syzkaller-repros/linux/88055a9984a626492205684d3d094d8d39d93979.c

// general protection fault in kfree (2)
// https://syzkaller.appspot.com/bug?id=88055a9984a626492205684d3d094d8d39d93979
// status:invalid
// autogenerated by syzkaller (http://github.com/google/syzkaller)

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

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;
      }
    }
  }
}

uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};
unsigned long long procid;
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    memcpy((void*)0x20000b80, "./file1", 8);
    syscall(__NR_mkdir, 0x20000b80, 0);
    break;
  case 1:
    res = syscall(__NR_pipe2, 0x20000240, 0);
    if (res != -1) {
      r[0] = *(uint32_t*)0x20000240;
      r[1] = *(uint32_t*)0x20000244;
    }
    break;
  case 2:
    memcpy((void*)0x20000140, "./file1", 8);
    memcpy((void*)0x20000180, "9p", 3);
    memcpy((void*)0x20000300, "trans=fd,", 9);
    memcpy((void*)0x20000309, "rfdno", 5);
    *(uint8_t*)0x2000030e = 0x3d;
    sprintf((char*)0x2000030f, "0x%016llx", (long long)r[0]);
    *(uint8_t*)0x20000321 = 0x2c;
    memcpy((void*)0x20000322, "wfdno", 5);
    *(uint8_t*)0x20000327 = 0x3d;
    sprintf((char*)0x20000328, "0x%016llx", (long long)r[1]);
    *(uint8_t*)0x2000033a = 0x2c;
    memcpy((void*)0x2000033b, "cache=loose", 11);
    *(uint8_t*)0x20000346 = 0x2c;
    memcpy((void*)0x20000347, "uname", 5);
    *(uint8_t*)0x2000034c = 0x3d;
    memcpy((void*)0x2000034d, "9P2000.u", 8);
    *(uint8_t*)0x20000355 = 0x2c;
    memcpy((void*)0x20000356, "posixacl", 8);
    *(uint8_t*)0x2000035e = 0x2c;
    memcpy((void*)0x2000035f, "uname", 5);
    *(uint8_t*)0x20000364 = 0x3d;
    memcpy((void*)0x20000365, "+", 1);
    *(uint8_t*)0x20000366 = 0x2c;
    memcpy((void*)0x20000367, "fscache", 7);
    *(uint8_t*)0x2000036e = 0x2c;
    memcpy((void*)0x2000036f, "mmap", 4);
    *(uint8_t*)0x20000373 = 0x2c;
    memcpy((void*)0x20000374, "access=client", 13);
    *(uint8_t*)0x20000381 = 0x2c;
    *(uint8_t*)0x20000382 = 0;
    syscall(__NR_mount, 0, 0x20000140, 0x20000180, 0, 0x20000300);
    break;
  case 3:
    *(uint32_t*)0x20000480 = 7;
    *(uint8_t*)0x20000484 = 0x65;
    *(uint16_t*)0x20000485 = -1;
    *(uint32_t*)0x20000487 = 0x295d;
    *(uint16_t*)0x2000048b = 0xfe5b;
    memcpy((void*)0x2000048d, "9P2000", 6);
    syscall(__NR_write, r[1], 0x20000480, 0x15);
    break;
  }
}

void execute_one()
{
  execute(4);
}

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;
}