text: // kernel BUG at net/rxrpc/conn_client.c:LINE!
  // https://syzkaller.appspot.com/bug?id=a09a653c91306c86a6be6d6a97e627951ec245c9
  // status:open
  // autogenerated by syzkaller (https://github.com/google/syzkaller)
  
  #define _GNU_SOURCE
  
  #include <arpa/inet.h>
  #include <dirent.h>
  #include <endian.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <net/if.h>
  #include <net/if_arp.h>
  #include <netinet/in.h>
  #include <pthread.h>
  #include <sched.h>
  #include <setjmp.h>
  #include <signal.h>
  #include <stdarg.h>
  #include <stdbool.h>
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/ioctl.h>
  #include <sys/mount.h>
  #include <sys/prctl.h>
  #include <sys/resource.h>
  #include <sys/socket.h>
  #include <sys/stat.h>
  #include <sys/syscall.h>
  #include <sys/time.h>
  #include <sys/types.h>
  #include <sys/uio.h>
  #include <sys/wait.h>
  #include <time.h>
  #include <unistd.h>
  
  #include <linux/capability.h>
  #include <linux/futex.h>
  #include <linux/if_addr.h>
  #include <linux/if_ether.h>
  #include <linux/if_link.h>
  #include <linux/if_tun.h>
  #include <linux/in6.h>
  #include <linux/ip.h>
  #include <linux/neighbour.h>
  #include <linux/net.h>
  #include <linux/netlink.h>
  #include <linux/rtnetlink.h>
  #include <linux/tcp.h>
  #include <linux/veth.h>
  
  unsigned long long procid;
  
  static __thread int skip_segv;
  static __thread jmp_buf segv_env;
  
  static void segv_handler(int sig, siginfo_t* info, void* ctx)
  {
    uintptr_t addr = (uintptr_t)info->si_addr;
    const uintptr_t prog_start = 1 << 20;
    const uintptr_t prog_end = 100 << 20;
    if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) &&
        (addr < prog_start || addr > prog_end)) {
      _longjmp(segv_env, 1);
    }
    exit(sig);
  }
  
  static void install_segv_handler(void)
  {
    struct sigaction sa;
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = SIG_IGN;
    syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
    syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);
    memset(&sa, 0, sizeof(sa));
    sa.sa_sigaction = segv_handler;
    sa.sa_flags = SA_NODEFER | SA_SIGINFO;
    sigaction(SIGSEGV, &sa, NULL);
    sigaction(SIGBUS, &sa, NULL);
  }
  
  #define NONFAILING(...)                                                        \
    {                                                                            \
      __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
      if (_setjmp(segv_env) == 0) {                                              \
        __VA_ARGS__;                                                             \
      }                                                                          \
      __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    }
  
  static void sleep_ms(uint64_t ms)
  {
    usleep(ms * 1000);
  }
  
  static uint64_t current_time_ms(void)
  {
    struct timespec ts;
    if (clock_gettime(CLOCK_MONOTONIC, &ts))
      exit(1);
    return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
  }
  
  static void use_temporary_dir(void)
  {
    char tmpdir_template[] = "./syzkaller.XXXXXX";
    char* tmpdir = mkdtemp(tmpdir_template);
    if (!tmpdir)
      exit(1);
    if (chmod(tmpdir, 0777))
      exit(1);
    if (chdir(tmpdir))
      exit(1);
  }
  
  static void thread_start(void* (*fn)(void*), void* arg)
  {
    pthread_t th;
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setstacksize(&attr, 128 << 10);
    int i;
    for (i = 0; i < 100; i++) {
      if (pthread_create(&th, &attr, fn, arg) == 0) {
        pthread_attr_destroy(&attr);
        return;
      }
      if (errno == EAGAIN) {
        usleep(50);
        continue;
      }
      break;
    }
    exit(1);
  }
  
  typedef struct {
    int state;
  } event_t;
  
  static void event_init(event_t* ev)
  {
    ev->state = 0;
  }
  
  static void event_reset(event_t* ev)
  {
    ev->state = 0;
  }
  
  static void event_set(event_t* ev)
  {
    if (ev->state)
      exit(1);
    __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
    syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG);
  }
  
  static void event_wait(event_t* ev)
  {
    while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
  }
  
  static int event_isset(event_t* ev)
  {
    return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
  }
  
  static int event_timedwait(event_t* ev, uint64_t timeout)
  {
    uint64_t start = current_time_ms();
    uint64_t now = start;
    for (;;) {
      uint64_t remain = timeout - (now - start);
      struct timespec ts;
      ts.tv_sec = remain / 1000;
      ts.tv_nsec = (remain % 1000) * 1000 * 1000;
      syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts);
      if (__atomic_load_n(&ev->state, __ATOMIC_RELAXED))
        return 1;
      now = current_time_ms();
      if (now - start > timeout)
        return 0;
    }
  }
  
  static bool write_file(const char* file, const char* what, ...)
  {
    char buf[1024];
    va_list args;
    va_start(args, what);
    vsnprintf(buf, sizeof(buf), what, args);
    va_end(args);
    buf[sizeof(buf) - 1] = 0;
    int len = strlen(buf);
    int fd = open(file, O_WRONLY | O_CLOEXEC);
    if (fd == -1)
      return false;
    if (write(fd, buf, len) != len) {
      int err = errno;
      close(fd);
      errno = err;
      return false;
    }
    close(fd);
    return true;
  }
  
  static struct {
    char* pos;
    int nesting;
    struct nlattr* nested[8];
    char buf[1024];
  } nlmsg;
  
  static void netlink_init(int typ, int flags, const void* data, int size)
  {
    memset(&nlmsg, 0, sizeof(nlmsg));
    struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg.buf;
    hdr->nlmsg_type = typ;
    hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
    memcpy(hdr + 1, data, size);
    nlmsg.pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
  }
  
  static void netlink_attr(int typ, const void* data, int size)
  {
    struct nlattr* attr = (struct nlattr*)nlmsg.pos;
    attr->nla_len = sizeof(*attr) + size;
    attr->nla_type = typ;
    memcpy(attr + 1, data, size);
    nlmsg.pos += NLMSG_ALIGN(attr->nla_len);
  }
  
  static void netlink_nest(int typ)
  {
    struct nlattr* attr = (struct nlattr*)nlmsg.pos;
    attr->nla_type = typ;
    nlmsg.pos += sizeof(*attr);
    nlmsg.nested[nlmsg.nesting++] = attr;
  }
  
  static void netlink_done(void)
  {
    struct nlattr* attr = nlmsg.nested[--nlmsg.nesting];
    attr->nla_len = nlmsg.pos - (char*)attr;
  }
  
