)++;
delta = jiffies - starttime;
*sum_onl += delta;
if (*min_onl < 0) {
*min_onl = delta;
*max_onl = delta;
}
if (*min_onl > delta)
*min_onl = delta;
if (*max_onl < delta)
*max_onl = delta;
WRITE_ONCE(torture_online_cpus, torture_online_cpus + 1);
}
return true;
}
EXPORT_SYMBOL_GPL(torture_online);
/*
* Get everything online at the beginning and ends of tests.
*/
static void torture_online_all(char *phase)
{
int cpu;
int ret;
for_each_possible_cpu(cpu) {
if (cpu_online(cpu))
continue;
ret = add_cpu(cpu);
if (ret && verbose) {
pr_alert("%s" TORTURE_FLAG
"%s: %s online %d: errno %d\n",
__func__, phase, torture_type, cpu, ret);
}
}
}
/*
* Execute random CPU-hotplug operations at the interval specified
* by the onoff_interval.
*/
static int
torture_onoff(void *arg)
{
int cpu;
int maxcpu = -1;
DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("torture_onoff task started");
for_each_online_cpu(cpu)
maxcpu = cpu;
WARN_ON(maxcpu < 0);
torture_online_all("Initial");
if (maxcpu == 0) {
VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
goto stop;
}
if (onoff_holdoff > 0) {
VERBOSE_TOROUT_STRING("torture_onoff begin holdoff");
torture_hrtimeout_jiffies(onoff_holdoff, &rand);
VERBOSE_TOROUT_STRING("torture_onoff end holdoff");
}
while (!torture_must_stop()) {
if (disable_onoff_at_boot && !rcu_inkernel_boot_has_ended()) {
torture_hrtimeout_jiffies(HZ / 10, &rand);
continue;
}
cpu = torture_random(&rand) % (maxcpu + 1);
if (!torture_offline(cpu,
&n_offline_attempts, &n_offline_successes,
&sum_offline, &min_offline, &max_offline))
torture_online(cpu,
&n_online_attempts, &n_online_successes,
&sum_online, &min_online, &max_online);
torture_hrtimeout_jiffies(onoff_interval, &rand);
}
stop:
torture_kthread_stopping("torture_onoff");
torture_online_all("Final");
return 0;
}
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
/*
* Initiate online-offline handling.
*/
int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f)
{
#ifdef CONFIG_HOTPLUG_CPU
onoff_holdoff = ooholdoff;
onoff_interval = oointerval;
onoff_f = f;
if (onoff_interval <= 0)
return 0;
return torture_create_kthread(torture_onoff, NULL, onoff_task);
#else /* #ifdef CONFIG_HOTPLUG_CPU */
return 0;
#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
}
EXPORT_SYMBOL_GPL(torture_onoff_init);
/*
* Clean up after online/offline testing.
*/
static void torture_onoff_cleanup(void)
{
#ifdef CONFIG_HOTPLUG_CPU
if (onoff_task == NULL)
return;
VERBOSE_TOROUT_STRING("Stopping torture_onoff task");
kthread_stop(onoff_task);
onoff_task = NULL;
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
}
/*
* Print online/offline testing statistics.
*/
void torture_onoff_stats(void)
{
#ifdef CONFIG_HOTPLUG_CPU
pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
n_online_successes, n_online_attempts,
n_offline_successes, n_offline_attempts,
min_online, max_online,
min_offline, max_offline,
sum_online, sum_offline, HZ);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
}
EXPORT_SYMBOL_GPL(torture_onoff_stats);
/*
* Were all the online/offline operations successful?
*/
bool torture_onoff_failures(void)
{
#ifdef CONFIG_HOTPLUG_CPU
return n_online_successes != n_online_attempts ||
n_offline_successes != n_offline_attempts;
#else /* #ifdef CONFIG_HOTPLUG_CPU */
return false;
#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
}
EXPORT_SYMBOL_GPL(torture_onoff_failures);
#define TORTURE_RANDOM_MULT 39916801 /* prime */
#define TORTURE_RANDOM_ADD 479001701 /* prime */
#define TORTURE_RANDOM_REFRESH 10000
/*
* Crude but fast random-number generator. Uses a linear congruential
* generator, with occasional help from cpu_clock().
*/
unsigned long
torture_random(struct torture_random_state *trsp)
{
if (--trsp->trs_count < 0) {
trsp->trs_state += (unsigned long)local_clock() + raw_smp_processor_id();
trsp->trs_count = TORTURE_RANDOM_REFRESH;
}
trsp->trs_state = trsp->trs_state * TORTURE_RANDOM_MULT +
TORTURE_RANDOM_ADD;
return swahw32(trsp->trs_state);
}
EXPORT_SYMBOL_GPL(torture_random);
/*
* Variables for shuffling. The idea is to ensure that each CPU stays
* idle for an extended period to test interactions with dyntick idle,
* as well as interactions with any per-CPU variables.
*/
struct shuffle_task {
struct list_head st_l;
struct task_struct *st_t;
};
static long shuffle_interval; /* In jiffies. */
static struct task_struct *shuffler_task;
static cpumask_var_t shuffle_tmp_mask;
static int shuffle_idle_cpu; /* Force all torture tasks off this CPU */
static struct list_head shuffle_task_list = LIST_HEAD_INIT(shuffle_task_list);
static DEFINE_MUTEX(shuffle_task_mutex);
/*
* Register a task to be shuffled. If there is no memory, just splat
* and don't bother registering.
*/
void torture_shuffle_task_register(struct task_struct *tp)
{
struct shuffle_task *stp;
if (WARN_ON_ONCE(tp == NULL))
return;
stp = kmalloc(sizeof(*stp), GFP_KERNEL);
if (WARN_ON_ONCE(stp == NULL))
return;
stp->st_t = tp;
mutex_lock(&shuffle_task_mutex);
list_add(&stp->st_l, &shuffle_task_list);
mutex_unlock(&shuffle_task_mutex);
}
EXPORT_SYMBOL_GPL(torture_shuffle_task_register);
/*
* Unregister all tasks, for example, at the end of the torture run.
*/
static void torture_shuffle_task_unregister_all(void)
{
struct shuffle_task *stp;
struct shuffle_task *p;
mutex_lock(&shuffle_task_mutex);
list_for_each_entry_safe(stp, p, &shuffle_task_list, st_l) {
list_del(&stp->st_l);
kfree(stp);
}
mutex_unlock(&shuffle_task_mutex);
}
/* Shuffle tasks such that we allow shuffle_idle_cpu to become idle.
* A special case is when shuffle_idle_cpu = -1, in which case we allow
* the tasks to run on all CPUs.
*/
static void torture_shuffle_tasks(void)
{
DEFINE_TORTURE_RANDOM(rand);
struct shuffle_task *stp;
cpumask_setall(shuffle_tmp_mask);
cpus_read_lock();
/* No point in shuffling if there is only one online CPU (ex: UP) */
if (num_online_cpus() == 1) {
cpus_read_unlock();
return;
}
/* Advance to the next CPU. Upon overflow, don't idle any CPUs. */
shuffle_idle_cpu = cpumask_next(shuffle_idle_cpu, shuffle_tmp_mask);
if (shuffle_idle_cpu >= nr_cpu_ids)
shuffle_idle_cpu = -1;
else
cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
mutex_lock(&shuffle_task_mutex);
list_for_each_entry(stp, &shuffle_task_list, st_l) {
if (!random_shuffle || torture_random(&rand) & 0x1)
set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
}
mutex_unlock(&shuffle_task_mutex);
cpus_read_unlock();
}
/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
* system to become idle at a time and cut off its timer ticks. This is meant
* to test the support for such tickless idle CPU in RCU.
*/
static int torture_shuffle(void *arg)
{
DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("torture_shuffle task started");
do {
torture_hrtimeout_jiffies(shuffle_interval, &rand);
torture_shuffle_tasks();
torture_shutdown_absorb("torture_shuffle");
} while (!torture_must_stop());
torture_kthread_stopping("torture_shuffle");
return 0;
}
/*
* Start the shuffler, with shuffint in jiffies.
*/
int torture_shuffle_init(long shuffint)
{
shuffle_interval = shuffint;
shuffle_idle_cpu = -1;
if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
TOROUT_ERRSTRING("Failed to alloc mask");
return -ENOMEM;
}
/* Create the shuffler thread */
return torture_create_kthread(torture_shuffle, NULL, shuffler_task);
}
EXPORT_SYMBOL_GPL(torture_shuffle_init);
/*
* Stop the shuffling.
*/
static void torture_shuffle_cleanup(void)
{
torture_shuffle_task_unregister_all();
if (shuffler_task) {
VERBOSE_TOROUT_STRING("Stopping torture_shuffle task");
kthread_stop(shuffler_task);
free_cpumask_var(shuffle_tmp_mask);
}
shuffler_task = NULL;
}
/*
* Variables for auto-shutdown. This allows "lights out" torture runs
* to be fully scripted.
*/
static struct task_struct *shutdown_task;
static ktime_t shutdown_time; /* time to system shutdown. */
static void (*torture_shutdown_hook)(void);
/*
* Absorb kthreads into a kernel function that won't return, so that
* they won't ever access module text or data again.
*/
void torture_shutdown_absorb(const char *title)
{
while (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
pr_notice("torture thread %s parking due to system shutdown\n",
title);
schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
}
}
EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
/*
* Cause the torture test to shutdown the system after the test has
* run for the time specified by the shutdown_secs parameter.
*/
static int torture_shutdown(void *arg)
{
ktime_t ktime_snap;
VERBOSE_TOROUT_STRING("torture_shutdown task started");
ktime_snap = ktime_get();
while (ktime_before(ktime_snap, shutdown_time) &&
!torture_must_stop()) {
if (verbose)
pr_alert("%s" TORTURE_FLAG
"torture_shutdown task: %llu ms remaining\n",
torture_type,
ktime_ms_delta(shutdown_time, ktime_snap));
set_current_state(TASK_INTERRUPTIBLE);
schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
ktime_snap = ktime_get();
}
if (torture_must_stop()) {
torture_kthread_stopping("torture_shutdown");
return 0;
}
/* OK, shut down the system. */
VERBOSE_TOROUT_STRING("torture_shutdown task shutting down system");
shutdown_task = NULL; /* Avoid self-kill deadlock. */
if (torture_shutdown_hook)
torture_shutdown_hook();
else
VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
if (ftrace_dump_at_shutdown)
rcu_ftrace_dump(DUMP_ALL);
kernel_power_off(); /* Shut down the system. */
return 0;
}
/*
* Start up the shutdown task.
*/
int torture_shutdown_init(int ssecs, void (*cleanup)(void))
{
torture_shutdown_hook = cleanup;
if (ssecs > 0) {
shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
return torture_create_kthread(torture_shutdown, NULL,
shutdown_task);
}
return 0;
}
EXPORT_SYMBOL_GPL(torture_shutdown_init);
/*
* Detect and respond to a system shutdown.
*/
static int torture_shutdown_notify(struct notifier_block *unused1,
unsigned long unused2, void *unused3)
{
mutex_lock(&fullstop_mutex);
if (READ_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
WRITE_ONCE(fullstop, FULLSTOP_SHUTDOWN);
} else {
pr_warn("Concurrent rmmod and shutdown illegal!\n");
}
mutex_unlock(&fullstop_mutex);
return NOTIFY_DONE;
}
static struct notifier_block torture_shutdown_nb = {
.notifier_call = torture_shutdown_notify,
};
/*
* Shut down the shutdown task. Say what??? Heh! This can happen if
* the torture module gets an rmmod before the shutdown time arrives. ;-)
*/
static void torture_shutdown_cleanup(void)
{
unregister_reboot_notifier(&torture_shutdown_nb);
if (shutdown_task != NULL) {
VERBOSE_TOROUT_STRING("Stopping torture_shutdown task");
kthread_stop(shutdown_task);
}
shutdown_task = NULL;
}
/*
* Variables for stuttering, which means to periodically pause and
* restart testing in order to catch bugs that appear when load is
* suddenly applied to or removed from the system.
*/
static struct task_struct *stutter_task;
static int stutter_pause_test;
static int stutter;
static int stutter_gap;
/*
* Block until the stutter interval ends. This must be called periodically
* by all running kthreads that need to be subject to stuttering.
*/
bool stutter_wait(const char *title)
{
unsigned int i = 0;
bool ret = false;
int spt;
cond_resched_tasks_rcu_qs();
spt = READ_ONCE(stutter_pause_test);
for (; spt; spt = READ_ONCE(stutter_pause_test)) {
if (!ret && !rt_task(current)) {
sched_set_normal(current, MAX_NICE);
ret = true;
}
if (spt == 1) {
torture_hrtimeout_jiffies(1, NULL);
} else if (spt == 2) {
while (READ_ONCE(stutter_pause_test)) {
if (!(i++ & 0xffff))
torture_hrtimeout_us(10, 0, NULL);
cond_resched();
}
} else {
torture_hrtimeout_jiffies(round_jiffies_relative(HZ), NULL);
}
torture_shutdown_absorb(title);
}
return ret;
}
EXPORT_SYMBOL_GPL(stutter_wait);
/*
* Cause the torture test to "stutter", starting and stopping all
* threads periodically.
*/
static int torture_stutter(void *arg)
{
DEFINE_TORTURE_RANDOM(rand);
int wtime;
VERBOSE_TOROUT_STRING("torture_stutter task started");
do {
if (!torture_must_stop() && stutter > 1) {
wtime = stutter;
if (stutter > 2) {
WRITE_ONCE(stutter_pause_test, 1);
wtime = stutter - 3;
torture_hrtimeout_jiffies(wtime, &rand);
wtime = 2;
}
WRITE_ONCE(stutter_pause_test, 2);
torture_hrtimeout_jiffies(wtime, NULL);
}
WRITE_ONCE(stutter_pause_test, 0);
if (!torture_must_stop())
torture_hrtimeout_jiffies(stutter_gap, NULL);
torture_shutdown_absorb("torture_stutter");
} while (!torture_must_stop());
torture_kthread_stopping("torture_stutter");
return 0;
}
/*
* Initialize and kick off the torture_stutter kthread.
*/
int torture_stutter_init(const int s, const int sgap)
{
stutter = s;
stutter_gap = sgap;
return torture_create_kthread(torture_stutter, NULL, stutter_task);
}
EXPORT_SYMBOL_GPL(torture_stutter_init);
/*
* Cleanup after the torture_stutter kthread.
*/
static void torture_stutter_cleanup(void)
{
if (!stutter_task)
return;
VERBOSE_TOROUT_STRING("Stopping torture_stutter task");
kthread_stop(stutter_task);
stutter_task = NULL;
}
/*
* Initialize torture module. Please note that this is -not- invoked via
* the usual module_init() mechanism, but rather by an explicit call from
* the client torture module. This call must be paired with a later
* torture_init_end().
*
* The runnable parameter points to a flag that controls whether or not
* the test is currently runnable. If there is no such flag, pass in NULL.
*/
bool torture_init_begin(char *ttype, int v)
{
mutex_lock(&fullstop_mutex);
if (torture_type != NULL) {
pr_alert("%s: Refusing %s init: %s running.\n",
__func__, ttype, torture_type);
pr_alert("%s: One torture test at a time!\n", __func__);
mutex_unlock(&fullstop_mutex);
return false;
}
torture_type = ttype;
verbose = v;
fullstop = FULLSTOP_DONTSTOP;
return true;
}
EXPORT_SYMBOL_GPL(torture_init_begin);
/*
* Tell the torture module that initialization is complete.
*/
void torture_init_end(void)
{
mutex_unlock(&fullstop_mutex);
register_reboot_notifier(&torture_shutdown_nb);
}
EXPORT_SYMBOL_GPL(torture_init_end);
/*
* Clean up torture module. Please note that this is -not- invoked via
* the usual module_exit() mechanism, but rather by an explicit call from
* the client torture module. Returns true if a race with system shutdown
* is detected, otherwise, all kthreads started by functions in this file
* will be shut down.
*
* This must be called before the caller starts shutting down its own
* kthreads.
*
* Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
* in order to correctly perform the cleanup. They are separated because
* threads can still need to reference the torture_type type, thus nullify
* only after completing all other relevant calls.
*/
bool torture_cleanup_begin(void)
{
mutex_lock(&fullstop_mutex);
if (READ_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
pr_warn("Concurrent rmmod and shutdown illegal!\n");
mutex_unlock(&fullstop_mutex);
schedule_timeout_uninterruptible(10);
return true;
}
WRITE_ONCE(fullstop, FULLSTOP_RMMOD);
mutex_unlock(&fullstop_mutex);
torture_shutdown_cleanup();
torture_shuffle_cleanup();
torture_stutter_cleanup();
torture_onoff_cleanup();
return false;
}
EXPORT_SYMBOL_GPL(torture_cleanup_begin);
void torture_cleanup_end(void)
{
mutex_lock(&fullstop_mutex);
torture_type = NULL;
mutex_unlock(&fullstop_mutex);
}
EXPORT_SYMBOL_GPL(torture_cleanup_end);
/*
* Is it time for the current torture test to stop?
*/
bool torture_must_stop(void)
{
return torture_must_stop_irq() || kthread_should_stop();
}
EXPORT_SYMBOL_GPL(torture_must_stop);
/*
* Is it time for the current torture test to stop? This is the irq-safe
* version, hence no check for kthread_should_stop().
*/
bool torture_must_stop_irq(void)
{
return READ_ONCE(fullstop) != FULLSTOP_DONTSTOP;
}
EXPORT_SYMBOL_GPL(torture_must_stop_irq);
/*
* Each kthread must wait for kthread_should_stop() before returning from
* its top-level function, otherwise segfaults ensue. This function
* prints a "stopping" message and waits for kthread_should_stop(), and
* should be called from all torture kthreads immediately prior to
* returning.
*/
void torture_kthread_stopping(char *title)
{
char buf[128];
snprintf(buf, sizeof(buf), "%s is stopping", title);
VERBOSE_TOROUT_STRING(buf);
while (!kthread_should_stop()) {
torture_shutdown_absorb(title);
schedule_timeout_uninterruptible(HZ / 20);
}
}
EXPORT_SYMBOL_GPL(torture_kthread_stopping);
/*
* Create a generic torture kthread that is immediately runnable. If you
* need the kthread to be stopped so that you can do something to it before
* it starts, you will need to open-code your own.
*/
int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
{
int ret = 0;
VERBOSE_TOROUT_STRING(m);
*tp = kthread_create(fn, arg, "%s", s);
if (IS_ERR(*tp)) {
ret = PTR_ERR(*tp);
TOROUT_ERRSTRING(f);
*tp = NULL;
return ret;
}
if (cbf)
cbf(*tp);
wake_up_process(*tp); // Process is sleeping, so ordering provided.
torture_shuffle_task_register(*tp);
return ret;
}
EXPORT_SYMBOL_GPL(_torture_create_kthread);
/*
* Stop a generic kthread, emitting a message.
*/
void _torture_stop_kthread(char *m, struct task_struct **tp)
{
if (*tp == NULL)
return;
VERBOSE_TOROUT_STRING(m);
kthread_stop(*tp);
*tp = NULL;
}
EXPORT_SYMBOL_GPL(_torture_stop_kthread);
| linux-master | kernel/torture.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Wrapper functions for 16bit uid back compatibility. All nicely tied
* together in the faint hope we can take the out in five years time.
*/
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include "uid16.h"
SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
return ksys_chown(filename, low2highuid(user), low2highgid(group));
}
SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
return ksys_lchown(filename, low2highuid(user), low2highgid(group));
}
SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
{
return ksys_fchown(fd, low2highuid(user), low2highgid(group));
}
SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
{
return __sys_setregid(low2highgid(rgid), low2highgid(egid));
}
SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
{
return __sys_setgid(low2highgid(gid));
}
SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
{
return __sys_setreuid(low2highuid(ruid), low2highuid(euid));
}
SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
{
return __sys_setuid(low2highuid(uid));
}
SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
{
return __sys_setresuid(low2highuid(ruid), low2highuid(euid),
low2highuid(suid));
}
SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
{
const struct cred *cred = current_cred();
int retval;
old_uid_t ruid, euid, suid;
ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
if (!(retval = put_user(ruid, ruidp)) &&
!(retval = put_user(euid, euidp)))
retval = put_user(suid, suidp);
return retval;
}
SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
{
return __sys_setresgid(low2highgid(rgid), low2highgid(egid),
low2highgid(sgid));
}
SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
{
const struct cred *cred = current_cred();
int retval;
old_gid_t rgid, egid, sgid;
rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
if (!(retval = put_user(rgid, rgidp)) &&
!(retval = put_user(egid, egidp)))
retval = put_user(sgid, sgidp);
return retval;
}
SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
{
return __sys_setfsuid(low2highuid(uid));
}
SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
{
return __sys_setfsgid(low2highgid(gid));
}
static int groups16_to_user(old_gid_t __user *grouplist,
struct group_info *group_info)
{
struct user_namespace *user_ns = current_user_ns();
int i;
old_gid_t group;
kgid_t kgid;
for (i = 0; i < group_info->ngroups; i++) {
kgid = group_info->gid[i];
group = high2lowgid(from_kgid_munged(user_ns, kgid));
if (put_user(group, grouplist+i))
return -EFAULT;
}
return 0;
}
static int groups16_from_user(struct group_info *group_info,
old_gid_t __user *grouplist)
{
struct user_namespace *user_ns = current_user_ns();
int i;
old_gid_t group;
kgid_t kgid;
for (i = 0; i < group_info->ngroups; i++) {
if (get_user(group, grouplist+i))
return -EFAULT;
kgid = make_kgid(user_ns, low2highgid(group));
if (!gid_valid(kgid))
return -EINVAL;
group_info->gid[i] = kgid;
}
return 0;
}
SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
const struct cred *cred = current_cred();
int i;
if (gidsetsize < 0)
return -EINVAL;
i = cred->group_info->ngroups;
if (gidsetsize) {
if (i > gidsetsize) {
i = -EINVAL;
goto out;
}
if (groups16_to_user(grouplist, cred->group_info)) {
i = -EFAULT;
goto out;
}
}
out:
return i;
}
SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
struct group_info *group_info;
int retval;
if (!may_setgroups())
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
group_info = groups_alloc(gidsetsize);
if (!group_info)
return -ENOMEM;
retval = groups16_from_user(group_info, grouplist);
if (retval) {
put_group_info(group_info);
return retval;
}
groups_sort(group_info);
retval = set_current_groups(group_info);
put_group_info(group_info);
return retval;
}
SYSCALL_DEFINE0(getuid16)
{
return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
}
SYSCALL_DEFINE0(geteuid16)
{
return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
}
SYSCALL_DEFINE0(getgid16)
{
return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
}
SYSCALL_DEFINE0(getegid16)
{
return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
}
| linux-master | kernel/uid16.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/* auditfilter.c -- filtering of audit events
*
* Copyright 2003-2004 Red Hat, Inc.
* Copyright 2005 Hewlett-Packard Development Company, L.P.
* Copyright 2005 IBM Corporation
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include "audit.h"
/*
* Locking model:
*
* audit_filter_mutex:
* Synchronizes writes and blocking reads of audit's filterlist
* data. Rcu is used to traverse the filterlist and access
* contents of structs audit_entry, audit_watch and opaque
* LSM rules during filtering. If modified, these structures
* must be copied and replace their counterparts in the filterlist.
* An audit_parent struct is not accessed during filtering, so may
* be written directly provided audit_filter_mutex is held.
