text: // SPDX-License-Identifier: GPL-2.0
  #include <dirent.h>
  #include <errno.h>
  #include <inttypes.h>
  #include <regex.h>
  #include <stdlib.h>
  #include "callchain.h"
  #include "debug.h"
  #include "dso.h"
  #include "env.h"
  #include "event.h"
  #include "evsel.h"
  #include "hist.h"
  #include "machine.h"
  #include "map.h"
  #include "map_symbol.h"
  #include "branch.h"
  #include "mem-events.h"
  #include "srcline.h"
  #include "symbol.h"
  #include "sort.h"
  #include "strlist.h"
  #include "target.h"
  #include "thread.h"
  #include "util.h"
  #include "vdso.h"
  #include <stdbool.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <unistd.h>
  #include "unwind.h"
  #include "linux/hash.h"
  #include "asm/bug.h"
  #include "bpf-event.h"
  #include <internal/lib.h> // page_size
  #include "cgroup.h"
  
  #include <linux/ctype.h>
  #include <symbol/kallsyms.h>
  #include <linux/mman.h>
  #include <linux/string.h>
  #include <linux/zalloc.h>
  
  static void __machine__remove_thread(struct machine *machine, struct thread *th, bool lock);
  
  static struct dso *machine__kernel_dso(struct machine *machine)
  {
  	return machine->vmlinux_map->dso;
  }
  
  static void dsos__init(struct dsos *dsos)
  {
  	INIT_LIST_HEAD(&dsos->head);
  	dsos->root = RB_ROOT;
  	init_rwsem(&dsos->lock);
  }
  
  static void machine__threads_init(struct machine *machine)
  {
  	int i;
  
  	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
  		struct threads *threads = &machine->threads[i];
  		threads->entries = RB_ROOT_CACHED;
  		init_rwsem(&threads->lock);
  		threads->nr = 0;
  		INIT_LIST_HEAD(&threads->dead);
  		threads->last_match = NULL;
  	}
  }
  
  static int machine__set_mmap_name(struct machine *machine)
  {
  	if (machine__is_host(machine))
  		machine->mmap_name = strdup("[kernel.kallsyms]");
  	else if (machine__is_default_guest(machine))
  		machine->mmap_name = strdup("[guest.kernel.kallsyms]");
  	else if (asprintf(&machine->mmap_name, "[guest.kernel.kallsyms.%d]",
  			  machine->pid) < 0)
  		machine->mmap_name = NULL;
  
  	return machine->mmap_name ? 0 : -ENOMEM;
  }
  
  int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
  {
  	int err = -ENOMEM;
  
  	memset(machine, 0, sizeof(*machine));
  	maps__init(&machine->kmaps, machine);
  	RB_CLEAR_NODE(&machine->rb_node);
  	dsos__init(&machine->dsos);
  
  	machine__threads_init(machine);
  
  	machine->vdso_info = NULL;
  	machine->env = NULL;
  
  	machine->pid = pid;
  
  	machine->id_hdr_size = 0;
  	machine->kptr_restrict_warned = false;
  	machine->comm_exec = false;
  	machine->kernel_start = 0;
  	machine->vmlinux_map = NULL;
  
  	machine->root_dir = strdup(root_dir);
  	if (machine->root_dir == NULL)
  		return -ENOMEM;
  
  	if (machine__set_mmap_name(machine))
  		goto out;
  
  	if (pid != HOST_KERNEL_ID) {
  		struct thread *thread = machine__findnew_thread(machine, -1,
  								pid);
  		char comm[64];
  
  		if (thread == NULL)
  			goto out;
  
  		snprintf(comm, sizeof(comm), "[guest/%d]", pid);
  		thread__set_comm(thread, comm, 0);
  		thread__put(thread);
  	}
  
  	machine->current_tid = NULL;
  	err = 0;
  
  out:
  	if (err) {
  		zfree(&machine->root_dir);
  		zfree(&machine->mmap_name);
  	}
  	return 0;
  }
  
  struct machine *machine__new_host(void)
  {
  	struct machine *machine = malloc(sizeof(*machine));
  
  	if (machine != NULL) {
  		machine__init(machine, "", HOST_KERNEL_ID);
  
  		if (machine__create_kernel_maps(machine) < 0)
  			goto out_delete;
  	}
  
  	return machine;
  out_delete:
  	free(machine);
  	return NULL;
  }
  
  struct machine *machine__new_kallsyms(void)
  {
  	struct machine *machine = machine__new_host();
  	/*
  	 * FIXME:
  	 * 1) We should switch to machine__load_kallsyms(), i.e. not explicitly
  	 *    ask for not using the kcore parsing code, once this one is fixed
  	 *    to create a map per module.
  	 */
  	if (machine && machine__load_kallsyms(machine, "/proc/kallsyms") <= 0) {
  		machine__delete(machine);
  		machine = NULL;
  	}
  
  	return machine;
  }
  
  static void dsos__purge(struct dsos *dsos)
  {
  	struct dso *pos, *n;
  
  	down_write(&dsos->lock);
  
  	list_for_each_entry_safe(pos, n, &dsos->head, node) {
  		RB_CLEAR_NODE(&pos->rb_node);
  		pos->root = NULL;
  		list_del_init(&pos->node);
  		dso__put(pos);
  	}
  
  	up_write(&dsos->lock);
  }
  
  static void dsos__exit(struct dsos *dsos)
  {
  	dsos__purge(dsos);
  	exit_rwsem(&dsos->lock);
  }
  
  void machine__delete_threads(struct machine *machine)
  {
  	struct rb_node *nd;
  	int i;
  
  	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
  		struct threads *threads = &machine->threads[i];
  		down_write(&threads->lock);
  		nd = rb_first_cached(&threads->entries);
  		while (nd) {
  			struct thread *t = rb_entry(nd, struct thread, rb_node);
  
  			nd = rb_next(nd);
  			__machine__remove_thread(machine, t, false);
  		}
  		up_write(&threads->lock);
  	}
  }
  
  void machine__exit(struct machine *machine)
  {
  	int i;
  
  	if (machine == NULL)
  		return;
  
  	machine__destroy_kernel_maps(machine);
  	maps__exit(&machine->kmaps);
  	dsos__exit(&machine->dsos);
  	machine__exit_vdso(machine);
  	zfree(&machine->root_dir);
  	zfree(&machine->mmap_name);
  	zfree(&machine->current_tid);
  
  	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
  		struct threads *threads = &machine->threads[i];
  		struct thread *thread, *n;
  		/*
  		 * Forget about the dead, at this point whatever threads were
  		 * left in the dead lists better have a reference count taken
  		 * by who is using them, and then, when they drop those references
  		 * and it finally hits zero, thread__put() will check and see that
  		 * its not in the dead threads list and will not try to remove it
  		 * from there, just calling thread__delete() straight away.
  		 */
  		list_for_each_entry_safe(thread, n, &threads->dead, node)
  			list_del_init(&thread->node);
  
  		exit_rwsem(&threads->lock);
  	}
  }
  
  void machine__delete(struct machine *machine)
  {
  	if (machine) {
  		machine__exit(machine);
  		free(machine);
  	}
  }
  
  void machines__init(struct machines *machines)
  {
  	machine__init(&machines->host, "", HOST_KERNEL_ID);
  	machines->guests = RB_ROOT_CACHED;
  }
  
  void machines__exit(struct machines *machines)
  {
  	machine__exit(&machines->host);
  	/* XXX exit guest */
  }
  
  struct machine *machines__add(struct machines *machines, pid_t pid,
  			      const char *root_dir)
  {
  	struct rb_node **p = &machines->guests.rb_root.rb_node;
  	struct rb_node *parent = NULL;
  	struct machine *pos, *machine = malloc(sizeof(*machine));
  	bool leftmost = true;
  
  	if (machine == NULL)
  		return NULL;
  
  	if (machine__init(machine, root_dir, pid) != 0) {
  		free(machine);
  		return NULL;
  	}
  
  	while (*p != NULL) {
  		parent = *p;
  		pos = rb_entry(parent, struct machine, rb_node);
  		if (pid < pos->pid)
  			p = &(*p)->rb_left;
  		else {
  			p = &(*p)->rb_right;
  			leftmost = false;
  		}
  	}
  
  	rb_link_node(&machine->rb_node, parent, p);
  	rb_insert_color_cached(&machine->rb_node, &machines->guests, leftmost);
  
  	return machine;
  }
  
  void machines__set_comm_exec(struct machines *machines, bool comm_exec)
  {
  	struct rb_node *nd;
  
  	machines->host.comm_exec = comm_exec;
  
  	for (nd = rb_first_cached(&machines->guests); nd; nd = rb_next(nd)) {
  		struct machine *machine = rb_entry(nd, struct machine, rb_node);
  
  		machine->comm_exec = comm_exec;
  	}
  }
  
  struct machine *machines__find(struct machines *machines, pid_t pid)
  {
  	struct rb_node **p = &machines->guests.rb_root.rb_node;
  	struct rb_node *parent = NULL;
  	struct machine *machine;
  	struct machine *default_machine = NULL;
  
  	if (pid == HOST_KERNEL_ID)
  		return &machines->host;
  
  	while (*p != NULL) {
  		parent = *p;
  		machine = rb_entry(parent, struct machine, rb_node);
  		if (pid < machine->pid)
  			p = &(*p)->rb_left;
  		else if (pid > machine->pid)
  			p = &(*p)->rb_right;
  		else
  			return machine;
  		if (!machine->pid)
  			default_machine = machine;
  	}
  
  	return default_machine;
  }
  
  struct machine *machines__findnew(struct machines *machines, pid_t pid)
  {
  	char path[PATH_MAX];
  	const char *root_dir = "";
  	struct machine *machine = machines__find(machines, pid);
  
  	if (machine && (machine->pid == pid))
  		goto out;
  
  	if ((pid != HOST_KERNEL_ID) &&
  	    (pid != DEFAULT_GUEST_KERNEL_ID) &&
  	    (symbol_conf.guestmount)) {
  		sprintf(path, "%s/%d", symbol_conf.guestmount, pid);
  		if (access(path, R_OK)) {
  			static struct strlist *seen;
  
  			if (!seen)
  				seen = strlist__new(NULL, NULL);
  
  			if (!strlist__has_entry(seen, path)) {
  				pr_err("Can't access file %s\n", path);
  				strlist__add(seen, path);
  			}
  			machine = NULL;
  			goto out;
  		}
  		root_dir = path;
  	}
  
  	machine = machines__add(machines, pid, root_dir);
  out:
  	return machine;
  }
  
  struct machine *machines__find_guest(struct machines *machines, pid_t pid)
  {
  	struct machine *machine = machines__find(machines, pid);
  
  	if (!machine)
  		machine = machines__findnew(machines, DEFAULT_GUEST_KERNEL_ID);
  	return machine;
  }
  
  void machines__process_guests(struct machines *machines,
  			      machine__process_t process, void *data)
  {
  	struct rb_node *nd;
  
  	for (nd = rb_first_cached(&machines->guests); nd; nd = rb_next(nd)) {
  		struct machine *pos = rb_entry(nd, struct machine, rb_node);
  		process(pos, data);
  	}
  }
  
  void machines__set_id_hdr_size(struct machines *machines, u16 id_hdr_size)
  {
  	struct rb_node *node;
  	struct machine *machine;
  
  	machines->host.id_hdr_size = id_hdr_size;
  
  	for (node = rb_first_cached(&machines->guests); node;
  	     node = rb_next(node)) {
  		machine = rb_entry(node, struct machine, rb_node);
  		machine->id_hdr_size = id_hdr_size;
  	}
  
  	return;
  }
  
  static void machine__update_thread_pid(struct machine *machine,
  				       struct thread *th, pid_t pid)
  {
  	struct thread *leader;
  
  	if (pid == th->pid_ || pid == -1 || th->pid_ != -1)
  		return;
  
  	th->pid_ = pid;
  
  	if (th->pid_ == th->tid)
  		return;
  
  	leader = __machine__findnew_thread(machine, th->pid_, th->pid_);
  	if (!leader)
  		goto out_err;
  
  	if (!leader->maps)
  		leader->maps = maps__new(machine);
  
  	if (!leader->maps)
  		goto out_err;
  
  	if (th->maps == leader->maps)
  		return;
  
  	if (th->maps) {
  		/*
  		 * Maps are created from MMAP events which provide the pid and
  		 * tid.  Consequently there never should be any maps on a thread
  		 * with an unknown pid.  Just print an error if there are.
  		 */
  		if (!maps__empty(th->maps))
  			pr_err("Discarding thread maps for %d:%d\n",
  			       th->pid_, th->tid);
  		maps__put(th->maps);
  	}
  
  	th->maps = maps__get(leader->maps);
  out_put:
  	thread__put(leader);
  	return;
  out_err:
  	pr_err("Failed to join map groups for %d:%d\n", th->pid_, th->tid);
  	goto out_put;
  }
  