  static int netlink_send(int sock)
  {
    if (nlmsg.pos > nlmsg.buf + sizeof(nlmsg.buf) || nlmsg.nesting)
      exit(1);
    struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg.buf;
    hdr->nlmsg_len = nlmsg.pos - nlmsg.buf;
    struct sockaddr_nl addr;
    memset(&addr, 0, sizeof(addr));
    addr.nl_family = AF_NETLINK;
    unsigned n = sendto(sock, nlmsg.buf, hdr->nlmsg_len, 0,
                        (struct sockaddr*)&addr, sizeof(addr));
    if (n != hdr->nlmsg_len)
      exit(1);
    n = recv(sock, nlmsg.buf, sizeof(nlmsg.buf), 0);
    if (n < sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))
      exit(1);
    if (hdr->nlmsg_type != NLMSG_ERROR)
      exit(1);
    return -((struct nlmsgerr*)(hdr + 1))->error;
  }
  
  static void netlink_add_device_impl(const char* type, const char* name)
  {
    struct ifinfomsg hdr;
    memset(&hdr, 0, sizeof(hdr));
    netlink_init(RTM_NEWLINK, NLM_F_EXCL | NLM_F_CREATE, &hdr, sizeof(hdr));
    if (name)
      netlink_attr(IFLA_IFNAME, name, strlen(name));
    netlink_nest(IFLA_LINKINFO);
    netlink_attr(IFLA_INFO_KIND, type, strlen(type));
  }
  
  static void netlink_add_device(int sock, const char* type, const char* name)
  {
    netlink_add_device_impl(type, name);
    netlink_done();
    int err = netlink_send(sock);
    (void)err;
  }
  
  static void netlink_add_veth(int sock, const char* name, const char* peer)
  {
    netlink_add_device_impl("veth", name);
    netlink_nest(IFLA_INFO_DATA);
    netlink_nest(VETH_INFO_PEER);
    nlmsg.pos += sizeof(struct ifinfomsg);
    netlink_attr(IFLA_IFNAME, peer, strlen(peer));
    netlink_done();
    netlink_done();
    netlink_done();
    int err = netlink_send(sock);
    (void)err;
  }
  
  static void netlink_add_hsr(int sock, const char* name, const char* slave1,
                              const char* slave2)
  {
    netlink_add_device_impl("hsr", name);
    netlink_nest(IFLA_INFO_DATA);
    int ifindex1 = if_nametoindex(slave1);
    netlink_attr(IFLA_HSR_SLAVE1, &ifindex1, sizeof(ifindex1));
    int ifindex2 = if_nametoindex(slave2);
    netlink_attr(IFLA_HSR_SLAVE2, &ifindex2, sizeof(ifindex2));
    netlink_done();
    netlink_done();
    int err = netlink_send(sock);
    (void)err;
  }
  
  static void netlink_device_change(int sock, const char* name, bool up,
                                    const char* master, const void* mac,
                                    int macsize)
  {
    struct ifinfomsg hdr;
    memset(&hdr, 0, sizeof(hdr));
    if (up)
      hdr.ifi_flags = hdr.ifi_change = IFF_UP;
    netlink_init(RTM_NEWLINK, 0, &hdr, sizeof(hdr));
    netlink_attr(IFLA_IFNAME, name, strlen(name));
    if (master) {
      int ifindex = if_nametoindex(master);
      netlink_attr(IFLA_MASTER, &ifindex, sizeof(ifindex));
    }
    if (macsize)
      netlink_attr(IFLA_ADDRESS, mac, macsize);
    int err = netlink_send(sock);
    (void)err;
  }
  
  static int netlink_add_addr(int sock, const char* dev, const void* addr,
                              int addrsize)
  {
    struct ifaddrmsg hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
    hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
    hdr.ifa_scope = RT_SCOPE_UNIVERSE;
    hdr.ifa_index = if_nametoindex(dev);
    netlink_init(RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr, sizeof(hdr));
    netlink_attr(IFA_LOCAL, addr, addrsize);
    netlink_attr(IFA_ADDRESS, addr, addrsize);
    return netlink_send(sock);
  }
  
  static void netlink_add_addr4(int sock, const char* dev, const char* addr)
  {
    struct in_addr in_addr;
    inet_pton(AF_INET, addr, &in_addr);
    int err = netlink_add_addr(sock, dev, &in_addr, sizeof(in_addr));
    (void)err;
  }
  
  static void netlink_add_addr6(int sock, const char* dev, const char* addr)
  {
    struct in6_addr in6_addr;
    inet_pton(AF_INET6, addr, &in6_addr);
    int err = netlink_add_addr(sock, dev, &in6_addr, sizeof(in6_addr));
    (void)err;
  }
  
  static void netlink_add_neigh(int sock, const char* name, const void* addr,
                                int addrsize, const void* mac, int macsize)
  {
    struct ndmsg hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
    hdr.ndm_ifindex = if_nametoindex(name);
    hdr.ndm_state = NUD_PERMANENT;
    netlink_init(RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr, sizeof(hdr));
    netlink_attr(NDA_DST, addr, addrsize);
    netlink_attr(NDA_LLADDR, mac, macsize);
    int err = netlink_send(sock);
    (void)err;
  }
  
  static int tunfd = -1;
  static int tun_frags_enabled;
  #define SYZ_TUN_MAX_PACKET_SIZE 1000
  
  #define TUN_IFACE "syz_tun"
  
  #define LOCAL_MAC 0xaaaaaaaaaaaa
  #define REMOTE_MAC 0xaaaaaaaaaabb
  
  #define LOCAL_IPV4 "172.20.20.170"
  #define REMOTE_IPV4 "172.20.20.187"
  
  #define LOCAL_IPV6 "fe80::aa"
  #define REMOTE_IPV6 "fe80::bb"
  
