// https://syzkaller.appspot.com/bug?id=de23f6e644d3432614a9ee76939949c960abea97
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.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/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include <linux/futex.h>

static void sleep_ms(uint64_t ms)
{
  usleep(ms * 1000);
}

uint64_t current_time_ms()
{
  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);
}

static void event_wait(event_t* ev)
{
  while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
    syscall(SYS_futex, &ev->state, FUTEX_WAIT, 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_ms)
{
  struct timespec ts;
  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    exit(1);
  const uint64_t kNsPerSec = 1000 * 1000 * 1000;
  uint64_t start_ns = (uint64_t)ts.tv_sec * kNsPerSec + (uint64_t)ts.tv_nsec;
  uint64_t now_ns = start_ns;
  uint64_t timeout_ns = timeout_ms * 1000 * 1000;
  for (;;) {
    uint64_t remain_ns = timeout_ns - (now_ns - start_ns);
    ts.tv_sec = remain_ns / kNsPerSec;
    ts.tv_nsec = remain_ns % kNsPerSec;
    syscall(SYS_futex, &ev->state, FUTEX_WAIT, 0, &ts);
    if (__atomic_load_n(&ev->state, __ATOMIC_RELAXED))
      return 1;
    if (clock_gettime(CLOCK_MONOTONIC, &ts))
      exit(1);
    now_ns = (uint64_t)ts.tv_sec * kNsPerSec + (uint64_t)ts.tv_nsec;
    if (now_ns - start_ns > timeout_ns)
      return 0;
  }
}

extern unsigned long long procid;

static void setup_loop()
{
}

static void reset_loop()
{
}

static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
}

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(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;
        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, 25);
      if (__atomic_load_n(&running, __ATOMIC_RELAXED))
        sleep_ms((call == num_calls - 1) ? 10 : 2);
      break;
    }
  }
}

static void execute_one();

#define WAIT_FLAGS __WALL

static void loop()
{
  setup_loop();
  int iter;
  for (iter = 0;; iter++) {
    reset_loop();
    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(-pid, SIGKILL);
      kill(pid, SIGKILL);
      while (waitpid(-1, &status, WAIT_FLAGS) != pid) {
      }
      break;
    }
  }
}

uint64_t r[1] = {0xffffffffffffffff};
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    memcpy((void*)0x20000040, "/dev/ptmx", 10);
    res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000040, 0, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 1:
    *(uint32_t*)0x20000080 = -1;
    *(uint16_t*)0x20000084 = 0x8502;
    *(uint16_t*)0x20000086 = 0;
    *(uint32_t*)0x20000088 = -1;
    *(uint16_t*)0x2000008c = 0x2002;
    *(uint16_t*)0x2000008e = 0;
    *(uint32_t*)0x20000090 = r[0];
    *(uint16_t*)0x20000094 = 0x400;
    *(uint16_t*)0x20000096 = 0;
    syscall(__NR_poll, 0x20000080, 3, 0xfffffffa);
    break;
  case 2:
    *(uint32_t*)0x20005a40 = r[0];
    *(uint16_t*)0x20005a44 = 0x18;
    *(uint16_t*)0x20005a46 = 0;
    *(uint32_t*)0x20005a48 = r[0];
    *(uint16_t*)0x20005a4c = 0x80;
    *(uint16_t*)0x20005a4e = 0;
    syscall(__NR_poll, 0x20005a40, 2, 0x574);
    break;
  }
}

void execute_one()
{
  execute(3);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (;;) {
    loop();
  }
  return 0;
}