  /*
   * Front-end cache - TID lookups come in blocks,
   * so most of the time we dont have to look up
   * the full rbtree:
   */
  static struct thread*
  __threads__get_last_match(struct threads *threads, struct machine *machine,
  			  int pid, int tid)
  {
  	struct thread *th;
  
  	th = threads->last_match;
  	if (th != NULL) {
  		if (th->tid == tid) {
  			machine__update_thread_pid(machine, th, pid);
  			return thread__get(th);
  		}
  
  		threads->last_match = NULL;
  	}
  
  	return NULL;
  }
  
  static struct thread*
  threads__get_last_match(struct threads *threads, struct machine *machine,
  			int pid, int tid)
  {
  	struct thread *th = NULL;
  
  	if (perf_singlethreaded)
  		th = __threads__get_last_match(threads, machine, pid, tid);
  
  	return th;
  }
  
  static void
  __threads__set_last_match(struct threads *threads, struct thread *th)
  {
  	threads->last_match = th;
  }
  
  static void
  threads__set_last_match(struct threads *threads, struct thread *th)
  {
  	if (perf_singlethreaded)
  		__threads__set_last_match(threads, th);
  }
  
  /*
   * Caller must eventually drop thread->refcnt returned with a successful
   * lookup/new thread inserted.
   */
  static struct thread *____machine__findnew_thread(struct machine *machine,
  						  struct threads *threads,
  						  pid_t pid, pid_t tid,
  						  bool create)
  {
  	struct rb_node **p = &threads->entries.rb_root.rb_node;
  	struct rb_node *parent = NULL;
  	struct thread *th;
  	bool leftmost = true;
  
  	th = threads__get_last_match(threads, machine, pid, tid);
  	if (th)
  		return th;
  
  	while (*p != NULL) {
  		parent = *p;
  		th = rb_entry(parent, struct thread, rb_node);
  
  		if (th->tid == tid) {
  			threads__set_last_match(threads, th);
  			machine__update_thread_pid(machine, th, pid);
  			return thread__get(th);
  		}
  
  		if (tid < th->tid)
  			p = &(*p)->rb_left;
  		else {
  			p = &(*p)->rb_right;
  			leftmost = false;
  		}
  	}
  
  	if (!create)
  		return NULL;
  
  	th = thread__new(pid, tid);
  	if (th != NULL) {
  		rb_link_node(&th->rb_node, parent, p);
  		rb_insert_color_cached(&th->rb_node, &threads->entries, leftmost);
  
  		/*
  		 * We have to initialize maps separately after rb tree is updated.
  		 *
  		 * The reason is that we call machine__findnew_thread
  		 * within thread__init_maps to find the thread
  		 * leader and that would screwed the rb tree.
  		 */
  		if (thread__init_maps(th, machine)) {
  			rb_erase_cached(&th->rb_node, &threads->entries);
  			RB_CLEAR_NODE(&th->rb_node);
  			thread__put(th);
  			return NULL;
  		}
  		/*
  		 * It is now in the rbtree, get a ref
  		 */
  		thread__get(th);
  		threads__set_last_match(threads, th);
  		++threads->nr;
  	}
  
  	return th;
  }
  
  struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid)
  {
  	return ____machine__findnew_thread(machine, machine__threads(machine, tid), pid, tid, true);
  }
  
  struct thread *machine__findnew_thread(struct machine *machine, pid_t pid,
  				       pid_t tid)
  {
  	struct threads *threads = machine__threads(machine, tid);
  	struct thread *th;
  
  	down_write(&threads->lock);
  	th = __machine__findnew_thread(machine, pid, tid);
  	up_write(&threads->lock);
  	return th;
  }
  
  struct thread *machine__find_thread(struct machine *machine, pid_t pid,
  				    pid_t tid)
  {
  	struct threads *threads = machine__threads(machine, tid);
  	struct thread *th;
  
  	down_read(&threads->lock);
  	th =  ____machine__findnew_thread(machine, threads, pid, tid, false);
  	up_read(&threads->lock);
  	return th;
  }
  
  /*
   * Threads are identified by pid and tid, and the idle task has pid == tid == 0.
   * So here a single thread is created for that, but actually there is a separate
   * idle task per cpu, so there should be one 'struct thread' per cpu, but there
   * is only 1. That causes problems for some tools, requiring workarounds. For
   * example get_idle_thread() in builtin-sched.c, or thread_stack__per_cpu().
   */
  struct thread *machine__idle_thread(struct machine *machine)
  {
  	struct thread *thread = machine__findnew_thread(machine, 0, 0);
  
  	if (!thread || thread__set_comm(thread, "swapper", 0) ||
  	    thread__set_namespaces(thread, 0, NULL))
  		pr_err("problem inserting idle task for machine pid %d\n", machine->pid);
  
  	return thread;
  }
  
  struct comm *machine__thread_exec_comm(struct machine *machine,
  				       struct thread *thread)
  {
  	if (machine->comm_exec)
  		return thread__exec_comm(thread);
  	else
  		return thread__comm(thread);
  }
  
  int machine__process_comm_event(struct machine *machine, union perf_event *event,
  				struct perf_sample *sample)
  {
  	struct thread *thread = machine__findnew_thread(machine,
  							event->comm.pid,
  							event->comm.tid);
  	bool exec = event->header.misc & PERF_RECORD_MISC_COMM_EXEC;
  	int err = 0;
  
  	if (exec)
  		machine->comm_exec = true;
  
  	if (dump_trace)
  		perf_event__fprintf_comm(event, stdout);
  
  	if (thread == NULL ||
  	    __thread__set_comm(thread, event->comm.comm, sample->time, exec)) {
  		dump_printf("problem processing PERF_RECORD_COMM, skipping event.\n");
  		err = -1;
  	}
  
  	thread__put(thread);
  
  	return err;
  }
  
  int machine__process_namespaces_event(struct machine *machine __maybe_unused,
  				      union perf_event *event,
  				      struct perf_sample *sample __maybe_unused)
  {
  	struct thread *thread = machine__findnew_thread(machine,
  							event->namespaces.pid,
  							event->namespaces.tid);
  	int err = 0;
  
  	WARN_ONCE(event->namespaces.nr_namespaces > NR_NAMESPACES,
  		  "\nWARNING: kernel seems to support more namespaces than perf"
  		  " tool.\nTry updating the perf tool..\n\n");
  
  	WARN_ONCE(event->namespaces.nr_namespaces < NR_NAMESPACES,
  		  "\nWARNING: perf tool seems to support more namespaces than"
  		  " the kernel.\nTry updating the kernel..\n\n");
  
  	if (dump_trace)
  		perf_event__fprintf_namespaces(event, stdout);
  
  	if (thread == NULL ||
  	    thread__set_namespaces(thread, sample->time, &event->namespaces)) {
  		dump_printf("problem processing PERF_RECORD_NAMESPACES, skipping event.\n");
  		err = -1;
  	}
  
  	thread__put(thread);
  
  	return err;
  }
  
  int machine__process_cgroup_event(struct machine *machine,
  				  union perf_event *event,
  				  struct perf_sample *sample __maybe_unused)
  {
  	struct cgroup *cgrp;
  
  	if (dump_trace)
  		perf_event__fprintf_cgroup(event, stdout);
  
  	cgrp = cgroup__findnew(machine->env, event->cgroup.id, event->cgroup.path);
  	if (cgrp == NULL)
  		return -ENOMEM;
  
  	return 0;
  }
  
  int machine__process_lost_event(struct machine *machine __maybe_unused,
  				union perf_event *event, struct perf_sample *sample __maybe_unused)
  {
  	dump_printf(": id:%" PRI_lu64 ": lost:%" PRI_lu64 "\n",
  		    event->lost.id, event->lost.lost);
  	return 0;
  }
  
  int machine__process_lost_samples_event(struct machine *machine __maybe_unused,
  					union perf_event *event, struct perf_sample *sample)
  {
  	dump_printf(": id:%" PRIu64 ": lost samples :%" PRI_lu64 "\n",
  		    sample->id, event->lost_samples.lost);
  	return 0;
  }
  
  static struct dso *machine__findnew_module_dso(struct machine *machine,
  					       struct kmod_path *m,
  					       const char *filename)
  {
  	struct dso *dso;
  
  	down_write(&machine->dsos.lock);
  
  	dso = __dsos__find(&machine->dsos, m->name, true);
  	if (!dso) {
  		dso = __dsos__addnew(&machine->dsos, m->name);
  		if (dso == NULL)
  			goto out_unlock;
  
  		dso__set_module_info(dso, m, machine);
  		dso__set_long_name(dso, strdup(filename), true);
  		dso->kernel = DSO_SPACE__KERNEL;
  	}
  
  	dso__get(dso);
  out_unlock:
  	up_write(&machine->dsos.lock);
  	return dso;
  }
  
  int machine__process_aux_event(struct machine *machine __maybe_unused,
  			       union perf_event *event)
  {
  	if (dump_trace)
  		perf_event__fprintf_aux(event, stdout);
  	return 0;
  }
  
  int machine__process_itrace_start_event(struct machine *machine __maybe_unused,
  					union perf_event *event)
  {
  	if (dump_trace)
  		perf_event__fprintf_itrace_start(event, stdout);
  	return 0;
  }
  
  int machine__process_switch_event(struct machine *machine __maybe_unused,
  				  union perf_event *event)
  {
  	if (dump_trace)
  		perf_event__fprintf_switch(event, stdout);
  	return 0;
  }
  
  static int machine__process_ksymbol_register(struct machine *machine,
  					     union perf_event *event,
  					     struct perf_sample *sample __maybe_unused)
  {
  	struct symbol *sym;
  	struct map *map = maps__find(&machine->kmaps, event->ksymbol.addr);
  
  	if (!map) {
  		struct dso *dso = dso__new(event->ksymbol.name);
  
  		if (dso) {
  			dso->kernel = DSO_SPACE__KERNEL;
  			map = map__new2(0, dso);
  			dso__put(dso);
  		}
  
  		if (!dso || !map) {
  			return -ENOMEM;
  		}
  
  		if (event->ksymbol.ksym_type == PERF_RECORD_KSYMBOL_TYPE_OOL) {
  			map->dso->binary_type = DSO_BINARY_TYPE__OOL;
  			map->dso->data.file_size = event->ksymbol.len;
  			dso__set_loaded(map->dso);
  		}
  
  		map->start = event->ksymbol.addr;
  		map->end = map->start + event->ksymbol.len;
  		maps__insert(&machine->kmaps, map);
  		map__put(map);
  		dso__set_loaded(dso);
  
  		if (is_bpf_image(event->ksymbol.name)) {
  			dso->binary_type = DSO_BINARY_TYPE__BPF_IMAGE;
  			dso__set_long_name(dso, "", false);
  		}
  	}
  
  	sym = symbol__new(map->map_ip(map, map->start),
  			  event->ksymbol.len,
  			  0, 0, event->ksymbol.name);
  	if (!sym)
  		return -ENOMEM;
  	dso__insert_symbol(map->dso, sym);
  	return 0;
  }
  
  static int machine__process_ksymbol_unregister(struct machine *machine,
  					       union perf_event *event,
  					       struct perf_sample *sample __maybe_unused)
  {
  	struct symbol *sym;
  	struct map *map;
  
  	map = maps__find(&machine->kmaps, event->ksymbol.addr);
  	if (!map)
  		return 0;
  
  	if (map != machine->vmlinux_map)
  		maps__remove(&machine->kmaps, map);
  	else {
  		sym = dso__find_symbol(map->dso, map->map_ip(map, map->start));
  		if (sym)
  			dso__delete_symbol(map->dso, sym);
  	}
  
  	return 0;
  }
  
  int machine__process_ksymbol(struct machine *machine __maybe_unused,
  			     union perf_event *event,
  			     struct perf_sample *sample)
  {
  	if (dump_trace)
  		perf_event__fprintf_ksymbol(event, stdout);
  
  	if (event->ksymbol.flags & PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER)
  		return machine__process_ksymbol_unregister(machine, event,
  							   sample);
  	return machine__process_ksymbol_register(machine, event, sample);
  }
  
  int machine__process_text_poke(struct machine *machine, union perf_event *event,
  			       struct perf_sample *sample __maybe_unused)
  {
  	struct map *map = maps__find(&machine->kmaps, event->text_poke.addr);
  	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
  
  	if (dump_trace)
  		perf_event__fprintf_text_poke(event, machine, stdout);
  
  	if (!event->text_poke.new_len)
  		return 0;
  
  	if (cpumode != PERF_RECORD_MISC_KERNEL) {
  		pr_debug("%s: unsupported cpumode - ignoring\n", __func__);
  		return 0;
  	}
  
  	if (map && map->dso) {
  		u8 *new_bytes = event->text_poke.bytes + event->text_poke.old_len;
  		int ret;
  