  #define IFF_NAPI 0x0010
  #define IFF_NAPI_FRAGS 0x0020
  
  static void initialize_tun(void)
  {
    tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
    if (tunfd == -1) {
      printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
      printf("otherwise fuzzing or reproducing might not work as intended\n");
      return;
    }
    const int kTunFd = 240;
    if (dup2(tunfd, kTunFd) < 0)
      exit(1);
    close(tunfd);
    tunfd = kTunFd;
    struct ifreq ifr;
    memset(&ifr, 0, sizeof(ifr));
    strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_NAPI | IFF_NAPI_FRAGS;
    if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
      ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
      if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
        exit(1);
    }
    if (ioctl(tunfd, TUNGETIFF, (void*)&ifr) < 0)
      exit(1);
    tun_frags_enabled = (ifr.ifr_flags & IFF_NAPI_FRAGS) != 0;
    char sysctl[64];
    sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
    write_file(sysctl, "0");
    sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
    write_file(sysctl, "0");
    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
    if (sock == -1)
      exit(1);
    netlink_add_addr4(sock, TUN_IFACE, LOCAL_IPV4);
    netlink_add_addr6(sock, TUN_IFACE, LOCAL_IPV6);
    uint64_t macaddr = REMOTE_MAC;
    struct in_addr in_addr;
    inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
    netlink_add_neigh(sock, TUN_IFACE, &in_addr, sizeof(in_addr), &macaddr,
                      ETH_ALEN);
    struct in6_addr in6_addr;
    inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
    netlink_add_neigh(sock, TUN_IFACE, &in6_addr, sizeof(in6_addr), &macaddr,
                      ETH_ALEN);
    macaddr = LOCAL_MAC;
    netlink_device_change(sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN);
    close(sock);
  }
  
  #define DEV_IPV4 "172.20.20.%d"
  #define DEV_IPV6 "fe80::%02x"
  #define DEV_MAC 0x00aaaaaaaaaa
  static void initialize_netdevices(void)
  {
    char netdevsim[16];
    sprintf(netdevsim, "netdevsim%d", (int)procid);
    struct {
      const char* type;
      const char* dev;
    } devtypes[] = {
        {"ip6gretap", "ip6gretap0"}, {"bridge", "bridge0"},
        {"vcan", "vcan0"},           {"bond", "bond0"},
        {"team", "team0"},           {"dummy", "dummy0"},
        {"nlmon", "nlmon0"},         {"caif", "caif0"},
        {"batadv", "batadv0"},       {"vxcan", "vxcan1"},
        {"netdevsim", netdevsim},    {"veth", 0},
    };
    const char* devmasters[] = {"bridge", "bond", "team"};
    struct {
      const char* name;
      int macsize;
      bool noipv6;
    } devices[] = {
        {"lo", ETH_ALEN},
        {"sit0", 0},
        {"bridge0", ETH_ALEN},
        {"vcan0", 0, true},
        {"tunl0", 0},
        {"gre0", 0},
        {"gretap0", ETH_ALEN},
        {"ip_vti0", 0},
        {"ip6_vti0", 0},
        {"ip6tnl0", 0},
        {"ip6gre0", 0},
        {"ip6gretap0", ETH_ALEN},
        {"erspan0", ETH_ALEN},
        {"bond0", ETH_ALEN},
        {"veth0", ETH_ALEN},
        {"veth1", ETH_ALEN},
        {"team0", ETH_ALEN},
        {"veth0_to_bridge", ETH_ALEN},
        {"veth1_to_bridge", ETH_ALEN},
        {"veth0_to_bond", ETH_ALEN},
        {"veth1_to_bond", ETH_ALEN},
        {"veth0_to_team", ETH_ALEN},
        {"veth1_to_team", ETH_ALEN},
        {"veth0_to_hsr", ETH_ALEN},
        {"veth1_to_hsr", ETH_ALEN},
        {"hsr0", 0},
        {"dummy0", ETH_ALEN},
        {"nlmon0", 0},
        {"vxcan1", 0, true},
        {"caif0", ETH_ALEN},
        {"batadv0", ETH_ALEN},
        {netdevsim, ETH_ALEN},
    };
    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
    if (sock == -1)
      exit(1);
    unsigned i;
    for (i = 0; i < sizeof(devtypes) / sizeof(devtypes[0]); i++)
      netlink_add_device(sock, devtypes[i].type, devtypes[i].dev);
    for (i = 0; i < sizeof(devmasters) / (sizeof(devmasters[0])); i++) {
      char master[32], slave0[32], veth0[32], slave1[32], veth1[32];
      sprintf(slave0, "%s_slave_0", devmasters[i]);
      sprintf(veth0, "veth0_to_%s", devmasters[i]);
      netlink_add_veth(sock, slave0, veth0);
      sprintf(slave1, "%s_slave_1", devmasters[i]);
      sprintf(veth1, "veth1_to_%s", devmasters[i]);
      netlink_add_veth(sock, slave1, veth1);
      sprintf(master, "%s0", devmasters[i]);
      netlink_device_change(sock, slave0, false, master, 0, 0);
      netlink_device_change(sock, slave1, false, master, 0, 0);
    }
    netlink_device_change(sock, "bridge_slave_0", true, 0, 0, 0);
    netlink_device_change(sock, "bridge_slave_1", true, 0, 0, 0);
    netlink_add_veth(sock, "hsr_slave_0", "veth0_to_hsr");
    netlink_add_veth(sock, "hsr_slave_1", "veth1_to_hsr");
    netlink_add_hsr(sock, "hsr0", "hsr_slave_0", "hsr_slave_1");
    netlink_device_change(sock, "hsr_slave_0", true, 0, 0, 0);
    netlink_device_change(sock, "hsr_slave_1", true, 0, 0, 0);
    for (i = 0; i < sizeof(devices) / (sizeof(devices[0])); i++) {
      char addr[32];
      sprintf(addr, DEV_IPV4, i + 10);
      netlink_add_addr4(sock, devices[i].name, addr);
      if (!devices[i].noipv6) {
        sprintf(addr, DEV_IPV6, i + 10);
        netlink_add_addr6(sock, devices[i].name, addr);
      }
      uint64_t macaddr = DEV_MAC + ((i + 10ull) << 40);
      netlink_device_change(sock, devices[i].name, true, 0, &macaddr,
                            devices[i].macsize);
    }
    close(sock);
  }
  static void initialize_netdevices_init(void)
  {
    int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
    if (sock == -1)
      exit(1);
    struct {
      const char* type;
      int macsize;
      bool noipv6;
      bool noup;
    } devtypes[] = {
        {"nr", 7, true}, {"rose", 5, true, true},
    };
    unsigned i;
    for (i = 0; i < sizeof(devtypes) / sizeof(devtypes[0]); i++) {
      char dev[32], addr[32];
      sprintf(dev, "%s%d", devtypes[i].type, (int)procid);
      sprintf(addr, "172.30.%d.%d", i, (int)procid + 1);
      netlink_add_addr4(sock, dev, addr);
      if (!devtypes[i].noipv6) {
        sprintf(addr, "fe88::%02x:%02x", i, (int)procid + 1);
        netlink_add_addr6(sock, dev, addr);
      }
      int macsize = devtypes[i].macsize;
      uint64_t macaddr = 0xbbbbbb +
                         ((unsigned long long)i << (8 * (macsize - 2))) +
                         (procid << (8 * (macsize - 1)));
      netlink_device_change(sock, dev, !devtypes[i].noup, 0, &macaddr, macsize);
    }
    close(sock);
  }
  
  static int read_tun(char* data, int size)
  {
    if (tunfd < 0)
      return -1;
    int rv = read(tunfd, data, size);
    if (rv < 0) {
      if (errno == EAGAIN)
        return -1;
      if (errno == EBADFD)
        return -1;
      exit(1);
    }
    return rv;
  }
  
  static void flush_tun()
  {
    char data[SYZ_TUN_MAX_PACKET_SIZE];
    while (read_tun(&data[0], sizeof(data)) != -1) {
    }
  }
  