*/
/* Audit filter lists, defined in <linux/audit.h> */
struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
LIST_HEAD_INIT(audit_filter_list[0]),
LIST_HEAD_INIT(audit_filter_list[1]),
LIST_HEAD_INIT(audit_filter_list[2]),
LIST_HEAD_INIT(audit_filter_list[3]),
LIST_HEAD_INIT(audit_filter_list[4]),
LIST_HEAD_INIT(audit_filter_list[5]),
LIST_HEAD_INIT(audit_filter_list[6]),
LIST_HEAD_INIT(audit_filter_list[7]),
#if AUDIT_NR_FILTERS != 8
#error Fix audit_filter_list initialiser
#endif
};
static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
LIST_HEAD_INIT(audit_rules_list[0]),
LIST_HEAD_INIT(audit_rules_list[1]),
LIST_HEAD_INIT(audit_rules_list[2]),
LIST_HEAD_INIT(audit_rules_list[3]),
LIST_HEAD_INIT(audit_rules_list[4]),
LIST_HEAD_INIT(audit_rules_list[5]),
LIST_HEAD_INIT(audit_rules_list[6]),
LIST_HEAD_INIT(audit_rules_list[7]),
};
DEFINE_MUTEX(audit_filter_mutex);
static void audit_free_lsm_field(struct audit_field *f)
{
switch (f->type) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
kfree(f->lsm_str);
security_audit_rule_free(f->lsm_rule);
}
}
static inline void audit_free_rule(struct audit_entry *e)
{
int i;
struct audit_krule *erule = &e->rule;
/* some rules don't have associated watches */
if (erule->watch)
audit_put_watch(erule->watch);
if (erule->fields)
for (i = 0; i < erule->field_count; i++)
audit_free_lsm_field(&erule->fields[i]);
kfree(erule->fields);
kfree(erule->filterkey);
kfree(e);
}
void audit_free_rule_rcu(struct rcu_head *head)
{
struct audit_entry *e = container_of(head, struct audit_entry, rcu);
audit_free_rule(e);
}
/* Initialize an audit filterlist entry. */
static inline struct audit_entry *audit_init_entry(u32 field_count)
{
struct audit_entry *entry;
struct audit_field *fields;
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (unlikely(!entry))
return NULL;
fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL);
if (unlikely(!fields)) {
kfree(entry);
return NULL;
}
entry->rule.fields = fields;
return entry;
}
/* Unpack a filter field's string representation from user-space
* buffer. */
char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
{
char *str;
if (!*bufp || (len == 0) || (len > *remain))
return ERR_PTR(-EINVAL);
/* Of the currently implemented string fields, PATH_MAX
* defines the longest valid length.
*/
if (len > PATH_MAX)
return ERR_PTR(-ENAMETOOLONG);
str = kmalloc(len + 1, GFP_KERNEL);
if (unlikely(!str))
return ERR_PTR(-ENOMEM);
memcpy(str, *bufp, len);
str[len] = 0;
*bufp += len;
*remain -= len;
return str;
}
/* Translate an inode field to kernel representation. */
static inline int audit_to_inode(struct audit_krule *krule,
struct audit_field *f)
{
if ((krule->listnr != AUDIT_FILTER_EXIT &&
krule->listnr != AUDIT_FILTER_URING_EXIT) ||
krule->inode_f || krule->watch || krule->tree ||
(f->op != Audit_equal && f->op != Audit_not_equal))
return -EINVAL;
krule->inode_f = f;
return 0;
}
static __u32 *classes[AUDIT_SYSCALL_CLASSES];
int __init audit_register_class(int class, unsigned *list)
{
__u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL);
if (!p)
return -ENOMEM;
while (*list != ~0U) {
unsigned n = *list++;
if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
kfree(p);
return -EINVAL;
}
p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
}
if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
kfree(p);
return -EINVAL;
}
classes[class] = p;
return 0;
}
int audit_match_class(int class, unsigned syscall)
{
if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
return 0;
if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
return 0;
return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
}
#ifdef CONFIG_AUDITSYSCALL
static inline int audit_match_class_bits(int class, u32 *mask)
{
int i;
if (classes[class]) {
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
if (mask[i] & classes[class][i])
return 0;
}
return 1;
}
static int audit_match_signal(struct audit_entry *entry)
{
struct audit_field *arch = entry->rule.arch_f;
if (!arch) {
/* When arch is unspecified, we must check both masks on biarch
* as syscall number alone is ambiguous. */
return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
entry->rule.mask) &&
audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
entry->rule.mask));
}
switch (audit_classify_arch(arch->val)) {
case 0: /* native */
return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
entry->rule.mask));
case 1: /* 32bit on biarch */
return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
entry->rule.mask));
default:
return 1;
}
}
#endif
/* Common user-space to kernel rule translation. */
static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule)
{
unsigned listnr;
struct audit_entry *entry;
int i, err;
err = -EINVAL;
listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
switch (listnr) {
default:
goto exit_err;
#ifdef CONFIG_AUDITSYSCALL
case AUDIT_FILTER_ENTRY:
pr_err("AUDIT_FILTER_ENTRY is deprecated\n");
goto exit_err;
case AUDIT_FILTER_EXIT:
case AUDIT_FILTER_URING_EXIT:
case AUDIT_FILTER_TASK:
#endif
case AUDIT_FILTER_USER:
case AUDIT_FILTER_EXCLUDE:
case AUDIT_FILTER_FS:
;
}
if (unlikely(rule->action == AUDIT_POSSIBLE)) {
pr_err("AUDIT_POSSIBLE is deprecated\n");
goto exit_err;
}
if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
goto exit_err;
if (rule->field_count > AUDIT_MAX_FIELDS)
goto exit_err;
err = -ENOMEM;
entry = audit_init_entry(rule->field_count);
if (!entry)
goto exit_err;
entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
entry->rule.listnr = listnr;
entry->rule.action = rule->action;
entry->rule.field_count = rule->field_count;
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
entry->rule.mask[i] = rule->mask[i];
for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
__u32 *class;
if (!(*p & AUDIT_BIT(bit)))
continue;
*p &= ~AUDIT_BIT(bit);
class = classes[i];
if (class) {
int j;
for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
entry->rule.mask[j] |= class[j];
}
}
return entry;
exit_err:
return ERR_PTR(err);
}
static u32 audit_ops[] =
{
[Audit_equal] = AUDIT_EQUAL,
[Audit_not_equal] = AUDIT_NOT_EQUAL,
[Audit_bitmask] = AUDIT_BIT_MASK,
[Audit_bittest] = AUDIT_BIT_TEST,
[Audit_lt] = AUDIT_LESS_THAN,
[Audit_gt] = AUDIT_GREATER_THAN,
[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
};
static u32 audit_to_op(u32 op)
{
u32 n;
for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
;
return n;
}
/* check if an audit field is valid */
static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
{
switch (f->type) {
case AUDIT_MSGTYPE:
if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE &&
entry->rule.listnr != AUDIT_FILTER_USER)
return -EINVAL;
break;
case AUDIT_FSTYPE:
if (entry->rule.listnr != AUDIT_FILTER_FS)
return -EINVAL;
break;
case AUDIT_PERM:
if (entry->rule.listnr == AUDIT_FILTER_URING_EXIT)
return -EINVAL;
break;
}
switch (entry->rule.listnr) {
case AUDIT_FILTER_FS:
switch (f->type) {
case AUDIT_FSTYPE:
case AUDIT_FILTERKEY:
break;
default:
return -EINVAL;
}
}
/* Check for valid field type and op */
switch (f->type) {
case AUDIT_ARG0:
case AUDIT_ARG1:
case AUDIT_ARG2:
case AUDIT_ARG3:
case AUDIT_PERS: /* <uapi/linux/personality.h> */
case AUDIT_DEVMINOR:
/* all ops are valid */
break;
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
case AUDIT_FSUID:
case AUDIT_LOGINUID:
case AUDIT_OBJ_UID:
case AUDIT_GID:
case AUDIT_EGID:
case AUDIT_SGID:
case AUDIT_FSGID:
case AUDIT_OBJ_GID:
case AUDIT_PID:
case AUDIT_MSGTYPE:
case AUDIT_PPID:
case AUDIT_DEVMAJOR:
case AUDIT_EXIT:
case AUDIT_SUCCESS:
case AUDIT_INODE:
case AUDIT_SESSIONID:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
case AUDIT_SADDR_FAM:
/* bit ops are only useful on syscall args */
if (f->op == Audit_bitmask || f->op == Audit_bittest)
return -EINVAL;
break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_WATCH:
case AUDIT_DIR:
case AUDIT_FILTERKEY:
case AUDIT_LOGINUID_SET:
case AUDIT_ARCH:
case AUDIT_FSTYPE:
case AUDIT_PERM:
case AUDIT_FILETYPE:
case AUDIT_FIELD_COMPARE:
case AUDIT_EXE:
/* only equal and not equal valid ops */
if (f->op != Audit_not_equal && f->op != Audit_equal)
return -EINVAL;
break;
default:
/* field not recognized */
return -EINVAL;
}
/* Check for select valid field values */
switch (f->type) {
case AUDIT_LOGINUID_SET:
if ((f->val != 0) && (f->val != 1))
return -EINVAL;
break;
case AUDIT_PERM:
if (f->val & ~15)
return -EINVAL;
break;
case AUDIT_FILETYPE:
if (f->val & ~S_IFMT)
return -EINVAL;
break;
case AUDIT_FIELD_COMPARE:
if (f->val > AUDIT_MAX_FIELD_COMPARE)
return -EINVAL;
break;
case AUDIT_SADDR_FAM:
if (f->val >= AF_MAX)
return -EINVAL;
break;
default:
break;
}
return 0;
}
/* Translate struct audit_rule_data to kernel's rule representation. */
static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
size_t datasz)
{
int err = 0;
struct audit_entry *entry;
void *bufp;
size_t remain = datasz - sizeof(struct audit_rule_data);
int i;
char *str;
struct audit_fsnotify_mark *audit_mark;
entry = audit_to_entry_common(data);
if (IS_ERR(entry))
goto exit_nofree;
bufp = data->buf;
for (i = 0; i < data->field_count; i++) {
struct audit_field *f = &entry->rule.fields[i];
u32 f_val;
err = -EINVAL;
f->op = audit_to_op(data->fieldflags[i]);
if (f->op == Audit_bad)
goto exit_free;
f->type = data->fields[i];
f_val = data->values[i];
/* Support legacy tests for a valid loginuid */
if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) {
f->type = AUDIT_LOGINUID_SET;
f_val = 0;
entry->rule.pflags |= AUDIT_LOGINUID_LEGACY;
}
err = audit_field_valid(entry, f);
if (err)
goto exit_free;
err = -EINVAL;
switch (f->type) {
case AUDIT_LOGINUID:
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
case AUDIT_FSUID:
case AUDIT_OBJ_UID:
f->uid = make_kuid(current_user_ns(), f_val);
if (!uid_valid(f->uid))
goto exit_free;
break;
case AUDIT_GID:
case AUDIT_EGID:
case AUDIT_SGID:
case AUDIT_FSGID:
case AUDIT_OBJ_GID:
f->gid = make_kgid(current_user_ns(), f_val);
if (!gid_valid(f->gid))
goto exit_free;
break;
case AUDIT_ARCH:
f->val = f_val;
entry->rule.arch_f = f;
break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
str = audit_unpack_string(&bufp, &remain, f_val);
if (IS_ERR(str)) {
err = PTR_ERR(str);
goto exit_free;
}
entry->rule.buflen += f_val;
f->lsm_str = str;
err = security_audit_rule_init(f->type, f->op, str,
(void **)&f->lsm_rule);
/* Keep currently invalid fields around in case they
* become valid after a policy reload. */
if (err == -EINVAL) {
pr_warn("audit rule for LSM \'%s\' is invalid\n",
str);
err = 0;
} else if (err)
goto exit_free;
break;
case AUDIT_WATCH:
str = audit_unpack_string(&bufp, &remain, f_val);
if (IS_ERR(str)) {
err = PTR_ERR(str);
goto exit_free;
}
err = audit_to_watch(&entry->rule, str, f_val, f->op);
if (err) {
kfree(str);
goto exit_free;
}
entry->rule.buflen += f_val;
break;
case AUDIT_DIR:
str = audit_unpack_string(&bufp, &remain, f_val);
if (IS_ERR(str)) {
err = PTR_ERR(str);
goto exit_free;
}
err = audit_make_tree(&entry->rule, str, f->op);
kfree(str);
if (err)
goto exit_free;
entry->rule.buflen += f_val;
break;
case AUDIT_INODE:
f->val = f_val;
err = audit_to_inode(&entry->rule, f);
if (err)
goto exit_free;
break;
case AUDIT_FILTERKEY:
if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN)
goto exit_free;
str = audit_unpack_string(&bufp, &remain, f_val);
if (IS_ERR(str)) {
err = PTR_ERR(str);
goto exit_free;
}
entry->rule.buflen += f_val;
entry->rule.filterkey = str;
break;
case AUDIT_EXE:
if (entry->rule.exe || f_val > PATH_MAX)
goto exit_free;
str = audit_unpack_string(&bufp, &remain, f_val);
if (IS_ERR(str)) {
err = PTR_ERR(str);
goto exit_free;
}
audit_mark = audit_alloc_mark(&entry->rule, str, f_val);
if (IS_ERR(audit_mark)) {
kfree(str);
err = PTR_ERR(audit_mark);
goto exit_free;
}
entry->rule.buflen += f_val;
entry->rule.exe = audit_mark;
break;
default:
f->val = f_val;
break;
}
}
if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
entry->rule.inode_f = NULL;
exit_nofree:
return entry;
exit_free:
if (entry->rule.tree)
audit_put_tree(entry->rule.tree); /* that's the temporary one */
if (entry->rule.exe)
audit_remove_mark(entry->rule.exe); /* that's the template one */
audit_free_rule(entry);
return ERR_PTR(err);
}
/* Pack a filter field's string representation into data block. */
static inline size_t audit_pack_string(void **bufp, const char *str)
{
size_t len = strlen(str);
memcpy(*bufp, str, len);
*bufp += len;
return len;
}
/* Translate kernel rule representation to struct audit_rule_data. */
static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
{
struct audit_rule_data *data;
void *bufp;
int i;
data = kmalloc(struct_size(data, buf, krule->buflen), GFP_KERNEL);
if (unlikely(!data))
return NULL;
memset(data, 0, sizeof(*data));
data->flags = krule->flags | krule->listnr;
data->action = krule->action;
data->field_count = krule->field_count;
bufp = data->buf;
for (i = 0; i < data->field_count; i++) {
struct audit_field *f = &krule->fields[i];
data->fields[i] = f->type;
data->fieldflags[i] = audit_ops[f->op];
switch (f->type) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
data->buflen += data->values[i] =
audit_pack_string(&bufp, f->lsm_str);
break;
case AUDIT_WATCH:
data->buflen += data->values[i] =
audit_pack_string(&bufp,
audit_watch_path(krule->watch));
break;
case AUDIT_DIR:
data->buflen += data->values[i] =
audit_pack_string(&bufp,
audit_tree_path(krule->tree));
break;
case AUDIT_FILTERKEY:
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->filterkey);
break;
case AUDIT_EXE:
data->buflen += data->values[i] =
audit_pack_string(&bufp, audit_mark_path(krule->exe));
break;
case AUDIT_LOGINUID_SET:
if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
data->fields[i] = AUDIT_LOGINUID;
data->values[i] = AUDIT_UID_UNSET;
break;
}
fallthrough; /* if set */
default:
data->values[i] = f->val;
}
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
data->mask[i] = krule->mask[i];
return data;
}
/* Compare two rules in kernel format. Considered success if rules
* don't match. */
static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
{
int i;
if (a->flags != b->flags ||
a->pflags != b->pflags ||
a->listnr != b->listnr ||
a->action != b->action ||
a->field_count != b->field_count)
return 1;
for (i = 0; i < a->field_count; i++) {
if (a->fields[i].type != b->fields[i].type ||
a->fields[i].op != b->fields[i].op)
return 1;
switch (a->fields[i].type) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
return 1;
break;
case AUDIT_WATCH:
if (strcmp(audit_watch_path(a->watch),
audit_watch_path(b->watch)))
return 1;
break;
case AUDIT_DIR:
if (strcmp(audit_tree_path(a->tree),
audit_tree_path(b->tree)))
return 1;
break;
case AUDIT_FILTERKEY:
/* both filterkeys exist based on above type compare */
if (strcmp(a->filterkey, b->filterkey))
return 1;
break;
case AUDIT_EXE:
/* both paths exist based on above type compare */
if (strcmp(audit_mark_path(a->exe),
audit_mark_path(b->exe)))
return 1;
break;
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
case AUDIT_FSUID:
case AUDIT_LOGINUID:
case AUDIT_OBJ_UID:
if (!uid_eq(a->fields[i].uid, b->fields[i].uid))
return 1;
break;
case AUDIT_GID:
case AUDIT_EGID:
case AUDIT_SGID:
case AUDIT_FSGID:
case AUDIT_OBJ_GID:
if (!gid_eq(a->fields[i].gid, b->fields[i].gid))
return 1;
break;
default:
if (a->fields[i].val != b->fields[i].val)
return 1;
}
}
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
if (a->mask[i] != b->mask[i])
return 1;
return 0;
}
/* Duplicate LSM field information. The lsm_rule is opaque, so must be
* re-initialized. */
static inline int audit_dupe_lsm_field(struct audit_field *df,
struct audit_field *sf)
{
int ret = 0;
char *lsm_str;
/* our own copy of lsm_str */
lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
if (unlikely(!lsm_str))
return -ENOMEM;
df->lsm_str = lsm_str;
/* our own (refreshed) copy of lsm_rule */
ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
(void **)&df->lsm_rule);
/* Keep currently invalid fields around in case they
* become valid after a policy reload. */
if (ret == -EINVAL) {
pr_warn("audit rule for LSM \'%s\' is invalid\n",
df->lsm_str);
ret = 0;
}
return ret;
}
/* Duplicate an audit rule. This will be a deep copy with the exception
* of the watch - that pointer is carried over. The LSM specific fields
* will be updated in the copy. The point is to be able to replace the old
* rule with the new rule in the filterlist, then free the old rule.
* The rlist element is undefined; list manipulations are handled apart from
* the initial copy. */
struct audit_entry *audit_dupe_rule(struct audit_krule *old)
{
u32 fcount = old->field_count;
struct audit_entry *entry;
struct audit_krule *new;
char *fk;
int i, err = 0;
entry = audit_init_entry(fcount);
if (unlikely(!entry))
return ERR_PTR(-ENOMEM);
new = &entry->rule;
new->flags = old->flags;
new->pflags = old->pflags;
new->listnr = old->listnr;
new->action = old->action;
for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
new->mask[i] = old->mask[i];
new->prio = old->prio;
new->buflen = old->buflen;
new->inode_f = old->inode_f;
new->field_count = old->field_count;
/*
* note that we are OK with not refcounting here; audit_match_tree()
* never dereferences tree and we can't get false positives there
* since we'd have to have rule gone from the list *and* removed
* before the chunks found by lookup had been allocated, i.e. before
* the beginning of list scan.
*/
new->tree = old->tree;
memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);
/* deep copy this information, updating the lsm_rule fields, because
* the originals will all be freed when the old rule is freed. */
for (i = 0; i < fcount; i++) {
switch (new->fields[i].type) {
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
case AUDIT_OBJ_USER:
case AUDIT_OBJ_ROLE:
case AUDIT_OBJ_TYPE:
case AUDIT_OBJ_LEV_LOW:
case AUDIT_OBJ_LEV_HIGH:
err = audit_dupe_lsm_field(&new->fields[i],
&old->fields[i]);
break;
case AUDIT_FILTERKEY:
fk = kstrdup(old->filterkey, GFP_KERNEL);
if (unlikely(!fk))
err = -ENOMEM;
else
new->filterkey = fk;
break;
case AUDIT_EXE:
err = audit_dupe_exe(new, old);
break;
}
if (err) {
if (new->exe)
audit_remove_mark(new->exe);
audit_free_rule(entry);
return ERR_PTR(err);
}
}
if (old->watch) {
audit_get_watch(old->watch);
new->watch = old->watch;
}
return entry;
}
/* Find an existing audit rule.
* Caller must hold audit_filter_mutex to prevent stale rule data. */
static struct audit_entry *audit_find_rule(struct audit_entry *entry,
struct list_head **p)
{
struct audit_entry *e, *found = NULL;
struct list_head *list;
int h;
if (entry->rule.inode_f) {
h = audit_hash_ino(entry->rule.inode_f->val);
*p = list = &audit_inode_hash[h];
} else if (entry->rule.watch) {
/* we don't know the inode number, so must walk entire hash */
for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
list = &audit_inode_hash[h];
list_for_each_entry(e, list, list)
if (!audit_compare_rule(&entry->rule, &e->rule)) {
found = e;
goto out;
}
}
goto out;
} else {
*p = list = &audit_filter_list[entry->rule.listnr];
}
list_for_each_entry(e, list, list)
if (!audit_compare_rule(&entry->rule, &e->rule)) {
found = e;
goto out;
}
out:
return found;
}
static u64 prio_low = ~0ULL/2;
static u64 prio_high = ~0ULL/2 - 1;
/* Add rule to given filterlist if not a duplicate. */
static inline int audit_add_rule(struct audit_entry *entry)
{
struct audit_entry *e;
struct audit_watch *watch = entry->rule.watch;
struct audit_tree *tree = entry->rule.tree;
struct list_head *list;
int err = 0;
#ifdef CONFIG_AUDITSYSCALL
int dont_count = 0;
/* If any of these, don't count towards total */
switch (entry->rule.listnr) {
case AUDIT_FILTER_USER:
case AUDIT_FILTER_EXCLUDE:
case AUDIT_FILTER_FS:
dont_count = 1;
}
#endif
mutex_lock(&audit_filter_mutex);
e = audit_find_rule(entry, &list);
if (e) {
mutex_unlock(&audit_filter_mutex);
err = -EEXIST;
/* normally audit_add_tree_rule() will free it on failure */
if (tree)
audit_put_tree(tree);
return err;
}
if (watch) {
/* audit_filter_mutex is dropped and re-taken during this call */
err = audit_add_watch(&entry->rule, &list);
if (err) {
mutex_unlock(&audit_filter_mutex);
/*
* normally audit_add_tree_rule() will free it
* on failure
*/
if (tree)
audit_put_tree(tree);
return err;
}
}
if (tree) {
err = audit_add_tree_rule(&entry->rule);
if (err) {
mutex_unlock(&audit_filter_mutex);
return err;
}
}
entry->rule.prio = ~0ULL;
if (entry->rule.listnr == AUDIT_FILTER_EXIT ||
entry->rule.listnr == AUDIT_FILTER_URING_EXIT) {
if (entry->rule.flags & AUDIT_FILTER_PREPEND)
entry->rule.prio = ++prio_high;
else
entry->rule.prio = --prio_low;
}
if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
list_add(&entry->rule.list,
&audit_rules_list[entry->rule.listnr]);
list_add_rcu(&entry->list, list);
entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
} else {
list_add_tail(&entry->rule.list,
&audit_rules_list[entry->rule.listnr]);
list_add_tail_rcu(&entry->list, list);
}
#ifdef CONFIG_AUDITSYSCALL
if (!dont_count)
audit_n_rules++;
if (!audit_match_signal(entry))
audit_signals++;
#endif
mutex_unlock(&audit_filter_mutex);
return err;
}
/* Remove an existing rule from filterlist. */
int audit_del_rule(struct audit_entry *entry)
{
struct audit_entry *e;
struct audit_tree *tree = entry->rule.tree;
struct list_head *list;
int ret = 0;
#ifdef CONFIG_AUDITSYSCALL
int dont_count = 0;
/* If any of these, don't count towards total */
switch (entry->rule.listnr) {
case AUDIT_FILTER_USER:
case AUDIT_FILTER_EXCLUDE:
case AUDIT_FILTER_FS:
dont_count = 1;
}
#endif
mutex_lock(&audit_filter_mutex);
e = audit_find_rule(entry, &list);
if (!e) {
ret = -ENOENT;
goto out;
}
if (e->rule.watch)
audit_remove_watch_rule(&e->rule);
if (e->rule.tree)
audit_remove_tree_rule(&e->rule);
if (e->rule.exe)
audit_remove_mark_rule(&e->rule);
#ifdef CONFIG_AUDITSYSCALL
if (!dont_count)
audit_n_rules--;
if (!audit_match_signal(entry))
audit_signals--;
#endif
list_del_rcu(&e->list);
list_del(&e->rule.list);
call_rcu(&e->rcu, audit_free_rule_rcu);
out:
mutex_unlock(&audit_filter_mutex);
if (tree)
audit_put_tree(tree); /* that's the temporary one */
return ret;
}
/* List rules using struct audit_rule_data. */
static void audit_list_rules(int seq, struct sk_buff_head *q)
{
struct sk_buff *skb;
struct audit_krule *r;
int i;
/* This is a blocking read, so use audit_filter_mutex instead of rcu
* iterator to sync with list writers. */
for (i = 0; i < AUDIT_NR_FILTERS; i++) {
list_for_each_entry(r, &audit_rules_list[i], list) {
struct audit_rule_data *data;
data = audit_krule_to_data(r);
if (unlikely(!data))
break;
skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1,
data,
struct_size(data, buf, data->buflen));
if (skb)
skb_queue_tail(q, skb);
kfree(data);
}
}
skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
if (skb)
skb_queue_tail(q, skb);
}
/* Log rule additions and removals */
static void audit_log_rule_change(char *action, struct audit_krule *rule, int res)
{
struct audit_buffer *ab;
if (!audit_enabled)
return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (!ab)
return;
audit_log_session_info(ab);
audit_log_task_context(ab);
audit_log_format(ab, " op=%s", action);
audit_log_key(ab, rule->filterkey);
audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
audit_log_end(ab);
}
/**
* audit_rule_change - apply all rules to the specified message type
* @type: audit message type
* @seq: netlink audit message sequence (serial) number
* @data: payload data
* @datasz: size of payload data
*/
int audit_rule_change(int type, int seq, void *data, size_t datasz)
{
int err = 0;
struct audit_entry *entry;
switch (type) {
case AUDIT_ADD_RULE:
entry = audit_data_to_entry(data, datasz);
if (IS_ERR(entry))
return PTR_ERR(entry);
err = audit_add_rule(entry);
audit_log_rule_change("add_rule", &entry->rule, !err);
break;
case AUDIT_DEL_RULE:
entry = audit_data_to_entry(data, datasz);
if (IS_ERR(entry))
return PTR_ERR(entry);
err = audit_del_rule(entry);
audit_log_rule_change("remove_rule", &entry->rule, !err);
break;
default:
WARN_ON(1);
return -EINVAL;
}
if (err || type == AUDIT_DEL_RULE) {
if (entry->rule.exe)
audit_remove_mark(entry->rule.exe);
audit_free_rule(entry);
}
return err;
}
/**
* audit_list_rules_send - list the audit rules
* @request_skb: skb of request we are replying to (used to target the reply)
* @seq: netlink audit message sequence (serial) number
*/
int audit_list_rules_send(struct sk_buff *request_skb, int seq)
{
struct task_struct *tsk;
struct audit_netlink_list *dest;
/* We can't just spew out the rules here because we might fill
* the available socket buffer space and deadlock waiting for
* auditctl to read from it... which isn't ever going to
* happen if we're actually running in the context of auditctl
* trying to _send_ the stuff */
dest = kmalloc(sizeof(*dest), GFP_KERNEL);
if (!dest)
return -ENOMEM;
dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
dest->portid = NETLINK_CB(request_skb).portid;
skb_queue_head_init(&dest->q);
mutex_lock(&audit_filter_mutex);
audit_list_rules(seq, &dest->q);
mutex_unlock(&audit_filter_mutex);
tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
if (IS_ERR(tsk)) {
skb_queue_purge(&dest->q);
put_net(dest->net);
kfree(dest);
return PTR_ERR(tsk);
}
return 0;
}
int audit_comparator(u32 left, u32 op, u32 right)
{
switch (op) {
case Audit_equal:
return (left == right);
case Audit_not_equal:
return (left != right);
case Audit_lt:
return (left < right);
case Audit_le:
return (left <= right);
case Audit_gt:
return (left > right);
case Audit_ge:
return (left >= right);
case Audit_bitmask:
return (left & right);
case Audit_bittest:
return ((left & right) == right);
default:
return 0;
}
}
int audit_uid_comparator(kuid_t left, u32 op, kuid_t right)
{
switch (op) {
case Audit_equal:
return uid_eq(left, right);
case Audit_not_equal:
return !uid_eq(left, right);
case Audit_lt:
return uid_lt(left, right);
case Audit_le:
return uid_lte(left, right);
case Audit_gt:
return uid_gt(left, right);
case Audit_ge:
return uid_gte(left, right);
case Audit_bitmask:
case Audit_bittest:
default:
return 0;
}
}
int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
{
switch (op) {
case Audit_equal:
return gid_eq(left, right);
case Audit_not_equal:
return !gid_eq(left, right);
case Audit_lt:
return gid_lt(left, right);
case Audit_le:
return gid_lte(left, right);
case Audit_gt:
return gid_gt(left, right);
case Audit_ge:
return gid_gte(left, right);
case Audit_bitmask:
case Audit_bittest:
default:
return 0;
}
}
/**
* parent_len - find the length of the parent portion of a pathname
* @path: pathname of which to determine length
*/
int parent_len(const char *path)
{
int plen;
const char *p;
plen = strlen(path);
if (plen == 0)
return plen;
/* disregard trailing slashes */
p = path + plen - 1;
while ((*p == '/') && (p > path))
p--;
/* walk backward until we find the next slash or hit beginning */
while ((*p != '/') && (p > path))
p--;
/* did we find a slash? Then increment to include it in path */
if (*p == '/')
p++;
return p - path;
}
/**
* audit_compare_dname_path - compare given dentry name with last component in
* given path. Return of 0 indicates a match.