  		/*
  		 * Kernel maps might be changed when loading symbols so loading
  		 * must be done prior to using kernel maps.
  		 */
  		map__load(map);
  		ret = dso__data_write_cache_addr(map->dso, map, machine,
  						 event->text_poke.addr,
  						 new_bytes,
  						 event->text_poke.new_len);
  		if (ret != event->text_poke.new_len)
  			pr_debug("Failed to write kernel text poke at %#" PRI_lx64 "\n",
  				 event->text_poke.addr);
  	} else {
  		pr_debug("Failed to find kernel text poke address map for %#" PRI_lx64 "\n",
  			 event->text_poke.addr);
  	}
  
  	return 0;
  }
  
  static struct map *machine__addnew_module_map(struct machine *machine, u64 start,
  					      const char *filename)
  {
  	struct map *map = NULL;
  	struct kmod_path m;
  	struct dso *dso;
  
  	if (kmod_path__parse_name(&m, filename))
  		return NULL;
  
  	dso = machine__findnew_module_dso(machine, &m, filename);
  	if (dso == NULL)
  		goto out;
  
  	map = map__new2(start, dso);
  	if (map == NULL)
  		goto out;
  
  	maps__insert(&machine->kmaps, map);
  
  	/* Put the map here because maps__insert already got it */
  	map__put(map);
  out:
  	/* put the dso here, corresponding to  machine__findnew_module_dso */
  	dso__put(dso);
  	zfree(&m.name);
  	return map;
  }
  
  size_t machines__fprintf_dsos(struct machines *machines, FILE *fp)
  {
  	struct rb_node *nd;
  	size_t ret = __dsos__fprintf(&machines->host.dsos.head, fp);
  
  	for (nd = rb_first_cached(&machines->guests); nd; nd = rb_next(nd)) {
  		struct machine *pos = rb_entry(nd, struct machine, rb_node);
  		ret += __dsos__fprintf(&pos->dsos.head, fp);
  	}
  
  	return ret;
  }
  
  size_t machine__fprintf_dsos_buildid(struct machine *m, FILE *fp,
  				     bool (skip)(struct dso *dso, int parm), int parm)
  {
  	return __dsos__fprintf_buildid(&m->dsos.head, fp, skip, parm);
  }
  
  size_t machines__fprintf_dsos_buildid(struct machines *machines, FILE *fp,
  				     bool (skip)(struct dso *dso, int parm), int parm)
  {
  	struct rb_node *nd;
  	size_t ret = machine__fprintf_dsos_buildid(&machines->host, fp, skip, parm);
  
  	for (nd = rb_first_cached(&machines->guests); nd; nd = rb_next(nd)) {
  		struct machine *pos = rb_entry(nd, struct machine, rb_node);
  		ret += machine__fprintf_dsos_buildid(pos, fp, skip, parm);
  	}
  	return ret;
  }
  
  size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp)
  {
  	int i;
  	size_t printed = 0;
  	struct dso *kdso = machine__kernel_dso(machine);
  
  	if (kdso->has_build_id) {
  		char filename[PATH_MAX];
  		if (dso__build_id_filename(kdso, filename, sizeof(filename),
  					   false))
  			printed += fprintf(fp, "[0] %s\n", filename);
  	}
  
  	for (i = 0; i < vmlinux_path__nr_entries; ++i)
  		printed += fprintf(fp, "[%d] %s\n",
  				   i + kdso->has_build_id, vmlinux_path[i]);
  
  	return printed;
  }
  
  size_t machine__fprintf(struct machine *machine, FILE *fp)
  {
  	struct rb_node *nd;
  	size_t ret;
  	int i;
  
  	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
  		struct threads *threads = &machine->threads[i];
  
  		down_read(&threads->lock);
  
  		ret = fprintf(fp, "Threads: %u\n", threads->nr);
  
  		for (nd = rb_first_cached(&threads->entries); nd;
  		     nd = rb_next(nd)) {
  			struct thread *pos = rb_entry(nd, struct thread, rb_node);
  
  			ret += thread__fprintf(pos, fp);
  		}
  
  		up_read(&threads->lock);
  	}
  	return ret;
  }
  
  static struct dso *machine__get_kernel(struct machine *machine)
  {
  	const char *vmlinux_name = machine->mmap_name;
  	struct dso *kernel;
  
  	if (machine__is_host(machine)) {
  		if (symbol_conf.vmlinux_name)
  			vmlinux_name = symbol_conf.vmlinux_name;
  
  		kernel = machine__findnew_kernel(machine, vmlinux_name,
  						 "[kernel]", DSO_SPACE__KERNEL);
  	} else {
  		if (symbol_conf.default_guest_vmlinux_name)
  			vmlinux_name = symbol_conf.default_guest_vmlinux_name;
  
  		kernel = machine__findnew_kernel(machine, vmlinux_name,
  						 "[guest.kernel]",
  						 DSO_SPACE__KERNEL_GUEST);
  	}
  
  	if (kernel != NULL && (!kernel->has_build_id))
  		dso__read_running_kernel_build_id(kernel, machine);
  
  	return kernel;
  }
  
  struct process_args {
  	u64 start;
  };
  
  void machine__get_kallsyms_filename(struct machine *machine, char *buf,
  				    size_t bufsz)
  {
  	if (machine__is_default_guest(machine))
  		scnprintf(buf, bufsz, "%s", symbol_conf.default_guest_kallsyms);
  	else
  		scnprintf(buf, bufsz, "%s/proc/kallsyms", machine->root_dir);
  }
  
  const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
  
  /* Figure out the start address of kernel map from /proc/kallsyms.
   * Returns the name of the start symbol in *symbol_name. Pass in NULL as
   * symbol_name if it's not that important.
   */
  static int machine__get_running_kernel_start(struct machine *machine,
  					     const char **symbol_name,
  					     u64 *start, u64 *end)
  {
  	char filename[PATH_MAX];
  	int i, err = -1;
  	const char *name;
  	u64 addr = 0;
  
  	machine__get_kallsyms_filename(machine, filename, PATH_MAX);
  
  	if (symbol__restricted_filename(filename, "/proc/kallsyms"))
  		return 0;
  
  	for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
  		err = kallsyms__get_function_start(filename, name, &addr);
  		if (!err)
  			break;
  	}
  
  	if (err)
  		return -1;
  
  	if (symbol_name)
  		*symbol_name = name;
  
  	*start = addr;
  
  	err = kallsyms__get_function_start(filename, "_etext", &addr);
  	if (!err)
  		*end = addr;
  
  	return 0;
  }
  
  int machine__create_extra_kernel_map(struct machine *machine,
  				     struct dso *kernel,
  				     struct extra_kernel_map *xm)
  {
  	struct kmap *kmap;
  	struct map *map;
  
  	map = map__new2(xm->start, kernel);
  	if (!map)
  		return -1;
  
  	map->end   = xm->end;
  	map->pgoff = xm->pgoff;
  
  	kmap = map__kmap(map);
  
  	strlcpy(kmap->name, xm->name, KMAP_NAME_LEN);
  
  	maps__insert(&machine->kmaps, map);
  
  	pr_debug2("Added extra kernel map %s %" PRIx64 "-%" PRIx64 "\n",
  		  kmap->name, map->start, map->end);
  
  	map__put(map);
  
  	return 0;
  }
  
  static u64 find_entry_trampoline(struct dso *dso)
  {
  	/* Duplicates are removed so lookup all aliases */
  	const char *syms[] = {
  		"_entry_trampoline",
  		"__entry_trampoline_start",
  		"entry_SYSCALL_64_trampoline",
  	};
  	struct symbol *sym = dso__first_symbol(dso);
  	unsigned int i;
  
  	for (; sym; sym = dso__next_symbol(sym)) {
  		if (sym->binding != STB_GLOBAL)
  			continue;
  		for (i = 0; i < ARRAY_SIZE(syms); i++) {
  			if (!strcmp(sym->name, syms[i]))
  				return sym->start;
  		}
  	}
  
  	return 0;
  }
  
  /*
   * These values can be used for kernels that do not have symbols for the entry
   * trampolines in kallsyms.
   */
  #define X86_64_CPU_ENTRY_AREA_PER_CPU	0xfffffe0000000000ULL
  #define X86_64_CPU_ENTRY_AREA_SIZE	0x2c000
  #define X86_64_ENTRY_TRAMPOLINE		0x6000
  
  /* Map x86_64 PTI entry trampolines */
  int machine__map_x86_64_entry_trampolines(struct machine *machine,
  					  struct dso *kernel)
  {
  	struct maps *kmaps = &machine->kmaps;
  	int nr_cpus_avail, cpu;
  	bool found = false;
  	struct map *map;
  	u64 pgoff;
  
  	/*
  	 * In the vmlinux case, pgoff is a virtual address which must now be
  	 * mapped to a vmlinux offset.
  	 */
  	maps__for_each_entry(kmaps, map) {
  		struct kmap *kmap = __map__kmap(map);
  		struct map *dest_map;
  
  		if (!kmap || !is_entry_trampoline(kmap->name))
  			continue;
  
  		dest_map = maps__find(kmaps, map->pgoff);
  		if (dest_map != map)
  			map->pgoff = dest_map->map_ip(dest_map, map->pgoff);
  		found = true;
  	}
  	if (found || machine->trampolines_mapped)
  		return 0;
  
  	pgoff = find_entry_trampoline(kernel);
  	if (!pgoff)
  		return 0;
  
  	nr_cpus_avail = machine__nr_cpus_avail(machine);
  
  	/* Add a 1 page map for each CPU's entry trampoline */
  	for (cpu = 0; cpu < nr_cpus_avail; cpu++) {
  		u64 va = X86_64_CPU_ENTRY_AREA_PER_CPU +
  			 cpu * X86_64_CPU_ENTRY_AREA_SIZE +
  			 X86_64_ENTRY_TRAMPOLINE;
  		struct extra_kernel_map xm = {
  			.start = va,
  			.end   = va + page_size,
  			.pgoff = pgoff,
  		};
  
  		strlcpy(xm.name, ENTRY_TRAMPOLINE_NAME, KMAP_NAME_LEN);
  
  		if (machine__create_extra_kernel_map(machine, kernel, &xm) < 0)
  			return -1;
  	}
  
  	machine->trampolines_mapped = nr_cpus_avail;
  
  	return 0;
  }
  
  int __weak machine__create_extra_kernel_maps(struct machine *machine __maybe_unused,
  					     struct dso *kernel __maybe_unused)
  {
  	return 0;
  }
  
  static int
  __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
  {
  	/* In case of renewal the kernel map, destroy previous one */
  	machine__destroy_kernel_maps(machine);
  
  	machine->vmlinux_map = map__new2(0, kernel);
  	if (machine->vmlinux_map == NULL)
  		return -1;
  
  	machine->vmlinux_map->map_ip = machine->vmlinux_map->unmap_ip = identity__map_ip;
  	maps__insert(&machine->kmaps, machine->vmlinux_map);
  	return 0;
  }
  
  void machine__destroy_kernel_maps(struct machine *machine)
  {
  	struct kmap *kmap;
  	struct map *map = machine__kernel_map(machine);
  
  	if (map == NULL)
  		return;
  
  	kmap = map__kmap(map);
  	maps__remove(&machine->kmaps, map);
  	if (kmap && kmap->ref_reloc_sym) {
  		zfree((char **)&kmap->ref_reloc_sym->name);
  		zfree(&kmap->ref_reloc_sym);
  	}
  
