syzkaller-repros/linux/2c9e43516d5dfb1913cdd13856f93842eaaffb79.c

// possible deadlock in do_io_accounting
// https://syzkaller.appspot.com/bug?id=2c9e43516d5dfb1913cdd13856f93842eaaffb79
// status:open
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/futex.h>

unsigned long long procid;

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 thread_start(void* (*fn)(void*), void* arg)
{
  pthread_t th;
  pthread_attr_t attr;
  pthread_attr_init(&attr);
  pthread_attr_setstacksize(&attr, 128 << 10);
  if (pthread_create(&th, &attr, fn, arg))
    exit(1);
  pthread_attr_destroy(&attr);
}

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 long syz_open_procfs(long a0, long a1)
{
  char buf[128];
  memset(buf, 0, sizeof(buf));
  if (a0 == 0) {
    snprintf(buf, sizeof(buf), "/proc/self/%s", (char*)a1);
  } else if (a0 == -1) {
    snprintf(buf, sizeof(buf), "/proc/thread-self/%s", (char*)a1);
  } else {
    snprintf(buf, sizeof(buf), "/proc/self/task/%d/%s", (int)a0, (char*)a1);
  }
  int fd = open(buf, O_RDWR);
  if (fd == -1)
    fd = open(buf, O_RDONLY);
  return fd;
}

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) {
  }
}

#define SYZ_HAVE_SETUP_TEST 1
static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
}

#define SYZ_HAVE_RESET_TEST 1
static void reset_test()
{
  int fd;
  for (fd = 3; fd < 30; fd++)
    close(fd);
}

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;
  for (call = 0; call < 15; 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);
      event_timedwait(&th->done, 45);
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      setup_test();
      execute_one();
      reset_test();
      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;
    }
  }
}

uint64_t r[7] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0xffffffffffffffff};

void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    memcpy((void*)0x20000100, "./cgroup.cpu", 13);
    res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000100, 0x200002, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 1:
    syscall(__NR_fchdir, r[0]);
    break;
  case 2:
    memcpy((void*)0x20000140, "net/igmp6", 10);
    res = syz_open_procfs(0, 0x20000140);
    if (res != -1)
      r[1] = res;
    break;
  case 3:
    memcpy((void*)0x20000080, "./bus", 6);
    res = syscall(__NR_creat, 0x20000080, 0);
    if (res != -1)
      r[2] = res;
    break;
  case 4:
    *(uint64_t*)0x20000040 = 0;
    syscall(__NR_sendfile, r[2], r[1], 0x20000040, 0x100000001);
    break;
  case 5:
    memcpy((void*)0x200003c0, "/selinux/commit_pending_bools", 30);
    res = syscall(__NR_openat, 0xffffffffffffff9c, 0x200003c0, 1, 0);
    if (res != -1)
      r[3] = res;
    break;
  case 6:
    res = syscall(__NR_pipe, 0x200001c0);
    if (res != -1) {
      r[4] = *(uint32_t*)0x200001c0;
      r[5] = *(uint32_t*)0x200001c4;
    }
    break;
  case 7:
    memcpy((void*)0x20000200, "4", 1);
    syscall(__NR_write, r[5], 0x20000200, 1);
    break;
  case 8:
    *(uint64_t*)0x20000100 = 0;
    syscall(__NR_splice, r[4], 0, r[3], 0x20000100, 0x400000000003, 0);
    break;
  case 9:
    memcpy((void*)0x20000000, "./file0", 8);
    syscall(__NR_unlink, 0x20000000);
    break;
  case 10:
    memcpy((void*)0x20000100, "system.posix_acl_access", 24);
    memcpy((void*)0x20000080, "\x02\x00\x00\x00\x11\x4f\xdd\xdf\x6b\x28\x46\x99"
                              "\xdf\x92\xd5\x3e\x6f\x4a\x02\x75\x9b\x94\x61"
                              "\xac",
           24);
    syscall(__NR_fsetxattr, -1, 0x20000100, 0x20000080, 0x18, 0);
    break;
  case 11:
    memcpy((void*)0x200000c0, "./file0", 8);
    syscall(__NR_mknod, 0x200000c0, 0x100000000001040, 0);
    break;
  case 12:
    memcpy((void*)0x20000000, "./file0", 8);
    syscall(__NR_execve, 0x20000000, 0x20000080, 0x20775000);
    break;
  case 13:
    memcpy((void*)0x20000400, "io", 3);
    res = syz_open_procfs(0, 0x20000400);
    if (res != -1)
      r[6] = res;
    break;
  case 14:
    syscall(__NR_pread64, r[6], 0x209f3000, 0x352, 0);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (procid = 0; procid < 6; procid++) {
    if (fork() == 0) {
      loop();
    }
  }
  sleep(1000000);
  return 0;
}