syzkaller-repros/linux/611b50e30eb1634e75688903289148fe2a042c1d.c

// BUG: unable to handle kernel paging request in do_mount
// https://syzkaller.appspot.com/bug?id=611b50e30eb1634e75688903289148fe2a042c1d
// status:fixed
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <endian.h>
#include <errno.h>
#include <fcntl.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 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 int inject_fault(int nth)
{
  int fd;
  char buf[16];
  fd = open("/proc/thread-self/fail-nth", O_RDWR);
  if (fd == -1)
    exit(1);
  sprintf(buf, "%d", nth + 1);
  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
    exit(1);
  return fd;
}

int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);

  memcpy((void*)0x20000000, "./file0", 8);
  syscall(__NR_mkdir, 0x20000000, 0);
  memcpy((void*)0x20000100, "./file0", 8);
  memcpy((void*)0x20000700, "bpf", 4);
  syscall(__NR_mount, 0x20000000, 0x20000100, 0x20000700, 0x2005890,
          0x20000740);
  memcpy((void*)0x200002c0, "./file0", 8);
  memcpy((void*)0x20000380, "bpf", 4);
  write_file("/sys/kernel/debug/failslab/ignore-gfp-wait", "N");
  write_file("/sys/kernel/debug/fail_futex/ignore-private", "N");
  inject_fault(3);
  syscall(__NR_mount, 0, 0x200002c0, 0x20000380, 0x1800a0, 0);
  return 0;
}