  #define XT_TABLE_SIZE 1536
  #define XT_MAX_ENTRIES 10
  
  struct xt_counters {
    uint64_t pcnt, bcnt;
  };
  
  struct ipt_getinfo {
    char name[32];
    unsigned int valid_hooks;
    unsigned int hook_entry[5];
    unsigned int underflow[5];
    unsigned int num_entries;
    unsigned int size;
  };
  
  struct ipt_get_entries {
    char name[32];
    unsigned int size;
    void* entrytable[XT_TABLE_SIZE / sizeof(void*)];
  };
  
  struct ipt_replace {
    char name[32];
    unsigned int valid_hooks;
    unsigned int num_entries;
    unsigned int size;
    unsigned int hook_entry[5];
    unsigned int underflow[5];
    unsigned int num_counters;
    struct xt_counters* counters;
    char entrytable[XT_TABLE_SIZE];
  };
  
  struct ipt_table_desc {
    const char* name;
    struct ipt_getinfo info;
    struct ipt_replace replace;
  };
  
  static struct ipt_table_desc ipv4_tables[] = {
      {.name = "filter"}, {.name = "nat"},      {.name = "mangle"},
      {.name = "raw"},    {.name = "security"},
  };
  
  static struct ipt_table_desc ipv6_tables[] = {
      {.name = "filter"}, {.name = "nat"},      {.name = "mangle"},
      {.name = "raw"},    {.name = "security"},
  };
  
  #define IPT_BASE_CTL 64
  #define IPT_SO_SET_REPLACE (IPT_BASE_CTL)
  #define IPT_SO_GET_INFO (IPT_BASE_CTL)
  #define IPT_SO_GET_ENTRIES (IPT_BASE_CTL + 1)
  
  struct arpt_getinfo {
    char name[32];
    unsigned int valid_hooks;
    unsigned int hook_entry[3];
    unsigned int underflow[3];
    unsigned int num_entries;
    unsigned int size;
  };
  
  struct arpt_get_entries {
    char name[32];
    unsigned int size;
    void* entrytable[XT_TABLE_SIZE / sizeof(void*)];
  };
  
  struct arpt_replace {
    char name[32];
    unsigned int valid_hooks;
    unsigned int num_entries;
    unsigned int size;
    unsigned int hook_entry[3];
    unsigned int underflow[3];
    unsigned int num_counters;
    struct xt_counters* counters;
    char entrytable[XT_TABLE_SIZE];
  };
  
  struct arpt_table_desc {
    const char* name;
    struct arpt_getinfo info;
    struct arpt_replace replace;
  };
  
  static struct arpt_table_desc arpt_tables[] = {
      {.name = "filter"},
  };
  
  #define ARPT_BASE_CTL 96
  #define ARPT_SO_SET_REPLACE (ARPT_BASE_CTL)
  #define ARPT_SO_GET_INFO (ARPT_BASE_CTL)
  #define ARPT_SO_GET_ENTRIES (ARPT_BASE_CTL + 1)
  
  static void checkpoint_iptables(struct ipt_table_desc* tables, int num_tables,
                                  int family, int level)
  {
    struct ipt_get_entries entries;
    socklen_t optlen;
    int fd, i;
    fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < num_tables; i++) {
      struct ipt_table_desc* table = &tables[i];
      strcpy(table->info.name, table->name);
      strcpy(table->replace.name, table->name);
      optlen = sizeof(table->info);
      if (getsockopt(fd, level, IPT_SO_GET_INFO, &table->info, &optlen)) {
        switch (errno) {
        case EPERM:
        case ENOENT:
        case ENOPROTOOPT:
          continue;
        }
        exit(1);
      }
      if (table->info.size > sizeof(table->replace.entrytable))
        exit(1);
      if (table->info.num_entries > XT_MAX_ENTRIES)
        exit(1);
      memset(&entries, 0, sizeof(entries));
      strcpy(entries.name, table->name);
      entries.size = table->info.size;
      optlen = sizeof(entries) - sizeof(entries.entrytable) + table->info.size;
      if (getsockopt(fd, level, IPT_SO_GET_ENTRIES, &entries, &optlen))
        exit(1);
      table->replace.valid_hooks = table->info.valid_hooks;
      table->replace.num_entries = table->info.num_entries;
      table->replace.size = table->info.size;
      memcpy(table->replace.hook_entry, table->info.hook_entry,
             sizeof(table->replace.hook_entry));
      memcpy(table->replace.underflow, table->info.underflow,
             sizeof(table->replace.underflow));
      memcpy(table->replace.entrytable, entries.entrytable, table->info.size);
    }
    close(fd);
  }
  
  static void reset_iptables(struct ipt_table_desc* tables, int num_tables,
                             int family, int level)
  {
    struct xt_counters counters[XT_MAX_ENTRIES];
    struct ipt_get_entries entries;
    struct ipt_getinfo info;
    socklen_t optlen;
    int fd, i;
    fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < num_tables; i++) {
      struct ipt_table_desc* table = &tables[i];
      if (table->info.valid_hooks == 0)
        continue;
      memset(&info, 0, sizeof(info));
      strcpy(info.name, table->name);
      optlen = sizeof(info);
      if (getsockopt(fd, level, IPT_SO_GET_INFO, &info, &optlen))
        exit(1);
      if (memcmp(&table->info, &info, sizeof(table->info)) == 0) {
        memset(&entries, 0, sizeof(entries));
        strcpy(entries.name, table->name);
        entries.size = table->info.size;
        optlen = sizeof(entries) - sizeof(entries.entrytable) + entries.size;
        if (getsockopt(fd, level, IPT_SO_GET_ENTRIES, &entries, &optlen))
          exit(1);
        if (memcmp(table->replace.entrytable, entries.entrytable,
                   table->info.size) == 0)
          continue;
      }
      table->replace.num_counters = info.num_entries;
      table->replace.counters = counters;
      optlen = sizeof(table->replace) - sizeof(table->replace.entrytable) +
               table->replace.size;
      if (setsockopt(fd, level, IPT_SO_SET_REPLACE, &table->replace, optlen))
        exit(1);
    }
    close(fd);
  }
  