  	map__zput(machine->vmlinux_map);
  }
  
  int machines__create_guest_kernel_maps(struct machines *machines)
  {
  	int ret = 0;
  	struct dirent **namelist = NULL;
  	int i, items = 0;
  	char path[PATH_MAX];
  	pid_t pid;
  	char *endp;
  
  	if (symbol_conf.default_guest_vmlinux_name ||
  	    symbol_conf.default_guest_modules ||
  	    symbol_conf.default_guest_kallsyms) {
  		machines__create_kernel_maps(machines, DEFAULT_GUEST_KERNEL_ID);
  	}
  
  	if (symbol_conf.guestmount) {
  		items = scandir(symbol_conf.guestmount, &namelist, NULL, NULL);
  		if (items <= 0)
  			return -ENOENT;
  		for (i = 0; i < items; i++) {
  			if (!isdigit(namelist[i]->d_name[0])) {
  				/* Filter out . and .. */
  				continue;
  			}
  			pid = (pid_t)strtol(namelist[i]->d_name, &endp, 10);
  			if ((*endp != '\0') ||
  			    (endp == namelist[i]->d_name) ||
  			    (errno == ERANGE)) {
  				pr_debug("invalid directory (%s). Skipping.\n",
  					 namelist[i]->d_name);
  				continue;
  			}
  			sprintf(path, "%s/%s/proc/kallsyms",
  				symbol_conf.guestmount,
  				namelist[i]->d_name);
  			ret = access(path, R_OK);
  			if (ret) {
  				pr_debug("Can't access file %s\n", path);
  				goto failure;
  			}
  			machines__create_kernel_maps(machines, pid);
  		}
  failure:
  		free(namelist);
  	}
  
  	return ret;
  }
  
  void machines__destroy_kernel_maps(struct machines *machines)
  {
  	struct rb_node *next = rb_first_cached(&machines->guests);
  
  	machine__destroy_kernel_maps(&machines->host);
  
  	while (next) {
  		struct machine *pos = rb_entry(next, struct machine, rb_node);
  
  		next = rb_next(&pos->rb_node);
  		rb_erase_cached(&pos->rb_node, &machines->guests);
  		machine__delete(pos);
  	}
  }
  
  int machines__create_kernel_maps(struct machines *machines, pid_t pid)
  {
  	struct machine *machine = machines__findnew(machines, pid);
  
  	if (machine == NULL)
  		return -1;
  
  	return machine__create_kernel_maps(machine);
  }
  
  int machine__load_kallsyms(struct machine *machine, const char *filename)
  {
  	struct map *map = machine__kernel_map(machine);
  	int ret = __dso__load_kallsyms(map->dso, filename, map, true);
  
  	if (ret > 0) {
  		dso__set_loaded(map->dso);
  		/*
  		 * Since /proc/kallsyms will have multiple sessions for the
  		 * kernel, with modules between them, fixup the end of all
  		 * sections.
  		 */
  		maps__fixup_end(&machine->kmaps);
  	}
  
  	return ret;
  }
  
  int machine__load_vmlinux_path(struct machine *machine)
  {
  	struct map *map = machine__kernel_map(machine);
  	int ret = dso__load_vmlinux_path(map->dso, map);
  
  	if (ret > 0)
  		dso__set_loaded(map->dso);
  
  	return ret;
  }
  
  static char *get_kernel_version(const char *root_dir)
  {
  	char version[PATH_MAX];
  	FILE *file;
  	char *name, *tmp;
  	const char *prefix = "Linux version ";
  
  	sprintf(version, "%s/proc/version", root_dir);
  	file = fopen(version, "r");
  	if (!file)
  		return NULL;
  
  	tmp = fgets(version, sizeof(version), file);
  	fclose(file);
  	if (!tmp)
  		return NULL;
  
  	name = strstr(version, prefix);
  	if (!name)
  		return NULL;
  	name += strlen(prefix);
  	tmp = strchr(name, ' ');
  	if (tmp)
  		*tmp = '\0';
  
  	return strdup(name);
  }
  
  static bool is_kmod_dso(struct dso *dso)
  {
  	return dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE ||
  	       dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE;
  }
  
  static int maps__set_module_path(struct maps *maps, const char *path, struct kmod_path *m)
  {
  	char *long_name;
  	struct map *map = maps__find_by_name(maps, m->name);
  
  	if (map == NULL)
  		return 0;
  
  	long_name = strdup(path);
  	if (long_name == NULL)
  		return -ENOMEM;
  
  	dso__set_long_name(map->dso, long_name, true);
  	dso__kernel_module_get_build_id(map->dso, "");
  
  	/*
  	 * Full name could reveal us kmod compression, so
  	 * we need to update the symtab_type if needed.
  	 */
  	if (m->comp && is_kmod_dso(map->dso)) {
  		map->dso->symtab_type++;
  		map->dso->comp = m->comp;
  	}
  
  	return 0;
  }
  
  static int maps__set_modules_path_dir(struct maps *maps, const char *dir_name, int depth)
  {
  	struct dirent *dent;
  	DIR *dir = opendir(dir_name);
  	int ret = 0;
  
  	if (!dir) {
  		pr_debug("%s: cannot open %s dir\n", __func__, dir_name);
  		return -1;
  	}
  
  	while ((dent = readdir(dir)) != NULL) {
  		char path[PATH_MAX];
  		struct stat st;
  
  		/*sshfs might return bad dent->d_type, so we have to stat*/
  		snprintf(path, sizeof(path), "%s/%s", dir_name, dent->d_name);
  		if (stat(path, &st))
  			continue;
  
  		if (S_ISDIR(st.st_mode)) {
  			if (!strcmp(dent->d_name, ".") ||
  			    !strcmp(dent->d_name, ".."))
  				continue;
  
  			/* Do not follow top-level source and build symlinks */
  			if (depth == 0) {
  				if (!strcmp(dent->d_name, "source") ||
  				    !strcmp(dent->d_name, "build"))
  					continue;
  			}
  
  			ret = maps__set_modules_path_dir(maps, path, depth + 1);
  			if (ret < 0)
  				goto out;
  		} else {
  			struct kmod_path m;
  
  			ret = kmod_path__parse_name(&m, dent->d_name);
  			if (ret)
  				goto out;
  
  			if (m.kmod)
  				ret = maps__set_module_path(maps, path, &m);
  
  			zfree(&m.name);
  
  			if (ret)
  				goto out;
  		}
  	}
  
  out:
  	closedir(dir);
  	return ret;
  }
  
  static int machine__set_modules_path(struct machine *machine)
  {
  	char *version;
  	char modules_path[PATH_MAX];
  
  	version = get_kernel_version(machine->root_dir);
  	if (!version)
  		return -1;
  
  	snprintf(modules_path, sizeof(modules_path), "%s/lib/modules/%s",
  		 machine->root_dir, version);
  	free(version);
  
  	return maps__set_modules_path_dir(&machine->kmaps, modules_path, 0);
  }
  int __weak arch__fix_module_text_start(u64 *start __maybe_unused,
  				u64 *size __maybe_unused,
  				const char *name __maybe_unused)
  {
  	return 0;
  }
  
  static int machine__create_module(void *arg, const char *name, u64 start,
  				  u64 size)
  {
  	struct machine *machine = arg;
  	struct map *map;
  
  	if (arch__fix_module_text_start(&start, &size, name) < 0)
  		return -1;
  
  	map = machine__addnew_module_map(machine, start, name);
  	if (map == NULL)
  		return -1;
  	map->end = start + size;
  
  	dso__kernel_module_get_build_id(map->dso, machine->root_dir);
  
  	return 0;
  }
  
  static int machine__create_modules(struct machine *machine)
  {
  	const char *modules;
  	char path[PATH_MAX];
  
  	if (machine__is_default_guest(machine)) {
  		modules = symbol_conf.default_guest_modules;
  	} else {
  		snprintf(path, PATH_MAX, "%s/proc/modules", machine->root_dir);
  		modules = path;
  	}
  
  	if (symbol__restricted_filename(modules, "/proc/modules"))
  		return -1;
  
  	if (modules__parse(modules, machine, machine__create_module))
  		return -1;
  
  	if (!machine__set_modules_path(machine))
  		return 0;
  
  	pr_debug("Problems setting modules path maps, continuing anyway...\n");
  
  	return 0;
  }
  
  static void machine__set_kernel_mmap(struct machine *machine,
  				     u64 start, u64 end)
  {
  	machine->vmlinux_map->start = start;
  	machine->vmlinux_map->end   = end;
  	/*
  	 * Be a bit paranoid here, some perf.data file came with
  	 * a zero sized synthesized MMAP event for the kernel.
  	 */
  	if (start == 0 && end == 0)
  		machine->vmlinux_map->end = ~0ULL;
  }
  
  static void machine__update_kernel_mmap(struct machine *machine,
  				     u64 start, u64 end)
  {
  	struct map *map = machine__kernel_map(machine);
  
  	map__get(map);
  	maps__remove(&machine->kmaps, map);
  
  	machine__set_kernel_mmap(machine, start, end);
  
  	maps__insert(&machine->kmaps, map);
  	map__put(map);
  }
  
  int machine__create_kernel_maps(struct machine *machine)
  {
  	struct dso *kernel = machine__get_kernel(machine);
  	const char *name = NULL;
  	struct map *map;
  	u64 start = 0, end = ~0ULL;
  	int ret;
  
  	if (kernel == NULL)
  		return -1;
  
  	ret = __machine__create_kernel_maps(machine, kernel);
  	if (ret < 0)
  		goto out_put;
  
  	if (symbol_conf.use_modules && machine__create_modules(machine) < 0) {
  		if (machine__is_host(machine))
  			pr_debug("Problems creating module maps, "
  				 "continuing anyway...\n");
  		else
  			pr_debug("Problems creating module maps for guest %d, "
  				 "continuing anyway...\n", machine->pid);
  	}
  
  	if (!machine__get_running_kernel_start(machine, &name, &start, &end)) {
  		if (name &&
  		    map__set_kallsyms_ref_reloc_sym(machine->vmlinux_map, name, start)) {
  			machine__destroy_kernel_maps(machine);
  			ret = -1;
  			goto out_put;
  		}
  
  		/*
  		 * we have a real start address now, so re-order the kmaps
  		 * assume it's the last in the kmaps
  		 */
  		machine__update_kernel_mmap(machine, start, end);
  	}
  
  	if (machine__create_extra_kernel_maps(machine, kernel))
  		pr_debug("Problems creating extra kernel maps, continuing anyway...\n");
  
  	if (end == ~0ULL) {
  		/* update end address of the kernel map using adjacent module address */
  		map = map__next(machine__kernel_map(machine));
  		if (map)
  			machine__set_kernel_mmap(machine, start, map->start);
  	}
  
  out_put:
  	dso__put(kernel);
  	return ret;
  }
  
  static bool machine__uses_kcore(struct machine *machine)
  {
  	struct dso *dso;
  
  	list_for_each_entry(dso, &machine->dsos.head, node) {
  		if (dso__is_kcore(dso))
  			return true;
  	}
  
  	return false;
  }
  
  static bool perf_event__is_extra_kernel_mmap(struct machine *machine,
  					     struct extra_kernel_map *xm)
  {
  	return machine__is(machine, "x86_64") &&
  	       is_entry_trampoline(xm->name);
  }
  
  static int machine__process_extra_kernel_map(struct machine *machine,
  					     struct extra_kernel_map *xm)
  {
  	struct dso *kernel = machine__kernel_dso(machine);
  
  	if (kernel == NULL)
  		return -1;
  
  	return machine__create_extra_kernel_map(machine, kernel, xm);
  }
  
  static int machine__process_kernel_mmap_event(struct machine *machine,
  					      struct extra_kernel_map *xm,
  					      struct build_id *bid)
  {
  	struct map *map;
  	enum dso_space_type dso_space;
  	bool is_kernel_mmap;
  
  	/* If we have maps from kcore then we do not need or want any others */
  	if (machine__uses_kcore(machine))
  		return 0;
  
  	if (machine__is_host(machine))
  		dso_space = DSO_SPACE__KERNEL;
  	else
  		dso_space = DSO_SPACE__KERNEL_GUEST;
  
  	is_kernel_mmap = memcmp(xm->name, machine->mmap_name,
  				strlen(machine->mmap_name) - 1) == 0;
  	if (xm->name[0] == '/' ||
  	    (!is_kernel_mmap && xm->name[0] == '[')) {
  		map = machine__addnew_module_map(machine, xm->start,
  						 xm->name);
  		if (map == NULL)
  			goto out_problem;
  
  		map->end = map->start + xm->end - xm->start;
  
  		if (build_id__is_defined(bid))
  			dso__set_build_id(map->dso, bid);
  
