// https://syzkaller.appspot.com/bug?id=565fa40a59038b0dd66d10e45f657e5d063d408a
// 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/mount.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <linux/futex.h>

#ifndef __NR_ioctl
#define __NR_ioctl 54
#endif
#ifndef __NR_mmap
#define __NR_mmap 192
#endif
#ifndef __NR_openat
#define __NR_openat 295
#endif
#undef __NR_mmap
#define __NR_mmap __NR_mmap2

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)
{
  if (write(1, "executing program\n", sizeof("executing program\n") - 1)) {
  }
  int i, call, thread;
  for (call = 0; call < 2; 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);
}

uint64_t r[1] = {0xffffffffffffffff};

void execute_call(int call)
{
  intptr_t res = 0;
  switch (call) {
  case 0:
    //  openat$udambuf arguments: [
    //    fd: const = 0xffffff9c (4 bytes)
    //    file: ptr[in, buffer] {
    //      buffer: {2f 64 65 76 2f 75 64 6d 61 62 75 66 00} (length 0xd)
    //    }
    //    flags: const = 0x2 (4 bytes)
    //  ]
    //  returns fd_udambuf
    memcpy((void*)0x80000000, "/dev/udmabuf\000", 13);
    res = syscall(__NR_openat, /*fd=*/0xffffff9c, /*file=*/0x80000000,
                  /*flags=*/2, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 1:
    //  ioctl$UDMABUF_CREATE arguments: [
    //    fd: fd_udambuf (resource)
    //    cmd: const = 0x40187542 (4 bytes)
    //    arg: ptr[in, udmabuf_create] {
    //      udmabuf_create {
    //        memfd: fd_memfd (resource)
    //        flags: int32 = 0x40000000 (4 bytes)
    //        offset: udmabuf_offset_size = 0x1000000 (8 bytes)
    //        size: udmabuf_offset_size = 0x1000000000000 (8 bytes)
    //      }
    //    }
    //  ]
    //  returns fd_dma_buf
    *(uint32_t*)0x80000100 = -1;
    *(uint32_t*)0x80000104 = 0x40000000;
    *(uint64_t*)0x80000108 = 0x1000000;
    *(uint64_t*)0x80000110 = 0x1000000000000;
    syscall(__NR_ioctl, /*fd=*/(intptr_t)r[0], /*cmd=*/0x40187542,
            /*arg=*/0x80000100);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x7ffff000, /*len=*/0x1000, /*prot=*/0,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32,
          /*fd=*/(intptr_t)-1, /*offset=*/0);
  syscall(__NR_mmap, /*addr=*/0x80000000, /*len=*/0x1000000,
          /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32,
          /*fd=*/(intptr_t)-1, /*offset=*/0);
  syscall(__NR_mmap, /*addr=*/0x81000000, /*len=*/0x1000, /*prot=*/0,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32,
          /*fd=*/(intptr_t)-1, /*offset=*/0);
  const char* reason;
  (void)reason;
  loop();
  return 0;
}