// https://syzkaller.appspot.com/bug?id=0660ec96c45e609f07f6a7a08f343f23b21ae1e7
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <linux/futex.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}
#include <errno.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void fail(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

static void exitf(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit(kRetryStatus);
}

static uint64_t current_time_ms()
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    fail("clock_gettime failed");
  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static void use_temporary_dir()
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    fail("failed to mkdtemp");
  if (chmod(tmpdir, 0777))
    fail("failed to chmod");
  if (chdir(tmpdir))
    fail("failed to chdir");
}

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) {
      exitf("opendir(%s) failed due to NOFILE, exiting", dir);
    }
    exitf("opendir(%s) failed", dir);
  }
  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))
      exitf("lstat(%s) failed", filename);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exitf("unlink(%s) failed", filename);
      if (umount2(filename, MNT_DETACH))
        exitf("umount(%s) failed", filename);
    }
  }
  closedir(dp);
  int i;
  for (i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, MNT_DETACH))
          exitf("umount(%s) failed", dir);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exitf("rmdir(%s) failed", dir);
  }
}

static void execute_one();
extern unsigned long long procid;

static void loop()
{
  int iter;
  for (iter = 0;; iter++) {
    char cwdbuf[32];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      fail("failed to mkdir");
    int pid = fork();
    if (pid < 0)
      fail("clone failed");
    if (pid == 0) {
      prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
      setpgrp();
      if (chdir(cwdbuf))
        fail("failed to chdir");
      execute_one();
      int fd;
      for (fd = 3; fd < 30; fd++)
        close(fd);
      doexit(0);
    }

    int status = 0;
    uint64_t start = current_time_ms();
    for (;;) {
      int res = waitpid(-1, &status, __WALL | WNOHANG);
      if (res == pid) {
        break;
      }
      usleep(1000);
      if (current_time_ms() - start < 5 * 1000)
        continue;
      kill(-pid, SIGKILL);
      kill(pid, SIGKILL);
      while (waitpid(-1, &status, __WALL) != pid) {
      }
      break;
    }
    remove_dir(cwdbuf);
  }
}

struct thread_t {
  int created, running, call;
  pthread_t th;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;
static int collide;

static void* thr(void* arg)
{
  struct thread_t* th = (struct thread_t*)arg;
  for (;;) {
    while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
    syscall(SYS_futex, &th->running, FUTEX_WAKE);
  }
  return 0;
}

static void execute(int num_calls)
{
  int call, thread;
  running = 0;
  for (call = 0; call < num_calls; call++) {
    for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        pthread_create(&th->th, &attr, thr, th);
      }
      if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
        syscall(SYS_futex, &th->running, FUTEX_WAKE);
        if (collide && call % 2)
          break;
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (__atomic_load_n(&running, __ATOMIC_RELAXED))
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

#ifndef __NR_mkdir
#define __NR_mkdir 39
#endif
#ifndef __NR_mount
#define __NR_mount 21
#endif
#ifndef __NR_mknod
#define __NR_mknod 14
#endif
#ifndef __NR_mmap
#define __NR_mmap 192
#endif
#ifndef __NR_pause
#define __NR_pause 29
#endif
#undef __NR_mmap
#define __NR_mmap __NR_mmap2

void execute_call(int call)
{
  switch (call) {
  case 0:
    syscall(__NR_pause);
    break;
  case 1:
    memcpy((void*)0x200001c0, "./file0", 8);
    syscall(__NR_mkdir, 0x200001c0, 0);
    break;
  case 2:
    memcpy((void*)0x2000a000, "./file0", 8);
    memcpy((void*)0x20026ff8, "./file0", 8);
    memcpy((void*)0x20000300, "ramfs", 6);
    syscall(__NR_mount, 0x2000a000, 0x20026ff8, 0x20000300, 0, 0x200007c0);
    break;
  case 3:
    memcpy((void*)0x20d04000, "./file0", 8);
    memcpy((void*)0x20903000, "./file0", 8);
    memcpy((void*)0x20000340, "bdev", 5);
    syscall(__NR_mount, 0x20d04000, 0x20903000, 0x20000340, 0x100000,
            0x200002c0);
    break;
  case 4:
    memcpy((void*)0x20000240, "./file0", 8);
    memcpy((void*)0x20000280, ".", 1);
    memcpy((void*)0x20000040, "\x04\x5b\x89\x8f\x73", 5);
    syscall(__NR_mount, 0x20000240, 0x20000280, 0x20000040, 0x1004, 0);
    break;
  case 5:
    memcpy((void*)0x20000000, "./file0", 8);
    memcpy((void*)0x200000c0, ".", 1);
    memcpy((void*)0x20000140, "vxfs", 5);
    syscall(__NR_mount, 0x20000000, 0x200000c0, 0x20000140, 0x3080, 0x20000200);
    break;
  case 6:
    memcpy((void*)0x200008c0, ".", 1);
    memcpy((void*)0x20000080, ".", 1);
    memcpy((void*)0x20753000, "mslos", 6);
    syscall(__NR_mount, 0x200008c0, 0x20000080, 0x20753000, 0x5010, 0x20000ac0);
    break;
  case 7:
    memcpy((void*)0x20fb6000, "./file0", 8);
    memcpy((void*)0x20d78000, ".", 1);
    memcpy((void*)0x20fdb000, "ubifs", 6);
    syscall(__NR_mount, 0x20fb6000, 0x20d78000, 0x20fdb000, 0x1003, 0);
    break;
  case 8:
    memcpy((void*)0x20000400, "./file0/file0", 14);
    syscall(__NR_mkdir, 0x20000400, 0);
    break;
  case 9:
    memcpy((void*)0x200002c0, "./file0/file0/file0", 20);
    syscall(__NR_mknod, 0x200002c0, 0, 0);
    break;
  case 10:
    memcpy((void*)0x20000100, "./file0/file0", 14);
    memcpy((void*)0x20000880, "./file0/file0", 14);
    memcpy((void*)0x20753000, "mslos", 6);
    syscall(__NR_mount, 0x20000100, 0x20000880, 0x20753000, 0x5010, 0x20000640);
    break;
  }
}

void execute_one()
{
  execute(11);
  collide = 1;
  execute(11);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  char* cwd = get_current_dir_name();
  for (;;) {
    if (chdir(cwd))
      fail("failed to chdir");
    use_temporary_dir();
    loop();
  }
}