* @dname: dentry name that we're comparing
* @path: full pathname that we're comparing
* @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
* here indicates that we must compute this value.
*/
int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen)
{
int dlen, pathlen;
const char *p;
dlen = dname->len;
pathlen = strlen(path);
if (pathlen < dlen)
return 1;
parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
if (pathlen - parentlen != dlen)
return 1;
p = path + parentlen;
return strncmp(p, dname->name, dlen);
}
int audit_filter(int msgtype, unsigned int listtype)
{
struct audit_entry *e;
int ret = 1; /* Audit by default */
rcu_read_lock();
list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
int i, result = 0;
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
pid_t pid;
u32 sid;
switch (f->type) {
case AUDIT_PID:
pid = task_pid_nr(current);
result = audit_comparator(pid, f->op, f->val);
break;
case AUDIT_UID:
result = audit_uid_comparator(current_uid(), f->op, f->uid);
break;
case AUDIT_GID:
result = audit_gid_comparator(current_gid(), f->op, f->gid);
break;
case AUDIT_LOGINUID:
result = audit_uid_comparator(audit_get_loginuid(current),
f->op, f->uid);
break;
case AUDIT_LOGINUID_SET:
result = audit_comparator(audit_loginuid_set(current),
f->op, f->val);
break;
case AUDIT_MSGTYPE:
result = audit_comparator(msgtype, f->op, f->val);
break;
case AUDIT_SUBJ_USER:
case AUDIT_SUBJ_ROLE:
case AUDIT_SUBJ_TYPE:
case AUDIT_SUBJ_SEN:
case AUDIT_SUBJ_CLR:
if (f->lsm_rule) {
security_current_getsecid_subj(&sid);
result = security_audit_rule_match(sid,
f->type, f->op, f->lsm_rule);
}
break;
case AUDIT_EXE:
result = audit_exe_compare(current, e->rule.exe);
if (f->op == Audit_not_equal)
result = !result;
break;
default:
goto unlock_and_return;
}
if (result < 0) /* error */
goto unlock_and_return;
if (!result)
break;
}
if (result > 0) {
if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE)
ret = 0;
break;
}
}
unlock_and_return:
rcu_read_unlock();
return ret;
}
static int update_lsm_rule(struct audit_krule *r)
{
struct audit_entry *entry = container_of(r, struct audit_entry, rule);
struct audit_entry *nentry;
int err = 0;
if (!security_audit_rule_known(r))
return 0;
nentry = audit_dupe_rule(r);
if (entry->rule.exe)
audit_remove_mark(entry->rule.exe);
if (IS_ERR(nentry)) {
/* save the first error encountered for the
* return value */
err = PTR_ERR(nentry);
audit_panic("error updating LSM filters");
if (r->watch)
list_del(&r->rlist);
list_del_rcu(&entry->list);
list_del(&r->list);
} else {
if (r->watch || r->tree)
list_replace_init(&r->rlist, &nentry->rule.rlist);
list_replace_rcu(&entry->list, &nentry->list);
list_replace(&r->list, &nentry->rule.list);
}
call_rcu(&entry->rcu, audit_free_rule_rcu);
return err;
}
/* This function will re-initialize the lsm_rule field of all applicable rules.
* It will traverse the filter lists serarching for rules that contain LSM
* specific filter fields. When such a rule is found, it is copied, the
* LSM field is re-initialized, and the old rule is replaced with the
* updated rule. */
int audit_update_lsm_rules(void)
{
struct audit_krule *r, *n;
int i, err = 0;
/* audit_filter_mutex synchronizes the writers */
mutex_lock(&audit_filter_mutex);
for (i = 0; i < AUDIT_NR_FILTERS; i++) {
list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
int res = update_lsm_rule(r);
if (!err)
err = res;
}
}
mutex_unlock(&audit_filter_mutex);
return err;
}
| linux-master | kernel/auditfilter.c |
// SPDX-License-Identifier: GPL-2.0
/*
* linux/kernel/capability.c
*
* Copyright (C) 1997 Andrew Main <[email protected]>
*
* Integrated into 2.1.97+, Andrew G. Morgan <[email protected]>
* 30 May 2002: Cleanup, Robert M. Love <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <linux/uaccess.h>
int file_caps_enabled = 1;
static int __init file_caps_disable(char *str)
{
file_caps_enabled = 0;
return 1;
}
__setup("no_file_caps", file_caps_disable);
#ifdef CONFIG_MULTIUSER
/*
* More recent versions of libcap are available from:
*
* http://www.kernel.org/pub/linux/libs/security/linux-privs/
*/
static void warn_legacy_capability_use(void)
{
char name[sizeof(current->comm)];
pr_info_once("warning: `%s' uses 32-bit capabilities (legacy support in use)\n",
get_task_comm(name, current));
}
/*
* Version 2 capabilities worked fine, but the linux/capability.h file
* that accompanied their introduction encouraged their use without
* the necessary user-space source code changes. As such, we have
* created a version 3 with equivalent functionality to version 2, but
* with a header change to protect legacy source code from using
* version 2 when it wanted to use version 1. If your system has code
* that trips the following warning, it is using version 2 specific
* capabilities and may be doing so insecurely.
*
* The remedy is to either upgrade your version of libcap (to 2.10+,
* if the application is linked against it), or recompile your
* application with modern kernel headers and this warning will go
* away.
*/
static void warn_deprecated_v2(void)
{
char name[sizeof(current->comm)];
pr_info_once("warning: `%s' uses deprecated v2 capabilities in a way that may be insecure\n",
get_task_comm(name, current));
}
/*
* Version check. Return the number of u32s in each capability flag
* array, or a negative value on error.
*/
static int cap_validate_magic(cap_user_header_t header, unsigned *tocopy)
{
__u32 version;
if (get_user(version, &header->version))
return -EFAULT;
switch (version) {
case _LINUX_CAPABILITY_VERSION_1:
warn_legacy_capability_use();
*tocopy = _LINUX_CAPABILITY_U32S_1;
break;
case _LINUX_CAPABILITY_VERSION_2:
warn_deprecated_v2();
fallthrough; /* v3 is otherwise equivalent to v2 */
case _LINUX_CAPABILITY_VERSION_3:
*tocopy = _LINUX_CAPABILITY_U32S_3;
break;
default:
if (put_user((u32)_KERNEL_CAPABILITY_VERSION, &header->version))
return -EFAULT;
return -EINVAL;
}
return 0;
}
/*
* The only thing that can change the capabilities of the current
* process is the current process. As such, we can't be in this code
* at the same time as we are in the process of setting capabilities
* in this process. The net result is that we can limit our use of
* locks to when we are reading the caps of another process.
*/
static inline int cap_get_target_pid(pid_t pid, kernel_cap_t *pEp,
kernel_cap_t *pIp, kernel_cap_t *pPp)
{
int ret;
if (pid && (pid != task_pid_vnr(current))) {
const struct task_struct *target;
rcu_read_lock();
target = find_task_by_vpid(pid);
if (!target)
ret = -ESRCH;
else
ret = security_capget(target, pEp, pIp, pPp);
rcu_read_unlock();
} else
ret = security_capget(current, pEp, pIp, pPp);
return ret;
}
/**
* sys_capget - get the capabilities of a given process.
* @header: pointer to struct that contains capability version and
* target pid data
* @dataptr: pointer to struct that contains the effective, permitted,
* and inheritable capabilities that are returned
*
* Returns 0 on success and < 0 on error.
*/
SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr)
{
int ret = 0;
pid_t pid;
unsigned tocopy;
kernel_cap_t pE, pI, pP;
struct __user_cap_data_struct kdata[2];
ret = cap_validate_magic(header, &tocopy);
if ((dataptr == NULL) || (ret != 0))
return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret;
if (get_user(pid, &header->pid))
return -EFAULT;
if (pid < 0)
return -EINVAL;
ret = cap_get_target_pid(pid, &pE, &pI, &pP);
if (ret)
return ret;
/*
* Annoying legacy format with 64-bit capabilities exposed
* as two sets of 32-bit fields, so we need to split the
* capability values up.
*/
kdata[0].effective = pE.val; kdata[1].effective = pE.val >> 32;
kdata[0].permitted = pP.val; kdata[1].permitted = pP.val >> 32;
kdata[0].inheritable = pI.val; kdata[1].inheritable = pI.val >> 32;
/*
* Note, in the case, tocopy < _KERNEL_CAPABILITY_U32S,
* we silently drop the upper capabilities here. This
* has the effect of making older libcap
* implementations implicitly drop upper capability
* bits when they perform a: capget/modify/capset
* sequence.
*
* This behavior is considered fail-safe
* behavior. Upgrading the application to a newer
* version of libcap will enable access to the newer
* capabilities.
*
* An alternative would be to return an error here
* (-ERANGE), but that causes legacy applications to
* unexpectedly fail; the capget/modify/capset aborts
* before modification is attempted and the application
* fails.
*/
if (copy_to_user(dataptr, kdata, tocopy * sizeof(kdata[0])))
return -EFAULT;
return 0;
}
static kernel_cap_t mk_kernel_cap(u32 low, u32 high)
{
return (kernel_cap_t) { (low | ((u64)high << 32)) & CAP_VALID_MASK };
}
/**
* sys_capset - set capabilities for a process or (*) a group of processes
* @header: pointer to struct that contains capability version and
* target pid data
* @data: pointer to struct that contains the effective, permitted,
* and inheritable capabilities
*
* Set capabilities for the current process only. The ability to any other
* process(es) has been deprecated and removed.
*
* The restrictions on setting capabilities are specified as:
*
* I: any raised capabilities must be a subset of the old permitted
* P: any raised capabilities must be a subset of the old permitted
* E: must be set to a subset of new permitted
*
* Returns 0 on success and < 0 on error.
*/
SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
{
struct __user_cap_data_struct kdata[2] = { { 0, }, };
unsigned tocopy, copybytes;
kernel_cap_t inheritable, permitted, effective;
struct cred *new;
int ret;
pid_t pid;
ret = cap_validate_magic(header, &tocopy);
if (ret != 0)
return ret;
if (get_user(pid, &header->pid))
return -EFAULT;
/* may only affect current now */
if (pid != 0 && pid != task_pid_vnr(current))
return -EPERM;
copybytes = tocopy * sizeof(struct __user_cap_data_struct);
if (copybytes > sizeof(kdata))
return -EFAULT;
if (copy_from_user(&kdata, data, copybytes))
return -EFAULT;
effective = mk_kernel_cap(kdata[0].effective, kdata[1].effective);
permitted = mk_kernel_cap(kdata[0].permitted, kdata[1].permitted);
inheritable = mk_kernel_cap(kdata[0].inheritable, kdata[1].inheritable);
new = prepare_creds();
if (!new)
return -ENOMEM;
ret = security_capset(new, current_cred(),
&effective, &inheritable, &permitted);
if (ret < 0)
goto error;
audit_log_capset(new, current_cred());
return commit_creds(new);
error:
abort_creds(new);
return ret;
}
/**
* has_ns_capability - Does a task have a capability in a specific user ns
* @t: The task in question
* @ns: target user namespace
* @cap: The capability to be tested for
*
* Return true if the specified task has the given superior capability
* currently in effect to the specified user namespace, false if not.
*
* Note that this does not set PF_SUPERPRIV on the task.
*/
bool has_ns_capability(struct task_struct *t,
struct user_namespace *ns, int cap)
{
int ret;
rcu_read_lock();
ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NONE);
rcu_read_unlock();
return (ret == 0);
}
/**
* has_capability - Does a task have a capability in init_user_ns
* @t: The task in question
* @cap: The capability to be tested for
*
* Return true if the specified task has the given superior capability
* currently in effect to the initial user namespace, false if not.
*
* Note that this does not set PF_SUPERPRIV on the task.
*/
bool has_capability(struct task_struct *t, int cap)
{
return has_ns_capability(t, &init_user_ns, cap);
}
EXPORT_SYMBOL(has_capability);
/**
* has_ns_capability_noaudit - Does a task have a capability (unaudited)
* in a specific user ns.
* @t: The task in question
* @ns: target user namespace
* @cap: The capability to be tested for
*
* Return true if the specified task has the given superior capability
* currently in effect to the specified user namespace, false if not.
* Do not write an audit message for the check.
*
* Note that this does not set PF_SUPERPRIV on the task.
*/
bool has_ns_capability_noaudit(struct task_struct *t,
struct user_namespace *ns, int cap)
{
int ret;
rcu_read_lock();
ret = security_capable(__task_cred(t), ns, cap, CAP_OPT_NOAUDIT);
rcu_read_unlock();
return (ret == 0);
}
/**
* has_capability_noaudit - Does a task have a capability (unaudited) in the
* initial user ns
* @t: The task in question
* @cap: The capability to be tested for
*
* Return true if the specified task has the given superior capability
* currently in effect to init_user_ns, false if not. Don't write an
* audit message for the check.
*
* Note that this does not set PF_SUPERPRIV on the task.
*/
bool has_capability_noaudit(struct task_struct *t, int cap)
{
return has_ns_capability_noaudit(t, &init_user_ns, cap);
}
EXPORT_SYMBOL(has_capability_noaudit);
static bool ns_capable_common(struct user_namespace *ns,
int cap,
unsigned int opts)
{
int capable;
if (unlikely(!cap_valid(cap))) {
pr_crit("capable() called with invalid cap=%u\n", cap);
BUG();
}
capable = security_capable(current_cred(), ns, cap, opts);
if (capable == 0) {
current->flags |= PF_SUPERPRIV;
return true;
}
return false;
}
/**
* ns_capable - Determine if the current task has a superior capability in effect
* @ns: The usernamespace we want the capability in
* @cap: The capability to be tested for
*
* Return true if the current task has the given superior capability currently
* available for use, false if not.
*
* This sets PF_SUPERPRIV on the task if the capability is available on the
* assumption that it's about to be used.
*/
bool ns_capable(struct user_namespace *ns, int cap)
{
return ns_capable_common(ns, cap, CAP_OPT_NONE);
}
EXPORT_SYMBOL(ns_capable);
/**
* ns_capable_noaudit - Determine if the current task has a superior capability
* (unaudited) in effect
* @ns: The usernamespace we want the capability in
* @cap: The capability to be tested for
*
* Return true if the current task has the given superior capability currently
* available for use, false if not.
*
* This sets PF_SUPERPRIV on the task if the capability is available on the
* assumption that it's about to be used.
*/
bool ns_capable_noaudit(struct user_namespace *ns, int cap)
{
return ns_capable_common(ns, cap, CAP_OPT_NOAUDIT);
}
EXPORT_SYMBOL(ns_capable_noaudit);
/**
* ns_capable_setid - Determine if the current task has a superior capability
* in effect, while signalling that this check is being done from within a
* setid or setgroups syscall.
* @ns: The usernamespace we want the capability in
* @cap: The capability to be tested for
*
* Return true if the current task has the given superior capability currently
* available for use, false if not.
*
* This sets PF_SUPERPRIV on the task if the capability is available on the
* assumption that it's about to be used.
*/
bool ns_capable_setid(struct user_namespace *ns, int cap)
{
return ns_capable_common(ns, cap, CAP_OPT_INSETID);
}
EXPORT_SYMBOL(ns_capable_setid);
/**
* capable - Determine if the current task has a superior capability in effect
* @cap: The capability to be tested for
*
* Return true if the current task has the given superior capability currently
* available for use, false if not.
*
* This sets PF_SUPERPRIV on the task if the capability is available on the
* assumption that it's about to be used.
*/
bool capable(int cap)
{
return ns_capable(&init_user_ns, cap);
}
EXPORT_SYMBOL(capable);
#endif /* CONFIG_MULTIUSER */
/**
* file_ns_capable - Determine if the file's opener had a capability in effect
* @file: The file we want to check
* @ns: The usernamespace we want the capability in
* @cap: The capability to be tested for
*
* Return true if task that opened the file had a capability in effect
* when the file was opened.
*
* This does not set PF_SUPERPRIV because the caller may not
* actually be privileged.
*/
bool file_ns_capable(const struct file *file, struct user_namespace *ns,
int cap)
{
if (WARN_ON_ONCE(!cap_valid(cap)))
return false;
if (security_capable(file->f_cred, ns, cap, CAP_OPT_NONE) == 0)
return true;
return false;
}
EXPORT_SYMBOL(file_ns_capable);
/**
* privileged_wrt_inode_uidgid - Do capabilities in the namespace work over the inode?
* @ns: The user namespace in question
* @idmap: idmap of the mount @inode was found from
* @inode: The inode in question
*
* Return true if the inode uid and gid are within the namespace.
*/
bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
struct mnt_idmap *idmap,
const struct inode *inode)
{
return vfsuid_has_mapping(ns, i_uid_into_vfsuid(idmap, inode)) &&
vfsgid_has_mapping(ns, i_gid_into_vfsgid(idmap, inode));
}
/**
* capable_wrt_inode_uidgid - Check nsown_capable and uid and gid mapped
* @idmap: idmap of the mount @inode was found from
* @inode: The inode in question
* @cap: The capability in question
*
* Return true if the current task has the given capability targeted at
* its own user namespace and that the given inode's uid and gid are
* mapped into the current user namespace.
*/
bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
const struct inode *inode, int cap)
{
struct user_namespace *ns = current_user_ns();
return ns_capable(ns, cap) &&
privileged_wrt_inode_uidgid(ns, idmap, inode);
}
EXPORT_SYMBOL(capable_wrt_inode_uidgid);
/**
* ptracer_capable - Determine if the ptracer holds CAP_SYS_PTRACE in the namespace
* @tsk: The task that may be ptraced
* @ns: The user namespace to search for CAP_SYS_PTRACE in
*
* Return true if the task that is ptracing the current task had CAP_SYS_PTRACE
* in the specified user namespace.
