syzkaller-repros/linux/34113200cfaa9abaab0c4b8926faeb2acb46dd41.c

// kernel BUG at lib/lockref.c:LINE!
// https://syzkaller.appspot.com/bug?id=34113200cfaa9abaab0c4b8926faeb2acb46dd41
// status:open
// autogenerated by syzkaller (https://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

unsigned long long procid;

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 use_temporary_dir(void)
{
  char tmpdir_template[] = "./syzkaller.XXXXXX";
  char* tmpdir = mkdtemp(tmpdir_template);
  if (!tmpdir)
    exit(1);
  if (chmod(tmpdir, 0777))
    exit(1);
  if (chdir(tmpdir))
    exit(1);
}

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;
}

#define FS_IOC_SETFLAGS _IOW('f', 2, long)
static void remove_dir(const char* dir)
{
  DIR* dp;
  struct dirent* ep;
  int iter = 0;
retry:
  while (umount2(dir, MNT_DETACH) == 0) {
  }
  dp = opendir(dir);
  if (dp == NULL) {
    if (errno == EMFILE) {
      exit(1);
    }
    exit(1);
  }
  while ((ep = readdir(dp))) {
    if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0)
      continue;
    char filename[FILENAME_MAX];
    snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name);
    while (umount2(filename, MNT_DETACH) == 0) {
    }
    struct stat st;
    if (lstat(filename, &st))
      exit(1);
    if (S_ISDIR(st.st_mode)) {
      remove_dir(filename);
      continue;
    }
    int i;
    for (i = 0;; i++) {
      if (unlink(filename) == 0)
        break;
      if (errno == EPERM) {
        int fd = open(filename, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0)
            close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno != EBUSY || i > 100)
        exit(1);
      if (umount2(filename, MNT_DETACH))
        exit(1);
    }
  }
  closedir(dp);
  int i;
  for (i = 0;; i++) {
    if (rmdir(dir) == 0)
      break;
    if (i < 100) {
      if (errno == EPERM) {
        int fd = open(dir, O_RDONLY);
        if (fd != -1) {
          long flags = 0;
          if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0)
            close(fd);
          continue;
        }
      }
      if (errno == EROFS) {
        break;
      }
      if (errno == EBUSY) {
        if (umount2(dir, MNT_DETACH))
          exit(1);
        continue;
      }
      if (errno == ENOTEMPTY) {
        if (iter < 100) {
          iter++;
          goto retry;
        }
      }
    }
    exit(1);
  }
}

static void kill_and_wait(int pid, int* status)
{
  kill(-pid, SIGKILL);
  kill(pid, SIGKILL);
  int i;
  for (i = 0; i < 100; i++) {
    if (waitpid(-1, status, WNOHANG | __WALL) == pid)
      return;
    usleep(1000);
  }
  DIR* dir = opendir("/sys/fs/fuse/connections");
  if (dir) {
    for (;;) {
      struct dirent* ent = readdir(dir);
      if (!ent)
        break;
      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
        continue;
      char abort[300];
      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
               ent->d_name);
      int fd = open(abort, O_WRONLY);
      if (fd == -1) {
        continue;
      }
      if (write(fd, abort, 1) < 0) {
      }
      close(fd);
    }
    closedir(dir);
  } else {
  }
  while (waitpid(-1, status, __WALL) != pid) {
  }
}

static void setup_test()
{
  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
  setpgrp();
  write_file("/proc/self/oom_score_adj", "1000");
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void)
{
  int iter;
  for (iter = 0;; iter++) {
    char cwdbuf[32];
    sprintf(cwdbuf, "./%d", iter);
    if (mkdir(cwdbuf, 0777))
      exit(1);
    int pid = fork();
    if (pid < 0)
      exit(1);
    if (pid == 0) {
      if (chdir(cwdbuf))
        exit(1);
      setup_test();
      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;
    }
    remove_dir(cwdbuf);
  }
}