  static void checkpoint_arptables(void)
  {
    struct arpt_get_entries entries;
    socklen_t optlen;
    unsigned i;
    int fd;
    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
      struct arpt_table_desc* table = &arpt_tables[i];
      strcpy(table->info.name, table->name);
      strcpy(table->replace.name, table->name);
      optlen = sizeof(table->info);
      if (getsockopt(fd, SOL_IP, ARPT_SO_GET_INFO, &table->info, &optlen)) {
        switch (errno) {
        case EPERM:
        case ENOENT:
        case ENOPROTOOPT:
          continue;
        }
        exit(1);
      }
      if (table->info.size > sizeof(table->replace.entrytable))
        exit(1);
      if (table->info.num_entries > XT_MAX_ENTRIES)
        exit(1);
      memset(&entries, 0, sizeof(entries));
      strcpy(entries.name, table->name);
      entries.size = table->info.size;
      optlen = sizeof(entries) - sizeof(entries.entrytable) + table->info.size;
      if (getsockopt(fd, SOL_IP, ARPT_SO_GET_ENTRIES, &entries, &optlen))
        exit(1);
      table->replace.valid_hooks = table->info.valid_hooks;
      table->replace.num_entries = table->info.num_entries;
      table->replace.size = table->info.size;
      memcpy(table->replace.hook_entry, table->info.hook_entry,
             sizeof(table->replace.hook_entry));
      memcpy(table->replace.underflow, table->info.underflow,
             sizeof(table->replace.underflow));
      memcpy(table->replace.entrytable, entries.entrytable, table->info.size);
    }
    close(fd);
  }
  
  static void reset_arptables()
  {
    struct xt_counters counters[XT_MAX_ENTRIES];
    struct arpt_get_entries entries;
    struct arpt_getinfo info;
    socklen_t optlen;
    unsigned i;
    int fd;
    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < sizeof(arpt_tables) / sizeof(arpt_tables[0]); i++) {
      struct arpt_table_desc* table = &arpt_tables[i];
      if (table->info.valid_hooks == 0)
        continue;
      memset(&info, 0, sizeof(info));
      strcpy(info.name, table->name);
      optlen = sizeof(info);
      if (getsockopt(fd, SOL_IP, ARPT_SO_GET_INFO, &info, &optlen))
        exit(1);
      if (memcmp(&table->info, &info, sizeof(table->info)) == 0) {
        memset(&entries, 0, sizeof(entries));
        strcpy(entries.name, table->name);
        entries.size = table->info.size;
        optlen = sizeof(entries) - sizeof(entries.entrytable) + entries.size;
        if (getsockopt(fd, SOL_IP, ARPT_SO_GET_ENTRIES, &entries, &optlen))
          exit(1);
        if (memcmp(table->replace.entrytable, entries.entrytable,
                   table->info.size) == 0)
          continue;
      } else {
      }
      table->replace.num_counters = info.num_entries;
      table->replace.counters = counters;
      optlen = sizeof(table->replace) - sizeof(table->replace.entrytable) +
               table->replace.size;
      if (setsockopt(fd, SOL_IP, ARPT_SO_SET_REPLACE, &table->replace, optlen))
        exit(1);
    }
    close(fd);
  }
  
  #define NF_BR_NUMHOOKS 6
  #define EBT_TABLE_MAXNAMELEN 32
  #define EBT_CHAIN_MAXNAMELEN 32
  #define EBT_BASE_CTL 128
  #define EBT_SO_SET_ENTRIES (EBT_BASE_CTL)
  #define EBT_SO_GET_INFO (EBT_BASE_CTL)
  #define EBT_SO_GET_ENTRIES (EBT_SO_GET_INFO + 1)
  #define EBT_SO_GET_INIT_INFO (EBT_SO_GET_ENTRIES + 1)
  #define EBT_SO_GET_INIT_ENTRIES (EBT_SO_GET_INIT_INFO + 1)
  
  struct ebt_replace {
    char name[EBT_TABLE_MAXNAMELEN];
    unsigned int valid_hooks;
    unsigned int nentries;
    unsigned int entries_size;
    struct ebt_entries* hook_entry[NF_BR_NUMHOOKS];
    unsigned int num_counters;
    struct ebt_counter* counters;
    char* entries;
  };
  
  struct ebt_entries {
    unsigned int distinguisher;
    char name[EBT_CHAIN_MAXNAMELEN];
    unsigned int counter_offset;
    int policy;
    unsigned int nentries;
    char data[0] __attribute__((aligned(__alignof__(struct ebt_replace))));
  };
  
  struct ebt_table_desc {
    const char* name;
    struct ebt_replace replace;
    char entrytable[XT_TABLE_SIZE];
  };
  
  static struct ebt_table_desc ebt_tables[] = {
      {.name = "filter"}, {.name = "nat"}, {.name = "broute"},
  };
  
  static void checkpoint_ebtables(void)
  {
    socklen_t optlen;
    unsigned i;
    int fd;
    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
      struct ebt_table_desc* table = &ebt_tables[i];
      strcpy(table->replace.name, table->name);
      optlen = sizeof(table->replace);
      if (getsockopt(fd, SOL_IP, EBT_SO_GET_INIT_INFO, &table->replace,
                     &optlen)) {
        switch (errno) {
        case EPERM:
        case ENOENT:
        case ENOPROTOOPT:
          continue;
        }
        exit(1);
      }
      if (table->replace.entries_size > sizeof(table->entrytable))
        exit(1);
      table->replace.num_counters = 0;
      table->replace.entries = table->entrytable;
      optlen = sizeof(table->replace) + table->replace.entries_size;
      if (getsockopt(fd, SOL_IP, EBT_SO_GET_INIT_ENTRIES, &table->replace,
                     &optlen))
        exit(1);
    }
    close(fd);
  }
  
