syzkaller-repros/linux/883431818e036ae6a9981156a64b821110f39187.c

// kernel panic: n_tty: init_tty
// https://syzkaller.appspot.com/bug?id=883431818e036ae6a9981156a64b821110f39187
// status:fixed
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}
#include <stdint.h>
#include <string.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void exitf(const char* msg, ...)
{
  int e = errno;
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit(kRetryStatus);
}

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) {
    close(fd);
    return false;
  }
  close(fd);
  return true;
}

static int inject_fault(int nth)
{
  int fd;
  char buf[16];

  fd = open("/proc/thread-self/fail-nth", O_RDWR);
  if (fd == -1)
    exitf("failed to open /proc/thread-self/fail-nth");
  sprintf(buf, "%d", nth + 1);
  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
    exitf("failed to write /proc/thread-self/fail-nth");
  return fd;
}

static void test();

void loop()
{
  while (1) {
    test();
  }
}

void test()
{
  syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0);
  *(uint32_t*)0x2025c000 = 2;
  *(uint32_t*)0x2025c004 = 0x78;
  *(uint8_t*)0x2025c008 = 0xe2;
  *(uint8_t*)0x2025c009 = 0;
  *(uint8_t*)0x2025c00a = 0;
  *(uint8_t*)0x2025c00b = 0;
  *(uint32_t*)0x2025c00c = 0;
  *(uint64_t*)0x2025c010 = 0;
  *(uint64_t*)0x2025c018 = 0;
  *(uint64_t*)0x2025c020 = 0;
  *(uint8_t*)0x2025c028 = 0x72;
  *(uint8_t*)0x2025c029 = 0;
  *(uint8_t*)0x2025c02a = 0;
  *(uint8_t*)0x2025c02b = 0;
  *(uint32_t*)0x2025c02c = 0;
  *(uint32_t*)0x2025c030 = 0;
  *(uint32_t*)0x2025c034 = 0;
  *(uint64_t*)0x2025c038 = 0;
  *(uint64_t*)0x2025c040 = 0;
  *(uint64_t*)0x2025c048 = 0;
  *(uint64_t*)0x2025c050 = 0;
  *(uint64_t*)0x2025c058 = 0;
  *(uint32_t*)0x2025c060 = 0;
  *(uint64_t*)0x2025c068 = 0;
  *(uint32_t*)0x2025c070 = 0;
  *(uint16_t*)0x2025c074 = 0;
  *(uint16_t*)0x2025c076 = 0;
  syscall(__NR_perf_event_open, 0x2025c000, 0, 0, -1, 0);
  memcpy((void*)0x204aeff6, "/dev/ptmx", 10);
  write_file("/sys/kernel/debug/failslab/ignore-gfp-wait", "N");
  write_file("/sys/kernel/debug/fail_futex/ignore-private", "N");
  inject_fault(6);
  syscall(__NR_openat, 0xffffffffffffff9c, 0x204aeff6, 0x4000, 0);
}

int main()
{
  for (;;) {
    loop();
  }
}