syzkaller-repros/linux/2aee9c7ed306d518b1cb499fb47587aa1396da50.c

// kernel BUG at fs/ext4/fsync.c:LINE!
// https://syzkaller.appspot.com/bug?id=2aee9c7ed306d518b1cb499fb47587aa1396da50
// 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 <signal.h>
#include <stdarg.h>
#include <stdbool.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>

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 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 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_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  write_file("/proc/self/oom_score_adj", "1000");
}

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();
      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;
    }
  }
}

#ifndef __NR_creat
#define __NR_creat 8
#endif
#ifndef __NR_fchdir
#define __NR_fchdir 133
#endif
#ifndef __NR_fcntl
#define __NR_fcntl 55
#endif
#ifndef __NR_io_setup
#define __NR_io_setup 245
#endif
#ifndef __NR_io_submit
#define __NR_io_submit 248
#endif
#ifndef __NR_ioctl
#define __NR_ioctl 54
#endif
#ifndef __NR_mmap
#define __NR_mmap 192
#endif
#ifndef __NR_openat
#define __NR_openat 295
#endif
#ifndef __NR_write
#define __NR_write 4
#endif
#undef __NR_mmap
#define __NR_mmap __NR_mmap2

uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0,
                 0xffffffffffffffff};

void execute_one(void)
{
  intptr_t res = 0;
  memcpy((void*)0x20000100, "./cgroup.cpu\000", 13);
  res = syscall(__NR_openat, 0xffffff9c, 0x20000100, 0x200002, 0);
  if (res != -1)
    r[0] = res;
  syscall(__NR_fchdir, (intptr_t)r[0]);
  memcpy((void*)0x20000180, "./bus\000", 6);
  res = syscall(__NR_creat, 0x20000180, 0);
  if (res != -1)
    r[1] = res;
  res = syscall(__NR_io_setup, 0x85, 0x20000040);
  if (res != -1)
    r[2] = *(uint32_t*)0x20000040;
  memcpy((void*)0x20000700, "./bus\000", 6);
  res = syscall(__NR_creat, 0x20000700, 0);
  if (res != -1)
    r[3] = res;
  syscall(__NR_fcntl, (intptr_t)r[1], 4, 0x44800);
  memcpy((void*)0x20000200, "threaded\000", 9);
  syscall(__NR_write, (intptr_t)r[3], 0x20000200, 0xf642e7e);
  *(uint32_t*)0x20000540 = 0x200000c0;
  *(uint64_t*)0x200000c0 = 0;
  *(uint32_t*)0x200000c8 = 0;
  *(uint32_t*)0x200000cc = 0;
  *(uint16_t*)0x200000d0 = 1;
  *(uint16_t*)0x200000d2 = 0;
  *(uint32_t*)0x200000d4 = r[1];
  *(uint64_t*)0x200000d8 = 0x20000000;
  *(uint64_t*)0x200000e0 = 0x10000;
  *(uint64_t*)0x200000e8 = 0;
  *(uint64_t*)0x200000f0 = 0;
  *(uint32_t*)0x200000f8 = 0;
  *(uint32_t*)0x200000fc = -1;
  syscall(__NR_io_submit, (intptr_t)r[2], 1, 0x20000540);
  *(uint32_t*)0x200001c0 = 0xa;
  syscall(__NR_ioctl, (intptr_t)r[1], 0x40046602, 0x200001c0);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  loop();
  return 0;
}