// https://syzkaller.appspot.com/bug?id=4f94742c0ef80b9ac04a6cf031fefa4302671e12
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.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 __thread int clone_ongoing;
static __thread int skip_segv;
static __thread jmp_buf segv_env;

static void segv_handler(int sig, siginfo_t* info, void* ctx)
{
  if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) {
    exit(sig);
  }
  uintptr_t addr = (uintptr_t)info->si_addr;
  const uintptr_t prog_start = 1 << 20;
  const uintptr_t prog_end = 100 << 20;
  int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0;
  int valid = addr < prog_start || addr > prog_end;
  if (skip && valid) {
    _longjmp(segv_env, 1);
  }
  exit(sig);
}

static void install_segv_handler(void)
{
  struct sigaction sa;
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_IGN;
  syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8);
  syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8);
  memset(&sa, 0, sizeof(sa));
  sa.sa_sigaction = segv_handler;
  sa.sa_flags = SA_NODEFER | SA_SIGINFO;
  sigaction(SIGSEGV, &sa, NULL);
  sigaction(SIGBUS, &sa, NULL);
}

#define NONFAILING(...)                                                        \
  ({                                                                           \
    int ok = 1;                                                                \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    if (_setjmp(segv_env) == 0) {                                              \
      __VA_ARGS__;                                                             \
    } else                                                                     \
      ok = 0;                                                                  \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    ok;                                                                        \
  })

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 < 6; 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[2] = {0xffffffffffffffff, 0x0};

void execute_call(int call)
{
  intptr_t res = 0;
  switch (call) {
  case 0:
    NONFAILING(memcpy((void*)0x20000000, "./file0\000", 8));
    syscall(__NR_mkdirat, /*fd=*/0xffffff9c, /*path=*/0x20000000ul,
            /*mode=S_IXGRP|S_IRGRP*/ 0x28ul);
    break;
  case 1:
    NONFAILING(memcpy((void*)0x200001c0, "syz\000", 4));
    NONFAILING(memcpy((void*)0x20000480, "./file0\000", 8));
    NONFAILING(memcpy((void*)0x200004c0, "9p\000", 3));
    NONFAILING(
        memcpy((void*)0x20000840,
               "\x78\x22\x6e\x6f\x65\x78\x61\x63\x63\x81\x73\x73\x3d\x61\x6e"
               "\x79\x2c\x63\x61\x63\x68\x65\x3d\x66\x73\x63\x61\x63\x68\x65",
               30));
    syscall(__NR_mount, /*src=*/0x200001c0ul, /*dst=*/0x20000480ul,
            /*type=*/0x200004c0ul, /*flags=*/0ul, /*opts=*/0x20000840ul);
    break;
  case 2:
    NONFAILING(memcpy((void*)0x20000280, "./file0\000", 8));
    syscall(__NR_chdir, /*dir=*/0x20000280ul);
    break;
  case 3:
    NONFAILING(memcpy((void*)0x20000000, "./file0\000", 8));
    res = syscall(__NR_openat, /*fd=*/0xffffff9c, /*file=*/0x20000000ul,
                  /*flags=O_NONBLOCK|O_NOFOLLOW|O_APPEND|O_WRONLY*/ 0x20c01ul,
                  /*mode=*/0ul);
    if (res != -1)
      r[0] = res;
    break;
  case 4:
    res = syscall(__NR_io_setup, /*n=*/0x1fe, /*ctx=*/0x20000200ul);
    if (res != -1)
      NONFAILING(r[1] = *(uint64_t*)0x20000200);
    break;
  case 5:
    NONFAILING(*(uint64_t*)0x20000700 = 0x20000440);
    NONFAILING(*(uint64_t*)0x20000440 = 0x18);
    NONFAILING(*(uint32_t*)0x20000448 = 0x7000000);
    NONFAILING(*(uint32_t*)0x2000044c = 4);
    NONFAILING(*(uint16_t*)0x20000450 = 1);
    NONFAILING(*(uint16_t*)0x20000452 = 0);
    NONFAILING(*(uint32_t*)0x20000454 = r[0]);
    NONFAILING(*(uint64_t*)0x20000458 = 0x20000180);
    NONFAILING(memset((void*)0x20000180, 0, 1));
    NONFAILING(*(uint64_t*)0x20000460 = 0x37000);
    NONFAILING(*(uint64_t*)0x20000468 = 0);
    NONFAILING(*(uint64_t*)0x20000470 = 0);
    NONFAILING(*(uint32_t*)0x20000478 = 0);
    NONFAILING(*(uint32_t*)0x2000047c = -1);
    syscall(__NR_io_submit, /*ctx=*/r[1], /*nr=*/0x140bul,
            /*iocbpp=*/0x20000700ul);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-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=*/-1,
          /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1,
          /*offset=*/0ul);
  const char* reason;
  (void)reason;
  install_segv_handler();
  loop();
  return 0;
}