// https://syzkaller.appspot.com/bug?id=0fb0ea958b706f72818cc47b182e3ac1dc5d355a
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <pthread.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

unsigned long long procid;

static __thread int skip_segv;
static __thread jmp_buf segv_env;

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

static void install_segv_handler(void)
{
  struct sigaction sa;
  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(...)                                                        \
  {                                                                            \
    __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
    if (_setjmp(segv_env) == 0) {                                              \
      __VA_ARGS__;                                                             \
    }                                                                          \
    __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST);                       \
  }

static void kill_and_wait(int pid, int* status)
{
  kill(pid, SIGKILL);
  while (waitpid(-1, status, 0) != pid) {
  }
}

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;
  for (i = 0; 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 {
  pthread_mutex_t mu;
  pthread_cond_t cv;
  int state;
} event_t;

static void event_init(event_t* ev)
{
  if (pthread_mutex_init(&ev->mu, 0))
    exit(1);
  if (pthread_cond_init(&ev->cv, 0))
    exit(1);
  ev->state = 0;
}

static void event_reset(event_t* ev)
{
  ev->state = 0;
}

static void event_set(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  if (ev->state)
    exit(1);
  ev->state = 1;
  pthread_mutex_unlock(&ev->mu);
  pthread_cond_broadcast(&ev->cv);
}

static void event_wait(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  while (!ev->state)
    pthread_cond_wait(&ev->cv, &ev->mu);
  pthread_mutex_unlock(&ev->mu);
}

static int event_isset(event_t* ev)
{
  pthread_mutex_lock(&ev->mu);
  int res = ev->state;
  pthread_mutex_unlock(&ev->mu);
  return res;
}

static int event_timedwait(event_t* ev, uint64_t timeout)
{
  uint64_t start = current_time_ms();
  uint64_t now = start;
  pthread_mutex_lock(&ev->mu);
  for (;;) {
    if (ev->state)
      break;
    uint64_t remain = timeout - (now - start);
    struct timespec ts;
    ts.tv_sec = remain / 1000;
    ts.tv_nsec = (remain % 1000) * 1000 * 1000;
    pthread_cond_timedwait(&ev->cv, &ev->mu, &ts);
    now = current_time_ms();
    if (now - start > timeout)
      break;
  }
  int res = ev->state;
  pthread_mutex_unlock(&ev->mu);
  return res;
}

#define __syscall syscall

static void sandbox_common()
{
  if (setsid() == -1)
    exit(1);
  struct rlimit rlim;
  rlim.rlim_cur = rlim.rlim_max = 8 << 20;
  setrlimit(RLIMIT_MEMLOCK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_FSIZE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 1 << 20;
  setrlimit(RLIMIT_STACK, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 0;
  setrlimit(RLIMIT_CORE, &rlim);
  rlim.rlim_cur = rlim.rlim_max = 256;
  setrlimit(RLIMIT_NOFILE, &rlim);
}

static void loop();

static int do_sandbox_none(void)
{
  sandbox_common();
  loop();
  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 execute_one(void)
{
  int i, call, thread;
  int collide = 0;
again:
  for (call = 0; call < 13; 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);
      break;
    }
  }
  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
    sleep_ms(1);
  if (!collide) {
    collide = 1;
    goto again;
  }
}

static void execute_one(void);

#define WAIT_FLAGS 0

static void loop(void)
{
  int iter;
  for (iter = 0;; iter++) {
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      execute_one();
      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_and_wait(pid, &status);
      break;
    }
  }
}

uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0xffffffffffffffff};

void execute_call(int call)
{
  intptr_t res;
  switch (call) {
  case 0:
    NONFAILING(memcpy((void*)0x20000ffa, "./bus\000", 6));
    syscall(SYS_mknod, 0x20000ffa, 0x1000, 0); /* major = 0, minor = 0 */
    break;
  case 1:
    NONFAILING(memcpy((void*)0x20000000, "./bus\000", 6));
    res = syscall(SYS_open, 0x20000000, 2, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 2:
    NONFAILING(memcpy((void*)0x20000040, "/dev/bpf\000", 9));
    res = syscall(SYS_openat, 0xffffffffffffff9c, 0x20000040, 0, 0);
    if (res != -1)
      r[1] = res;
    break;
  case 3:
    NONFAILING(memcpy((void*)0x20000480, "tap", 3));
    NONFAILING(*(uint8_t*)0x20000483 = 0x30 + procid * 1);
    NONFAILING(*(uint8_t*)0x20000484 = 0);
    syscall(SYS_ioctl, r[1], 0x8020426c, 0x20000480);
    break;
  case 4:
    NONFAILING(*(uint32_t*)0x20000000 = 0);
    NONFAILING(*(uint64_t*)0x20000008 = 0);
    syscall(SYS_ioctl, r[1], 0x80104267, 0x20000000);
    break;
  case 5:
    NONFAILING(memcpy((void*)0x20000040, "/dev/bpf\000", 9));
    res = syscall(SYS_openat, 0xffffffffffffff9c, 0x20000040, 0, 0);
    if (res != -1)
      r[2] = res;
    break;
  case 6:
    syscall(SYS_ioctl, r[2], 0x8020426c, 0);
    break;
  case 7:
    syscall(SYS_ioctl, r[2], 0x80104267, 0);
    break;
  case 8:
    res = syscall(SYS_fcntl, r[1], 0xa, r[2]);
    if (res != -1)
      r[3] = res;
    break;
  case 9:
    NONFAILING(memcpy((void*)0x200000c0, "tap", 3));
    NONFAILING(*(uint8_t*)0x200000c3 = 0x30 + procid * 1);
    NONFAILING(*(uint8_t*)0x200000c4 = 0);
    syscall(SYS_ioctl, r[3], 0x8020426c, 0x200000c0);
    break;
  case 10:
    syscall(SYS_mprotect, 0x20000000, 0x800000, 5);
    break;
  case 11:
    NONFAILING(*(uint32_t*)0x200000c0 = 0);
    syscall(SYS_ioctl, r[0], 0x80206979, 0x200000c0);
    break;
  case 12:
    NONFAILING(*(uint32_t*)0x200000c0 = 0);
    syscall(SYS_ioctl, r[0], 0x8020697a, 0x200000c0);
    break;
  }
}
int main(void)
{
  syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0, 0);
  install_segv_handler();
  for (procid = 0; procid < 2; procid++) {
    if (fork() == 0) {
      do_sandbox_none();
    }
  }
  sleep(1000000);
  return 0;
}