  	} else if (is_kernel_mmap) {
  		const char *symbol_name = (xm->name + strlen(machine->mmap_name));
  		/*
  		 * Should be there already, from the build-id table in
  		 * the header.
  		 */
  		struct dso *kernel = NULL;
  		struct dso *dso;
  
  		down_read(&machine->dsos.lock);
  
  		list_for_each_entry(dso, &machine->dsos.head, node) {
  
  			/*
  			 * The cpumode passed to is_kernel_module is not the
  			 * cpumode of *this* event. If we insist on passing
  			 * correct cpumode to is_kernel_module, we should
  			 * record the cpumode when we adding this dso to the
  			 * linked list.
  			 *
  			 * However we don't really need passing correct
  			 * cpumode.  We know the correct cpumode must be kernel
  			 * mode (if not, we should not link it onto kernel_dsos
  			 * list).
  			 *
  			 * Therefore, we pass PERF_RECORD_MISC_CPUMODE_UNKNOWN.
  			 * is_kernel_module() treats it as a kernel cpumode.
  			 */
  
  			if (!dso->kernel ||
  			    is_kernel_module(dso->long_name,
  					     PERF_RECORD_MISC_CPUMODE_UNKNOWN))
  				continue;
  
  
  			kernel = dso;
  			break;
  		}
  
  		up_read(&machine->dsos.lock);
  
  		if (kernel == NULL)
  			kernel = machine__findnew_dso(machine, machine->mmap_name);
  		if (kernel == NULL)
  			goto out_problem;
  
  		kernel->kernel = dso_space;
  		if (__machine__create_kernel_maps(machine, kernel) < 0) {
  			dso__put(kernel);
  			goto out_problem;
  		}
  
  		if (strstr(kernel->long_name, "vmlinux"))
  			dso__set_short_name(kernel, "[kernel.vmlinux]", false);
  
  		machine__update_kernel_mmap(machine, xm->start, xm->end);
  
  		if (build_id__is_defined(bid))
  			dso__set_build_id(kernel, bid);
  
  		/*
  		 * Avoid using a zero address (kptr_restrict) for the ref reloc
  		 * symbol. Effectively having zero here means that at record
  		 * time /proc/sys/kernel/kptr_restrict was non zero.
  		 */
  		if (xm->pgoff != 0) {
  			map__set_kallsyms_ref_reloc_sym(machine->vmlinux_map,
  							symbol_name,
  							xm->pgoff);
  		}
  
  		if (machine__is_default_guest(machine)) {
  			/*
  			 * preload dso of guest kernel and modules
  			 */
  			dso__load(kernel, machine__kernel_map(machine));
  		}
  	} else if (perf_event__is_extra_kernel_mmap(machine, xm)) {
  		return machine__process_extra_kernel_map(machine, xm);
  	}
  	return 0;
  out_problem:
  	return -1;
  }
  
  int machine__process_mmap2_event(struct machine *machine,
  				 union perf_event *event,
  				 struct perf_sample *sample)
  {
  	struct thread *thread;
  	struct map *map;
  	struct dso_id dso_id = {
  		.maj = event->mmap2.maj,
  		.min = event->mmap2.min,
  		.ino = event->mmap2.ino,
  		.ino_generation = event->mmap2.ino_generation,
  	};
  	struct build_id __bid, *bid = NULL;
  	int ret = 0;
  
  	if (dump_trace)
  		perf_event__fprintf_mmap2(event, stdout);
  
  	if (event->header.misc & PERF_RECORD_MISC_MMAP_BUILD_ID) {
  		bid = &__bid;
  		build_id__init(bid, event->mmap2.build_id, event->mmap2.build_id_size);
  	}
  
  	if (sample->cpumode == PERF_RECORD_MISC_GUEST_KERNEL ||
  	    sample->cpumode == PERF_RECORD_MISC_KERNEL) {
  		struct extra_kernel_map xm = {
  			.start = event->mmap2.start,
  			.end   = event->mmap2.start + event->mmap2.len,
  			.pgoff = event->mmap2.pgoff,
  		};
  
  		strlcpy(xm.name, event->mmap2.filename, KMAP_NAME_LEN);
  		ret = machine__process_kernel_mmap_event(machine, &xm, bid);
  		if (ret < 0)
  			goto out_problem;
  		return 0;
  	}
  
  	thread = machine__findnew_thread(machine, event->mmap2.pid,
  					event->mmap2.tid);
  	if (thread == NULL)
  		goto out_problem;
  
  	map = map__new(machine, event->mmap2.start,
  			event->mmap2.len, event->mmap2.pgoff,
  			&dso_id, event->mmap2.prot,
  			event->mmap2.flags, bid,
  			event->mmap2.filename, thread);
  
  	if (map == NULL)
  		goto out_problem_map;
  
  	ret = thread__insert_map(thread, map);
  	if (ret)
  		goto out_problem_insert;
  
  	thread__put(thread);
  	map__put(map);
  	return 0;
  
  out_problem_insert:
  	map__put(map);
  out_problem_map:
  	thread__put(thread);
  out_problem:
  	dump_printf("problem processing PERF_RECORD_MMAP2, skipping event.\n");
  	return 0;
  }
  
  int machine__process_mmap_event(struct machine *machine, union perf_event *event,
  				struct perf_sample *sample)
  {
  	struct thread *thread;
  	struct map *map;
  	u32 prot = 0;
  	int ret = 0;
  
  	if (dump_trace)
  		perf_event__fprintf_mmap(event, stdout);
  
  	if (sample->cpumode == PERF_RECORD_MISC_GUEST_KERNEL ||
  	    sample->cpumode == PERF_RECORD_MISC_KERNEL) {
  		struct extra_kernel_map xm = {
  			.start = event->mmap.start,
  			.end   = event->mmap.start + event->mmap.len,
  			.pgoff = event->mmap.pgoff,
  		};
  
  		strlcpy(xm.name, event->mmap.filename, KMAP_NAME_LEN);
  		ret = machine__process_kernel_mmap_event(machine, &xm, NULL);
  		if (ret < 0)
  			goto out_problem;
  		return 0;
  	}
  
  	thread = machine__findnew_thread(machine, event->mmap.pid,
  					 event->mmap.tid);
  	if (thread == NULL)
  		goto out_problem;
  
  	if (!(event->header.misc & PERF_RECORD_MISC_MMAP_DATA))
  		prot = PROT_EXEC;
  
  	map = map__new(machine, event->mmap.start,
  			event->mmap.len, event->mmap.pgoff,
  			NULL, prot, 0, NULL, event->mmap.filename, thread);
  
  	if (map == NULL)
  		goto out_problem_map;
  
  	ret = thread__insert_map(thread, map);
  	if (ret)
  		goto out_problem_insert;
  
  	thread__put(thread);
  	map__put(map);
  	return 0;
  
  out_problem_insert:
  	map__put(map);
  out_problem_map:
  	thread__put(thread);
  out_problem:
  	dump_printf("problem processing PERF_RECORD_MMAP, skipping event.\n");
  	return 0;
  }
  
  static void __machine__remove_thread(struct machine *machine, struct thread *th, bool lock)
  {
  	struct threads *threads = machine__threads(machine, th->tid);
  
  	if (threads->last_match == th)
  		threads__set_last_match(threads, NULL);
  
  	if (lock)
  		down_write(&threads->lock);
  
  	BUG_ON(refcount_read(&th->refcnt) == 0);
  
  	rb_erase_cached(&th->rb_node, &threads->entries);
  	RB_CLEAR_NODE(&th->rb_node);
  	--threads->nr;
  	/*
  	 * Move it first to the dead_threads list, then drop the reference,
  	 * if this is the last reference, then the thread__delete destructor
  	 * will be called and we will remove it from the dead_threads list.
  	 */
  	list_add_tail(&th->node, &threads->dead);
  
  	/*
  	 * We need to do the put here because if this is the last refcount,
  	 * then we will be touching the threads->dead head when removing the
  	 * thread.
  	 */
  	thread__put(th);
  
  	if (lock)
  		up_write(&threads->lock);
  }
  
  void machine__remove_thread(struct machine *machine, struct thread *th)
  {
  	return __machine__remove_thread(machine, th, true);
  }
  
  int machine__process_fork_event(struct machine *machine, union perf_event *event,
  				struct perf_sample *sample)
  {
  	struct thread *thread = machine__find_thread(machine,
  						     event->fork.pid,
  						     event->fork.tid);
  	struct thread *parent = machine__findnew_thread(machine,
  							event->fork.ppid,
  							event->fork.ptid);
  	bool do_maps_clone = true;
  	int err = 0;
  
  	if (dump_trace)
  		perf_event__fprintf_task(event, stdout);
  
  	/*
  	 * There may be an existing thread that is not actually the parent,
  	 * either because we are processing events out of order, or because the
  	 * (fork) event that would have removed the thread was lost. Assume the
  	 * latter case and continue on as best we can.
  	 */
  	if (parent->pid_ != (pid_t)event->fork.ppid) {
  		dump_printf("removing erroneous parent thread %d/%d\n",
  			    parent->pid_, parent->tid);
  		machine__remove_thread(machine, parent);
  		thread__put(parent);
  		parent = machine__findnew_thread(machine, event->fork.ppid,
  						 event->fork.ptid);
  	}
  
  	/* if a thread currently exists for the thread id remove it */
  	if (thread != NULL) {
  		machine__remove_thread(machine, thread);
  		thread__put(thread);
  	}
  
  	thread = machine__findnew_thread(machine, event->fork.pid,
  					 event->fork.tid);
  	/*
  	 * When synthesizing FORK events, we are trying to create thread
  	 * objects for the already running tasks on the machine.
  	 *
  	 * Normally, for a kernel FORK event, we want to clone the parent's
  	 * maps because that is what the kernel just did.
  	 *
  	 * But when synthesizing, this should not be done.  If we do, we end up
  	 * with overlapping maps as we process the synthesized MMAP2 events that
  	 * get delivered shortly thereafter.
  	 *
  	 * Use the FORK event misc flags in an internal way to signal this
  	 * situation, so we can elide the map clone when appropriate.
  	 */
  	if (event->fork.header.misc & PERF_RECORD_MISC_FORK_EXEC)
  		do_maps_clone = false;
  
  	if (thread == NULL || parent == NULL ||
  	    thread__fork(thread, parent, sample->time, do_maps_clone) < 0) {
  		dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n");
  		err = -1;
  	}
  	thread__put(thread);
  	thread__put(parent);
  
  	return err;
  }
  
  int machine__process_exit_event(struct machine *machine, union perf_event *event,
  				struct perf_sample *sample __maybe_unused)
  {
  	struct thread *thread = machine__find_thread(machine,
  						     event->fork.pid,
  						     event->fork.tid);
  
  	if (dump_trace)
  		perf_event__fprintf_task(event, stdout);
  
  	if (thread != NULL) {
  		thread__exited(thread);
  		thread__put(thread);
  	}
  
  	return 0;
  }
  
  int machine__process_event(struct machine *machine, union perf_event *event,
  			   struct perf_sample *sample)
  {
  	int ret;
  
  	switch (event->header.type) {
  	case PERF_RECORD_COMM:
  		ret = machine__process_comm_event(machine, event, sample); break;
  	case PERF_RECORD_MMAP:
  		ret = machine__process_mmap_event(machine, event, sample); break;
  	case PERF_RECORD_NAMESPACES:
  		ret = machine__process_namespaces_event(machine, event, sample); break;
  	case PERF_RECORD_CGROUP:
  		ret = machine__process_cgroup_event(machine, event, sample); break;
  	case PERF_RECORD_MMAP2:
  		ret = machine__process_mmap2_event(machine, event, sample); break;
  	case PERF_RECORD_FORK:
  		ret = machine__process_fork_event(machine, event, sample); break;
  	case PERF_RECORD_EXIT:
  		ret = machine__process_exit_event(machine, event, sample); break;
  	case PERF_RECORD_LOST:
  		ret = machine__process_lost_event(machine, event, sample); break;
  	case PERF_RECORD_AUX:
  		ret = machine__process_aux_event(machine, event); break;
  	case PERF_RECORD_ITRACE_START:
  		ret = machine__process_itrace_start_event(machine, event); break;
  	case PERF_RECORD_LOST_SAMPLES:
  		ret = machine__process_lost_samples_event(machine, event, sample); break;
  	case PERF_RECORD_SWITCH:
  	case PERF_RECORD_SWITCH_CPU_WIDE:
  		ret = machine__process_switch_event(machine, event); break;
  	case PERF_RECORD_KSYMBOL:
  		ret = machine__process_ksymbol(machine, event, sample); break;
  	case PERF_RECORD_BPF_EVENT:
  		ret = machine__process_bpf(machine, event, sample); break;
  	case PERF_RECORD_TEXT_POKE:
  		ret = machine__process_text_poke(machine, event, sample); break;
  	default:
  		ret = -1;
  		break;
  	}
  
