// https://syzkaller.appspot.com/bug?id=07efcda7def16f07f564f78762ebd6739b9eb41f
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <pthread.h>
#include <sched.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>
#include <linux/sched.h>

#ifndef __NR_clone3
#define __NR_clone3 435
#endif
#ifndef __NR_exit
#define __NR_exit 93
#endif
#ifndef __NR_mmap
#define __NR_mmap 222
#endif

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;
  }
}

#define USLEEP_FORKED_CHILD (3 * 50 * 1000)

static long handle_clone_ret(long ret)
{
  if (ret != 0) {
    return ret;
  }
  usleep(USLEEP_FORKED_CHILD);
  syscall(__NR_exit, 0);
  while (1) {
  }
}

#define MAX_CLONE_ARGS_BYTES 256
static long syz_clone3(volatile long a0, volatile long a1)
{
  unsigned long copy_size = a1;
  if (copy_size < sizeof(uint64_t) || copy_size > MAX_CLONE_ARGS_BYTES)
    return -1;
  char clone_args[MAX_CLONE_ARGS_BYTES];
  memcpy(&clone_args, (void*)a0, copy_size);
  uint64_t* flags = (uint64_t*)&clone_args;
  *flags &= ~CLONE_VM;
  return handle_clone_ret((long)syscall(__NR_clone3, &clone_args, copy_size));
}

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)
{
  if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
  }
  int i, call, thread;
  for (call = 0; call < 1; 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, 50);
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
}

void execute_call(int call)
{
  switch (call) {
  case 0:
    //  syz_clone3 arguments: [
    //    args: ptr[in, clone_args] {
    //      clone_args {
    //        flags: clone3_flags = 0x100107200 (8 bytes)
    //        pidfd: nil
    //        child_tid: nil
    //        parent_tid: ptr[out, pid] {
    //          pid (resource)
    //        }
    //        exit_signal: align64[signalno] {
    //          v: int32 = 0x1d (4 bytes)
    //          pad = 0x0 (4 bytes)
    //        }
    //        stack: nil
    //        stack_size: bytesize = 0x0 (8 bytes)
    //        tls: nil
    //        set_tid: nil
    //        set_tid_size: len = 0x0 (8 bytes)
    //        cgroup: align64[fd_cgroup] {
    //          v: fd_cgroup (resource)
    //          pad = 0x0 (4 bytes)
    //        }
    //      }
    //    }
    //    size: bytesize = 0x58 (8 bytes)
    //  ]
    //  returns pid
    *(uint64_t*)0x200004c0 = 0x100107200;
    *(uint64_t*)0x200004c8 = 0;
    *(uint64_t*)0x200004d0 = 0;
    *(uint64_t*)0x200004d8 = 0x20000200;
    *(uint32_t*)0x200004e0 = 0x1d;
    *(uint64_t*)0x200004e8 = 0;
    *(uint64_t*)0x200004f0 = 0;
    *(uint64_t*)0x200004f8 = 0;
    *(uint64_t*)0x20000500 = 0;
    *(uint64_t*)0x20000508 = 0;
    *(uint32_t*)0x20000510 = -1;
    syz_clone3(/*args=*/0x200004c0, /*size=*/0x58);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul,
          /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  const char* reason;
  (void)reason;
  loop();
  return 0;
}