// https://syzkaller.appspot.com/bug?id=19dfac511f79715d862d3b7c9c783913189892ab
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <fcntl.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/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

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;
  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 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()
{
  static 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_enable", "1"},
      {"/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/net/ipv4/ping_group_range", "0 65535"},
      {"/proc/sys/kernel/keys/gc_delay", "1"},
      {"/proc/sys/vm/nr_overcommit_hugepages", "4"},
      {"/proc/sys/vm/oom_kill_allocating_task", "1"},
  };
  for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) {
    if (!write_file(files[i].name, files[i].data))
      printf("write to %s failed: %s\n", files[i].name, strerror(errno));
  }
}

uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0};

int main(void)
{
  syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
  syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
  setup_sysctl();
  install_segv_handler();
  intptr_t res = 0;
  NONFAILING(memcpy((void*)0x20000000, "/proc/self/exe\000", 15));
  res = syscall(__NR_openat, 0xffffff9c, 0x20000000ul, 0ul, 0ul);
  if (res != -1)
    r[0] = res;
  NONFAILING(memcpy((void*)0x20000300, "./bus\000", 6));
  res = syscall(__NR_creat, 0x20000300ul, 0ul);
  if (res != -1)
    r[1] = res;
  res = syscall(__NR_io_setup, 2, 0x20000140ul);
  if (res != -1)
    NONFAILING(r[2] = *(uint64_t*)0x20000140);
  NONFAILING(*(uint64_t*)0x20000540 = 0x200000c0);
  NONFAILING(*(uint64_t*)0x200000c0 = 0);
  NONFAILING(*(uint32_t*)0x200000c8 = 0);
  NONFAILING(*(uint32_t*)0x200000cc = 0);
  NONFAILING(*(uint16_t*)0x200000d0 = 1);
  NONFAILING(*(uint16_t*)0x200000d2 = 0);
  NONFAILING(*(uint32_t*)0x200000d4 = r[1]);
  NONFAILING(*(uint64_t*)0x200000d8 = 0x20000000);
  NONFAILING(*(uint64_t*)0x200000e0 = 0x200a00);
  NONFAILING(*(uint64_t*)0x200000e8 = 0);
  NONFAILING(*(uint64_t*)0x200000f0 = 0);
  NONFAILING(*(uint32_t*)0x200000f8 = 0);
  NONFAILING(*(uint32_t*)0x200000fc = -1);
  syscall(__NR_io_submit, r[2], 8ul, 0x20000540ul);
  syscall(__NR_mmap, 0x20000000ul, 0x800000ul, 0x100000aul, 0x12ul, r[0], 0ul);
  return 0;
}