*/
bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns)
{
int ret = 0; /* An absent tracer adds no restrictions */
const struct cred *cred;
rcu_read_lock();
cred = rcu_dereference(tsk->ptracer_cred);
if (cred)
ret = security_capable(cred, ns, CAP_SYS_PTRACE,
CAP_OPT_NOAUDIT);
rcu_read_unlock();
return (ret == 0);
}
| linux-master | kernel/capability.c |
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* taskstats.c - Export per-task statistics to userland
*
* Copyright (C) Shailabh Nagar, IBM Corp. 2006
* (C) Balbir Singh, IBM Corp. 2006
*/
#include <linux/kernel.h>
#include <linux/taskstats_kern.h>
#include <linux/tsacct_kern.h>
#include <linux/acct.h>
#include <linux/delayacct.h>
#include <linux/cpumask.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/cgroupstats.h>
#include <linux/cgroup.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pid_namespace.h>
#include <net/genetlink.h>
#include <linux/atomic.h>
#include <linux/sched/cputime.h>
/*
* Maximum length of a cpumask that can be specified in
* the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
*/
#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
static DEFINE_PER_CPU(__u32, taskstats_seqnum);
static int family_registered;
struct kmem_cache *taskstats_cache;
static struct genl_family family;
static const struct nla_policy taskstats_cmd_get_policy[] = {
[TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
[TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
static const struct nla_policy cgroupstats_cmd_get_policy[] = {
[CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
};
struct listener {
struct list_head list;
pid_t pid;
char valid;
};
struct listener_list {
struct rw_semaphore sem;
struct list_head list;
};
static DEFINE_PER_CPU(struct listener_list, listener_array);
enum actions {
REGISTER,
DEREGISTER,
CPU_DONT_CARE
};
static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
size_t size)
{
struct sk_buff *skb;
void *reply;
/*
* If new attributes are added, please revisit this allocation
*/
skb = genlmsg_new(size, GFP_KERNEL);
if (!skb)
return -ENOMEM;
if (!info) {
int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
} else
reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
if (reply == NULL) {
nlmsg_free(skb);
return -EINVAL;
}
*skbp = skb;
return 0;
}
/*
* Send taskstats data in @skb to listener with nl_pid @pid
*/
static int send_reply(struct sk_buff *skb, struct genl_info *info)
{
struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
void *reply = genlmsg_data(genlhdr);
genlmsg_end(skb, reply);
return genlmsg_reply(skb, info);
}
/*
* Send taskstats data in @skb to listeners registered for @cpu's exit data
*/
static void send_cpu_listeners(struct sk_buff *skb,
struct listener_list *listeners)
{
struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
struct listener *s, *tmp;
struct sk_buff *skb_next, *skb_cur = skb;
void *reply = genlmsg_data(genlhdr);
int delcount = 0;
genlmsg_end(skb, reply);
down_read(&listeners->sem);
list_for_each_entry(s, &listeners->list, list) {
int rc;
skb_next = NULL;
if (!list_is_last(&s->list, &listeners->list)) {
skb_next = skb_clone(skb_cur, GFP_KERNEL);
if (!skb_next)
break;
}
rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
if (rc == -ECONNREFUSED) {
s->valid = 0;
delcount++;
}
skb_cur = skb_next;
}
up_read(&listeners->sem);
if (skb_cur)
nlmsg_free(skb_cur);
if (!delcount)
return;
/* Delete invalidated entries */
down_write(&listeners->sem);
list_for_each_entry_safe(s, tmp, &listeners->list, list) {
if (!s->valid) {
list_del(&s->list);
kfree(s);
}
}
up_write(&listeners->sem);
}
static void exe_add_tsk(struct taskstats *stats, struct task_struct *tsk)
{
/* No idea if I'm allowed to access that here, now. */
struct file *exe_file = get_task_exe_file(tsk);
if (exe_file) {
/* Following cp_new_stat64() in stat.c . */
stats->ac_exe_dev =
huge_encode_dev(exe_file->f_inode->i_sb->s_dev);
stats->ac_exe_inode = exe_file->f_inode->i_ino;
fput(exe_file);
} else {
stats->ac_exe_dev = 0;
stats->ac_exe_inode = 0;
}
}
static void fill_stats(struct user_namespace *user_ns,
struct pid_namespace *pid_ns,
struct task_struct *tsk, struct taskstats *stats)
{
memset(stats, 0, sizeof(*stats));
/*
* Each accounting subsystem adds calls to its functions to
* fill in relevant parts of struct taskstsats as follows
*
* per-task-foo(stats, tsk);
*/
delayacct_add_tsk(stats, tsk);
/* fill in basic acct fields */
stats->version = TASKSTATS_VERSION;
stats->nvcsw = tsk->nvcsw;
stats->nivcsw = tsk->nivcsw;
bacct_add_tsk(user_ns, pid_ns, stats, tsk);
/* fill in extended acct fields */
xacct_add_tsk(stats, tsk);
/* add executable info */
exe_add_tsk(stats, tsk);
}
static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
{
struct task_struct *tsk;
tsk = find_get_task_by_vpid(pid);
if (!tsk)
return -ESRCH;
fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
put_task_struct(tsk);
return 0;
}
static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
{
struct task_struct *tsk, *first;
unsigned long flags;
int rc = -ESRCH;
u64 delta, utime, stime;
u64 start_time;
/*
* Add additional stats from live tasks except zombie thread group
* leaders who are already counted with the dead tasks
*/
rcu_read_lock();
first = find_task_by_vpid(tgid);
if (!first || !lock_task_sighand(first, &flags))
goto out;
if (first->signal->stats)
memcpy(stats, first->signal->stats, sizeof(*stats));
else
memset(stats, 0, sizeof(*stats));
tsk = first;
start_time = ktime_get_ns();
do {
if (tsk->exit_state)
continue;
/*
* Accounting subsystem can call its functions here to
* fill in relevant parts of struct taskstsats as follows
*
* per-task-foo(stats, tsk);
*/
delayacct_add_tsk(stats, tsk);
/* calculate task elapsed time in nsec */
delta = start_time - tsk->start_time;
/* Convert to micro seconds */
do_div(delta, NSEC_PER_USEC);
stats->ac_etime += delta;
task_cputime(tsk, &utime, &stime);
stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
stats->nvcsw += tsk->nvcsw;
stats->nivcsw += tsk->nivcsw;
} while_each_thread(first, tsk);
unlock_task_sighand(first, &flags);
rc = 0;
out:
rcu_read_unlock();
stats->version = TASKSTATS_VERSION;
/*
* Accounting subsystems can also add calls here to modify
* fields of taskstats.
*/
return rc;
}
static void fill_tgid_exit(struct task_struct *tsk)
{
unsigned long flags;
spin_lock_irqsave(&tsk->sighand->siglock, flags);
if (!tsk->signal->stats)
goto ret;
/*
* Each accounting subsystem calls its functions here to
* accumalate its per-task stats for tsk, into the per-tgid structure
*
* per-task-foo(tsk->signal->stats, tsk);
*/
delayacct_add_tsk(tsk->signal->stats, tsk);
ret:
spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
return;
}
static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
{
struct listener_list *listeners;
struct listener *s, *tmp, *s2;
unsigned int cpu;
int ret = 0;
if (!cpumask_subset(mask, cpu_possible_mask))
return -EINVAL;
if (current_user_ns() != &init_user_ns)
return -EINVAL;
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
if (isadd == REGISTER) {
for_each_cpu(cpu, mask) {
s = kmalloc_node(sizeof(struct listener),
GFP_KERNEL, cpu_to_node(cpu));
if (!s) {
ret = -ENOMEM;
goto cleanup;
}
s->pid = pid;
s->valid = 1;
listeners = &per_cpu(listener_array, cpu);
down_write(&listeners->sem);
list_for_each_entry(s2, &listeners->list, list) {
if (s2->pid == pid && s2->valid)
goto exists;
}
list_add(&s->list, &listeners->list);
s = NULL;
exists:
up_write(&listeners->sem);
kfree(s); /* nop if NULL */
}
return 0;
}
/* Deregister or cleanup */
cleanup:
for_each_cpu(cpu, mask) {
listeners = &per_cpu(listener_array, cpu);
down_write(&listeners->sem);
list_for_each_entry_safe(s, tmp, &listeners->list, list) {
if (s->pid == pid) {
list_del(&s->list);
kfree(s);
break;
}
}
up_write(&listeners->sem);
}
return ret;
}
static int parse(struct nlattr *na, struct cpumask *mask)
{
char *data;
int len;
int ret;
if (na == NULL)
return 1;
len = nla_len(na);
if (len > TASKSTATS_CPUMASK_MAXLEN)
return -E2BIG;
if (len < 1)
return -EINVAL;
data = kmalloc(len, GFP_KERNEL);
if (!data)
return -ENOMEM;
nla_strscpy(data, na, len);
ret = cpulist_parse(data, mask);
kfree(data);
return ret;
}
static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
{
struct nlattr *na, *ret;
int aggr;
aggr = (type == TASKSTATS_TYPE_PID)
? TASKSTATS_TYPE_AGGR_PID
: TASKSTATS_TYPE_AGGR_TGID;
na = nla_nest_start_noflag(skb, aggr);
if (!na)
goto err;
if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
nla_nest_cancel(skb, na);
goto err;
}
ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
if (!ret) {
nla_nest_cancel(skb, na);
goto err;
}
nla_nest_end(skb, na);
return nla_data(ret);
err:
return NULL;
}
static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
{
int rc = 0;
struct sk_buff *rep_skb;
struct cgroupstats *stats;
struct nlattr *na;
size_t size;
u32 fd;
struct fd f;
na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
if (!na)
return -EINVAL;
fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
f = fdget(fd);
if (!f.file)
return 0;
size = nla_total_size(sizeof(struct cgroupstats));
rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
size);
if (rc < 0)
goto err;
na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
sizeof(struct cgroupstats));
if (na == NULL) {
nlmsg_free(rep_skb);
rc = -EMSGSIZE;
goto err;
}
stats = nla_data(na);
memset(stats, 0, sizeof(*stats));
rc = cgroupstats_build(stats, f.file->f_path.dentry);
if (rc < 0) {
nlmsg_free(rep_skb);
goto err;
}
rc = send_reply(rep_skb, info);
err:
fdput(f);
return rc;
}
static int cmd_attr_register_cpumask(struct genl_info *info)
{
cpumask_var_t mask;
int rc;
if (!alloc_cpumask_var(&mask, GFP_KERNEL))
return -ENOMEM;
rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
if (rc < 0)
goto out;
rc = add_del_listener(info->snd_portid, mask, REGISTER);
out:
free_cpumask_var(mask);
return rc;
}
static int cmd_attr_deregister_cpumask(struct genl_info *info)
{
cpumask_var_t mask;
int rc;
if (!alloc_cpumask_var(&mask, GFP_KERNEL))
return -ENOMEM;
rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
if (rc < 0)
goto out;
rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
out:
free_cpumask_var(mask);
return rc;
}
static size_t taskstats_packet_size(void)
{
size_t size;
size = nla_total_size(sizeof(u32)) +
nla_total_size_64bit(sizeof(struct taskstats)) +
nla_total_size(0);
return size;
}
static int cmd_attr_pid(struct genl_info *info)
{
struct taskstats *stats;
struct sk_buff *rep_skb;
size_t size;
u32 pid;
int rc;
size = taskstats_packet_size();
rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
if (rc < 0)
return rc;
rc = -EINVAL;
pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
if (!stats)
goto err;
rc = fill_stats_for_pid(pid, stats);
if (rc < 0)
goto err;
return send_reply(rep_skb, info);
err:
nlmsg_free(rep_skb);
return rc;
}
static int cmd_attr_tgid(struct genl_info *info)
{
struct taskstats *stats;
struct sk_buff *rep_skb;
size_t size;
u32 tgid;
int rc;
size = taskstats_packet_size();
rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
if (rc < 0)
return rc;
rc = -EINVAL;
tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
if (!stats)
goto err;
rc = fill_stats_for_tgid(tgid, stats);
if (rc < 0)
goto err;
return send_reply(rep_skb, info);
err:
nlmsg_free(rep_skb);
return rc;
}
static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
{
if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
return cmd_attr_register_cpumask(info);
else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
return cmd_attr_deregister_cpumask(info);
else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
return cmd_attr_pid(info);
else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
return cmd_attr_tgid(info);
else
return -EINVAL;
}
static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
{
struct signal_struct *sig = tsk->signal;
struct taskstats *stats_new, *stats;
/* Pairs with smp_store_release() below. */
stats = smp_load_acquire(&sig->stats);
if (stats || thread_group_empty(tsk))
return stats;
/* No problem if kmem_cache_zalloc() fails */
stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
spin_lock_irq(&tsk->sighand->siglock);
stats = sig->stats;
if (!stats) {
/*
* Pairs with smp_store_release() above and order the
* kmem_cache_zalloc().
*/
smp_store_release(&sig->stats, stats_new);
stats = stats_new;
stats_new = NULL;
}
spin_unlock_irq(&tsk->sighand->siglock);
if (stats_new)
kmem_cache_free(taskstats_cache, stats_new);
return stats;
}
/* Send pid data out on exit */
void taskstats_exit(struct task_struct *tsk, int group_dead)
{
int rc;
struct listener_list *listeners;
struct taskstats *stats;
struct sk_buff *rep_skb;
size_t size;
int is_thread_group;
if (!family_registered)
return;
/*
* Size includes space for nested attributes
*/
size = taskstats_packet_size();
is_thread_group = !!taskstats_tgid_alloc(tsk);
if (is_thread_group) {
/* PID + STATS + TGID + STATS */
size = 2 * size;
/* fill the tsk->signal->stats structure */
fill_tgid_exit(tsk);
}
listeners = raw_cpu_ptr(&listener_array);
if (list_empty(&listeners->list))
return;
rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
if (rc < 0)
return;
stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
task_pid_nr_ns(tsk, &init_pid_ns));
if (!stats)
goto err;
fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
if (group_dead)
stats->ac_flag |= AGROUP;
/*
* Doesn't matter if tsk is the leader or the last group member leaving
*/
if (!is_thread_group || !group_dead)
goto send;
stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
task_tgid_nr_ns(tsk, &init_pid_ns));
if (!stats)
goto err;
memcpy(stats, tsk->signal->stats, sizeof(*stats));
send:
send_cpu_listeners(rep_skb, listeners);
return;
err:
nlmsg_free(rep_skb);
}
static const struct genl_ops taskstats_ops[] = {
{
.cmd = TASKSTATS_CMD_GET,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = taskstats_user_cmd,
.policy = taskstats_cmd_get_policy,
.maxattr = ARRAY_SIZE(taskstats_cmd_get_policy) - 1,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = CGROUPSTATS_CMD_GET,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.doit = cgroupstats_user_cmd,
.policy = cgroupstats_cmd_get_policy,
.maxattr = ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1,
},
};
static struct genl_family family __ro_after_init = {
.name = TASKSTATS_GENL_NAME,
.version = TASKSTATS_GENL_VERSION,
.module = THIS_MODULE,
.ops = taskstats_ops,
.n_ops = ARRAY_SIZE(taskstats_ops),
.resv_start_op = CGROUPSTATS_CMD_GET + 1,
.netnsok = true,
};
/* Needed early in initialization */
void __init taskstats_init_early(void)
{
unsigned int i;
taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
for_each_possible_cpu(i) {
INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
init_rwsem(&(per_cpu(listener_array, i).sem));
}
}
static int __init taskstats_init(void)
{
int rc;
rc = genl_register_family(&family);
if (rc)
return rc;
family_registered = 1;
pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
return 0;
}
/*
* late initcall ensures initialization of statistics collection
* mechanisms precedes initialization of the taskstats interface
*/
late_initcall(taskstats_init);
| linux-master | kernel/taskstats.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* ksyms_common.c: A split of kernel/kallsyms.c
* Contains a few generic function definations independent of config KALLSYMS.
*/
#include <linux/kallsyms.h>
#include <linux/security.h>
static inline int kallsyms_for_perf(void)
{
#ifdef CONFIG_PERF_EVENTS
extern int sysctl_perf_event_paranoid;
if (sysctl_perf_event_paranoid <= 1)
return 1;
#endif
return 0;
}
/*
* We show kallsyms information even to normal users if we've enabled
* kernel profiling and are explicitly not paranoid (so kptr_restrict
* is clear, and sysctl_perf_event_paranoid isn't set).
*
* Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
* block even that).
*/
bool kallsyms_show_value(const struct cred *cred)
{
switch (kptr_restrict) {
case 0:
if (kallsyms_for_perf())
return true;
fallthrough;
case 1:
if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
CAP_OPT_NOAUDIT) == 0)
return true;
fallthrough;
default:
return false;
}
}
| linux-master | kernel/ksyms_common.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* umh - the kernel usermode helper
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/binfmts.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/cred.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fs_struct.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/mount.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/resource.h>
#include <linux/notifier.h>
#include <linux/suspend.h>
#include <linux/rwsem.h>
#include <linux/ptrace.h>
#include <linux/async.h>
#include <linux/uaccess.h>
#include <linux/initrd.h>
#include <linux/freezer.h>
#include <trace/events/module.h>
static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
static DEFINE_SPINLOCK(umh_sysctl_lock);
static DECLARE_RWSEM(umhelper_sem);
static void call_usermodehelper_freeinfo(struct subprocess_info *info)
{
if (info->cleanup)
(*info->cleanup)(info);
kfree(info);
}
static void umh_complete(struct subprocess_info *sub_info)
{
struct completion *comp = xchg(&sub_info->complete, NULL);
/*
* See call_usermodehelper_exec(). If xchg() returns NULL
* we own sub_info, the UMH_KILLABLE caller has gone away
* or the caller used UMH_NO_WAIT.
*/
if (comp)
complete(comp);
else
call_usermodehelper_freeinfo(sub_info);
}
/*
* This is the task which runs the usermode application
*/
static int call_usermodehelper_exec_async(void *data)
{
struct subprocess_info *sub_info = data;
struct cred *new;
int retval;
spin_lock_irq(¤t->sighand->siglock);
flush_signal_handlers(current, 1);
spin_unlock_irq(¤t->sighand->siglock);
/*
* Initial kernel threads share ther FS with init, in order to
* get the init root directory. But we've now created a new
* thread that is going to execve a user process and has its own
* 'struct fs_struct'. Reset umask to the default.
*/
current->fs->umask = 0022;
/*
* Our parent (unbound workqueue) runs with elevated scheduling
* priority. Avoid propagating that into the userspace child.
*/
set_user_nice(current, 0);
retval = -ENOMEM;
new = prepare_kernel_cred(current);
if (!new)
goto out;
spin_lock(&umh_sysctl_lock);
new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);
new->cap_inheritable = cap_intersect(usermodehelper_inheritable,
new->cap_inheritable);
spin_unlock(&umh_sysctl_lock);
if (sub_info->init) {
retval = sub_info->init(sub_info, new);
if (retval) {
abort_creds(new);
goto out;
}
}
commit_creds(new);
wait_for_initramfs();
retval = kernel_execve(sub_info->path,
(const char *const *)sub_info->argv,
(const char *const *)sub_info->envp);
out:
sub_info->retval = retval;
/*
* call_usermodehelper_exec_sync() will call umh_complete
* if UHM_WAIT_PROC.
*/
if (!(sub_info->wait & UMH_WAIT_PROC))
umh_complete(sub_info);
if (!retval)
return 0;
do_exit(0);
}
/* Handles UMH_WAIT_PROC. */
static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info)
{
pid_t pid;
/* If SIGCLD is ignored do_wait won't populate the status. */
kernel_sigaction(SIGCHLD, SIG_DFL);
pid = user_mode_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
if (pid < 0)
sub_info->retval = pid;
else
kernel_wait(pid, &sub_info->retval);
/* Restore default kernel sig handler */
kernel_sigaction(SIGCHLD, SIG_IGN);
umh_complete(sub_info);
}
/*
* We need to create the usermodehelper kernel thread from a task that is affine
* to an optimized set of CPUs (or nohz housekeeping ones) such that they
* inherit a widest affinity irrespective of call_usermodehelper() callers with
* possibly reduced affinity (eg: per-cpu workqueues). We don't want
* usermodehelper targets to contend a busy CPU.
*
* Unbound workqueues provide such wide affinity and allow to block on
* UMH_WAIT_PROC requests without blocking pending request (up to some limit).
*
* Besides, workqueues provide the privilege level that caller might not have
* to perform the usermodehelper request.
*
*/
static void call_usermodehelper_exec_work(struct work_struct *work)
{
struct subprocess_info *sub_info =
container_of(work, struct subprocess_info, work);
if (sub_info->wait & UMH_WAIT_PROC) {
call_usermodehelper_exec_sync(sub_info);
} else {
pid_t pid;
/*
* Use CLONE_PARENT to reparent it to kthreadd; we do not
* want to pollute current->children, and we need a parent
* that always ignores SIGCHLD to ensure auto-reaping.
*/
pid = user_mode_thread(call_usermodehelper_exec_async, sub_info,
CLONE_PARENT | SIGCHLD);
if (pid < 0) {
sub_info->retval = pid;
umh_complete(sub_info);
}
}
}
/*
* If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
* (used for preventing user land processes from being created after the user
* land has been frozen during a system-wide hibernation or suspend operation).
* Should always be manipulated under umhelper_sem acquired for write.
*/
static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED;
/* Number of helpers running */
static atomic_t running_helpers = ATOMIC_INIT(0);
/*
* Wait queue head used by usermodehelper_disable() to wait for all running
* helpers to finish.
*/
static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
/*
* Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
* to become 'false'.
*/
static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq);
/*
* Time to wait for running_helpers to become zero before the setting of
* usermodehelper_disabled in usermodehelper_disable() fails
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
int usermodehelper_read_trylock(void)
{
DEFINE_WAIT(wait);
int ret = 0;
down_read(&umhelper_sem);
for (;;) {
prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
TASK_INTERRUPTIBLE);
if (!usermodehelper_disabled)
break;
if (usermodehelper_disabled == UMH_DISABLED)
ret = -EAGAIN;
up_read(&umhelper_sem);
if (ret)
break;
schedule();
try_to_freeze();
down_read(&umhelper_sem);
}
finish_wait(&usermodehelper_disabled_waitq, &wait);
return ret;
}
EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
long usermodehelper_read_lock_wait(long timeout)
{
DEFINE_WAIT(wait);
if (timeout < 0)
return -EINVAL;
down_read(&umhelper_sem);
for (;;) {
prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
TASK_UNINTERRUPTIBLE);
if (!usermodehelper_disabled)
break;
up_read(&umhelper_sem);
timeout = schedule_timeout(timeout);
if (!timeout)
break;
down_read(&umhelper_sem);
}
finish_wait(&usermodehelper_disabled_waitq, &wait);
return timeout;
}
EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait);
void usermodehelper_read_unlock(void)
{
up_read(&umhelper_sem);
}
EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
/**
* __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
* @depth: New value to assign to usermodehelper_disabled.
*
* Change the value of usermodehelper_disabled (under umhelper_sem locked for
* writing) and wakeup tasks waiting for it to change.
*/
void __usermodehelper_set_disable_depth(enum umh_disable_depth depth)
{
down_write(&umhelper_sem);
usermodehelper_disabled = depth;
wake_up(&usermodehelper_disabled_waitq);
up_write(&umhelper_sem);
}
/**
* __usermodehelper_disable - Prevent new helpers from being started.
* @depth: New value to assign to usermodehelper_disabled.
*
* Set usermodehelper_disabled to @depth and wait for running helpers to exit.
*/
int __usermodehelper_disable(enum umh_disable_depth depth)
{
long retval;
if (!depth)
return -EINVAL;
down_write(&umhelper_sem);
usermodehelper_disabled = depth;
up_write(&umhelper_sem);
/*
* From now on call_usermodehelper_exec() won't start any new
* helpers, so it is sufficient if running_helpers turns out to
* be zero at one point (it may be increased later, but that
* doesn't matter).
*/
retval = wait_event_timeout(running_helpers_waitq,
atomic_read(&running_helpers) == 0,
RUNNING_HELPERS_TIMEOUT);
if (retval)
return 0;
__usermodehelper_set_disable_depth(UMH_ENABLED);
return -EAGAIN;
}
static void helper_lock(void)
{
atomic_inc(&running_helpers);
smp_mb__after_atomic();
}
static void helper_unlock(void)
{
if (atomic_dec_and_test(&running_helpers))
wake_up(&running_helpers_waitq);
}
/**
* call_usermodehelper_setup - prepare to call a usermode helper
* @path: path to usermode executable
* @argv: arg vector for process
* @envp: environment for process
* @gfp_mask: gfp mask for memory allocation
* @init: an init function
* @cleanup: a cleanup function
* @data: arbitrary context sensitive data
*
* Returns either %NULL on allocation failure, or a subprocess_info
* structure. This should be passed to call_usermodehelper_exec to
* exec the process and free the structure.
*
* The init function is used to customize the helper process prior to
* exec. A non-zero return code causes the process to error out, exit,
* and return the failure to the calling process
*
* The cleanup function is just before the subprocess_info is about to
* be freed. This can be used for freeing the argv and envp. The
* Function must be runnable in either a process context or the
* context in which call_usermodehelper_exec is called.
*/
struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
char **envp, gfp_t gfp_mask,
int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *info),
void *data)
{
struct subprocess_info *sub_info;
sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);
if (!sub_info)
goto out;
INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
#ifdef CONFIG_STATIC_USERMODEHELPER
sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;
#else
sub_info->path = path;
#endif
sub_info->argv = argv;
sub_info->envp = envp;
sub_info->cleanup = cleanup;
sub_info->init = init;
sub_info->data = data;
out:
return sub_info;
}
EXPORT_SYMBOL(call_usermodehelper_setup);
/**
* call_usermodehelper_exec - start a usermode application
* @sub_info: information about the subprocess
* @wait: wait for the application to finish and return status.
* when UMH_NO_WAIT don't wait at all, but you get no useful error back
* when the program couldn't be exec'ed. This makes it safe to call
* from interrupt context.