  static void reset_ebtables()
  {
    struct ebt_replace replace;
    char entrytable[XT_TABLE_SIZE];
    socklen_t optlen;
    unsigned i, j, h;
    int fd;
    fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (fd == -1) {
      switch (errno) {
      case EAFNOSUPPORT:
      case ENOPROTOOPT:
        return;
      }
      exit(1);
    }
    for (i = 0; i < sizeof(ebt_tables) / sizeof(ebt_tables[0]); i++) {
      struct ebt_table_desc* table = &ebt_tables[i];
      if (table->replace.valid_hooks == 0)
        continue;
      memset(&replace, 0, sizeof(replace));
      strcpy(replace.name, table->name);
      optlen = sizeof(replace);
      if (getsockopt(fd, SOL_IP, EBT_SO_GET_INFO, &replace, &optlen))
        exit(1);
      replace.num_counters = 0;
      table->replace.entries = 0;
      for (h = 0; h < NF_BR_NUMHOOKS; h++)
        table->replace.hook_entry[h] = 0;
      if (memcmp(&table->replace, &replace, sizeof(table->replace)) == 0) {
        memset(&entrytable, 0, sizeof(entrytable));
        replace.entries = entrytable;
        optlen = sizeof(replace) + replace.entries_size;
        if (getsockopt(fd, SOL_IP, EBT_SO_GET_ENTRIES, &replace, &optlen))
          exit(1);
        if (memcmp(table->entrytable, entrytable, replace.entries_size) == 0)
          continue;
      }
      for (j = 0, h = 0; h < NF_BR_NUMHOOKS; h++) {
        if (table->replace.valid_hooks & (1 << h)) {
          table->replace.hook_entry[h] =
              (struct ebt_entries*)table->entrytable + j;
          j++;
        }
      }
      table->replace.entries = table->entrytable;
      optlen = sizeof(table->replace) + table->replace.entries_size;
      if (setsockopt(fd, SOL_IP, EBT_SO_SET_ENTRIES, &table->replace, optlen))
        exit(1);
    }
    close(fd);
  }
  
  static void checkpoint_net_namespace(void)
  {
    checkpoint_ebtables();
    checkpoint_arptables();
    checkpoint_iptables(ipv4_tables, sizeof(ipv4_tables) / sizeof(ipv4_tables[0]),
                        AF_INET, SOL_IP);
    checkpoint_iptables(ipv6_tables, sizeof(ipv6_tables) / sizeof(ipv6_tables[0]),
                        AF_INET6, SOL_IPV6);
  }
  
  static void reset_net_namespace(void)
  {
    reset_ebtables();
    reset_arptables();
    reset_iptables(ipv4_tables, sizeof(ipv4_tables) / sizeof(ipv4_tables[0]),
                   AF_INET, SOL_IP);
    reset_iptables(ipv6_tables, sizeof(ipv6_tables) / sizeof(ipv6_tables[0]),
                   AF_INET6, SOL_IPV6);
  }
  
  static void setup_cgroups()
  {
    if (mkdir("/syzcgroup", 0777)) {
    }
    if (mkdir("/syzcgroup/unified", 0777)) {
    }
    if (mount("none", "/syzcgroup/unified", "cgroup2", 0, NULL)) {
    }
    if (chmod("/syzcgroup/unified", 0777)) {
    }
    write_file("/syzcgroup/unified/cgroup.subtree_control",
               "+cpu +memory +io +pids +rdma");
    if (mkdir("/syzcgroup/cpu", 0777)) {
    }
    if (mount("none", "/syzcgroup/cpu", "cgroup", 0,
              "cpuset,cpuacct,perf_event,hugetlb")) {
    }
    write_file("/syzcgroup/cpu/cgroup.clone_children", "1");
    if (chmod("/syzcgroup/cpu", 0777)) {
    }
    if (mkdir("/syzcgroup/net", 0777)) {
    }
    if (mount("none", "/syzcgroup/net", "cgroup", 0,
              "net_cls,net_prio,devices,freezer")) {
    }
    if (chmod("/syzcgroup/net", 0777)) {
    }
  }
  
  static void setup_cgroups_loop()
  {
    int pid = getpid();
    char file[128];
    char cgroupdir[64];
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid);
    if (mkdir(cgroupdir, 0777)) {
    }
    snprintf(file, sizeof(file), "%s/pids.max", cgroupdir);
    write_file(file, "32");
    snprintf(file, sizeof(file), "%s/memory.low", cgroupdir);
    write_file(file, "%d", 298 << 20);
    snprintf(file, sizeof(file), "%s/memory.high", cgroupdir);
    write_file(file, "%d", 299 << 20);
    snprintf(file, sizeof(file), "%s/memory.max", cgroupdir);
    write_file(file, "%d", 300 << 20);
    snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir);
    write_file(file, "%d", pid);
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid);
    if (mkdir(cgroupdir, 0777)) {
    }
    snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir);
    write_file(file, "%d", pid);
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid);
    if (mkdir(cgroupdir, 0777)) {
    }
    snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir);
    write_file(file, "%d", pid);
  }
  
  static void setup_cgroups_test()
  {
    char cgroupdir[64];
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid);
    if (symlink(cgroupdir, "./cgroup")) {
    }
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid);
    if (symlink(cgroupdir, "./cgroup.cpu")) {
    }
    snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid);
    if (symlink(cgroupdir, "./cgroup.net")) {
    }
  }
  
  static void setup_common()
  {
    if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
    }
    setup_cgroups();
  }
  
  static void loop();
  
  static void sandbox_common()
  {
    prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
    setpgrp();
    setsid();
    struct rlimit rlim;
    rlim.rlim_cur = rlim.rlim_max = (200 << 20);
    setrlimit(RLIMIT_AS, &rlim);
    rlim.rlim_cur = rlim.rlim_max = 32 << 20;
    setrlimit(RLIMIT_MEMLOCK, &rlim);
    rlim.rlim_cur = rlim.rlim_max = 136 << 20;
    setrlimit(RLIMIT_FSIZE, &rlim);
    rlim.rlim_cur = rlim.rlim_max = 1 << 20;
    setrlimit(RLIMIT_STACK, &rlim);
    rlim.rlim_cur = rlim.rlim_max = 0;
    setrlimit(RLIMIT_CORE, &rlim);
    rlim.rlim_cur = rlim.rlim_max = 256;
    setrlimit(RLIMIT_NOFILE, &rlim);
    if (unshare(CLONE_NEWNS)) {
    }
    if (unshare(CLONE_NEWIPC)) {
    }
    if (unshare(0x02000000)) {
    }
    if (unshare(CLONE_NEWUTS)) {
    }
    if (unshare(CLONE_SYSVSEM)) {
    }
    typedef struct {
      const char* name;
      const char* value;
    } sysctl_t;
    static const sysctl_t sysctls[] = {
        {"/proc/sys/kernel/shmmax", "16777216"},
        {"/proc/sys/kernel/shmall", "536870912"},
        {"/proc/sys/kernel/shmmni", "1024"},
        {"/proc/sys/kernel/msgmax", "8192"},
        {"/proc/sys/kernel/msgmni", "1024"},
        {"/proc/sys/kernel/msgmnb", "1024"},
        {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
    };
    unsigned i;
    for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
      write_file(sysctls[i].name, sysctls[i].value);
  }
  
