// https://syzkaller.appspot.com/bug?id=6b3ae152f8eaf04739cc4362d4a9c1204e23fc99
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <linux/futex.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 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 = 0;
  for (; 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, 1000000);
}

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_ACQUIRE))
      return 1;
    now = current_time_ms();
    if (now - start > timeout)
      return 0;
  }
}

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 loop(void)
{
  int i, call, thread;
  int collide = 0;
again:
  for (call = 0; call < 3; 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 + (call == 2 ? 500 : 0));
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
  if (!collide) {
    collide = 1;
    goto again;
  }
}

#ifndef __NR_bpf
#define __NR_bpf 321
#endif

uint64_t r[1] = {0xffffffffffffffff};

void execute_call(int call)
{
  intptr_t res = 0;
  switch (call) {
  case 0:
    syscall(__NR_unshare, 0x400ul);
    break;
  case 1:
    *(uint32_t*)0x20000440 = 0x11;
    *(uint32_t*)0x20000444 = 6;
    *(uint64_t*)0x20000448 = 0x20000100;
    memcpy((void*)0x20000100,
           "\x05\x00\x00\x00\x00\x00\x00\x00\x61\x11\x0c\x00\x00\x00\x00\x00"
           "\x85\x10\x00\x00\x02\x00\x00\x00\x85\x00\x00\x00\x05\x00\x00\x00"
           "\x95\x00\x00\x00\x00\x00\x00\x00\x95\x00\xa5\x05\x00\x00\x00\x00"
           "\x77\x51\xe8\xba\x63\x9a\x67\x88\xa3\x41\xcc\xa5\x55\xfe\xdb\xe9"
           "\xd8\xf3\xb4\x23\xcd\xac\xfa\x7e\x32\xfe\x02\x31\x36\x8b\x22\x64"
           "\xf9\xdc\x3f\x45\xf9\xf6\x55\x15\xb0\xe1\xa3\x8d\x86\x65\x52\x2b"
           "\xe1\x8b\xd1\x0a\x48\xb0\x43\xcc\xc4\x26\x46\xd2\x5d\xfd\x73\xa0"
           "\x15\xe0\xca\x7f\xc2\x50\x6a\x0f\x68\xa7\xd0\x6d\x75\x35\xf7\x86"
           "\x69\x07\xdc\x67\x51\xdf\xb2\x65\xa0\xe3\xcc\xae\x66\x9e\x17\x3a"
           "\x64\x9c\x1c\xfd\x65\x87\xd4\x52\xd6\x4e\x7c\xc9\x57\xd7\x75\x78"
           "\xf4\xc3\x52\x35\x13\x8d\x55\x21\xf9\x45\x35\x59\xc3\x5d\xa8\x60"
           "\xe8\xef\xbc\x6f\x2b\x2a\x3e\x31\x73\xd5\x66\x1c\xfe\xec\x79\xc6"
           "\x6c\x54\xc3",
           195);
    *(uint64_t*)0x20000450 = 0x20000080;
    memcpy((void*)0x20000080, "GPL\000", 4);
    *(uint32_t*)0x20000458 = 5;
    *(uint32_t*)0x2000045c = 0x29e;
    *(uint64_t*)0x20000460 = 0x2000cf3d;
    *(uint32_t*)0x20000468 = 0;
    *(uint32_t*)0x2000046c = 0;
    *(uint8_t*)0x20000470 = 0;
    *(uint8_t*)0x20000471 = 0;
    *(uint8_t*)0x20000472 = 0;
    *(uint8_t*)0x20000473 = 0;
    *(uint8_t*)0x20000474 = 0;
    *(uint8_t*)0x20000475 = 0;
    *(uint8_t*)0x20000476 = 0;
    *(uint8_t*)0x20000477 = 0;
    *(uint8_t*)0x20000478 = 0;
    *(uint8_t*)0x20000479 = 0;
    *(uint8_t*)0x2000047a = 0;
    *(uint8_t*)0x2000047b = 0;
    *(uint8_t*)0x2000047c = 0;
    *(uint8_t*)0x2000047d = 0;
    *(uint8_t*)0x2000047e = 0;
    *(uint8_t*)0x2000047f = 0;
    *(uint32_t*)0x20000480 = 0;
    *(uint32_t*)0x20000484 = 0;
    *(uint32_t*)0x20000488 = -1;
    *(uint32_t*)0x2000048c = 6;
    *(uint64_t*)0x20000490 = 0;
    *(uint32_t*)0x20000498 = 0;
    *(uint32_t*)0x2000049c = 0x10;
    *(uint64_t*)0x200004a0 = 0;
    *(uint32_t*)0x200004a8 = 0;
    *(uint32_t*)0x200004ac = 0;
    *(uint32_t*)0x200004b0 = -1;
    res = syscall(__NR_bpf, 5ul, 0x20000440ul, 0x70ul);
    if (res != -1)
      r[0] = res;
    break;
  case 2:
    *(uint64_t*)0x20000080 = 0x20000040;
    memcpy((void*)0x20000040, "ext4_find_delalloc_range\000", 25);
    *(uint32_t*)0x20000088 = r[0];
    syscall(__NR_bpf, 0x11ul, 0x20000080ul, 0x10ul);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  loop();
  return 0;
}