*
* Runs a user-space application. The application is started
* asynchronously if wait is not set, and runs as a child of system workqueues.
* (ie. it runs with full root capabilities and optimized affinity).
*
* Note: successful return value does not guarantee the helper was called at
* all. You can't rely on sub_info->{init,cleanup} being called even for
* UMH_WAIT_* wait modes as STATIC_USERMODEHELPER_PATH="" turns all helpers
* into a successful no-op.
*/
int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
{
unsigned int state = TASK_UNINTERRUPTIBLE;
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
if (!sub_info->path) {
call_usermodehelper_freeinfo(sub_info);
return -EINVAL;
}
helper_lock();
if (usermodehelper_disabled) {
retval = -EBUSY;
goto out;
}
/*
* If there is no binary for us to call, then just return and get out of
* here. This allows us to set STATIC_USERMODEHELPER_PATH to "" and
* disable all call_usermodehelper() calls.
*/
if (strlen(sub_info->path) == 0)
goto out;
/*
* Set the completion pointer only if there is a waiter.
* This makes it possible to use umh_complete to free
* the data structure in case of UMH_NO_WAIT.
*/
sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
sub_info->wait = wait;
queue_work(system_unbound_wq, &sub_info->work);
if (wait == UMH_NO_WAIT) /* task has freed sub_info */
goto unlock;
if (wait & UMH_FREEZABLE)
state |= TASK_FREEZABLE;
if (wait & UMH_KILLABLE) {
retval = wait_for_completion_state(&done, state | TASK_KILLABLE);
if (!retval)
goto wait_done;
/* umh_complete() will see NULL and free sub_info */
if (xchg(&sub_info->complete, NULL))
goto unlock;
/*
* fallthrough; in case of -ERESTARTSYS now do uninterruptible
* wait_for_completion_state(). Since umh_complete() shall call
* complete() in a moment if xchg() above returned NULL, this
* uninterruptible wait_for_completion_state() will not block
* SIGKILL'ed processes for long.
*/
}
wait_for_completion_state(&done, state);
wait_done:
retval = sub_info->retval;
out:
call_usermodehelper_freeinfo(sub_info);
unlock:
helper_unlock();
return retval;
}
EXPORT_SYMBOL(call_usermodehelper_exec);
/**
* call_usermodehelper() - prepare and start a usermode application
* @path: path to usermode executable
* @argv: arg vector for process
* @envp: environment for process
* @wait: wait for the application to finish and return status.
* when UMH_NO_WAIT don't wait at all, but you get no useful error back
* when the program couldn't be exec'ed. This makes it safe to call
* from interrupt context.
*
* This function is the equivalent to use call_usermodehelper_setup() and
* call_usermodehelper_exec().
*/
int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
{
struct subprocess_info *info;
gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
NULL, NULL, NULL);
if (info == NULL)
return -ENOMEM;
return call_usermodehelper_exec(info, wait);
}
EXPORT_SYMBOL(call_usermodehelper);
#if defined(CONFIG_SYSCTL)
static int proc_cap_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table t;
unsigned long cap_array[2];
kernel_cap_t new_cap, *cap;
int err;
if (write && (!capable(CAP_SETPCAP) ||
!capable(CAP_SYS_MODULE)))
return -EPERM;
/*
* convert from the global kernel_cap_t to the ulong array to print to
* userspace if this is a read.
*
* Legacy format: capabilities are exposed as two 32-bit values
*/
cap = table->data;
spin_lock(&umh_sysctl_lock);
cap_array[0] = (u32) cap->val;
cap_array[1] = cap->val >> 32;
spin_unlock(&umh_sysctl_lock);
t = *table;
t.data = &cap_array;
/*
* actually read or write and array of ulongs from userspace. Remember
* these are least significant 32 bits first
*/
err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
if (err < 0)
return err;
new_cap.val = (u32)cap_array[0];
new_cap.val += (u64)cap_array[1] << 32;
/*
* Drop everything not in the new_cap (but don't add things)
*/
if (write) {
spin_lock(&umh_sysctl_lock);
*cap = cap_intersect(*cap, new_cap);
spin_unlock(&umh_sysctl_lock);
}
return 0;
}
static struct ctl_table usermodehelper_table[] = {
{
.procname = "bset",
.data = &usermodehelper_bset,
.maxlen = 2 * sizeof(unsigned long),
.mode = 0600,
.proc_handler = proc_cap_handler,
},
{
.procname = "inheritable",
.data = &usermodehelper_inheritable,
.maxlen = 2 * sizeof(unsigned long),
.mode = 0600,
.proc_handler = proc_cap_handler,
},
{ }
};
static int __init init_umh_sysctls(void)
{
register_sysctl_init("kernel/usermodehelper", usermodehelper_table);
return 0;
}
early_initcall(init_umh_sysctls);
#endif /* CONFIG_SYSCTL */
| linux-master | kernel/umh.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic helpers for smp ipi calls
*
* (C) Jens Axboe <[email protected]> 2008
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/irq_work.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/sched/idle.h>
#include <linux/hypervisor.h>
#include <linux/sched/clock.h>
#include <linux/nmi.h>
#include <linux/sched/debug.h>
#include <linux/jump_label.h>
#include <trace/events/ipi.h>
#define CREATE_TRACE_POINTS
#include <trace/events/csd.h>
#undef CREATE_TRACE_POINTS
#include "smpboot.h"
#include "sched/smp.h"
#define CSD_TYPE(_csd) ((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK)
struct call_function_data {
call_single_data_t __percpu *csd;
cpumask_var_t cpumask;
cpumask_var_t cpumask_ipi;
};
static DEFINE_PER_CPU_ALIGNED(struct call_function_data, cfd_data);
static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
static DEFINE_PER_CPU(atomic_t, trigger_backtrace) = ATOMIC_INIT(1);
static void __flush_smp_call_function_queue(bool warn_cpu_offline);
int smpcfd_prepare_cpu(unsigned int cpu)
{
struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
cpu_to_node(cpu)))
return -ENOMEM;
if (!zalloc_cpumask_var_node(&cfd->cpumask_ipi, GFP_KERNEL,
cpu_to_node(cpu))) {
free_cpumask_var(cfd->cpumask);
return -ENOMEM;
}
cfd->csd = alloc_percpu(call_single_data_t);
if (!cfd->csd) {
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
return -ENOMEM;
}
return 0;
}
int smpcfd_dead_cpu(unsigned int cpu)
{
struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
free_percpu(cfd->csd);
return 0;
}
int smpcfd_dying_cpu(unsigned int cpu)
{
/*
* The IPIs for the smp-call-function callbacks queued by other
* CPUs might arrive late, either due to hardware latencies or
* because this CPU disabled interrupts (inside stop-machine)
* before the IPIs were sent. So flush out any pending callbacks
* explicitly (without waiting for the IPIs to arrive), to
* ensure that the outgoing CPU doesn't go offline with work
* still pending.
*/
__flush_smp_call_function_queue(false);
irq_work_run();
return 0;
}
void __init call_function_init(void)
{
int i;
for_each_possible_cpu(i)
init_llist_head(&per_cpu(call_single_queue, i));
smpcfd_prepare_cpu(smp_processor_id());
}
static __always_inline void
send_call_function_single_ipi(int cpu)
{
if (call_function_single_prep_ipi(cpu)) {
trace_ipi_send_cpu(cpu, _RET_IP_,
generic_smp_call_function_single_interrupt);
arch_send_call_function_single_ipi(cpu);
}
}
static __always_inline void
send_call_function_ipi_mask(struct cpumask *mask)
{
trace_ipi_send_cpumask(mask, _RET_IP_,
generic_smp_call_function_single_interrupt);
arch_send_call_function_ipi_mask(mask);
}
static __always_inline void
csd_do_func(smp_call_func_t func, void *info, struct __call_single_data *csd)
{
trace_csd_function_entry(func, csd);
func(info);
trace_csd_function_exit(func, csd);
}
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
static DEFINE_STATIC_KEY_MAYBE(CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT, csdlock_debug_enabled);
/*
* Parse the csdlock_debug= kernel boot parameter.
*
* If you need to restore the old "ext" value that once provided
* additional debugging information, reapply the following commits:
*
* de7b09ef658d ("locking/csd_lock: Prepare more CSD lock debugging")
* a5aabace5fb8 ("locking/csd_lock: Add more data to CSD lock debugging")
*/
static int __init csdlock_debug(char *str)
{
int ret;
unsigned int val = 0;
ret = get_option(&str, &val);
if (ret) {
if (val)
static_branch_enable(&csdlock_debug_enabled);
else
static_branch_disable(&csdlock_debug_enabled);
}
return 1;
}
__setup("csdlock_debug=", csdlock_debug);
static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);
static DEFINE_PER_CPU(void *, cur_csd_info);
static ulong csd_lock_timeout = 5000; /* CSD lock timeout in milliseconds. */
module_param(csd_lock_timeout, ulong, 0444);
static atomic_t csd_bug_count = ATOMIC_INIT(0);
/* Record current CSD work for current CPU, NULL to erase. */
static void __csd_lock_record(struct __call_single_data *csd)
{
if (!csd) {
smp_mb(); /* NULL cur_csd after unlock. */
__this_cpu_write(cur_csd, NULL);
return;
}
__this_cpu_write(cur_csd_func, csd->func);
__this_cpu_write(cur_csd_info, csd->info);
smp_wmb(); /* func and info before csd. */
__this_cpu_write(cur_csd, csd);
smp_mb(); /* Update cur_csd before function call. */
/* Or before unlock, as the case may be. */
}
static __always_inline void csd_lock_record(struct __call_single_data *csd)
{
if (static_branch_unlikely(&csdlock_debug_enabled))
__csd_lock_record(csd);
}
static int csd_lock_wait_getcpu(struct __call_single_data *csd)
{
unsigned int csd_type;
csd_type = CSD_TYPE(csd);
if (csd_type == CSD_TYPE_ASYNC || csd_type == CSD_TYPE_SYNC)
return csd->node.dst; /* Other CSD_TYPE_ values might not have ->dst. */
return -1;
}
/*
* Complain if too much time spent waiting. Note that only
* the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
* so waiting on other types gets much less information.
*/
static bool csd_lock_wait_toolong(struct __call_single_data *csd, u64 ts0, u64 *ts1, int *bug_id)
{
int cpu = -1;
int cpux;
bool firsttime;
u64 ts2, ts_delta;
call_single_data_t *cpu_cur_csd;
unsigned int flags = READ_ONCE(csd->node.u_flags);
unsigned long long csd_lock_timeout_ns = csd_lock_timeout * NSEC_PER_MSEC;
if (!(flags & CSD_FLAG_LOCK)) {
if (!unlikely(*bug_id))
return true;
cpu = csd_lock_wait_getcpu(csd);
pr_alert("csd: CSD lock (#%d) got unstuck on CPU#%02d, CPU#%02d released the lock.\n",
*bug_id, raw_smp_processor_id(), cpu);
return true;
}
ts2 = sched_clock();
ts_delta = ts2 - *ts1;
if (likely(ts_delta <= csd_lock_timeout_ns || csd_lock_timeout_ns == 0))
return false;
firsttime = !*bug_id;
if (firsttime)
*bug_id = atomic_inc_return(&csd_bug_count);
cpu = csd_lock_wait_getcpu(csd);
if (WARN_ONCE(cpu < 0 || cpu >= nr_cpu_ids, "%s: cpu = %d\n", __func__, cpu))
cpux = 0;
else
cpux = cpu;
cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */
pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n",
firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts2 - ts0,
cpu, csd->func, csd->info);
if (cpu_cur_csd && csd != cpu_cur_csd) {
pr_alert("\tcsd: CSD lock (#%d) handling prior %pS(%ps) request.\n",
*bug_id, READ_ONCE(per_cpu(cur_csd_func, cpux)),
READ_ONCE(per_cpu(cur_csd_info, cpux)));
} else {
pr_alert("\tcsd: CSD lock (#%d) %s.\n",
*bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
}
if (cpu >= 0) {
if (atomic_cmpxchg_acquire(&per_cpu(trigger_backtrace, cpu), 1, 0))
dump_cpu_task(cpu);
if (!cpu_cur_csd) {
pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
arch_send_call_function_single_ipi(cpu);
}
}
if (firsttime)
dump_stack();
*ts1 = ts2;
return false;
}
/*
* csd_lock/csd_unlock used to serialize access to per-cpu csd resources
*
* For non-synchronous ipi calls the csd can still be in use by the
* previous function call. For multi-cpu calls its even more interesting
* as we'll have to ensure no other cpu is observing our csd.
*/
static void __csd_lock_wait(struct __call_single_data *csd)
{
int bug_id = 0;
u64 ts0, ts1;
ts1 = ts0 = sched_clock();
for (;;) {
if (csd_lock_wait_toolong(csd, ts0, &ts1, &bug_id))
break;
cpu_relax();
}
smp_acquire__after_ctrl_dep();
}
static __always_inline void csd_lock_wait(struct __call_single_data *csd)
{
if (static_branch_unlikely(&csdlock_debug_enabled)) {
__csd_lock_wait(csd);
return;
}
smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
}
#else
static void csd_lock_record(struct __call_single_data *csd)
{
}
static __always_inline void csd_lock_wait(struct __call_single_data *csd)
{
smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
}
#endif
static __always_inline void csd_lock(struct __call_single_data *csd)
{
csd_lock_wait(csd);
csd->node.u_flags |= CSD_FLAG_LOCK;
/*
* prevent CPU from reordering the above assignment
* to ->flags with any subsequent assignments to other
* fields of the specified call_single_data_t structure:
*/
smp_wmb();
}
static __always_inline void csd_unlock(struct __call_single_data *csd)
{
WARN_ON(!(csd->node.u_flags & CSD_FLAG_LOCK));
/*
* ensure we're all done before releasing data:
*/
smp_store_release(&csd->node.u_flags, 0);
}
static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
void __smp_call_single_queue(int cpu, struct llist_node *node)
{
/*
* We have to check the type of the CSD before queueing it, because
* once queued it can have its flags cleared by
* flush_smp_call_function_queue()
* even if we haven't sent the smp_call IPI yet (e.g. the stopper
* executes migration_cpu_stop() on the remote CPU).
*/
if (trace_csd_queue_cpu_enabled()) {
call_single_data_t *csd;
smp_call_func_t func;
csd = container_of(node, call_single_data_t, node.llist);
func = CSD_TYPE(csd) == CSD_TYPE_TTWU ?
sched_ttwu_pending : csd->func;
trace_csd_queue_cpu(cpu, _RET_IP_, func, csd);
}
/*
* The list addition should be visible to the target CPU when it pops
* the head of the list to pull the entry off it in the IPI handler
* because of normal cache coherency rules implied by the underlying
* llist ops.
*
* If IPIs can go out of order to the cache coherency protocol
* in an architecture, sufficient synchronisation should be added
* to arch code to make it appear to obey cache coherency WRT
* locking and barrier primitives. Generic code isn't really
* equipped to do the right thing...
*/
if (llist_add(node, &per_cpu(call_single_queue, cpu)))
send_call_function_single_ipi(cpu);
}
/*
* Insert a previously allocated call_single_data_t element
* for execution on the given CPU. data must already have
* ->func, ->info, and ->flags set.
*/
static int generic_exec_single(int cpu, struct __call_single_data *csd)
{
if (cpu == smp_processor_id()) {
smp_call_func_t func = csd->func;
void *info = csd->info;
unsigned long flags;
/*
* We can unlock early even for the synchronous on-stack case,
* since we're doing this from the same CPU..
*/
csd_lock_record(csd);
csd_unlock(csd);
local_irq_save(flags);
csd_do_func(func, info, NULL);
csd_lock_record(NULL);
local_irq_restore(flags);
return 0;
}
if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
csd_unlock(csd);
return -ENXIO;
}
__smp_call_single_queue(cpu, &csd->node.llist);
return 0;
}
/**
* generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks
*
* Invoked by arch to handle an IPI for call function single.
* Must be called with interrupts disabled.
*/
void generic_smp_call_function_single_interrupt(void)
{
__flush_smp_call_function_queue(true);
}
/**
* __flush_smp_call_function_queue - Flush pending smp-call-function callbacks
*
* @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
* offline CPU. Skip this check if set to 'false'.
*
* Flush any pending smp-call-function callbacks queued on this CPU. This is
* invoked by the generic IPI handler, as well as by a CPU about to go offline,
* to ensure that all pending IPI callbacks are run before it goes completely
* offline.
*
* Loop through the call_single_queue and run all the queued callbacks.
* Must be called with interrupts disabled.
*/
static void __flush_smp_call_function_queue(bool warn_cpu_offline)
{
call_single_data_t *csd, *csd_next;
struct llist_node *entry, *prev;
struct llist_head *head;
static bool warned;
atomic_t *tbt;
lockdep_assert_irqs_disabled();
/* Allow waiters to send backtrace NMI from here onwards */
tbt = this_cpu_ptr(&trigger_backtrace);
atomic_set_release(tbt, 1);
head = this_cpu_ptr(&call_single_queue);
entry = llist_del_all(head);
entry = llist_reverse_order(entry);
/* There shouldn't be any pending callbacks on an offline CPU. */
if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) &&
!warned && entry != NULL)) {
warned = true;
WARN(1, "IPI on offline CPU %d\n", smp_processor_id());
/*
* We don't have to use the _safe() variant here
* because we are not invoking the IPI handlers yet.
*/
llist_for_each_entry(csd, entry, node.llist) {
switch (CSD_TYPE(csd)) {
case CSD_TYPE_ASYNC:
case CSD_TYPE_SYNC:
case CSD_TYPE_IRQ_WORK:
pr_warn("IPI callback %pS sent to offline CPU\n",
csd->func);
break;
case CSD_TYPE_TTWU:
pr_warn("IPI task-wakeup sent to offline CPU\n");
break;
default:
pr_warn("IPI callback, unknown type %d, sent to offline CPU\n",
CSD_TYPE(csd));
break;
}
}
}
/*
* First; run all SYNC callbacks, people are waiting for us.
*/
prev = NULL;
llist_for_each_entry_safe(csd, csd_next, entry, node.llist) {
/* Do we wait until *after* callback? */
if (CSD_TYPE(csd) == CSD_TYPE_SYNC) {
smp_call_func_t func = csd->func;
void *info = csd->info;
if (prev) {
prev->next = &csd_next->node.llist;
} else {
entry = &csd_next->node.llist;
}
csd_lock_record(csd);
csd_do_func(func, info, csd);
csd_unlock(csd);
csd_lock_record(NULL);
} else {
prev = &csd->node.llist;
}
}
if (!entry)
return;
/*
* Second; run all !SYNC callbacks.
*/
prev = NULL;
llist_for_each_entry_safe(csd, csd_next, entry, node.llist) {
int type = CSD_TYPE(csd);
if (type != CSD_TYPE_TTWU) {
if (prev) {
prev->next = &csd_next->node.llist;
} else {
entry = &csd_next->node.llist;
}
if (type == CSD_TYPE_ASYNC) {
smp_call_func_t func = csd->func;
void *info = csd->info;
csd_lock_record(csd);
csd_unlock(csd);
csd_do_func(func, info, csd);
csd_lock_record(NULL);
} else if (type == CSD_TYPE_IRQ_WORK) {
irq_work_single(csd);
}
} else {
prev = &csd->node.llist;
}
}
/*
* Third; only CSD_TYPE_TTWU is left, issue those.
*/
if (entry) {
csd = llist_entry(entry, typeof(*csd), node.llist);
csd_do_func(sched_ttwu_pending, entry, csd);
}
}
/**
* flush_smp_call_function_queue - Flush pending smp-call-function callbacks
* from task context (idle, migration thread)
*
* When TIF_POLLING_NRFLAG is supported and a CPU is in idle and has it
* set, then remote CPUs can avoid sending IPIs and wake the idle CPU by
* setting TIF_NEED_RESCHED. The idle task on the woken up CPU has to
* handle queued SMP function calls before scheduling.
*
* The migration thread has to ensure that an eventually pending wakeup has
* been handled before it migrates a task.
*/
void flush_smp_call_function_queue(void)
{
unsigned int was_pending;
unsigned long flags;
if (llist_empty(this_cpu_ptr(&call_single_queue)))
return;
local_irq_save(flags);
/* Get the already pending soft interrupts for RT enabled kernels */
was_pending = local_softirq_pending();
__flush_smp_call_function_queue(true);
if (local_softirq_pending())
do_softirq_post_smp_call_flush(was_pending);
local_irq_restore(flags);
}
/*
* smp_call_function_single - Run a function on a specific CPU
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait until function has completed on other CPUs.
*
* Returns 0 on success, else a negative status code.
*/
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
int wait)
{
call_single_data_t *csd;
call_single_data_t csd_stack = {
.node = { .u_flags = CSD_FLAG_LOCK | CSD_TYPE_SYNC, },
};
int this_cpu;
int err;
/*
* prevent preemption and reschedule on another processor,
* as well as CPU removal
*/
this_cpu = get_cpu();
/*
* Can deadlock when called with interrupts disabled.
* We allow cpu's that are not yet online though, as no one else can
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
&& !oops_in_progress);
/*
* When @wait we can deadlock when we interrupt between llist_add() and
* arch_send_call_function_ipi*(); when !@wait we can deadlock due to
* csd_lock() on because the interrupt context uses the same csd
* storage.
*/
WARN_ON_ONCE(!in_task());
csd = &csd_stack;
if (!wait) {
csd = this_cpu_ptr(&csd_data);
csd_lock(csd);
}
csd->func = func;
csd->info = info;
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
#endif
err = generic_exec_single(cpu, csd);
if (wait)
csd_lock_wait(csd);
put_cpu();
return err;
}
EXPORT_SYMBOL(smp_call_function_single);
/**
* smp_call_function_single_async() - Run an asynchronous function on a
* specific CPU.
* @cpu: The CPU to run on.
* @csd: Pre-allocated and setup data structure
*
* Like smp_call_function_single(), but the call is asynchonous and
* can thus be done from contexts with disabled interrupts.
*
* The caller passes his own pre-allocated data structure
* (ie: embedded in an object) and is responsible for synchronizing it
* such that the IPIs performed on the @csd are strictly serialized.
*
* If the function is called with one csd which has not yet been
* processed by previous call to smp_call_function_single_async(), the
* function will return immediately with -EBUSY showing that the csd
* object is still in progress.
*
* NOTE: Be careful, there is unfortunately no current debugging facility to
* validate the correctness of this serialization.
*
* Return: %0 on success or negative errno value on error
*/
int smp_call_function_single_async(int cpu, struct __call_single_data *csd)
{
int err = 0;
preempt_disable();
if (csd->node.u_flags & CSD_FLAG_LOCK) {
err = -EBUSY;
goto out;
}
csd->node.u_flags = CSD_FLAG_LOCK;
smp_wmb();
err = generic_exec_single(cpu, csd);
out:
preempt_enable();
return err;
}
EXPORT_SYMBOL_GPL(smp_call_function_single_async);
/*
* smp_call_function_any - Run a function on any of the given cpus
* @mask: The mask of cpus it can run on.
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait until function has completed.
*
* Returns 0 on success, else a negative status code (if no cpus were online).
*
* Selection preference:
* 1) current cpu if in @mask
* 2) any cpu of current node if in @mask
* 3) any other online cpu in @mask
*/
int smp_call_function_any(const struct cpumask *mask,
smp_call_func_t func, void *info, int wait)
{
unsigned int cpu;
const struct cpumask *nodemask;
int ret;
/* Try for same CPU (cheapest) */
cpu = get_cpu();
if (cpumask_test_cpu(cpu, mask))
goto call;
/* Try for same node. */
nodemask = cpumask_of_node(cpu_to_node(cpu));
for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
cpu = cpumask_next_and(cpu, nodemask, mask)) {
if (cpu_online(cpu))
goto call;
}
/* Any online will do: smp_call_function_single handles nr_cpu_ids. */
cpu = cpumask_any_and(mask, cpu_online_mask);
call:
ret = smp_call_function_single(cpu, func, info, wait);
put_cpu();
return ret;
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
/*
* Flags to be used as scf_flags argument of smp_call_function_many_cond().