  int wait_for_loop(int pid)
  {
    if (pid < 0)
      exit(1);
    int status = 0;
    while (waitpid(-1, &status, __WALL) != pid) {
    }
    return WEXITSTATUS(status);
  }
  
  static void drop_caps(void)
  {
    struct __user_cap_header_struct cap_hdr = {};
    struct __user_cap_data_struct cap_data[2] = {};
    cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
    cap_hdr.pid = getpid();
    if (syscall(SYS_capget, &cap_hdr, &cap_data))
      exit(1);
    const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
    cap_data[0].effective &= ~drop;
    cap_data[0].permitted &= ~drop;
    cap_data[0].inheritable &= ~drop;
    if (syscall(SYS_capset, &cap_hdr, &cap_data))
      exit(1);
  }
  
  static int do_sandbox_none(void)
  {
    if (unshare(CLONE_NEWPID)) {
    }
    int pid = fork();
    if (pid != 0)
      return wait_for_loop(pid);
    setup_common();
    sandbox_common();
    drop_caps();
    initialize_netdevices_init();
    if (unshare(CLONE_NEWNET)) {
    }
    initialize_tun();
    initialize_netdevices();
    loop();
    exit(1);
  }
  
  #define FS_IOC_SETFLAGS _IOW('f', 2, long)
  static void remove_dir(const char* dir)
  {
    DIR* dp;
    struct dirent* ep;
    int iter = 0;
  retry:
    while (umount2(dir, MNT_DETACH) == 0) {
    }
    dp = opendir(dir);
    if (dp == NULL) {
      if (errno == EMFILE) {
        exit(1);
      }
      exit(1);
    }
    while ((ep = readdir(dp))) {
      if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
        continue;
      char filename[FILENAME_MAX];
      snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
      while (umount2(filename, MNT_DETACH) == 0) {
      }
      struct stat st;
      if (lstat(filename, &st))
        exit(1);
      if (S_ISDIR(st.st_mode)) {
        remove_dir(filename);
        continue;
      }
      int i;
      for (i = 0;; i++) {
        if (unlink(filename) == 0)
          break;
        if (errno == EPERM) {
          int fd = open(filename, O_RDONLY);
          if (fd != -1) {
            long flags = 0;
            if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0)
              close(fd);
            continue;
          }
        }
        if (errno == EROFS) {
          break;
        }
        if (errno != EBUSY || i > 100)
          exit(1);
        if (umount2(filename, MNT_DETACH))
          exit(1);
      }
    }
    closedir(dp);
    int i;
    for (i = 0;; i++) {
      if (rmdir(dir) == 0)
        break;
      if (i < 100) {
        if (errno == EPERM) {
          int fd = open(dir, O_RDONLY);
          if (fd != -1) {
            long flags = 0;
            if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0)
              close(fd);
            continue;
          }
        }
        if (errno == EROFS) {
          break;
        }
        if (errno == EBUSY) {
          if (umount2(dir, MNT_DETACH))
            exit(1);
          continue;
        }
        if (errno == ENOTEMPTY) {
          if (iter < 100) {
            iter++;
            goto retry;
          }
        }
      }
      exit(1);
    }
  }
  
  static void kill_and_wait(int pid, int* status)
  {
    kill(-pid, SIGKILL);
    kill(pid, SIGKILL);
    int i;
    for (i = 0; i < 100; i++) {
      if (waitpid(-1, status, WNOHANG | __WALL) == pid)
        return;
      usleep(1000);
    }
    DIR* dir = opendir("/sys/fs/fuse/connections");
    if (dir) {
      for (;;) {
        struct dirent* ent = readdir(dir);
        if (!ent)
          break;
        if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
          continue;
        char abort[300];
        snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
                 ent->d_name);
        int fd = open(abort, O_WRONLY);
        if (fd == -1) {
          continue;
        }
        if (write(fd, abort, 1) < 0) {
        }
        close(fd);
      }
      closedir(dir);
    } else {
    }
    while (waitpid(-1, status, __WALL) != pid) {
    }
  }
  
  static void setup_loop()
  {
    setup_cgroups_loop();
    checkpoint_net_namespace();
  }
  
  static void reset_loop()
  {
    reset_net_namespace();
  }
  
  static void setup_test()
  {
    prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
    setpgrp();
    setup_cgroups_test();
    write_file("/proc/self/oom_score_adj", "1000");
    flush_tun();
  }
  
  static void close_fds()
  {
    int fd;
    for (fd = 3; fd < 30; fd++)
      close(fd);
  }
  
  static void setup_binfmt_misc()
  {
    if (mount(0, "/proc/sys/fs/binfmt_misc", "binfmt_misc", 0, 0)) {
    }
    write_file("/proc/sys/fs/binfmt_misc/register", ":syz0:M:0:\x01::./file0:");
    write_file("/proc/sys/fs/binfmt_misc/register",
               ":syz1:M:1:\x02::./file0:POC");
  }
  
  struct thread_t {
    int created, call;
    event_t ready, done;
  };
  
  static struct thread_t threads[16];
  static void execute_call(int call);
  static int running;
  
  static void* thr(void* arg)
  {
    struct thread_t* th = (struct thread_t*)arg;
    for (;;) {
      event_wait(&th->ready);
      event_reset(&th->ready);
      execute_call(th->call);
      __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
      event_set(&th->done);
    }
    return 0;
  }
  
  static void execute_one(void)
  {
    int i, call, thread;
    int collide = 0;
  again:
    for (call = 0; call < 8; call++) {
      for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
           thread++) {
        struct thread_t* th = &threads[thread];
        if (!th->created) {
          th->created = 1;
          event_init(&th->ready);
          event_init(&th->done);
          event_set(&th->done);
          thread_start(thr, th);
        }
        if (!event_isset(&th->done))
          continue;
        event_reset(&th->done);
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        event_set(&th->ready);
        if (collide && (call % 2) == 0)
          break;
        event_timedwait(&th->done, 45);
        break;
      }
    }
    for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
      sleep_ms(1);
    close_fds();
    if (!collide) {
      collide = 1;
      goto again;
    }
  }
  
  static void execute_one(void);
  
