// https://syzkaller.appspot.com/bug?id=83e91e35d1a158427aea209a1172c277bc93dc55
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.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;
  }
}

static bool write_file(const char* file, const char* what, ...)
{
  char buf[1024];
  va_list args;
  va_start(args, what);
  vsnprintf(buf, sizeof(buf), what, args);
  va_end(args);
  buf[sizeof(buf) - 1] = 0;
  int len = strlen(buf);
  int fd = open(file, O_WRONLY | O_CLOEXEC);
  if (fd == -1)
    return false;
  if (write(fd, buf, len) != len) {
    int err = errno;
    close(fd);
    errno = err;
    return false;
  }
  close(fd);
  return true;
}

static void setup_sysctl()
{
  int cad_pid = fork();
  if (cad_pid < 0)
    exit(1);
  if (cad_pid == 0) {
    for (;;)
      sleep(100);
  }
  char tmppid[32];
  snprintf(tmppid, sizeof(tmppid), "%d", cad_pid);
  struct {
    const char* name;
    const char* data;
  } files[] = {
      {"/sys/kernel/debug/x86/nmi_longest_ns", "10000000000"},
      {"/proc/sys/kernel/hung_task_check_interval_secs", "20"},
      {"/proc/sys/net/core/bpf_jit_kallsyms", "1"},
      {"/proc/sys/net/core/bpf_jit_harden", "0"},
      {"/proc/sys/kernel/kptr_restrict", "0"},
      {"/proc/sys/kernel/softlockup_all_cpu_backtrace", "1"},
      {"/proc/sys/fs/mount-max", "100"},
      {"/proc/sys/vm/oom_dump_tasks", "0"},
      {"/proc/sys/debug/exception-trace", "0"},
      {"/proc/sys/kernel/printk", "7 4 1 3"},
      {"/proc/sys/kernel/keys/gc_delay", "1"},
      {"/proc/sys/vm/oom_kill_allocating_task", "1"},
      {"/proc/sys/kernel/ctrl-alt-del", "0"},
      {"/proc/sys/kernel/cad_pid", tmppid},
  };
  for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) {
    if (!write_file(files[i].name, files[i].data)) {
    }
  }
  kill(cad_pid, SIGKILL);
  while (waitpid(cad_pid, NULL, 0) != cad_pid)
    ;
}

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 < 5; 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:
    //  mkdir arguments: [
    //    path: ptr[in, buffer] {
    //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
    //    }
    //    mode: open_mode = 0x80 (8 bytes)
    //  ]
    memcpy((void*)0x200000000040, "./file0\000", 8);
    syscall(__NR_mkdir, /*path=*/0x200000000040ul, /*mode=S_IWUSR*/ 0x80ul);
    break;
  case 1:
    //  mount$9p_virtio arguments: [
    //    src: ptr[in, buffer] {
    //      buffer: {73 79 7a 00} (length 0x4)
    //    }
    //    dst: ptr[in, buffer] {
    //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
    //    }
    //    type: ptr[in, buffer] {
    //      buffer: {39 70 00} (length 0x3)
    //    }
    //    flags: mount_flags = 0x0 (8 bytes)
    //    opts: nil
    //  ]
    memcpy((void*)0x2000000001c0, "syz\000", 4);
    memcpy((void*)0x200000000080, "./file0\000", 8);
    memcpy((void*)0x2000000004c0, "9p\000", 3);
    syscall(__NR_mount, /*src=*/0x2000000001c0ul, /*dst=*/0x200000000080ul,
            /*type=*/0x2000000004c0ul, /*flags=*/0ul, /*opts=*/0ul);
    break;
  case 2:
    //  creat arguments: [
    //    file: ptr[in, buffer] {
    //      buffer: {2e 2f 66 69 6c 65 30 2f 66 69 6c 65 31 00} (length 0xe)
    //    }
    //    mode: open_mode = 0x4 (8 bytes)
    //  ]
    //  returns fd
    memcpy((void*)0x2000000002c0, "./file0/file1\000", 14);
    res = syscall(__NR_creat, /*file=*/0x2000000002c0ul, /*mode=S_IROTH*/ 4ul);
    if (res != -1)
      r[0] = res;
    break;
  case 3:
    //  write$cgroup_int arguments: [
    //    fd: fd_cgroup_int (resource)
    //    buf: ptr[in, int64] {
    //      int64 = 0x0 (18 bytes)
    //    }
    //    len: bytesize = 0xfffffdd8 (8 bytes)
    //  ]
    sprintf((char*)0x200000000540, "0x%016llx", (long long)0);
    syscall(__NR_write, /*fd=*/r[0], /*buf=*/0x200000000540ul,
            /*len=*/0xfffffdd8ul);
    break;
  case 4:
    //  umount2 arguments: [
    //    path: ptr[in, buffer] {
    //      buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8)
    //    }
    //    flags: umount_flags = 0x1 (8 bytes)
    //  ]
    memcpy((void*)0x2000000001c0, "./file0\000", 8);
    syscall(__NR_umount2, /*path=*/0x2000000001c0ul, /*flags=MNT_FORCE*/ 1ul);
    break;
  }
}
int main(void)
{
  syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*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=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
          /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul,
          /*fd=*/(intptr_t)-1, /*offset=*/0ul);
  setup_sysctl();
  const char* reason;
  (void)reason;
  loop();
  return 0;
}