*
* %SCF_WAIT: Wait until function execution is completed
* %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
*/
#define SCF_WAIT (1U << 0)
#define SCF_RUN_LOCAL (1U << 1)
static void smp_call_function_many_cond(const struct cpumask *mask,
smp_call_func_t func, void *info,
unsigned int scf_flags,
smp_cond_func_t cond_func)
{
int cpu, last_cpu, this_cpu = smp_processor_id();
struct call_function_data *cfd;
bool wait = scf_flags & SCF_WAIT;
int nr_cpus = 0;
bool run_remote = false;
bool run_local = false;
lockdep_assert_preemption_disabled();
/*
* Can deadlock when called with interrupts disabled.
* We allow cpu's that are not yet online though, as no one else can
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
if (cpu_online(this_cpu) && !oops_in_progress &&
!early_boot_irqs_disabled)
lockdep_assert_irqs_enabled();
/*
* When @wait we can deadlock when we interrupt between llist_add() and
* arch_send_call_function_ipi*(); when !@wait we can deadlock due to
* csd_lock() on because the interrupt context uses the same csd
* storage.
*/
WARN_ON_ONCE(!in_task());
/* Check if we need local execution. */
if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask))
run_local = true;
/* Check if we need remote execution, i.e., any CPU excluding this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
if (cpu == this_cpu)
cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
if (cpu < nr_cpu_ids)
run_remote = true;
if (run_remote) {
cfd = this_cpu_ptr(&cfd_data);
cpumask_and(cfd->cpumask, mask, cpu_online_mask);
__cpumask_clear_cpu(this_cpu, cfd->cpumask);
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
if (cond_func && !cond_func(cpu, info)) {
__cpumask_clear_cpu(cpu, cfd->cpumask);
continue;
}
csd_lock(csd);
if (wait)
csd->node.u_flags |= CSD_TYPE_SYNC;
csd->func = func;
csd->info = info;
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
#endif
trace_csd_queue_cpu(cpu, _RET_IP_, func, csd);
if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
nr_cpus++;
last_cpu = cpu;
}
}
/*
* Choose the most efficient way to send an IPI. Note that the
* number of CPUs might be zero due to concurrent changes to the
* provided mask.
*/
if (nr_cpus == 1)
send_call_function_single_ipi(last_cpu);
else if (likely(nr_cpus > 1))
send_call_function_ipi_mask(cfd->cpumask_ipi);
}
if (run_local && (!cond_func || cond_func(this_cpu, info))) {
unsigned long flags;
local_irq_save(flags);
csd_do_func(func, info, NULL);
local_irq_restore(flags);
}
if (run_remote && wait) {
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd;
csd = per_cpu_ptr(cfd->csd, cpu);
csd_lock_wait(csd);
}
}
}
/**
* smp_call_function_many(): Run a function on a set of CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait
* (atomically) until function has completed on other CPUs. If
* %SCF_RUN_LOCAL is set, the function will also be run locally
* if the local CPU is set in the @cpumask.
*
* If @wait is true, then returns once @func has returned.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. Preemption
* must be disabled when calling this function.
*/
void smp_call_function_many(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
{
smp_call_function_many_cond(mask, func, info, wait * SCF_WAIT, NULL);
}
EXPORT_SYMBOL(smp_call_function_many);
/**
* smp_call_function(): Run a function on all other CPUs.
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
* Returns 0.
*
* If @wait is true, then returns once @func has returned; otherwise
* it returns just before the target cpu calls @func.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler.
*/
void smp_call_function(smp_call_func_t func, void *info, int wait)
{
preempt_disable();
smp_call_function_many(cpu_online_mask, func, info, wait);
preempt_enable();
}
EXPORT_SYMBOL(smp_call_function);
/* Setup configured maximum number of CPUs to activate */
unsigned int setup_max_cpus = NR_CPUS;
EXPORT_SYMBOL(setup_max_cpus);
/*
* Setup routine for controlling SMP activation
*
* Command-line option of "nosmp" or "maxcpus=0" will disable SMP
* activation entirely (the MPS table probe still happens, though).
*
* Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
* greater than 0, limits the maximum number of CPUs activated in
* SMP mode to <NUM>.
*/
void __weak __init arch_disable_smp_support(void) { }
static int __init nosmp(char *str)
{
setup_max_cpus = 0;
arch_disable_smp_support();
return 0;
}
early_param("nosmp", nosmp);
/* this is hard limit */
static int __init nrcpus(char *str)
{
int nr_cpus;
if (get_option(&str, &nr_cpus) && nr_cpus > 0 && nr_cpus < nr_cpu_ids)
set_nr_cpu_ids(nr_cpus);
return 0;
}
early_param("nr_cpus", nrcpus);
static int __init maxcpus(char *str)
{
get_option(&str, &setup_max_cpus);
if (setup_max_cpus == 0)
arch_disable_smp_support();
return 0;
}
early_param("maxcpus", maxcpus);
#if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS)
/* Setup number of possible processor ids */
unsigned int nr_cpu_ids __read_mostly = NR_CPUS;
EXPORT_SYMBOL(nr_cpu_ids);
#endif
/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
void __init setup_nr_cpu_ids(void)
{
set_nr_cpu_ids(find_last_bit(cpumask_bits(cpu_possible_mask), NR_CPUS) + 1);
}
/* Called by boot processor to activate the rest. */
void __init smp_init(void)
{
int num_nodes, num_cpus;
idle_threads_init();
cpuhp_threads_init();
pr_info("Bringing up secondary CPUs ...\n");
bringup_nonboot_cpus(setup_max_cpus);
num_nodes = num_online_nodes();
num_cpus = num_online_cpus();
pr_info("Brought up %d node%s, %d CPU%s\n",
num_nodes, (num_nodes > 1 ? "s" : ""),
num_cpus, (num_cpus > 1 ? "s" : ""));
/* Any cleanup work */
smp_cpus_done(setup_max_cpus);
}
/*
* on_each_cpu_cond(): Call a function on each processor for which
* the supplied function cond_func returns true, optionally waiting
* for all the required CPUs to finish. This may include the local
* processor.
* @cond_func: A callback function that is passed a cpu id and
* the info parameter. The function is called
* with preemption disabled. The function should
* return a blooean value indicating whether to IPI
* the specified CPU.
* @func: The function to run on all applicable CPUs.
* This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to both functions.
* @wait: If true, wait (atomically) until function has
* completed on other CPUs.
*
* Preemption is disabled to protect against CPUs going offline but not online.
* CPUs going online during the call will not be seen or sent an IPI.
*
* You must not call this function with disabled interrupts or
* from a hardware interrupt handler or from a bottom half handler.
*/
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask)
{
unsigned int scf_flags = SCF_RUN_LOCAL;
if (wait)
scf_flags |= SCF_WAIT;
preempt_disable();
smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
static void do_nothing(void *unused)
{
}
/**
* kick_all_cpus_sync - Force all cpus out of idle
*
* Used to synchronize the update of pm_idle function pointer. It's
* called after the pointer is updated and returns after the dummy
* callback function has been executed on all cpus. The execution of
* the function can only happen on the remote cpus after they have
* left the idle function which had been called via pm_idle function
* pointer. So it's guaranteed that nothing uses the previous pointer
* anymore.
*/
void kick_all_cpus_sync(void)
{
/* Make sure the change is visible before we kick the cpus */
smp_mb();
smp_call_function(do_nothing, NULL, 1);
}
EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
/**
* wake_up_all_idle_cpus - break all cpus out of idle
* wake_up_all_idle_cpus try to break all cpus which is in idle state even
* including idle polling cpus, for non-idle cpus, we will do nothing
* for them.
*/
void wake_up_all_idle_cpus(void)
{
int cpu;
for_each_possible_cpu(cpu) {
preempt_disable();
if (cpu != smp_processor_id() && cpu_online(cpu))
wake_up_if_idle(cpu);
preempt_enable();
}
}
EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);
/**
* struct smp_call_on_cpu_struct - Call a function on a specific CPU
* @work: &work_struct
* @done: &completion to signal
* @func: function to call
* @data: function's data argument
* @ret: return value from @func
* @cpu: target CPU (%-1 for any CPU)
*
* Used to call a function on a specific cpu and wait for it to return.
* Optionally make sure the call is done on a specified physical cpu via vcpu
* pinning in order to support virtualized environments.
*/
struct smp_call_on_cpu_struct {
struct work_struct work;
struct completion done;
int (*func)(void *);
void *data;
int ret;
int cpu;
};
static void smp_call_on_cpu_callback(struct work_struct *work)
{
struct smp_call_on_cpu_struct *sscs;
sscs = container_of(work, struct smp_call_on_cpu_struct, work);
if (sscs->cpu >= 0)
hypervisor_pin_vcpu(sscs->cpu);
sscs->ret = sscs->func(sscs->data);
if (sscs->cpu >= 0)
hypervisor_pin_vcpu(-1);
complete(&sscs->done);
}
int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
{
struct smp_call_on_cpu_struct sscs = {
.done = COMPLETION_INITIALIZER_ONSTACK(sscs.done),
.func = func,
.data = par,
.cpu = phys ? cpu : -1,
};
INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback);
if (cpu >= nr_cpu_ids || !cpu_online(cpu))
return -ENXIO;
queue_work_on(cpu, system_wq, &sscs.work);
wait_for_completion(&sscs.done);
return sscs.ret;
}
EXPORT_SYMBOL_GPL(smp_call_on_cpu);
| linux-master | kernel/smp.c |
// SPDX-License-Identifier: GPL-2.0
/*
* Shadow Call Stack support.
*
* Copyright (C) 2019 Google LLC
*/
#include <linux/cpuhotplug.h>
#include <linux/kasan.h>
#include <linux/mm.h>
#include <linux/scs.h>
#include <linux/vmalloc.h>
#include <linux/vmstat.h>
#ifdef CONFIG_DYNAMIC_SCS
DEFINE_STATIC_KEY_FALSE(dynamic_scs_enabled);
#endif
static void __scs_account(void *s, int account)
{
struct page *scs_page = vmalloc_to_page(s);
mod_node_page_state(page_pgdat(scs_page), NR_KERNEL_SCS_KB,
account * (SCS_SIZE / SZ_1K));
}
/* Matches NR_CACHED_STACKS for VMAP_STACK */
#define NR_CACHED_SCS 2
static DEFINE_PER_CPU(void *, scs_cache[NR_CACHED_SCS]);
static void *__scs_alloc(int node)
{
int i;
void *s;
for (i = 0; i < NR_CACHED_SCS; i++) {
s = this_cpu_xchg(scs_cache[i], NULL);
if (s) {
s = kasan_unpoison_vmalloc(s, SCS_SIZE,
KASAN_VMALLOC_PROT_NORMAL);
memset(s, 0, SCS_SIZE);
goto out;
}
}
s = __vmalloc_node_range(SCS_SIZE, 1, VMALLOC_START, VMALLOC_END,
GFP_SCS, PAGE_KERNEL, 0, node,
__builtin_return_address(0));
out:
return kasan_reset_tag(s);
}
void *scs_alloc(int node)
{
void *s;
s = __scs_alloc(node);
if (!s)
return NULL;
*__scs_magic(s) = SCS_END_MAGIC;
/*
* Poison the allocation to catch unintentional accesses to
* the shadow stack when KASAN is enabled.
*/
kasan_poison_vmalloc(s, SCS_SIZE);
__scs_account(s, 1);
return s;
}
void scs_free(void *s)
{
int i;
__scs_account(s, -1);
/*
* We cannot sleep as this can be called in interrupt context,
* so use this_cpu_cmpxchg to update the cache, and vfree_atomic
* to free the stack.
*/
for (i = 0; i < NR_CACHED_SCS; i++)
if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL)
return;
kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_PROT_NORMAL);
vfree_atomic(s);
}
static int scs_cleanup(unsigned int cpu)
{
int i;
void **cache = per_cpu_ptr(scs_cache, cpu);
for (i = 0; i < NR_CACHED_SCS; i++) {
vfree(cache[i]);
cache[i] = NULL;
}
return 0;
}
void __init scs_init(void)
{
if (!scs_is_enabled())
return;
cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "scs:scs_cache", NULL,
scs_cleanup);
}
int scs_prepare(struct task_struct *tsk, int node)
{
void *s;
if (!scs_is_enabled())
return 0;
s = scs_alloc(node);
if (!s)
return -ENOMEM;
task_scs(tsk) = task_scs_sp(tsk) = s;
return 0;
}
static void scs_check_usage(struct task_struct *tsk)
{
static unsigned long highest;
unsigned long *p, prev, curr = highest, used = 0;
if (!IS_ENABLED(CONFIG_DEBUG_STACK_USAGE))
return;
for (p = task_scs(tsk); p < __scs_magic(tsk); ++p) {
if (!READ_ONCE_NOCHECK(*p))
break;
used += sizeof(*p);
}
while (used > curr) {
prev = cmpxchg_relaxed(&highest, curr, used);
if (prev == curr) {
pr_info("%s (%d): highest shadow stack usage: %lu bytes\n",
tsk->comm, task_pid_nr(tsk), used);
break;
}
curr = prev;
}
}
void scs_release(struct task_struct *tsk)
{
void *s = task_scs(tsk);
if (!scs_is_enabled() || !s)
return;
WARN(task_scs_end_corrupted(tsk),
"corrupted shadow stack detected when freeing task\n");
scs_check_usage(tsk);
scs_free(s);
}
| linux-master | kernel/scs.c |
// SPDX-License-Identifier: GPL-2.0-only
/*
* Context tracking: Probe on high level context boundaries such as kernel,
* userspace, guest or idle.
*
* This is used by RCU to remove its dependency on the timer tick while a CPU
* runs in idle, userspace or guest mode.
*
* User/guest tracking started by Frederic Weisbecker:
*
* Copyright (C) 2012 Red Hat, Inc., Frederic Weisbecker
*
* Many thanks to Gilad Ben-Yossef, Paul McKenney, Ingo Molnar, Andrew Morton,
* Steven Rostedt, Peter Zijlstra for suggestions and improvements.
*
* RCU extended quiescent state bits imported from kernel/rcu/tree.c
* where the relevant authorship may be found.
*/
#include <linux/context_tracking.h>
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/hardirq.h>
#include <linux/export.h>
#include <linux/kprobes.h>
#include <trace/events/rcu.h>
DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
#ifdef CONFIG_CONTEXT_TRACKING_IDLE
.dynticks_nesting = 1,
.dynticks_nmi_nesting = DYNTICK_IRQ_NONIDLE,
#endif
.state = ATOMIC_INIT(RCU_DYNTICKS_IDX),
};
EXPORT_SYMBOL_GPL(context_tracking);
#ifdef CONFIG_CONTEXT_TRACKING_IDLE
#define TPS(x) tracepoint_string(x)
/* Record the current task on dyntick-idle entry. */
static __always_inline void rcu_dynticks_task_enter(void)
{
#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
WRITE_ONCE(current->rcu_tasks_idle_cpu, smp_processor_id());
#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
}
/* Record no current task on dyntick-idle exit. */
static __always_inline void rcu_dynticks_task_exit(void)
{
#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
WRITE_ONCE(current->rcu_tasks_idle_cpu, -1);
#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
}
/* Turn on heavyweight RCU tasks trace readers on idle/user entry. */
static __always_inline void rcu_dynticks_task_trace_enter(void)
{
#ifdef CONFIG_TASKS_TRACE_RCU
if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
current->trc_reader_special.b.need_mb = true;
#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
}
/* Turn off heavyweight RCU tasks trace readers on idle/user exit. */
static __always_inline void rcu_dynticks_task_trace_exit(void)
{
#ifdef CONFIG_TASKS_TRACE_RCU
if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
current->trc_reader_special.b.need_mb = false;
#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
}
/*
* Record entry into an extended quiescent state. This is only to be
* called when not already in an extended quiescent state, that is,
* RCU is watching prior to the call to this function and is no longer
* watching upon return.
*/
static noinstr void ct_kernel_exit_state(int offset)
{
int seq;
/*
* CPUs seeing atomic_add_return() must see prior RCU read-side
* critical sections, and we also must force ordering with the
* next idle sojourn.
*/
rcu_dynticks_task_trace_enter(); // Before ->dynticks update!
seq = ct_state_inc(offset);
// RCU is no longer watching. Better be in extended quiescent state!
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && (seq & RCU_DYNTICKS_IDX));
}
/*
* Record exit from an extended quiescent state. This is only to be
* called from an extended quiescent state, that is, RCU is not watching
* prior to the call to this function and is watching upon return.
*/
static noinstr void ct_kernel_enter_state(int offset)
{
int seq;
/*
* CPUs seeing atomic_add_return() must see prior idle sojourns,
* and we also must force ordering with the next RCU read-side
* critical section.
*/
seq = ct_state_inc(offset);
// RCU is now watching. Better not be in an extended quiescent state!
rcu_dynticks_task_trace_exit(); // After ->dynticks update!
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(seq & RCU_DYNTICKS_IDX));
}
/*
* Enter an RCU extended quiescent state, which can be either the
* idle loop or adaptive-tickless usermode execution.
*
* We crowbar the ->dynticks_nmi_nesting field to zero to allow for
* the possibility of usermode upcalls having messed up our count
* of interrupt nesting level during the prior busy period.
*/
static void noinstr ct_kernel_exit(bool user, int offset)
{
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
WARN_ON_ONCE(ct_dynticks_nmi_nesting() != DYNTICK_IRQ_NONIDLE);
WRITE_ONCE(ct->dynticks_nmi_nesting, 0);
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) &&
ct_dynticks_nesting() == 0);
if (ct_dynticks_nesting() != 1) {
// RCU will still be watching, so just do accounting and leave.
ct->dynticks_nesting--;
return;
}
instrumentation_begin();
lockdep_assert_irqs_disabled();
trace_rcu_dyntick(TPS("Start"), ct_dynticks_nesting(), 0, ct_dynticks());
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current));
rcu_preempt_deferred_qs(current);
// instrumentation for the noinstr ct_kernel_exit_state()
instrument_atomic_write(&ct->state, sizeof(ct->state));
instrumentation_end();
WRITE_ONCE(ct->dynticks_nesting, 0); /* Avoid irq-access tearing. */
// RCU is watching here ...
ct_kernel_exit_state(offset);
// ... but is no longer watching here.
rcu_dynticks_task_enter();
}
/*
* Exit an RCU extended quiescent state, which can be either the
* idle loop or adaptive-tickless usermode execution.
*
* We crowbar the ->dynticks_nmi_nesting field to DYNTICK_IRQ_NONIDLE to
* allow for the possibility of usermode upcalls messing up our count of
* interrupt nesting level during the busy period that is just now starting.
*/
static void noinstr ct_kernel_enter(bool user, int offset)
{
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
long oldval;
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_irqs_disabled());
oldval = ct_dynticks_nesting();
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && oldval < 0);
if (oldval) {
// RCU was already watching, so just do accounting and leave.
ct->dynticks_nesting++;
return;
}
rcu_dynticks_task_exit();
// RCU is not watching here ...
ct_kernel_enter_state(offset);
// ... but is watching here.
instrumentation_begin();
// instrumentation for the noinstr ct_kernel_enter_state()
instrument_atomic_write(&ct->state, sizeof(ct->state));
trace_rcu_dyntick(TPS("End"), ct_dynticks_nesting(), 1, ct_dynticks());
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current));
WRITE_ONCE(ct->dynticks_nesting, 1);
WARN_ON_ONCE(ct_dynticks_nmi_nesting());
WRITE_ONCE(ct->dynticks_nmi_nesting, DYNTICK_IRQ_NONIDLE);
instrumentation_end();
}
/**
* ct_nmi_exit - inform RCU of exit from NMI context
*
* If we are returning from the outermost NMI handler that interrupted an
* RCU-idle period, update ct->state and ct->dynticks_nmi_nesting
* to let the RCU grace-period handling know that the CPU is back to
* being RCU-idle.
*
* If you add or remove a call to ct_nmi_exit(), be sure to test
* with CONFIG_RCU_EQS_DEBUG=y.
*/
void noinstr ct_nmi_exit(void)
{
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
instrumentation_begin();
/*
* Check for ->dynticks_nmi_nesting underflow and bad ->dynticks.
* (We are exiting an NMI handler, so RCU better be paying attention
* to us!)
*/
WARN_ON_ONCE(ct_dynticks_nmi_nesting() <= 0);
WARN_ON_ONCE(rcu_dynticks_curr_cpu_in_eqs());
/*
* If the nesting level is not 1, the CPU wasn't RCU-idle, so
* leave it in non-RCU-idle state.
*/
if (ct_dynticks_nmi_nesting() != 1) {
trace_rcu_dyntick(TPS("--="), ct_dynticks_nmi_nesting(), ct_dynticks_nmi_nesting() - 2,
ct_dynticks());
WRITE_ONCE(ct->dynticks_nmi_nesting, /* No store tearing. */
ct_dynticks_nmi_nesting() - 2);
instrumentation_end();
return;
}
/* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
trace_rcu_dyntick(TPS("Startirq"), ct_dynticks_nmi_nesting(), 0, ct_dynticks());
WRITE_ONCE(ct->dynticks_nmi_nesting, 0); /* Avoid store tearing. */
// instrumentation for the noinstr ct_kernel_exit_state()
instrument_atomic_write(&ct->state, sizeof(ct->state));
instrumentation_end();
// RCU is watching here ...
ct_kernel_exit_state(RCU_DYNTICKS_IDX);
// ... but is no longer watching here.
if (!in_nmi())
rcu_dynticks_task_enter();
}
/**
* ct_nmi_enter - inform RCU of entry to NMI context
*
* If the CPU was idle from RCU's viewpoint, update ct->state and
* ct->dynticks_nmi_nesting to let the RCU grace-period handling know
* that the CPU is active. This implementation permits nested NMIs, as
* long as the nesting level does not overflow an int. (You will probably
* run out of stack space first.)
*
* If you add or remove a call to ct_nmi_enter(), be sure to test
* with CONFIG_RCU_EQS_DEBUG=y.
*/
void noinstr ct_nmi_enter(void)
{
long incby = 2;
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
/* Complain about underflow. */
WARN_ON_ONCE(ct_dynticks_nmi_nesting() < 0);
/*
* If idle from RCU viewpoint, atomically increment ->dynticks
* to mark non-idle and increment ->dynticks_nmi_nesting by one.
* Otherwise, increment ->dynticks_nmi_nesting by two. This means
* if ->dynticks_nmi_nesting is equal to one, we are guaranteed
* to be in the outermost NMI handler that interrupted an RCU-idle
* period (observation due to Andy Lutomirski).
*/
if (rcu_dynticks_curr_cpu_in_eqs()) {
if (!in_nmi())
rcu_dynticks_task_exit();
// RCU is not watching here ...
ct_kernel_enter_state(RCU_DYNTICKS_IDX);
// ... but is watching here.
instrumentation_begin();
// instrumentation for the noinstr rcu_dynticks_curr_cpu_in_eqs()
instrument_atomic_read(&ct->state, sizeof(ct->state));
// instrumentation for the noinstr ct_kernel_enter_state()
instrument_atomic_write(&ct->state, sizeof(ct->state));
incby = 1;
} else if (!in_nmi()) {
instrumentation_begin();
rcu_irq_enter_check_tick();
} else {
instrumentation_begin();
}
trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
ct_dynticks_nmi_nesting(),
ct_dynticks_nmi_nesting() + incby, ct_dynticks());
instrumentation_end();
WRITE_ONCE(ct->dynticks_nmi_nesting, /* Prevent store tearing. */
ct_dynticks_nmi_nesting() + incby);
barrier();
}
/**
* ct_idle_enter - inform RCU that current CPU is entering idle
*
* Enter idle mode, in other words, -leave- the mode in which RCU
* read-side critical sections can occur. (Though RCU read-side
* critical sections can occur in irq handlers in idle, a possibility
* handled by irq_enter() and irq_exit().)
*
* If you add or remove a call to ct_idle_enter(), be sure to test with
* CONFIG_RCU_EQS_DEBUG=y.
*/
void noinstr ct_idle_enter(void)
{
WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !raw_irqs_disabled());
ct_kernel_exit(false, RCU_DYNTICKS_IDX + CONTEXT_IDLE);
}
EXPORT_SYMBOL_GPL(ct_idle_enter);
/**
* ct_idle_exit - inform RCU that current CPU is leaving idle
*
* Exit idle mode, in other words, -enter- the mode in which RCU
* read-side critical sections can occur.
*
* If you add or remove a call to ct_idle_exit(), be sure to test with
* CONFIG_RCU_EQS_DEBUG=y.