  	return ret;
  }
  
  static bool symbol__match_regex(struct symbol *sym, regex_t *regex)
  {
  	if (!regexec(regex, sym->name, 0, NULL, 0))
  		return true;
  	return false;
  }
  
  static void ip__resolve_ams(struct thread *thread,
  			    struct addr_map_symbol *ams,
  			    u64 ip)
  {
  	struct addr_location al;
  
  	memset(&al, 0, sizeof(al));
  	/*
  	 * We cannot use the header.misc hint to determine whether a
  	 * branch stack address is user, kernel, guest, hypervisor.
  	 * Branches may straddle the kernel/user/hypervisor boundaries.
  	 * Thus, we have to try consecutively until we find a match
  	 * or else, the symbol is unknown
  	 */
  	thread__find_cpumode_addr_location(thread, ip, &al);
  
  	ams->addr = ip;
  	ams->al_addr = al.addr;
  	ams->ms.maps = al.maps;
  	ams->ms.sym = al.sym;
  	ams->ms.map = al.map;
  	ams->phys_addr = 0;
  	ams->data_page_size = 0;
  }
  
  static void ip__resolve_data(struct thread *thread,
  			     u8 m, struct addr_map_symbol *ams,
  			     u64 addr, u64 phys_addr, u64 daddr_page_size)
  {
  	struct addr_location al;
  
  	memset(&al, 0, sizeof(al));
  
  	thread__find_symbol(thread, m, addr, &al);
  
  	ams->addr = addr;
  	ams->al_addr = al.addr;
  	ams->ms.maps = al.maps;
  	ams->ms.sym = al.sym;
  	ams->ms.map = al.map;
  	ams->phys_addr = phys_addr;
  	ams->data_page_size = daddr_page_size;
  }
  
  struct mem_info *sample__resolve_mem(struct perf_sample *sample,
  				     struct addr_location *al)
  {
  	struct mem_info *mi = mem_info__new();
  
  	if (!mi)
  		return NULL;
  
  	ip__resolve_ams(al->thread, &mi->iaddr, sample->ip);
  	ip__resolve_data(al->thread, al->cpumode, &mi->daddr,
  			 sample->addr, sample->phys_addr,
  			 sample->data_page_size);
  	mi->data_src.val = sample->data_src;
  
  	return mi;
  }
  
  static char *callchain_srcline(struct map_symbol *ms, u64 ip)
  {
  	struct map *map = ms->map;
  	char *srcline = NULL;
  
  	if (!map || callchain_param.key == CCKEY_FUNCTION)
  		return srcline;
  
  	srcline = srcline__tree_find(&map->dso->srclines, ip);
  	if (!srcline) {
  		bool show_sym = false;
  		bool show_addr = callchain_param.key == CCKEY_ADDRESS;
  
  		srcline = get_srcline(map->dso, map__rip_2objdump(map, ip),
  				      ms->sym, show_sym, show_addr, ip);
  		srcline__tree_insert(&map->dso->srclines, ip, srcline);
  	}
  
  	return srcline;
  }
  
  struct iterations {
  	int nr_loop_iter;
  	u64 cycles;
  };
  
  static int add_callchain_ip(struct thread *thread,
  			    struct callchain_cursor *cursor,
  			    struct symbol **parent,
  			    struct addr_location *root_al,
  			    u8 *cpumode,
  			    u64 ip,
  			    bool branch,
  			    struct branch_flags *flags,
  			    struct iterations *iter,
  			    u64 branch_from)
  {
  	struct map_symbol ms;
  	struct addr_location al;
  	int nr_loop_iter = 0;
  	u64 iter_cycles = 0;
  	const char *srcline = NULL;
  
  	al.filtered = 0;
  	al.sym = NULL;
  	al.srcline = NULL;
  	if (!cpumode) {
  		thread__find_cpumode_addr_location(thread, ip, &al);
  	} else {
  		if (ip >= PERF_CONTEXT_MAX) {
  			switch (ip) {
  			case PERF_CONTEXT_HV:
  				*cpumode = PERF_RECORD_MISC_HYPERVISOR;
  				break;
  			case PERF_CONTEXT_KERNEL:
  				*cpumode = PERF_RECORD_MISC_KERNEL;
  				break;
  			case PERF_CONTEXT_USER:
  				*cpumode = PERF_RECORD_MISC_USER;
  				break;
  			default:
  				pr_debug("invalid callchain context: "
  					 "%"PRId64"\n", (s64) ip);
  				/*
  				 * It seems the callchain is corrupted.
  				 * Discard all.
  				 */
  				callchain_cursor_reset(cursor);
  				return 1;
  			}
  			return 0;
  		}
  		thread__find_symbol(thread, *cpumode, ip, &al);
  	}
  
  	if (al.sym != NULL) {
  		if (perf_hpp_list.parent && !*parent &&
  		    symbol__match_regex(al.sym, &parent_regex))
  			*parent = al.sym;
  		else if (have_ignore_callees && root_al &&
  		  symbol__match_regex(al.sym, &ignore_callees_regex)) {
  			/* Treat this symbol as the root,
  			   forgetting its callees. */
  			*root_al = al;
  			callchain_cursor_reset(cursor);
  		}
  	}
  
  	if (symbol_conf.hide_unresolved && al.sym == NULL)
  		return 0;
  
  	if (iter) {
  		nr_loop_iter = iter->nr_loop_iter;
  		iter_cycles = iter->cycles;
  	}
  
  	ms.maps = al.maps;
  	ms.map = al.map;
  	ms.sym = al.sym;
  	srcline = callchain_srcline(&ms, al.addr);
  	return callchain_cursor_append(cursor, ip, &ms,
  				       branch, flags, nr_loop_iter,
  				       iter_cycles, branch_from, srcline);
  }
  
  struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
  					   struct addr_location *al)
  {
  	unsigned int i;
  	const struct branch_stack *bs = sample->branch_stack;
  	struct branch_entry *entries = perf_sample__branch_entries(sample);
  	struct branch_info *bi = calloc(bs->nr, sizeof(struct branch_info));
  
  	if (!bi)
  		return NULL;
  
  	for (i = 0; i < bs->nr; i++) {
  		ip__resolve_ams(al->thread, &bi[i].to, entries[i].to);
  		ip__resolve_ams(al->thread, &bi[i].from, entries[i].from);
  		bi[i].flags = entries[i].flags;
  	}
  	return bi;
  }
  
  static void save_iterations(struct iterations *iter,
  			    struct branch_entry *be, int nr)
  {
  	int i;
  
  	iter->nr_loop_iter++;
  	iter->cycles = 0;
  
  	for (i = 0; i < nr; i++)
  		iter->cycles += be[i].flags.cycles;
  }
  
  #define CHASHSZ 127
  #define CHASHBITS 7
  #define NO_ENTRY 0xff
  
  #define PERF_MAX_BRANCH_DEPTH 127
  
  /* Remove loops. */
  static int remove_loops(struct branch_entry *l, int nr,
  			struct iterations *iter)
  {
  	int i, j, off;
  	unsigned char chash[CHASHSZ];
  
  	memset(chash, NO_ENTRY, sizeof(chash));
  
  	BUG_ON(PERF_MAX_BRANCH_DEPTH > 255);
  
  	for (i = 0; i < nr; i++) {
  		int h = hash_64(l[i].from, CHASHBITS) % CHASHSZ;
  
  		/* no collision handling for now */
  		if (chash[h] == NO_ENTRY) {
  			chash[h] = i;
  		} else if (l[chash[h]].from == l[i].from) {
  			bool is_loop = true;
  			/* check if it is a real loop */
  			off = 0;
  			for (j = chash[h]; j < i && i + off < nr; j++, off++)
  				if (l[j].from != l[i + off].from) {
  					is_loop = false;
  					break;
  				}
  			if (is_loop) {
  				j = nr - (i + off);
  				if (j > 0) {
  					save_iterations(iter + i + off,
  						l + i, off);
  
  					memmove(iter + i, iter + i + off,
  						j * sizeof(*iter));
  
  					memmove(l + i, l + i + off,
  						j * sizeof(*l));
  				}
  
  				nr -= off;
  			}
  		}
  	}
  	return nr;
  }
  
  static int lbr_callchain_add_kernel_ip(struct thread *thread,
  				       struct callchain_cursor *cursor,
  				       struct perf_sample *sample,
  				       struct symbol **parent,
  				       struct addr_location *root_al,
  				       u64 branch_from,
  				       bool callee, int end)
  {
  	struct ip_callchain *chain = sample->callchain;
  	u8 cpumode = PERF_RECORD_MISC_USER;
  	int err, i;
  
  	if (callee) {
  		for (i = 0; i < end + 1; i++) {
  			err = add_callchain_ip(thread, cursor, parent,
  					       root_al, &cpumode, chain->ips[i],
  					       false, NULL, NULL, branch_from);
  			if (err)
  				return err;
  		}
  		return 0;
  	}
  
  	for (i = end; i >= 0; i--) {
  		err = add_callchain_ip(thread, cursor, parent,
  				       root_al, &cpumode, chain->ips[i],
  				       false, NULL, NULL, branch_from);
  		if (err)
  			return err;
  	}
  
  	return 0;
  }
  
  static void save_lbr_cursor_node(struct thread *thread,
  				 struct callchain_cursor *cursor,
  				 int idx)
  {
  	struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
  
  	if (!lbr_stitch)
  		return;
  
  	if (cursor->pos == cursor->nr) {
  		lbr_stitch->prev_lbr_cursor[idx].valid = false;
  		return;
  	}
  
  	if (!cursor->curr)
  		cursor->curr = cursor->first;
  	else
  		cursor->curr = cursor->curr->next;
  	memcpy(&lbr_stitch->prev_lbr_cursor[idx], cursor->curr,
  	       sizeof(struct callchain_cursor_node));
  
  	lbr_stitch->prev_lbr_cursor[idx].valid = true;
  	cursor->pos++;
  }
  
  static int lbr_callchain_add_lbr_ip(struct thread *thread,
  				    struct callchain_cursor *cursor,
  				    struct perf_sample *sample,
  				    struct symbol **parent,
  				    struct addr_location *root_al,
  				    u64 *branch_from,
  				    bool callee)
  {
  	struct branch_stack *lbr_stack = sample->branch_stack;
  	struct branch_entry *entries = perf_sample__branch_entries(sample);
  	u8 cpumode = PERF_RECORD_MISC_USER;
  	int lbr_nr = lbr_stack->nr;
  	struct branch_flags *flags;
  	int err, i;
  	u64 ip;
  
  	/*
  	 * The curr and pos are not used in writing session. They are cleared
  	 * in callchain_cursor_commit() when the writing session is closed.
  	 * Using curr and pos to track the current cursor node.
  	 */
  	if (thread->lbr_stitch) {
  		cursor->curr = NULL;
  		cursor->pos = cursor->nr;
  		if (cursor->nr) {
  			cursor->curr = cursor->first;
  			for (i = 0; i < (int)(cursor->nr - 1); i++)
  				cursor->curr = cursor->curr->next;
  		}
  	}
  
  	if (callee) {
  		/* Add LBR ip from first entries.to */
  		ip = entries[0].to;
  		flags = &entries[0].flags;
  		*branch_from = entries[0].from;
  		err = add_callchain_ip(thread, cursor, parent,
  				       root_al, &cpumode, ip,
  				       true, flags, NULL,
  				       *branch_from);
  		if (err)
  			return err;
  
  		/*
  		 * The number of cursor node increases.
  		 * Move the current cursor node.
  		 * But does not need to save current cursor node for entry 0.
  		 * It's impossible to stitch the whole LBRs of previous sample.
  		 */
  		if (thread->lbr_stitch && (cursor->pos != cursor->nr)) {
  			if (!cursor->curr)
  				cursor->curr = cursor->first;
  			else
  				cursor->curr = cursor->curr->next;
  			cursor->pos++;
  		}
  
