syzkaller-repros/linux/3c0c173ff55822aacb81ce7ae27a6676fba29a5c.c

// INFO: task hung in iterate_supers
// https://syzkaller.appspot.com/bug?id=3c0c173ff55822aacb81ce7ae27a6676fba29a5c
// status:open
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE
#include <endian.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>

static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)
{
  if (a0 == 0xc || a0 == 0xb) {
    char buf[128];
    sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1,
            (uint8_t)a2);
    return open(buf, O_RDWR, 0);
  } else {
    char buf[1024];
    char* hash;
    strncpy(buf, (char*)a0, sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = 0;
    while ((hash = strchr(buf, '#'))) {
      *hash = '0' + (char)(a1 % 10);
      a1 /= 10;
    }
    return open(buf, a2, 0);
  }
}

static void execute_one();
extern unsigned long long procid;

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

struct thread_t {
  int created, running, call;
  pthread_t th;
};

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 (;;) {
    while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
      syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
    execute_call(th->call);
    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
    __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
    syscall(SYS_futex, &th->running, FUTEX_WAKE);
  }
  return 0;
}

static void execute(int num_calls)
{
  int call, thread;
  running = 0;
  for (call = 0; call < num_calls; call++) {
    for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
      struct thread_t* th = &threads[thread];
      if (!th->created) {
        th->created = 1;
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 128 << 10);
        pthread_create(&th->th, &attr, thr, th);
      }
      if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
        th->call = call;
        __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
        __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
        syscall(SYS_futex, &th->running, FUTEX_WAKE);
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (__atomic_load_n(&running, __ATOMIC_RELAXED))
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

#ifndef __NR_memfd_create
#define __NR_memfd_create 319
#endif

uint64_t r[4] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
                 0xffffffffffffffff};
unsigned long long procid;
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    syscall(__NR_socket, 0xa, 0x1000000000002, 0);
    break;
  case 1:
    memcpy((void*)0x20000200, "/dev/loop#", 11);
    res = syz_open_dev(0x20000200, 0, 0x1000082);
    if (res != -1)
      r[0] = res;
    break;
  case 2:
    memcpy((void*)0x20000140,
           "\x74\x08\x6e\x75\x00\x00\x00\x00\x00\x00\x00\x00\x00\x8c\x00", 15);
    res = syscall(__NR_memfd_create, 0x20000140, 2);
    if (res != -1)
      r[1] = res;
    break;
  case 3:
    syscall(__NR_ioctl, r[0], 0x4c00, r[1]);
    break;
  case 4:
    syscall(__NR_sync);
    break;
  case 5:
    *(uint64_t*)0x20000180 = 0x20000040;
    *(uint64_t*)0x20000188 = 0;
    syscall(__NR_pwritev, r[0], 0x20000180, 1, 0);
    break;
  case 6:
    res = syscall(__NR_pipe2, 0x20000500, 0);
    if (res != -1) {
      r[2] = *(uint32_t*)0x20000500;
      r[3] = *(uint32_t*)0x20000504;
    }
    break;
  case 7:
    memcpy((void*)0x20000140, "./file0", 8);
    syscall(__NR_mkdir, 0x20000140, 0);
    break;
  case 8:
    memcpy((void*)0x200000c0, "./file0", 8);
    memcpy((void*)0x20000340, "9p", 3);
    memcpy((void*)0x200003c0, "trans=fd,", 9);
    memcpy((void*)0x200003c9, "rfdno", 5);
    *(uint8_t*)0x200003ce = 0x3d;
    sprintf((char*)0x200003cf, "0x%016llx", (long long)r[2]);
    *(uint8_t*)0x200003e1 = 0x2c;
    memcpy((void*)0x200003e2, "wfdno", 5);
    *(uint8_t*)0x200003e7 = 0x3d;
    sprintf((char*)0x200003e8, "0x%016llx", (long long)r[3]);
    *(uint8_t*)0x200003fa = 0x2c;
    memcpy((void*)0x200003fb, "version=9p2000.u", 16);
    *(uint8_t*)0x2000040b = 0x2c;
    *(uint8_t*)0x2000040c = 0;
    syscall(__NR_mount, 0, 0x200000c0, 0x20000340, 0, 0x200003c0);
    break;
  case 9:
    memcpy((void*)0x20000180,
           "\x79\x04\x00\x00\x7d\x01\x00\x05\x00\x58\x00\x00\x00\x00\x00\x00"
           "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
           "\x00\x00\x00\x00\x00\x00\x00\x00\x23\x00\x00\x00\x00\x39\x00\x00"
           "\x00\x00\x00\x10\x00\x76\x65\x72\x73\x69\x6f\x6e\x3d\x39\x70\x32"
           "\x30\x30\x30\x2e\x75\x0d\x00\x77\x6c\x61\x6e\x31\x76\x62\x6f\x78"
           "\x6e\x65\x74\x30\x03\x00\x39\x70\x00\x05\x00\x72\x66\x64\x6e\x6f"
           "\x0c\x00\x76\x9a\xae\x6d\x5f\xff\xf0\x68\xa6\xbe\x6b\x2c\xc3\xfd"
           "\x62\x6f\x78\x6e\x65\x74\x31\x28\x7d\x25\x24",
           123);
    *(uint32_t*)0x200001fb = 0;
    *(uint32_t*)0x200001ff = 0;
    *(uint32_t*)0x20000203 = 0;
    syscall(__NR_write, r[3], 0x20000180, 0x87);
    break;
  }
}

void execute_one()
{
  execute(10);
}

int main()
{
  syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
  for (procid = 0; procid < 8; procid++) {
    if (fork() == 0) {
      for (;;) {
        loop();
      }
    }
  }
  sleep(1000000);
  return 0;
}