  #define WAIT_FLAGS __WALL
  
  static void loop(void)
  {
    setup_loop();
    int iter;
    for (iter = 0;; iter++) {
      char cwdbuf[32];
      sprintf(cwdbuf, "./%d", iter);
      if (mkdir(cwdbuf, 0777))
        exit(1);
      reset_loop();
      int pid = fork();
      if (pid < 0)
        exit(1);
      if (pid == 0) {
        if (chdir(cwdbuf))
          exit(1);
        setup_test();
        execute_one();
        exit(0);
      }
      int status = 0;
      uint64_t start = current_time_ms();
      for (;;) {
        if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
          break;
        sleep_ms(1);
        if (current_time_ms() - start < 5 * 1000)
          continue;
        kill_and_wait(pid, &status);
        break;
      }
      remove_dir(cwdbuf);
    }
  }
  
  uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff};
  
  void execute_call(int call)
  {
    intptr_t res;
    switch (call) {
    case 0:
      NONFAILING(memcpy((void*)0x20000080, "./file0\000", 8));
      res = syscall(__NR_open, 0x20000080, 0x5a002, 8);
      if (res != -1)
        r[0] = res;
      break;
    case 1:
      syscall(__NR_ioctl, r[0], 0x801054db, 0x200000c0);
      break;
    case 2:
      res = syscall(__NR_socket, 0x2000000000000021, 2, 2);
      if (res != -1)
        r[1] = res;
      break;
    case 3:
      NONFAILING(*(uint16_t*)0x20000040 = 0x21);
      NONFAILING(*(uint16_t*)0x20000042 = 0);
      NONFAILING(*(uint16_t*)0x20000044 = 2);
      NONFAILING(*(uint16_t*)0x20000046 = 0x10);
      NONFAILING(*(uint16_t*)0x20000048 = 2);
      NONFAILING(*(uint16_t*)0x2000004a = htobe16(0));
      NONFAILING(*(uint8_t*)0x2000004c = 0xac);
      NONFAILING(*(uint8_t*)0x2000004d = 0x14);
      NONFAILING(*(uint8_t*)0x2000004e = 0x14);
      NONFAILING(*(uint8_t*)0x2000004f = 0xbb);
      syscall(__NR_connect, r[1], 0x20000040, 0x24);
      break;
    case 4:
      NONFAILING(*(uint64_t*)0x20005c00 = 0);
      NONFAILING(*(uint32_t*)0x20005c08 = 0);
      NONFAILING(*(uint64_t*)0x20005c10 = 0);
      NONFAILING(*(uint64_t*)0x20005c18 = 0);
      NONFAILING(*(uint64_t*)0x20005c20 = 0x200003c0);
      NONFAILING(memcpy(
          (void*)0x200003c0,
          "\x18\x00\x00\x00\x00\x00\x00\x00\x10\x01\x00\x00\x01\x00\x00\x00\x77"
          "\x00\x00\x00\x0b\xdf\x00\x40\x93\x30\xb3\xe7\xd8\xed\x12\x7c\xaa\x87"
          "\xf7\x54\x78\x75\x92\x07\xd1\x06\x04\xec\x95\xff\x7b\xcb\x0d\x6b\x9b"
          "\x12\x5e\xc8\x5a\x36\x6a\xbe\x4f\x50\x11\x1f\x0a\x03\xdb\xd1\xb4\xde"
          "\xa0\x5a\x8b\x5b\x29\xe8\x4e\x4f\xad\xaa\x6e\xbe\x73\x64\x27\xe4\x4d"
          "\xc6\x50\x5d\x24\x23\x48\x26\xa2\x67\xf7\x5c\x74\x3d\xb9\x65\x04\x1c"
          "\x09\xc5\x90\x47\xf7\xf7\x94\xfd\xff\xff\x80\xb6\xd7\x24\xc8\xf3\x56"
          "\xb5\xc2\x8a\xff\xff\xff\xff\xff\x81\x93\xb1\xa5\xc3\x43\x84\x95\xd9"
          "\x29\xce\x2f\x1a\xe8\x93\xaf\xaf\x3f\x05\xd3\x2d\x0b\xfa\x67\xb3\xda"
          "\x43\xab\x98\x13\x13\xe7\x55\x22\x38\x86\xb1\x80\xa2\x69\x91\x7d\xb5"
          "\x43\x0e\xf9\xae\xc0\x71\xe4\x4c\xd1\x9c\xb1\x8e\x4e\x05\x28\xac\xd1"
          "\x34\x71\xf4\x4d\x80\xd2\x1e\xd5\xde\x4b\x4c\xa3\x1f\x42\x69\xa8\x81"
          "\x15\xbe\xce\x67\x6d\x0f\xbf\x16\x5b\x08\xc3\x51\x78\xe5\x98\x93\x79"
          "\xcc\x9d\xf9\xe1\x21\xa9\x57\x31\xd0\x88\xd6",
          232));
      NONFAILING(*(uint64_t*)0x20005c28 = 0x18);
      NONFAILING(*(uint32_t*)0x20005c30 = 0);
      NONFAILING(*(uint32_t*)0x20005c38 = 0);
      syscall(__NR_sendmmsg, r[1], 0x20005c00, 1, 0);
      break;
    case 5:
      NONFAILING(*(uint64_t*)0x20005c00 = 0);
      NONFAILING(*(uint32_t*)0x20005c08 = 0xfffffd95);
      NONFAILING(*(uint64_t*)0x20005c10 = 0);
      NONFAILING(*(uint64_t*)0x20005c18 = 0);
      NONFAILING(*(uint64_t*)0x20005c20 = 0x20000000);
      NONFAILING(*(uint64_t*)0x20000000 = 0x18);
      NONFAILING(*(uint32_t*)0x20000008 = 0x110);
      NONFAILING(*(uint32_t*)0x2000000c = 1);
      NONFAILING(memcpy((void*)0x20000010, "\xec", 1));
      NONFAILING(*(uint64_t*)0x20005c28 = 0x18);
      NONFAILING(*(uint32_t*)0x20005c30 = 0);
      NONFAILING(*(uint32_t*)0x20005c38 = 0);
      syscall(__NR_sendmmsg, r[1], 0x20005c00, 1, 0);
      break;
    case 6:
      res = syscall(__NR_socket, 0x10, 3, 6);
      if (res != -1)
        r[2] = res;
      break;
    case 7:
      NONFAILING(*(uint32_t*)0x20000180 = 4);
      syscall(__NR_getsockopt, r[2], 1, 0x1e, 0x20000140, 0x20000180);
      break;
    }
  }
  int main(void)
  {
    syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
    setup_binfmt_misc();
    install_segv_handler();
    for (procid = 0; procid < 6; procid++) {
      if (fork() == 0) {
        use_temporary_dir();
        do_sandbox_none();
      }
    }
    sleep(1000000);
    return 0;
  }
  