  		/* Add LBR ip from entries.from one by one. */
  		for (i = 0; i < lbr_nr; i++) {
  			ip = entries[i].from;
  			flags = &entries[i].flags;
  			err = add_callchain_ip(thread, cursor, parent,
  					       root_al, &cpumode, ip,
  					       true, flags, NULL,
  					       *branch_from);
  			if (err)
  				return err;
  			save_lbr_cursor_node(thread, cursor, i);
  		}
  		return 0;
  	}
  
  	/* Add LBR ip from entries.from one by one. */
  	for (i = lbr_nr - 1; i >= 0; i--) {
  		ip = entries[i].from;
  		flags = &entries[i].flags;
  		err = add_callchain_ip(thread, cursor, parent,
  				       root_al, &cpumode, ip,
  				       true, flags, NULL,
  				       *branch_from);
  		if (err)
  			return err;
  		save_lbr_cursor_node(thread, cursor, i);
  	}
  
  	/* Add LBR ip from first entries.to */
  	ip = entries[0].to;
  	flags = &entries[0].flags;
  	*branch_from = entries[0].from;
  	err = add_callchain_ip(thread, cursor, parent,
  			       root_al, &cpumode, ip,
  			       true, flags, NULL,
  			       *branch_from);
  	if (err)
  		return err;
  
  	return 0;
  }
  
  static int lbr_callchain_add_stitched_lbr_ip(struct thread *thread,
  					     struct callchain_cursor *cursor)
  {
  	struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
  	struct callchain_cursor_node *cnode;
  	struct stitch_list *stitch_node;
  	int err;
  
  	list_for_each_entry(stitch_node, &lbr_stitch->lists, node) {
  		cnode = &stitch_node->cursor;
  
  		err = callchain_cursor_append(cursor, cnode->ip,
  					      &cnode->ms,
  					      cnode->branch,
  					      &cnode->branch_flags,
  					      cnode->nr_loop_iter,
  					      cnode->iter_cycles,
  					      cnode->branch_from,
  					      cnode->srcline);
  		if (err)
  			return err;
  	}
  	return 0;
  }
  
  static struct stitch_list *get_stitch_node(struct thread *thread)
  {
  	struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
  	struct stitch_list *stitch_node;
  
  	if (!list_empty(&lbr_stitch->free_lists)) {
  		stitch_node = list_first_entry(&lbr_stitch->free_lists,
  					       struct stitch_list, node);
  		list_del(&stitch_node->node);
  
  		return stitch_node;
  	}
  
  	return malloc(sizeof(struct stitch_list));
  }
  
  static bool has_stitched_lbr(struct thread *thread,
  			     struct perf_sample *cur,
  			     struct perf_sample *prev,
  			     unsigned int max_lbr,
  			     bool callee)
  {
  	struct branch_stack *cur_stack = cur->branch_stack;
  	struct branch_entry *cur_entries = perf_sample__branch_entries(cur);
  	struct branch_stack *prev_stack = prev->branch_stack;
  	struct branch_entry *prev_entries = perf_sample__branch_entries(prev);
  	struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
  	int i, j, nr_identical_branches = 0;
  	struct stitch_list *stitch_node;
  	u64 cur_base, distance;
  
  	if (!cur_stack || !prev_stack)
  		return false;
  
  	/* Find the physical index of the base-of-stack for current sample. */
  	cur_base = max_lbr - cur_stack->nr + cur_stack->hw_idx + 1;
  
  	distance = (prev_stack->hw_idx > cur_base) ? (prev_stack->hw_idx - cur_base) :
  						     (max_lbr + prev_stack->hw_idx - cur_base);
  	/* Previous sample has shorter stack. Nothing can be stitched. */
  	if (distance + 1 > prev_stack->nr)
  		return false;
  
  	/*
  	 * Check if there are identical LBRs between two samples.
  	 * Identical LBRs must have same from, to and flags values. Also,
  	 * they have to be saved in the same LBR registers (same physical
  	 * index).
  	 *
  	 * Starts from the base-of-stack of current sample.
  	 */
  	for (i = distance, j = cur_stack->nr - 1; (i >= 0) && (j >= 0); i--, j--) {
  		if ((prev_entries[i].from != cur_entries[j].from) ||
  		    (prev_entries[i].to != cur_entries[j].to) ||
  		    (prev_entries[i].flags.value != cur_entries[j].flags.value))
  			break;
  		nr_identical_branches++;
  	}
  
  	if (!nr_identical_branches)
  		return false;
  
  	/*
  	 * Save the LBRs between the base-of-stack of previous sample
  	 * and the base-of-stack of current sample into lbr_stitch->lists.
  	 * These LBRs will be stitched later.
  	 */
  	for (i = prev_stack->nr - 1; i > (int)distance; i--) {
  
  		if (!lbr_stitch->prev_lbr_cursor[i].valid)
  			continue;
  
  		stitch_node = get_stitch_node(thread);
  		if (!stitch_node)
  			return false;
  
  		memcpy(&stitch_node->cursor, &lbr_stitch->prev_lbr_cursor[i],
  		       sizeof(struct callchain_cursor_node));
  
  		if (callee)
  			list_add(&stitch_node->node, &lbr_stitch->lists);
  		else
  			list_add_tail(&stitch_node->node, &lbr_stitch->lists);
  	}
  
  	return true;
  }
  
  static bool alloc_lbr_stitch(struct thread *thread, unsigned int max_lbr)
  {
  	if (thread->lbr_stitch)
  		return true;
  
  	thread->lbr_stitch = zalloc(sizeof(*thread->lbr_stitch));
  	if (!thread->lbr_stitch)
  		goto err;
  
  	thread->lbr_stitch->prev_lbr_cursor = calloc(max_lbr + 1, sizeof(struct callchain_cursor_node));
  	if (!thread->lbr_stitch->prev_lbr_cursor)
  		goto free_lbr_stitch;
  
  	INIT_LIST_HEAD(&thread->lbr_stitch->lists);
  	INIT_LIST_HEAD(&thread->lbr_stitch->free_lists);
  
  	return true;
  
  free_lbr_stitch:
  	zfree(&thread->lbr_stitch);
  err:
  	pr_warning("Failed to allocate space for stitched LBRs. Disable LBR stitch\n");
  	thread->lbr_stitch_enable = false;
  	return false;
  }
  
  /*
   * Resolve LBR callstack chain sample
   * Return:
   * 1 on success get LBR callchain information
   * 0 no available LBR callchain information, should try fp
   * negative error code on other errors.
   */
  static int resolve_lbr_callchain_sample(struct thread *thread,
  					struct callchain_cursor *cursor,
  					struct perf_sample *sample,
  					struct symbol **parent,
  					struct addr_location *root_al,
  					int max_stack,
  					unsigned int max_lbr)
  {
  	bool callee = (callchain_param.order == ORDER_CALLEE);
  	struct ip_callchain *chain = sample->callchain;
  	int chain_nr = min(max_stack, (int)chain->nr), i;
  	struct lbr_stitch *lbr_stitch;
  	bool stitched_lbr = false;
  	u64 branch_from = 0;
  	int err;
  
  	for (i = 0; i < chain_nr; i++) {
  		if (chain->ips[i] == PERF_CONTEXT_USER)
  			break;
  	}
  
  	/* LBR only affects the user callchain */
  	if (i == chain_nr)
  		return 0;
  
  	if (thread->lbr_stitch_enable && !sample->no_hw_idx &&
  	    (max_lbr > 0) && alloc_lbr_stitch(thread, max_lbr)) {
  		lbr_stitch = thread->lbr_stitch;
  
  		stitched_lbr = has_stitched_lbr(thread, sample,
  						&lbr_stitch->prev_sample,
  						max_lbr, callee);
  
  		if (!stitched_lbr && !list_empty(&lbr_stitch->lists)) {
  			list_replace_init(&lbr_stitch->lists,
  					  &lbr_stitch->free_lists);
  		}
  		memcpy(&lbr_stitch->prev_sample, sample, sizeof(*sample));
  	}
  
  	if (callee) {
  		/* Add kernel ip */
  		err = lbr_callchain_add_kernel_ip(thread, cursor, sample,
  						  parent, root_al, branch_from,
  						  true, i);
  		if (err)
  			goto error;
  
  		err = lbr_callchain_add_lbr_ip(thread, cursor, sample, parent,
  					       root_al, &branch_from, true);
  		if (err)
  			goto error;
  
  		if (stitched_lbr) {
  			err = lbr_callchain_add_stitched_lbr_ip(thread, cursor);
  			if (err)
  				goto error;
  		}
  
  	} else {
  		if (stitched_lbr) {
  			err = lbr_callchain_add_stitched_lbr_ip(thread, cursor);
  			if (err)
  				goto error;
  		}
  		err = lbr_callchain_add_lbr_ip(thread, cursor, sample, parent,
  					       root_al, &branch_from, false);
  		if (err)
  			goto error;
  
  		/* Add kernel ip */
  		err = lbr_callchain_add_kernel_ip(thread, cursor, sample,
  						  parent, root_al, branch_from,
  						  false, i);
  		if (err)
  			goto error;
  	}
  	return 1;
  
  error:
  	return (err < 0) ? err : 0;
  }
  
  static int find_prev_cpumode(struct ip_callchain *chain, struct thread *thread,
  			     struct callchain_cursor *cursor,
  			     struct symbol **parent,
  			     struct addr_location *root_al,
  			     u8 *cpumode, int ent)
  {
  	int err = 0;
  
  	while (--ent >= 0) {
  		u64 ip = chain->ips[ent];
  
  		if (ip >= PERF_CONTEXT_MAX) {
  			err = add_callchain_ip(thread, cursor, parent,
  					       root_al, cpumode, ip,
  					       false, NULL, NULL, 0);
  			break;
  		}
  	}
  	return err;
  }
  
  static int thread__resolve_callchain_sample(struct thread *thread,
  					    struct callchain_cursor *cursor,
  					    struct evsel *evsel,
  					    struct perf_sample *sample,
  					    struct symbol **parent,
  					    struct addr_location *root_al,
  					    int max_stack)
  {
  	struct branch_stack *branch = sample->branch_stack;
  	struct branch_entry *entries = perf_sample__branch_entries(sample);
  	struct ip_callchain *chain = sample->callchain;
  	int chain_nr = 0;
  	u8 cpumode = PERF_RECORD_MISC_USER;
  	int i, j, err, nr_entries;
  	int skip_idx = -1;
  	int first_call = 0;
  
  	if (chain)
  		chain_nr = chain->nr;
  
  	if (evsel__has_branch_callstack(evsel)) {
  		struct perf_env *env = evsel__env(evsel);
  
  		err = resolve_lbr_callchain_sample(thread, cursor, sample, parent,
  						   root_al, max_stack,
  						   !env ? 0 : env->max_branches);
  		if (err)
  			return (err < 0) ? err : 0;
  	}
  
  	/*
  	 * Based on DWARF debug information, some architectures skip
  	 * a callchain entry saved by the kernel.
  	 */
  	skip_idx = arch_skip_callchain_idx(thread, chain);
  
  	/*
  	 * Add branches to call stack for easier browsing. This gives
  	 * more context for a sample than just the callers.
  	 *
  	 * This uses individual histograms of paths compared to the
  	 * aggregated histograms the normal LBR mode uses.
  	 *
  	 * Limitations for now:
  	 * - No extra filters
  	 * - No annotations (should annotate somehow)
  	 */
  
  	if (branch && callchain_param.branch_callstack) {
  		int nr = min(max_stack, (int)branch->nr);
  		struct branch_entry be[nr];
  		struct iterations iter[nr];
  
  		if (branch->nr > PERF_MAX_BRANCH_DEPTH) {
  			pr_warning("corrupted branch chain. skipping...\n");
  			goto check_calls;
  		}
  
  		for (i = 0; i < nr; i++) {
  			if (callchain_param.order == ORDER_CALLEE) {
  				be[i] = entries[i];
  
  				if (chain == NULL)
  					continue;
  