*/
void noinstr ct_idle_exit(void)
{
unsigned long flags;
raw_local_irq_save(flags);
ct_kernel_enter(false, RCU_DYNTICKS_IDX - CONTEXT_IDLE);
raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(ct_idle_exit);
/**
* ct_irq_enter - inform RCU that current CPU is entering irq away from idle
*
* Enter an interrupt handler, which might possibly result in exiting
* idle mode, in other words, entering the mode in which read-side critical
* sections can occur. The caller must have disabled interrupts.
*
* Note that the Linux kernel is fully capable of entering an interrupt
* handler that it never exits, for example when doing upcalls to user mode!
* This code assumes that the idle loop never does upcalls to user mode.
* If your architecture's idle loop does do upcalls to user mode (or does
* anything else that results in unbalanced calls to the irq_enter() and
* irq_exit() functions), RCU will give you what you deserve, good and hard.
* But very infrequently and irreproducibly.
*
* Use things like work queues to work around this limitation.
*
* You have been warned.
*
* If you add or remove a call to ct_irq_enter(), be sure to test with
* CONFIG_RCU_EQS_DEBUG=y.
*/
noinstr void ct_irq_enter(void)
{
lockdep_assert_irqs_disabled();
ct_nmi_enter();
}
/**
* ct_irq_exit - inform RCU that current CPU is exiting irq towards idle
*
* Exit from an interrupt handler, which might possibly result in entering
* idle mode, in other words, leaving the mode in which read-side critical
* sections can occur. The caller must have disabled interrupts.
*
* This code assumes that the idle loop never does anything that might
* result in unbalanced calls to irq_enter() and irq_exit(). If your
* architecture's idle loop violates this assumption, RCU will give you what
* you deserve, good and hard. But very infrequently and irreproducibly.
*
* Use things like work queues to work around this limitation.
*
* You have been warned.
*
* If you add or remove a call to ct_irq_exit(), be sure to test with
* CONFIG_RCU_EQS_DEBUG=y.
*/
noinstr void ct_irq_exit(void)
{
lockdep_assert_irqs_disabled();
ct_nmi_exit();
}
/*
* Wrapper for ct_irq_enter() where interrupts are enabled.
*
* If you add or remove a call to ct_irq_enter_irqson(), be sure to test
* with CONFIG_RCU_EQS_DEBUG=y.
*/
void ct_irq_enter_irqson(void)
{
unsigned long flags;
local_irq_save(flags);
ct_irq_enter();
local_irq_restore(flags);
}
/*
* Wrapper for ct_irq_exit() where interrupts are enabled.
*
* If you add or remove a call to ct_irq_exit_irqson(), be sure to test
* with CONFIG_RCU_EQS_DEBUG=y.
*/
void ct_irq_exit_irqson(void)
{
unsigned long flags;
local_irq_save(flags);
ct_irq_exit();
local_irq_restore(flags);
}
#else
static __always_inline void ct_kernel_exit(bool user, int offset) { }
static __always_inline void ct_kernel_enter(bool user, int offset) { }
#endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */
#ifdef CONFIG_CONTEXT_TRACKING_USER
#define CREATE_TRACE_POINTS
#include <trace/events/context_tracking.h>
DEFINE_STATIC_KEY_FALSE(context_tracking_key);
EXPORT_SYMBOL_GPL(context_tracking_key);
static noinstr bool context_tracking_recursion_enter(void)
{
int recursion;
recursion = __this_cpu_inc_return(context_tracking.recursion);
if (recursion == 1)
return true;
WARN_ONCE((recursion < 1), "Invalid context tracking recursion value %d\n", recursion);
__this_cpu_dec(context_tracking.recursion);
return false;
}
static __always_inline void context_tracking_recursion_exit(void)
{
__this_cpu_dec(context_tracking.recursion);
}
/**
* __ct_user_enter - Inform the context tracking that the CPU is going
* to enter user or guest space mode.
*
* This function must be called right before we switch from the kernel
* to user or guest space, when it's guaranteed the remaining kernel
* instructions to execute won't use any RCU read side critical section
* because this function sets RCU in extended quiescent state.
*/
void noinstr __ct_user_enter(enum ctx_state state)
{
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
lockdep_assert_irqs_disabled();
/* Kernel threads aren't supposed to go to userspace */
WARN_ON_ONCE(!current->mm);
if (!context_tracking_recursion_enter())
return;
if (__ct_state() != state) {
if (ct->active) {
/*
* At this stage, only low level arch entry code remains and
* then we'll run in userspace. We can assume there won't be
* any RCU read-side critical section until the next call to
* user_exit() or ct_irq_enter(). Let's remove RCU's dependency
* on the tick.
*/
if (state == CONTEXT_USER) {
instrumentation_begin();
trace_user_enter(0);
vtime_user_enter(current);
instrumentation_end();
}
/*
* Other than generic entry implementation, we may be past the last
* rescheduling opportunity in the entry code. Trigger a self IPI
* that will fire and reschedule once we resume in user/guest mode.
*/
rcu_irq_work_resched();
/*
* Enter RCU idle mode right before resuming userspace. No use of RCU
* is permitted between this call and rcu_eqs_exit(). This way the
* CPU doesn't need to maintain the tick for RCU maintenance purposes
* when the CPU runs in userspace.
*/
ct_kernel_exit(true, RCU_DYNTICKS_IDX + state);
/*
* Special case if we only track user <-> kernel transitions for tickless
* cputime accounting but we don't support RCU extended quiescent state.
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
raw_atomic_set(&ct->state, state);
} else {
/*
* Even if context tracking is disabled on this CPU, because it's outside
* the full dynticks mask for example, we still have to keep track of the
* context transitions and states to prevent inconsistency on those of
* other CPUs.
* If a task triggers an exception in userspace, sleep on the exception
* handler and then migrate to another CPU, that new CPU must know where
* the exception returns by the time we call exception_exit().
* This information can only be provided by the previous CPU when it called
* exception_enter().
* OTOH we can spare the calls to vtime and RCU when context_tracking.active
* is false because we know that CPU is not tickless.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
raw_atomic_set(&ct->state, state);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
* with NMIs. OTOH we don't care about ordering here since
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
raw_atomic_add(state, &ct->state);
}
}
}
context_tracking_recursion_exit();
}
EXPORT_SYMBOL_GPL(__ct_user_enter);
/*
* OBSOLETE:
* This function should be noinstr but the below local_irq_restore() is
* unsafe because it involves illegal RCU uses through tracing and lockdep.
* This is unlikely to be fixed as this function is obsolete. The preferred
* way is to call __context_tracking_enter() through user_enter_irqoff()
* or context_tracking_guest_enter(). It should be the arch entry code
* responsibility to call into context tracking with IRQs disabled.
*/
void ct_user_enter(enum ctx_state state)
{
unsigned long flags;
/*
* Some contexts may involve an exception occuring in an irq,
* leading to that nesting:
* ct_irq_enter() rcu_eqs_exit(true) rcu_eqs_enter(true) ct_irq_exit()
* This would mess up the dyntick_nesting count though. And rcu_irq_*()
* helpers are enough to protect RCU uses inside the exception. So
* just return immediately if we detect we are in an IRQ.
*/
if (in_interrupt())
return;
local_irq_save(flags);
__ct_user_enter(state);
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(ct_user_enter);
EXPORT_SYMBOL_GPL(ct_user_enter);
/**
* user_enter_callable() - Unfortunate ASM callable version of user_enter() for
* archs that didn't manage to check the context tracking
* static key from low level code.
*
* This OBSOLETE function should be noinstr but it unsafely calls
* local_irq_restore(), involving illegal RCU uses through tracing and lockdep.
* This is unlikely to be fixed as this function is obsolete. The preferred
* way is to call user_enter_irqoff(). It should be the arch entry code
* responsibility to call into context tracking with IRQs disabled.
*/
void user_enter_callable(void)
{
user_enter();
}
NOKPROBE_SYMBOL(user_enter_callable);
/**
* __ct_user_exit - Inform the context tracking that the CPU is
* exiting user or guest mode and entering the kernel.
*
* This function must be called after we entered the kernel from user or
* guest space before any use of RCU read side critical section. This
* potentially include any high level kernel code like syscalls, exceptions,
* signal handling, etc...
*
* This call supports re-entrancy. This way it can be called from any exception
* handler without needing to know if we came from userspace or not.
*/
void noinstr __ct_user_exit(enum ctx_state state)
{
struct context_tracking *ct = this_cpu_ptr(&context_tracking);
if (!context_tracking_recursion_enter())
return;
if (__ct_state() == state) {
if (ct->active) {
/*
* Exit RCU idle mode while entering the kernel because it can
* run a RCU read side critical section anytime.
*/
ct_kernel_enter(true, RCU_DYNTICKS_IDX - state);
if (state == CONTEXT_USER) {
instrumentation_begin();
vtime_user_exit(current);
trace_user_exit(0);
instrumentation_end();
}
/*
* Special case if we only track user <-> kernel transitions for tickless
* cputime accounting but we don't support RCU extended quiescent state.
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
raw_atomic_set(&ct->state, CONTEXT_KERNEL);
} else {
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
raw_atomic_set(&ct->state, CONTEXT_KERNEL);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
* with NMIs. OTOH we don't care about ordering here since
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
raw_atomic_sub(state, &ct->state);
}
}
}
context_tracking_recursion_exit();
}
EXPORT_SYMBOL_GPL(__ct_user_exit);
/*
* OBSOLETE:
* This function should be noinstr but the below local_irq_save() is
* unsafe because it involves illegal RCU uses through tracing and lockdep.
* This is unlikely to be fixed as this function is obsolete. The preferred
* way is to call __context_tracking_exit() through user_exit_irqoff()
* or context_tracking_guest_exit(). It should be the arch entry code
* responsibility to call into context tracking with IRQs disabled.
*/
void ct_user_exit(enum ctx_state state)
{
unsigned long flags;
if (in_interrupt())
return;
local_irq_save(flags);
__ct_user_exit(state);
local_irq_restore(flags);
}
NOKPROBE_SYMBOL(ct_user_exit);
EXPORT_SYMBOL_GPL(ct_user_exit);
/**
* user_exit_callable() - Unfortunate ASM callable version of user_exit() for
* archs that didn't manage to check the context tracking
* static key from low level code.
*
* This OBSOLETE function should be noinstr but it unsafely calls local_irq_save(),
* involving illegal RCU uses through tracing and lockdep. This is unlikely
* to be fixed as this function is obsolete. The preferred way is to call
* user_exit_irqoff(). It should be the arch entry code responsibility to
* call into context tracking with IRQs disabled.
*/
void user_exit_callable(void)
{
user_exit();
}
NOKPROBE_SYMBOL(user_exit_callable);
void __init ct_cpu_track_user(int cpu)
{
static __initdata bool initialized = false;
if (!per_cpu(context_tracking.active, cpu)) {
per_cpu(context_tracking.active, cpu) = true;
static_branch_inc(&context_tracking_key);
}
if (initialized)
return;
#ifdef CONFIG_HAVE_TIF_NOHZ
/*
* Set TIF_NOHZ to init/0 and let it propagate to all tasks through fork
* This assumes that init is the only task at this early boot stage.
*/
set_tsk_thread_flag(&init_task, TIF_NOHZ);
#endif
WARN_ON_ONCE(!tasklist_empty());
initialized = true;
}
#ifdef CONFIG_CONTEXT_TRACKING_USER_FORCE
void __init context_tracking_init(void)
{
int cpu;
for_each_possible_cpu(cpu)
ct_cpu_track_user(cpu);
}
#endif
#endif /* #ifdef CONFIG_CONTEXT_TRACKING_USER */
| linux-master | kernel/context_tracking.c |
/*
* Public API and common code for kernel->userspace relay file support.
*
* See Documentation/filesystems/relay.rst for an overview.
*
* Copyright (C) 2002-2005 - Tom Zanussi ([email protected]), IBM Corp
* Copyright (C) 1999-2005 - Karim Yaghmour ([email protected])
*
* Moved to kernel/relay.c by Paul Mundt, 2006.
* November 2006 - CPU hotplug support by Mathieu Desnoyers
* ([email protected])
*
* This file is released under the GPL.
*/
#include <linux/errno.h>
#include <linux/stddef.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/relay.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/cpu.h>
#include <linux/splice.h>
/* list of open channels, for cpu hotplug */
static DEFINE_MUTEX(relay_channels_mutex);
static LIST_HEAD(relay_channels);
/*
* fault() vm_op implementation for relay file mapping.
*/
static vm_fault_t relay_buf_fault(struct vm_fault *vmf)
{
struct page *page;
struct rchan_buf *buf = vmf->vma->vm_private_data;
pgoff_t pgoff = vmf->pgoff;
if (!buf)
return VM_FAULT_OOM;
page = vmalloc_to_page(buf->start + (pgoff << PAGE_SHIFT));
if (!page)
return VM_FAULT_SIGBUS;
get_page(page);
vmf->page = page;
return 0;
}
/*
* vm_ops for relay file mappings.
*/
static const struct vm_operations_struct relay_file_mmap_ops = {
.fault = relay_buf_fault,
};
/*
* allocate an array of pointers of struct page
*/
static struct page **relay_alloc_page_array(unsigned int n_pages)
{
return kvcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
}
/*
* free an array of pointers of struct page
*/
static void relay_free_page_array(struct page **array)
{
kvfree(array);
}
/**
* relay_mmap_buf: - mmap channel buffer to process address space
* @buf: relay channel buffer
* @vma: vm_area_struct describing memory to be mapped
*
* Returns 0 if ok, negative on error
*
* Caller should already have grabbed mmap_lock.
*/
static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
{
unsigned long length = vma->vm_end - vma->vm_start;
if (!buf)
return -EBADF;
if (length != (unsigned long)buf->chan->alloc_size)
return -EINVAL;
vma->vm_ops = &relay_file_mmap_ops;
vm_flags_set(vma, VM_DONTEXPAND);
vma->vm_private_data = buf;
return 0;
}
/**
* relay_alloc_buf - allocate a channel buffer
* @buf: the buffer struct
* @size: total size of the buffer
*
* Returns a pointer to the resulting buffer, %NULL if unsuccessful. The
* passed in size will get page aligned, if it isn't already.
*/
static void *relay_alloc_buf(struct rchan_buf *buf, size_t *size)
{
void *mem;
unsigned int i, j, n_pages;
*size = PAGE_ALIGN(*size);
n_pages = *size >> PAGE_SHIFT;
buf->page_array = relay_alloc_page_array(n_pages);
if (!buf->page_array)
return NULL;
for (i = 0; i < n_pages; i++) {
buf->page_array[i] = alloc_page(GFP_KERNEL);
if (unlikely(!buf->page_array[i]))
goto depopulate;
set_page_private(buf->page_array[i], (unsigned long)buf);
}
mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
if (!mem)
goto depopulate;
memset(mem, 0, *size);
buf->page_count = n_pages;
return mem;
depopulate:
for (j = 0; j < i; j++)
__free_page(buf->page_array[j]);
relay_free_page_array(buf->page_array);
return NULL;
}
/**
* relay_create_buf - allocate and initialize a channel buffer
* @chan: the relay channel
*
* Returns channel buffer if successful, %NULL otherwise.
*/
static struct rchan_buf *relay_create_buf(struct rchan *chan)
{
struct rchan_buf *buf;
if (chan->n_subbufs > KMALLOC_MAX_SIZE / sizeof(size_t))
return NULL;
buf = kzalloc(sizeof(struct rchan_buf), GFP_KERNEL);
if (!buf)
return NULL;
buf->padding = kmalloc_array(chan->n_subbufs, sizeof(size_t),
GFP_KERNEL);
if (!buf->padding)
goto free_buf;
buf->start = relay_alloc_buf(buf, &chan->alloc_size);
if (!buf->start)
goto free_buf;
buf->chan = chan;
kref_get(&buf->chan->kref);
return buf;
free_buf:
kfree(buf->padding);
kfree(buf);
return NULL;
}
/**
* relay_destroy_channel - free the channel struct
* @kref: target kernel reference that contains the relay channel
*
* Should only be called from kref_put().
*/
static void relay_destroy_channel(struct kref *kref)
{
struct rchan *chan = container_of(kref, struct rchan, kref);
free_percpu(chan->buf);
kfree(chan);
}
/**
* relay_destroy_buf - destroy an rchan_buf struct and associated buffer
* @buf: the buffer struct
*/
static void relay_destroy_buf(struct rchan_buf *buf)
{
struct rchan *chan = buf->chan;
unsigned int i;
if (likely(buf->start)) {
vunmap(buf->start);
for (i = 0; i < buf->page_count; i++)
__free_page(buf->page_array[i]);
relay_free_page_array(buf->page_array);
}
*per_cpu_ptr(chan->buf, buf->cpu) = NULL;
kfree(buf->padding);
kfree(buf);
kref_put(&chan->kref, relay_destroy_channel);
}
/**
* relay_remove_buf - remove a channel buffer
* @kref: target kernel reference that contains the relay buffer
*
* Removes the file from the filesystem, which also frees the
* rchan_buf_struct and the channel buffer. Should only be called from
* kref_put().
*/
static void relay_remove_buf(struct kref *kref)
{
struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
relay_destroy_buf(buf);
}
/**
* relay_buf_empty - boolean, is the channel buffer empty?
* @buf: channel buffer
*
* Returns 1 if the buffer is empty, 0 otherwise.
*/
static int relay_buf_empty(struct rchan_buf *buf)
{
return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
}
/**
* relay_buf_full - boolean, is the channel buffer full?
* @buf: channel buffer
*
* Returns 1 if the buffer is full, 0 otherwise.
*/
int relay_buf_full(struct rchan_buf *buf)
{
size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
return (ready >= buf->chan->n_subbufs) ? 1 : 0;
}
EXPORT_SYMBOL_GPL(relay_buf_full);
/*
* High-level relay kernel API and associated functions.
*/
static int relay_subbuf_start(struct rchan_buf *buf, void *subbuf,
void *prev_subbuf, size_t prev_padding)
{
if (!buf->chan->cb->subbuf_start)
return !relay_buf_full(buf);
return buf->chan->cb->subbuf_start(buf, subbuf,
prev_subbuf, prev_padding);
}
/**
* wakeup_readers - wake up readers waiting on a channel
* @work: contains the channel buffer
*
* This is the function used to defer reader waking
*/
static void wakeup_readers(struct irq_work *work)
{
struct rchan_buf *buf;
buf = container_of(work, struct rchan_buf, wakeup_work);
wake_up_interruptible(&buf->read_wait);
}
/**
* __relay_reset - reset a channel buffer
* @buf: the channel buffer
* @init: 1 if this is a first-time initialization
*
* See relay_reset() for description of effect.
*/
static void __relay_reset(struct rchan_buf *buf, unsigned int init)
{
size_t i;
if (init) {
init_waitqueue_head(&buf->read_wait);
kref_init(&buf->kref);
init_irq_work(&buf->wakeup_work, wakeup_readers);
} else {
irq_work_sync(&buf->wakeup_work);
}
buf->subbufs_produced = 0;
buf->subbufs_consumed = 0;
buf->bytes_consumed = 0;
buf->finalized = 0;
buf->data = buf->start;
buf->offset = 0;
for (i = 0; i < buf->chan->n_subbufs; i++)
buf->padding[i] = 0;
relay_subbuf_start(buf, buf->data, NULL, 0);
}
/**
* relay_reset - reset the channel
* @chan: the channel
*
* This has the effect of erasing all data from all channel buffers
* and restarting the channel in its initial state. The buffers
* are not freed, so any mappings are still in effect.
*
* NOTE. Care should be taken that the channel isn't actually
* being used by anything when this call is made.
*/
void relay_reset(struct rchan *chan)
{
struct rchan_buf *buf;
unsigned int i;
if (!chan)
return;
if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) {
__relay_reset(buf, 0);
return;
}
mutex_lock(&relay_channels_mutex);
for_each_possible_cpu(i)
if ((buf = *per_cpu_ptr(chan->buf, i)))
__relay_reset(buf, 0);
mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_reset);
static inline void relay_set_buf_dentry(struct rchan_buf *buf,
struct dentry *dentry)
{
buf->dentry = dentry;
d_inode(buf->dentry)->i_size = buf->early_bytes;
}
static struct dentry *relay_create_buf_file(struct rchan *chan,
struct rchan_buf *buf,
unsigned int cpu)
{
struct dentry *dentry;
char *tmpname;
tmpname = kzalloc(NAME_MAX + 1, GFP_KERNEL);
if (!tmpname)
return NULL;
snprintf(tmpname, NAME_MAX, "%s%d", chan->base_filename, cpu);
/* Create file in fs */
dentry = chan->cb->create_buf_file(tmpname, chan->parent,
S_IRUSR, buf,
&chan->is_global);
if (IS_ERR(dentry))
dentry = NULL;
kfree(tmpname);
return dentry;
}
/*
* relay_open_buf - create a new relay channel buffer
*
* used by relay_open() and CPU hotplug.
*/
static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
{
struct rchan_buf *buf;
struct dentry *dentry;
if (chan->is_global)
return *per_cpu_ptr(chan->buf, 0);
buf = relay_create_buf(chan);
if (!buf)
return NULL;
if (chan->has_base_filename) {
dentry = relay_create_buf_file(chan, buf, cpu);
if (!dentry)
goto free_buf;
relay_set_buf_dentry(buf, dentry);
} else {
/* Only retrieve global info, nothing more, nothing less */
dentry = chan->cb->create_buf_file(NULL, NULL,
S_IRUSR, buf,
&chan->is_global);
if (IS_ERR_OR_NULL(dentry))
goto free_buf;
}
buf->cpu = cpu;
__relay_reset(buf, 1);
if(chan->is_global) {
*per_cpu_ptr(chan->buf, 0) = buf;
buf->cpu = 0;
}
return buf;
free_buf:
relay_destroy_buf(buf);
return NULL;
}
/**
* relay_close_buf - close a channel buffer
* @buf: channel buffer
*
* Marks the buffer finalized and restores the default callbacks.
* The channel buffer and channel buffer data structure are then freed
* automatically when the last reference is given up.
*/
static void relay_close_buf(struct rchan_buf *buf)
{
buf->finalized = 1;
irq_work_sync(&buf->wakeup_work);
buf->chan->cb->remove_buf_file(buf->dentry);
kref_put(&buf->kref, relay_remove_buf);
}
int relay_prepare_cpu(unsigned int cpu)
{
struct rchan *chan;
struct rchan_buf *buf;
mutex_lock(&relay_channels_mutex);
list_for_each_entry(chan, &relay_channels, list) {
if (*per_cpu_ptr(chan->buf, cpu))
continue;
buf = relay_open_buf(chan, cpu);
if (!buf) {
pr_err("relay: cpu %d buffer creation failed\n", cpu);
mutex_unlock(&relay_channels_mutex);
return -ENOMEM;
}
*per_cpu_ptr(chan->buf, cpu) = buf;
}
mutex_unlock(&relay_channels_mutex);
return 0;
}
/**
* relay_open - create a new relay channel
* @base_filename: base name of files to create, %NULL for buffering only
* @parent: dentry of parent directory, %NULL for root directory or buffer
* @subbuf_size: size of sub-buffers
* @n_subbufs: number of sub-buffers
* @cb: client callback functions
* @private_data: user-defined data
*
* Returns channel pointer if successful, %NULL otherwise.
*
* Creates a channel buffer for each cpu using the sizes and
* attributes specified. The created channel buffer files
* will be named base_filename0...base_filenameN-1. File
* permissions will be %S_IRUSR.
*
* If opening a buffer (@parent = NULL) that you later wish to register
* in a filesystem, call relay_late_setup_files() once the @parent dentry
* is available.