void execute_one(void)
{
  memcpy((void*)0x20000200, "/dev/net/tun\000", 13);
  syscall(__NR_openat, 0xffffffffffffff9c, 0x20000200, 0, 0);
  syscall(__NR_socketpair, 1, 0, 0, 0);
  syscall(__NR_mmap, 0x20001000, 0x1000, 0, 0x11, -1, 0);
  *(uint32_t*)0x20000240 = 8;
  *(uint32_t*)0x20000244 = 9;
  *(uint32_t*)0x20000248 = 0x40;
  memcpy((void*)0x2000024c, "queue1\000\000\000\000\000\000\000\000\000\000\000"
                            "\000\000\000\000\000\000\000\000\000\000\000\000"
                            "\000\000\000\000\000\000\000\000\000\000\000\000"
                            "\000\000\000\000\000\000\000\000\000\000\000\000"
                            "\000\000\000\000\000\000\000\000\000\000\000",
         64);
  *(uint32_t*)0x2000028c = 0xfff;
  *(uint8_t*)0x20000290 = 0;
  *(uint8_t*)0x20000291 = 0;
  *(uint8_t*)0x20000292 = 0;
  *(uint8_t*)0x20000293 = 0;
  *(uint8_t*)0x20000294 = 0;
  *(uint8_t*)0x20000295 = 0;
  *(uint8_t*)0x20000296 = 0;
  *(uint8_t*)0x20000297 = 0;
  *(uint8_t*)0x20000298 = 0;
  *(uint8_t*)0x20000299 = 0;
  *(uint8_t*)0x2000029a = 0;
  *(uint8_t*)0x2000029b = 0;
  *(uint8_t*)0x2000029c = 0;
  *(uint8_t*)0x2000029d = 0;
  *(uint8_t*)0x2000029e = 0;
  *(uint8_t*)0x2000029f = 0;
  *(uint8_t*)0x200002a0 = 0;
  *(uint8_t*)0x200002a1 = 0;
  *(uint8_t*)0x200002a2 = 0;
  *(uint8_t*)0x200002a3 = 0;
  *(uint8_t*)0x200002a4 = 0;
  *(uint8_t*)0x200002a5 = 0;
  *(uint8_t*)0x200002a6 = 0;
  *(uint8_t*)0x200002a7 = 0;
  *(uint8_t*)0x200002a8 = 0;
  *(uint8_t*)0x200002a9 = 0;
  *(uint8_t*)0x200002aa = 0;
  *(uint8_t*)0x200002ab = 0;
  *(uint8_t*)0x200002ac = 0;
  *(uint8_t*)0x200002ad = 0;
  *(uint8_t*)0x200002ae = 0;
  *(uint8_t*)0x200002af = 0;
  *(uint8_t*)0x200002b0 = 0;
  *(uint8_t*)0x200002b1 = 0;
  *(uint8_t*)0x200002b2 = 0;
  *(uint8_t*)0x200002b3 = 0;
  *(uint8_t*)0x200002b4 = 0;
  *(uint8_t*)0x200002b5 = 0;
  *(uint8_t*)0x200002b6 = 0;
  *(uint8_t*)0x200002b7 = 0;
  *(uint8_t*)0x200002b8 = 0;
  *(uint8_t*)0x200002b9 = 0;
  *(uint8_t*)0x200002ba = 0;
  *(uint8_t*)0x200002bb = 0;
  *(uint8_t*)0x200002bc = 0;
  *(uint8_t*)0x200002bd = 0;
  *(uint8_t*)0x200002be = 0;
  *(uint8_t*)0x200002bf = 0;
  *(uint8_t*)0x200002c0 = 0;
  *(uint8_t*)0x200002c1 = 0;
  *(uint8_t*)0x200002c2 = 0;
  *(uint8_t*)0x200002c3 = 0;
  *(uint8_t*)0x200002c4 = 0;
  *(uint8_t*)0x200002c5 = 0;
  *(uint8_t*)0x200002c6 = 0;
  *(uint8_t*)0x200002c7 = 0;
  *(uint8_t*)0x200002c8 = 0;
  *(uint8_t*)0x200002c9 = 0;
  *(uint8_t*)0x200002ca = 0;
  *(uint8_t*)0x200002cb = 0;
  syscall(__NR_ioctl, -1, 0xc08c5336, 0x20000240);
  *(uint16_t*)0x20000100 = 0xa;
  *(uint16_t*)0x20000102 = htobe16(0);
  *(uint32_t*)0x20000104 = htobe32(0);
  *(uint8_t*)0x20000108 = 0xfe;
  *(uint8_t*)0x20000109 = 0x80;
  *(uint8_t*)0x2000010a = 0;
  *(uint8_t*)0x2000010b = 0;
  *(uint8_t*)0x2000010c = 0;
  *(uint8_t*)0x2000010d = 0;
  *(uint8_t*)0x2000010e = 0;
  *(uint8_t*)0x2000010f = 0;
  *(uint8_t*)0x20000110 = 0;
  *(uint8_t*)0x20000111 = 0;
  *(uint8_t*)0x20000112 = 0;
  *(uint8_t*)0x20000113 = 0;
  *(uint8_t*)0x20000114 = 0;
  *(uint8_t*)0x20000115 = 0;
  *(uint8_t*)0x20000116 = 0;
  *(uint8_t*)0x20000117 = 0;
  *(uint32_t*)0x20000118 = 0;
  syscall(__NR_connect, -1, 0x20000100, 0x1c);
  memcpy((void*)0x20000040, "./file0\000", 8);
  syscall(__NR_mkdir, 0x20000040, 0);
  memcpy((void*)0x20000000, "./file0\000", 8);
  syscall(__NR_mount, 0, 0x20000000, 0, 0, 0);
  memcpy((void*)0x200000c0, "./file0/file0\000", 14);
  syscall(__NR_mkdir, 0x200000c0, 0);
  memcpy((void*)0x200004c0, "./file0/file0\000", 14);
  syscall(__NR_mount, 0x20000000, 0x200004c0, 0, 0x588e, 0);
  memcpy((void*)0x200005c0, "./file0/file0\000", 14);
  syscall(__NR_mount, 0, 0x200005c0, 0, 0x1910824, 0);
}
int main(void)
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (procid = 0; procid < 6; procid++) {
    if (fork() == 0) {
      use_temporary_dir();
      loop();
    }
  }
  sleep(1000000);
  return 0;
}