  				/*
  				 * Check for overlap into the callchain.
  				 * The return address is one off compared to
  				 * the branch entry. To adjust for this
  				 * assume the calling instruction is not longer
  				 * than 8 bytes.
  				 */
  				if (i == skip_idx ||
  				    chain->ips[first_call] >= PERF_CONTEXT_MAX)
  					first_call++;
  				else if (be[i].from < chain->ips[first_call] &&
  				    be[i].from >= chain->ips[first_call] - 8)
  					first_call++;
  			} else
  				be[i] = entries[branch->nr - i - 1];
  		}
  
  		memset(iter, 0, sizeof(struct iterations) * nr);
  		nr = remove_loops(be, nr, iter);
  
  		for (i = 0; i < nr; i++) {
  			err = add_callchain_ip(thread, cursor, parent,
  					       root_al,
  					       NULL, be[i].to,
  					       true, &be[i].flags,
  					       NULL, be[i].from);
  
  			if (!err)
  				err = add_callchain_ip(thread, cursor, parent, root_al,
  						       NULL, be[i].from,
  						       true, &be[i].flags,
  						       &iter[i], 0);
  			if (err == -EINVAL)
  				break;
  			if (err)
  				return err;
  		}
  
  		if (chain_nr == 0)
  			return 0;
  
  		chain_nr -= nr;
  	}
  
  check_calls:
  	if (chain && callchain_param.order != ORDER_CALLEE) {
  		err = find_prev_cpumode(chain, thread, cursor, parent, root_al,
  					&cpumode, chain->nr - first_call);
  		if (err)
  			return (err < 0) ? err : 0;
  	}
  	for (i = first_call, nr_entries = 0;
  	     i < chain_nr && nr_entries < max_stack; i++) {
  		u64 ip;
  
  		if (callchain_param.order == ORDER_CALLEE)
  			j = i;
  		else
  			j = chain->nr - i - 1;
  
  #ifdef HAVE_SKIP_CALLCHAIN_IDX
  		if (j == skip_idx)
  			continue;
  #endif
  		ip = chain->ips[j];
  		if (ip < PERF_CONTEXT_MAX)
                         ++nr_entries;
  		else if (callchain_param.order != ORDER_CALLEE) {
  			err = find_prev_cpumode(chain, thread, cursor, parent,
  						root_al, &cpumode, j);
  			if (err)
  				return (err < 0) ? err : 0;
  			continue;
  		}
  
  		err = add_callchain_ip(thread, cursor, parent,
  				       root_al, &cpumode, ip,
  				       false, NULL, NULL, 0);
  
  		if (err)
  			return (err < 0) ? err : 0;
  	}
  
  	return 0;
  }
  
  static int append_inlines(struct callchain_cursor *cursor, struct map_symbol *ms, u64 ip)
  {
  	struct symbol *sym = ms->sym;
  	struct map *map = ms->map;
  	struct inline_node *inline_node;
  	struct inline_list *ilist;
  	u64 addr;
  	int ret = 1;
  
  	if (!symbol_conf.inline_name || !map || !sym)
  		return ret;
  
  	addr = map__map_ip(map, ip);
  	addr = map__rip_2objdump(map, addr);
  
  	inline_node = inlines__tree_find(&map->dso->inlined_nodes, addr);
  	if (!inline_node) {
  		inline_node = dso__parse_addr_inlines(map->dso, addr, sym);
  		if (!inline_node)
  			return ret;
  		inlines__tree_insert(&map->dso->inlined_nodes, inline_node);
  	}
  
  	list_for_each_entry(ilist, &inline_node->val, list) {
  		struct map_symbol ilist_ms = {
  			.maps = ms->maps,
  			.map = map,
  			.sym = ilist->symbol,
  		};
  		ret = callchain_cursor_append(cursor, ip, &ilist_ms, false,
  					      NULL, 0, 0, 0, ilist->srcline);
  
  		if (ret != 0)
  			return ret;
  	}
  
  	return ret;
  }
  
  static int unwind_entry(struct unwind_entry *entry, void *arg)
  {
  	struct callchain_cursor *cursor = arg;
  	const char *srcline = NULL;
  	u64 addr = entry->ip;
  
  	if (symbol_conf.hide_unresolved && entry->ms.sym == NULL)
  		return 0;
  
  	if (append_inlines(cursor, &entry->ms, entry->ip) == 0)
  		return 0;
  
  	/*
  	 * Convert entry->ip from a virtual address to an offset in
  	 * its corresponding binary.
  	 */
  	if (entry->ms.map)
  		addr = map__map_ip(entry->ms.map, entry->ip);
  
  	srcline = callchain_srcline(&entry->ms, addr);
  	return callchain_cursor_append(cursor, entry->ip, &entry->ms,
  				       false, NULL, 0, 0, 0, srcline);
  }
  
  static int thread__resolve_callchain_unwind(struct thread *thread,
  					    struct callchain_cursor *cursor,
  					    struct evsel *evsel,
  					    struct perf_sample *sample,
  					    int max_stack)
  {
  	/* Can we do dwarf post unwind? */
  	if (!((evsel->core.attr.sample_type & PERF_SAMPLE_REGS_USER) &&
  	      (evsel->core.attr.sample_type & PERF_SAMPLE_STACK_USER)))
  		return 0;
  
  	/* Bail out if nothing was captured. */
  	if ((!sample->user_regs.regs) ||
  	    (!sample->user_stack.size))
  		return 0;
  
  	return unwind__get_entries(unwind_entry, cursor,
  				   thread, sample, max_stack);
  }
  
  int thread__resolve_callchain(struct thread *thread,
  			      struct callchain_cursor *cursor,
  			      struct evsel *evsel,
  			      struct perf_sample *sample,
  			      struct symbol **parent,
  			      struct addr_location *root_al,
  			      int max_stack)
  {
  	int ret = 0;
  
  	callchain_cursor_reset(cursor);
  
  	if (callchain_param.order == ORDER_CALLEE) {
  		ret = thread__resolve_callchain_sample(thread, cursor,
  						       evsel, sample,
  						       parent, root_al,
  						       max_stack);
  		if (ret)
  			return ret;
  		ret = thread__resolve_callchain_unwind(thread, cursor,
  						       evsel, sample,
  						       max_stack);
  	} else {
  		ret = thread__resolve_callchain_unwind(thread, cursor,
  						       evsel, sample,
  						       max_stack);
  		if (ret)
  			return ret;
  		ret = thread__resolve_callchain_sample(thread, cursor,
  						       evsel, sample,
  						       parent, root_al,
  						       max_stack);
  	}
  
  	return ret;
  }
  
  int machine__for_each_thread(struct machine *machine,
  			     int (*fn)(struct thread *thread, void *p),
  			     void *priv)
  {
  	struct threads *threads;
  	struct rb_node *nd;
  	struct thread *thread;
  	int rc = 0;
  	int i;
  
  	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
  		threads = &machine->threads[i];
  		for (nd = rb_first_cached(&threads->entries); nd;
  		     nd = rb_next(nd)) {
  			thread = rb_entry(nd, struct thread, rb_node);
  			rc = fn(thread, priv);
  			if (rc != 0)
  				return rc;
  		}
  
  		list_for_each_entry(thread, &threads->dead, node) {
  			rc = fn(thread, priv);
  			if (rc != 0)
  				return rc;
  		}
  	}
  	return rc;
  }
  
  int machines__for_each_thread(struct machines *machines,
  			      int (*fn)(struct thread *thread, void *p),
  			      void *priv)
  {
  	struct rb_node *nd;
  	int rc = 0;
  
  	rc = machine__for_each_thread(&machines->host, fn, priv);
  	if (rc != 0)
  		return rc;
  
  	for (nd = rb_first_cached(&machines->guests); nd; nd = rb_next(nd)) {
  		struct machine *machine = rb_entry(nd, struct machine, rb_node);
  
  		rc = machine__for_each_thread(machine, fn, priv);
  		if (rc != 0)
  			return rc;
  	}
  	return rc;
  }
  
  pid_t machine__get_current_tid(struct machine *machine, int cpu)
  {
  	int nr_cpus = min(machine->env->nr_cpus_avail, MAX_NR_CPUS);
  
  	if (cpu < 0 || cpu >= nr_cpus || !machine->current_tid)
  		return -1;
  
  	return machine->current_tid[cpu];
  }
  
  int machine__set_current_tid(struct machine *machine, int cpu, pid_t pid,
  			     pid_t tid)
  {
  	struct thread *thread;
  	int nr_cpus = min(machine->env->nr_cpus_avail, MAX_NR_CPUS);
  
  	if (cpu < 0)
  		return -EINVAL;
  
  	if (!machine->current_tid) {
  		int i;
  
  		machine->current_tid = calloc(nr_cpus, sizeof(pid_t));
  		if (!machine->current_tid)
  			return -ENOMEM;
  		for (i = 0; i < nr_cpus; i++)
  			machine->current_tid[i] = -1;
  	}
  
  	if (cpu >= nr_cpus) {
  		pr_err("Requested CPU %d too large. ", cpu);
  		pr_err("Consider raising MAX_NR_CPUS\n");
  		return -EINVAL;
  	}
  
  	machine->current_tid[cpu] = tid;
  
  	thread = machine__findnew_thread(machine, pid, tid);
  	if (!thread)
  		return -ENOMEM;
  
  	thread->cpu = cpu;
  	thread__put(thread);
  
  	return 0;
  }
  
  /*
   * Compares the raw arch string. N.B. see instead perf_env__arch() if a
   * normalized arch is needed.
   */
  bool machine__is(struct machine *machine, const char *arch)
  {
  	return machine && !strcmp(perf_env__raw_arch(machine->env), arch);
  }
  
  int machine__nr_cpus_avail(struct machine *machine)
  {
  	return machine ? perf_env__nr_cpus_avail(machine->env) : 0;
  }
  
  int machine__get_kernel_start(struct machine *machine)
  {
  	struct map *map = machine__kernel_map(machine);
  	int err = 0;
  
  	/*
  	 * The only addresses above 2^63 are kernel addresses of a 64-bit
  	 * kernel.  Note that addresses are unsigned so that on a 32-bit system
  	 * all addresses including kernel addresses are less than 2^32.  In
  	 * that case (32-bit system), if the kernel mapping is unknown, all
  	 * addresses will be assumed to be in user space - see
  	 * machine__kernel_ip().
  	 */
  	machine->kernel_start = 1ULL << 63;
  	if (map) {
  		err = map__load(map);
  		/*
  		 * On x86_64, PTI entry trampolines are less than the
  		 * start of kernel text, but still above 2^63. So leave
  		 * kernel_start = 1ULL << 63 for x86_64.
  		 */
  		if (!err && !machine__is(machine, "x86_64"))
  			machine->kernel_start = map->start;
  	}
  	return err;
  }
  
  u8 machine__addr_cpumode(struct machine *machine, u8 cpumode, u64 addr)
  {
  	u8 addr_cpumode = cpumode;
  	bool kernel_ip;
  
  	if (!machine->single_address_space)
  		goto out;
  
  	kernel_ip = machine__kernel_ip(machine, addr);
  	switch (cpumode) {
  	case PERF_RECORD_MISC_KERNEL:
  	case PERF_RECORD_MISC_USER:
  		addr_cpumode = kernel_ip ? PERF_RECORD_MISC_KERNEL :
  					   PERF_RECORD_MISC_USER;
  		break;
  	case PERF_RECORD_MISC_GUEST_KERNEL:
  	case PERF_RECORD_MISC_GUEST_USER:
  		addr_cpumode = kernel_ip ? PERF_RECORD_MISC_GUEST_KERNEL :
  					   PERF_RECORD_MISC_GUEST_USER;
  		break;
  	default:
  		break;
  	}
  out:
  	return addr_cpumode;
  }
  
  struct dso *machine__findnew_dso_id(struct machine *machine, const char *filename, struct dso_id *id)
  {
  	return dsos__findnew_id(&machine->dsos, filename, id);
  }
  
  struct dso *machine__findnew_dso(struct machine *machine, const char *filename)
  {
  	return machine__findnew_dso_id(machine, filename, NULL);
  }
  
  char *machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp)
  {
  	struct machine *machine = vmachine;
  	struct map *map;
  	struct symbol *sym = machine__find_kernel_symbol(machine, *addrp, &map);
  
  	if (sym == NULL)
  		return NULL;
  
  	*modp = __map__is_kmodule(map) ? (char *)map->dso->short_name : NULL;
  	*addrp = map->unmap_ip(map, sym->start);
  	return sym->name;
  }
  
  int machine__for_each_dso(struct machine *machine, machine__dso_t fn, void *priv)
  {
  	struct dso *pos;
  	int err = 0;
  
  	list_for_each_entry(pos, &machine->dsos.head, node) {
  		if (fn(pos, machine, priv))
  			err = -1;
  	}
  	return err;
  }
  