*/
struct rchan *relay_open(const char *base_filename,
struct dentry *parent,
size_t subbuf_size,
size_t n_subbufs,
const struct rchan_callbacks *cb,
void *private_data)
{
unsigned int i;
struct rchan *chan;
struct rchan_buf *buf;
if (!(subbuf_size && n_subbufs))
return NULL;
if (subbuf_size > UINT_MAX / n_subbufs)
return NULL;
if (!cb || !cb->create_buf_file || !cb->remove_buf_file)
return NULL;
chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
if (!chan)
return NULL;
chan->buf = alloc_percpu(struct rchan_buf *);
if (!chan->buf) {
kfree(chan);
return NULL;
}
chan->version = RELAYFS_CHANNEL_VERSION;
chan->n_subbufs = n_subbufs;
chan->subbuf_size = subbuf_size;
chan->alloc_size = PAGE_ALIGN(subbuf_size * n_subbufs);
chan->parent = parent;
chan->private_data = private_data;
if (base_filename) {
chan->has_base_filename = 1;
strscpy(chan->base_filename, base_filename, NAME_MAX);
}
chan->cb = cb;
kref_init(&chan->kref);
mutex_lock(&relay_channels_mutex);
for_each_online_cpu(i) {
buf = relay_open_buf(chan, i);
if (!buf)
goto free_bufs;
*per_cpu_ptr(chan->buf, i) = buf;
}
list_add(&chan->list, &relay_channels);
mutex_unlock(&relay_channels_mutex);
return chan;
free_bufs:
for_each_possible_cpu(i) {
if ((buf = *per_cpu_ptr(chan->buf, i)))
relay_close_buf(buf);
}
kref_put(&chan->kref, relay_destroy_channel);
mutex_unlock(&relay_channels_mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(relay_open);
struct rchan_percpu_buf_dispatcher {
struct rchan_buf *buf;
struct dentry *dentry;
};
/* Called in atomic context. */
static void __relay_set_buf_dentry(void *info)
{
struct rchan_percpu_buf_dispatcher *p = info;
relay_set_buf_dentry(p->buf, p->dentry);
}
/**
* relay_late_setup_files - triggers file creation
* @chan: channel to operate on
* @base_filename: base name of files to create
* @parent: dentry of parent directory, %NULL for root directory
*
* Returns 0 if successful, non-zero otherwise.
*
* Use to setup files for a previously buffer-only channel created
* by relay_open() with a NULL parent dentry.
*
* For example, this is useful for perfomring early tracing in kernel,
* before VFS is up and then exposing the early results once the dentry
* is available.
*/
int relay_late_setup_files(struct rchan *chan,
const char *base_filename,
struct dentry *parent)
{
int err = 0;
unsigned int i, curr_cpu;
unsigned long flags;
struct dentry *dentry;
struct rchan_buf *buf;
struct rchan_percpu_buf_dispatcher disp;
if (!chan || !base_filename)
return -EINVAL;
strscpy(chan->base_filename, base_filename, NAME_MAX);
mutex_lock(&relay_channels_mutex);
/* Is chan already set up? */
if (unlikely(chan->has_base_filename)) {
mutex_unlock(&relay_channels_mutex);
return -EEXIST;
}
chan->has_base_filename = 1;
chan->parent = parent;
if (chan->is_global) {
err = -EINVAL;
buf = *per_cpu_ptr(chan->buf, 0);
if (!WARN_ON_ONCE(!buf)) {
dentry = relay_create_buf_file(chan, buf, 0);
if (dentry && !WARN_ON_ONCE(!chan->is_global)) {
relay_set_buf_dentry(buf, dentry);
err = 0;
}
}
mutex_unlock(&relay_channels_mutex);
return err;
}
curr_cpu = get_cpu();
/*
* The CPU hotplug notifier ran before us and created buffers with
* no files associated. So it's safe to call relay_setup_buf_file()
* on all currently online CPUs.
*/
for_each_online_cpu(i) {
buf = *per_cpu_ptr(chan->buf, i);
if (unlikely(!buf)) {
WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n");
err = -EINVAL;
break;
}
dentry = relay_create_buf_file(chan, buf, i);
if (unlikely(!dentry)) {
err = -EINVAL;
break;
}
if (curr_cpu == i) {
local_irq_save(flags);
relay_set_buf_dentry(buf, dentry);
local_irq_restore(flags);
} else {
disp.buf = buf;
disp.dentry = dentry;
smp_mb();
/* relay_channels_mutex must be held, so wait. */
err = smp_call_function_single(i,
__relay_set_buf_dentry,
&disp, 1);
}
if (unlikely(err))
break;
}
put_cpu();
mutex_unlock(&relay_channels_mutex);
return err;
}
EXPORT_SYMBOL_GPL(relay_late_setup_files);
/**
* relay_switch_subbuf - switch to a new sub-buffer
* @buf: channel buffer
* @length: size of current event
*
* Returns either the length passed in or 0 if full.
*
* Performs sub-buffer-switch tasks such as invoking callbacks,
* updating padding counts, waking up readers, etc.
*/
size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
{
void *old, *new;
size_t old_subbuf, new_subbuf;
if (unlikely(length > buf->chan->subbuf_size))
goto toobig;
if (buf->offset != buf->chan->subbuf_size + 1) {
buf->prev_padding = buf->chan->subbuf_size - buf->offset;
old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
buf->padding[old_subbuf] = buf->prev_padding;
buf->subbufs_produced++;
if (buf->dentry)
d_inode(buf->dentry)->i_size +=
buf->chan->subbuf_size -
buf->padding[old_subbuf];
else
buf->early_bytes += buf->chan->subbuf_size -
buf->padding[old_subbuf];
smp_mb();
if (waitqueue_active(&buf->read_wait)) {
/*
* Calling wake_up_interruptible() from here
* will deadlock if we happen to be logging
* from the scheduler (trying to re-grab
* rq->lock), so defer it.
*/
irq_work_queue(&buf->wakeup_work);
}
}
old = buf->data;
new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
new = buf->start + new_subbuf * buf->chan->subbuf_size;
buf->offset = 0;
if (!relay_subbuf_start(buf, new, old, buf->prev_padding)) {
buf->offset = buf->chan->subbuf_size + 1;
return 0;
}
buf->data = new;
buf->padding[new_subbuf] = 0;
if (unlikely(length + buf->offset > buf->chan->subbuf_size))
goto toobig;
return length;
toobig:
buf->chan->last_toobig = length;
return 0;
}
EXPORT_SYMBOL_GPL(relay_switch_subbuf);
/**
* relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
* @chan: the channel
* @cpu: the cpu associated with the channel buffer to update
* @subbufs_consumed: number of sub-buffers to add to current buf's count
*
* Adds to the channel buffer's consumed sub-buffer count.
* subbufs_consumed should be the number of sub-buffers newly consumed,
* not the total consumed.
*
* NOTE. Kernel clients don't need to call this function if the channel
* mode is 'overwrite'.
*/
void relay_subbufs_consumed(struct rchan *chan,
unsigned int cpu,
size_t subbufs_consumed)
{
struct rchan_buf *buf;
if (!chan || cpu >= NR_CPUS)
return;
buf = *per_cpu_ptr(chan->buf, cpu);
if (!buf || subbufs_consumed > chan->n_subbufs)
return;
if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed)
buf->subbufs_consumed = buf->subbufs_produced;
else
buf->subbufs_consumed += subbufs_consumed;
}
EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
/**
* relay_close - close the channel
* @chan: the channel
*
* Closes all channel buffers and frees the channel.
*/
void relay_close(struct rchan *chan)
{
struct rchan_buf *buf;
unsigned int i;
if (!chan)
return;
mutex_lock(&relay_channels_mutex);
if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0)))
relay_close_buf(buf);
else
for_each_possible_cpu(i)
if ((buf = *per_cpu_ptr(chan->buf, i)))
relay_close_buf(buf);
if (chan->last_toobig)
printk(KERN_WARNING "relay: one or more items not logged "
"[item size (%zd) > sub-buffer size (%zd)]\n",
chan->last_toobig, chan->subbuf_size);
list_del(&chan->list);
kref_put(&chan->kref, relay_destroy_channel);
mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_close);
/**
* relay_flush - close the channel
* @chan: the channel
*
* Flushes all channel buffers, i.e. forces buffer switch.
*/
void relay_flush(struct rchan *chan)
{
struct rchan_buf *buf;
unsigned int i;
if (!chan)
return;
if (chan->is_global && (buf = *per_cpu_ptr(chan->buf, 0))) {
relay_switch_subbuf(buf, 0);
return;
}
mutex_lock(&relay_channels_mutex);
for_each_possible_cpu(i)
if ((buf = *per_cpu_ptr(chan->buf, i)))
relay_switch_subbuf(buf, 0);
mutex_unlock(&relay_channels_mutex);
}
EXPORT_SYMBOL_GPL(relay_flush);
/**
* relay_file_open - open file op for relay files
* @inode: the inode
* @filp: the file
*
* Increments the channel buffer refcount.
*/
static int relay_file_open(struct inode *inode, struct file *filp)
{
struct rchan_buf *buf = inode->i_private;
kref_get(&buf->kref);
filp->private_data = buf;
return nonseekable_open(inode, filp);
}
/**
* relay_file_mmap - mmap file op for relay files
* @filp: the file
* @vma: the vma describing what to map
*
* Calls upon relay_mmap_buf() to map the file into user space.
*/
static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct rchan_buf *buf = filp->private_data;
return relay_mmap_buf(buf, vma);
}
/**
* relay_file_poll - poll file op for relay files
* @filp: the file
* @wait: poll table
*
* Poll implemention.
*/
static __poll_t relay_file_poll(struct file *filp, poll_table *wait)
{
__poll_t mask = 0;
struct rchan_buf *buf = filp->private_data;
if (buf->finalized)
return EPOLLERR;
if (filp->f_mode & FMODE_READ) {
poll_wait(filp, &buf->read_wait, wait);
if (!relay_buf_empty(buf))
mask |= EPOLLIN | EPOLLRDNORM;
}
return mask;
}
/**
* relay_file_release - release file op for relay files
* @inode: the inode
* @filp: the file
*
* Decrements the channel refcount, as the filesystem is
* no longer using it.
*/
static int relay_file_release(struct inode *inode, struct file *filp)
{
struct rchan_buf *buf = filp->private_data;
kref_put(&buf->kref, relay_remove_buf);
return 0;
}
/*
* relay_file_read_consume - update the consumed count for the buffer
*/
static void relay_file_read_consume(struct rchan_buf *buf,
size_t read_pos,
size_t bytes_consumed)
{
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
size_t read_subbuf;
if (buf->subbufs_produced == buf->subbufs_consumed &&
buf->offset == buf->bytes_consumed)
return;
if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
buf->bytes_consumed = 0;
}
buf->bytes_consumed += bytes_consumed;
if (!read_pos)
read_subbuf = buf->subbufs_consumed % n_subbufs;
else
read_subbuf = read_pos / buf->chan->subbuf_size;
if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
(buf->offset == subbuf_size))
return;
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
buf->bytes_consumed = 0;
}
}
/*
* relay_file_read_avail - boolean, are there unconsumed bytes available?
*/
static int relay_file_read_avail(struct rchan_buf *buf)
{
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
size_t produced = buf->subbufs_produced;
size_t consumed;
relay_file_read_consume(buf, 0, 0);
consumed = buf->subbufs_consumed;
if (unlikely(buf->offset > subbuf_size)) {
if (produced == consumed)
return 0;
return 1;
}
if (unlikely(produced - consumed >= n_subbufs)) {
consumed = produced - n_subbufs + 1;
buf->subbufs_consumed = consumed;
buf->bytes_consumed = 0;
}
produced = (produced % n_subbufs) * subbuf_size + buf->offset;
consumed = (consumed % n_subbufs) * subbuf_size + buf->bytes_consumed;
if (consumed > produced)
produced += n_subbufs * subbuf_size;
if (consumed == produced) {
if (buf->offset == subbuf_size &&
buf->subbufs_produced > buf->subbufs_consumed)
return 1;
return 0;
}
return 1;
}
/**
* relay_file_read_subbuf_avail - return bytes available in sub-buffer
* @read_pos: file read position
* @buf: relay channel buffer
*/
static size_t relay_file_read_subbuf_avail(size_t read_pos,
struct rchan_buf *buf)
{
size_t padding, avail = 0;
size_t read_subbuf, read_offset, write_subbuf, write_offset;
size_t subbuf_size = buf->chan->subbuf_size;
write_subbuf = (buf->data - buf->start) / subbuf_size;
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
read_subbuf = read_pos / subbuf_size;
read_offset = read_pos % subbuf_size;
padding = buf->padding[read_subbuf];
if (read_subbuf == write_subbuf) {
if (read_offset + padding < write_offset)
avail = write_offset - (read_offset + padding);
} else
avail = (subbuf_size - padding) - read_offset;
return avail;
}
/**
* relay_file_read_start_pos - find the first available byte to read
* @buf: relay channel buffer
*
* If the read_pos is in the middle of padding, return the
* position of the first actually available byte, otherwise
* return the original value.
*/
static size_t relay_file_read_start_pos(struct rchan_buf *buf)
{
size_t read_subbuf, padding, padding_start, padding_end;
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
size_t consumed = buf->subbufs_consumed % n_subbufs;
size_t read_pos = (consumed * subbuf_size + buf->bytes_consumed)
% (n_subbufs * subbuf_size);
read_subbuf = read_pos / subbuf_size;
padding = buf->padding[read_subbuf];
padding_start = (read_subbuf + 1) * subbuf_size - padding;
padding_end = (read_subbuf + 1) * subbuf_size;
if (read_pos >= padding_start && read_pos < padding_end) {
read_subbuf = (read_subbuf + 1) % n_subbufs;
read_pos = read_subbuf * subbuf_size;
}
return read_pos;
}
/**
* relay_file_read_end_pos - return the new read position
* @read_pos: file read position
* @buf: relay channel buffer
* @count: number of bytes to be read
*/
static size_t relay_file_read_end_pos(struct rchan_buf *buf,
size_t read_pos,
size_t count)
{
size_t read_subbuf, padding, end_pos;
size_t subbuf_size = buf->chan->subbuf_size;
size_t n_subbufs = buf->chan->n_subbufs;
read_subbuf = read_pos / subbuf_size;
padding = buf->padding[read_subbuf];
if (read_pos % subbuf_size + count + padding == subbuf_size)
end_pos = (read_subbuf + 1) * subbuf_size;
else
end_pos = read_pos + count;
if (end_pos >= subbuf_size * n_subbufs)
end_pos = 0;
return end_pos;
}
static ssize_t relay_file_read(struct file *filp,
char __user *buffer,
size_t count,
loff_t *ppos)
{
struct rchan_buf *buf = filp->private_data;
size_t read_start, avail;
size_t written = 0;
int ret;
if (!count)
return 0;
inode_lock(file_inode(filp));
do {
void *from;
if (!relay_file_read_avail(buf))
break;
read_start = relay_file_read_start_pos(buf);
avail = relay_file_read_subbuf_avail(read_start, buf);
if (!avail)
break;
avail = min(count, avail);
from = buf->start + read_start;
ret = avail;
if (copy_to_user(buffer, from, avail))
break;
buffer += ret;
written += ret;
count -= ret;
relay_file_read_consume(buf, read_start, ret);
*ppos = relay_file_read_end_pos(buf, read_start, ret);
} while (count);
inode_unlock(file_inode(filp));
return written;
}
static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)
{
rbuf->bytes_consumed += bytes_consumed;
if (rbuf->bytes_consumed >= rbuf->chan->subbuf_size) {
relay_subbufs_consumed(rbuf->chan, rbuf->cpu, 1);
rbuf->bytes_consumed %= rbuf->chan->subbuf_size;
}
}
static void relay_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct rchan_buf *rbuf;
rbuf = (struct rchan_buf *)page_private(buf->page);
relay_consume_bytes(rbuf, buf->private);
}
static const struct pipe_buf_operations relay_pipe_buf_ops = {
.release = relay_pipe_buf_release,
.try_steal = generic_pipe_buf_try_steal,
.get = generic_pipe_buf_get,
};
static void relay_page_release(struct splice_pipe_desc *spd, unsigned int i)
{
}
/*
* subbuf_splice_actor - splice up to one subbuf's worth of data
*/
static ssize_t subbuf_splice_actor(struct file *in,
loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len,
unsigned int flags,
int *nonpad_ret)
{
unsigned int pidx, poff, total_len, subbuf_pages, nr_pages;
struct rchan_buf *rbuf = in->private_data;
unsigned int subbuf_size = rbuf->chan->subbuf_size;
uint64_t pos = (uint64_t) *ppos;
uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size;
size_t read_start = (size_t) do_div(pos, alloc_size);
size_t read_subbuf = read_start / subbuf_size;
size_t padding = rbuf->padding[read_subbuf];
size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding;
struct page *pages[PIPE_DEF_BUFFERS];
struct partial_page partial[PIPE_DEF_BUFFERS];
struct splice_pipe_desc spd = {
.pages = pages,
.nr_pages = 0,
.nr_pages_max = PIPE_DEF_BUFFERS,
.partial = partial,
.ops = &relay_pipe_buf_ops,
.spd_release = relay_page_release,
};
ssize_t ret;
if (rbuf->subbufs_produced == rbuf->subbufs_consumed)
return 0;
if (splice_grow_spd(pipe, &spd))
return -ENOMEM;
/*
* Adjust read len, if longer than what is available
*/
if (len > (subbuf_size - read_start % subbuf_size))
len = subbuf_size - read_start % subbuf_size;
subbuf_pages = rbuf->chan->alloc_size >> PAGE_SHIFT;
pidx = (read_start / PAGE_SIZE) % subbuf_pages;
poff = read_start & ~PAGE_MASK;
nr_pages = min_t(unsigned int, subbuf_pages, spd.nr_pages_max);
for (total_len = 0; spd.nr_pages < nr_pages; spd.nr_pages++) {
unsigned int this_len, this_end, private;
unsigned int cur_pos = read_start + total_len;
if (!len)
break;
this_len = min_t(unsigned long, len, PAGE_SIZE - poff);
private = this_len;
spd.pages[spd.nr_pages] = rbuf->page_array[pidx];
spd.partial[spd.nr_pages].offset = poff;
this_end = cur_pos + this_len;
if (this_end >= nonpad_end) {
this_len = nonpad_end - cur_pos;
private = this_len + padding;
}
spd.partial[spd.nr_pages].len = this_len;
spd.partial[spd.nr_pages].private = private;
len -= this_len;
total_len += this_len;
poff = 0;
pidx = (pidx + 1) % subbuf_pages;
if (this_end >= nonpad_end) {
spd.nr_pages++;
break;
}
}
ret = 0;
if (!spd.nr_pages)
goto out;
ret = *nonpad_ret = splice_to_pipe(pipe, &spd);
if (ret < 0 || ret < total_len)
goto out;
if (read_start + ret == nonpad_end)
ret += padding;
out:
splice_shrink_spd(&spd);
return ret;
}
static ssize_t relay_file_splice_read(struct file *in,
loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len,
unsigned int flags)
{
ssize_t spliced;
int ret;
int nonpad_ret = 0;
ret = 0;
spliced = 0;
while (len && !spliced) {
ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
if (ret < 0)
break;
else if (!ret) {
if (flags & SPLICE_F_NONBLOCK)
ret = -EAGAIN;
break;
}
*ppos += ret;
if (ret > len)
len = 0;
else
len -= ret;
spliced += nonpad_ret;
nonpad_ret = 0;
}
if (spliced)
return spliced;
return ret;
}
const struct file_operations relay_file_operations = {
.open = relay_file_open,
.poll = relay_file_poll,
.mmap = relay_file_mmap,
.read = relay_file_read,
.llseek = no_llseek,
.release = relay_file_release,
.splice_read = relay_file_splice_read,
};
EXPORT_SYMBOL_GPL(relay_file_operations);
| linux-master | kernel/relay.c |
// SPDX-License-Identifier: GPL-2.0
#include <linux/spinlock.h>
#include <linux/task_work.h>
#include <linux/resume_user_mode.h>
static struct callback_head work_exited; /* all we need is ->next == NULL */
/**
* task_work_add - ask the @task to execute @work->func()
* @task: the task which should run the callback
* @work: the callback to run
* @notify: how to notify the targeted task
*
* Queue @work for task_work_run() below and notify the @task if @notify
* is @TWA_RESUME, @TWA_SIGNAL, or @TWA_SIGNAL_NO_IPI.
*
* @TWA_SIGNAL works like signals, in that the it will interrupt the targeted
* task and run the task_work, regardless of whether the task is currently
* running in the kernel or userspace.
* @TWA_SIGNAL_NO_IPI works like @TWA_SIGNAL, except it doesn't send a
* reschedule IPI to force the targeted task to reschedule and run task_work.
* This can be advantageous if there's no strict requirement that the
* task_work be run as soon as possible, just whenever the task enters the
* kernel anyway.
* @TWA_RESUME work is run only when the task exits the kernel and returns to
* user mode, or before entering guest mode.
*
* Fails if the @task is exiting/exited and thus it can't process this @work.
* Otherwise @work->func() will be called when the @task goes through one of
* the aforementioned transitions, or exits.
*
* If the targeted task is exiting, then an error is returned and the work item
* is not queued. It's up to the caller to arrange for an alternative mechanism
* in that case.
*
* Note: there is no ordering guarantee on works queued here. The task_work
* list is LIFO.
*
* RETURNS:
* 0 if succeeds or -ESRCH.
*/
int task_work_add(struct task_struct *task, struct callback_head *work,
enum task_work_notify_mode notify)
{
struct callback_head *head;
/* record the work call stack in order to print it in KASAN reports */
kasan_record_aux_stack(work);
head = READ_ONCE(task->task_works);
do {
if (unlikely(head == &work_exited))
return -ESRCH;
work->next = head;
} while (!try_cmpxchg(&task->task_works, &head, work));
switch (notify) {
case TWA_NONE:
break;
case TWA_RESUME:
set_notify_resume(task);
break;
case TWA_SIGNAL:
set_notify_signal(task);
break;
case TWA_SIGNAL_NO_IPI:
__set_notify_signal(task);
break;
default:
WARN_ON_ONCE(1);
break;
}
return 0;
}
/**
* task_work_cancel_match - cancel a pending work added by task_work_add()
* @task: the task which should execute the work
* @match: match function to call
* @data: data to be passed in to match function
*
* RETURNS:
* The found work or NULL if not found.
*/
struct callback_head *
task_work_cancel_match(struct task_struct *task,
bool (*match)(struct callback_head *, void *data),
void *data)
{
struct callback_head **pprev = &task->task_works;
struct callback_head *work;
unsigned long flags;
if (likely(!task_work_pending(task)))
return NULL;
/*
* If cmpxchg() fails we continue without updating pprev.
* Either we raced with task_work_add() which added the
* new entry before this work, we will find it again. Or
* we raced with task_work_run(), *pprev == NULL/exited.
*/
raw_spin_lock_irqsave(&task->pi_lock, flags);
work = READ_ONCE(*pprev);
while (work) {
if (!match(work, data)) {
pprev = &work->next;
work = READ_ONCE(*pprev);
} else if (try_cmpxchg(pprev, &work, work->next))
break;
}
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
return work;
}
static bool task_work_func_match(struct callback_head *cb, void *data)
{
return cb->func == data;
}
/**
* task_work_cancel - cancel a pending work added by task_work_add()
* @task: the task which should execute the work
* @func: identifies the work to remove
*
* Find the last queued pending work with ->func == @func and remove
* it from queue.
*
* RETURNS:
* The found work or NULL if not found.
*/
struct callback_head *
task_work_cancel(struct task_struct *task, task_work_func_t func)
{
return task_work_cancel_match(task, task_work_func_match, func);
}
/**
* task_work_run - execute the works added by task_work_add()
*
* Flush the pending works. Should be used by the core kernel code.
* Called before the task returns to the user-mode or stops, or when
* it exits. In the latter case task_work_add() can no longer add the
* new work after task_work_run() returns.
*/
void task_work_run(void)
{
struct task_struct *task = current;
struct callback_head *work, *head, *next;
for (;;) {
/*
* work->func() can do task_work_add(), do not set
* work_exited unless the list is empty.
*/
work = READ_ONCE(task->task_works);
do {
head = NULL;
if (!work) {
if (task->flags & PF_EXITING)
head = &work_exited;
else
break;
}
} while (!try_cmpxchg(&task->task_works, &work, head));
if (!work)
break;
/*
* Synchronize with task_work_cancel(). It can not remove
* the first entry == work, cmpxchg(task_works) must fail.
* But it can remove another entry from the ->next list.
*/
raw_spin_lock_irq(&task->pi_lock);
raw_spin_unlock_irq(&task->pi_lock);
do {
next = work->next;
work->func(work);
work = next;
cond_resched();
} while (work);
}
}
| linux-master | kernel/task_work.c |
Subsets and Splits