syzkaller-repros/linux/b64beb52ad2e7733f606ab098fff1c717fd6a923.c

// DATA RACE in semaphore.(*Set).checkPerms
// https://syzkaller.appspot.com/bug?id=b64beb52ad2e7733f606ab098fff1c717fd6a923
// status:fixed
// 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 <stdlib.h>
#include <string.h>
#include <sys/syscall.h>
#include <unistd.h>

#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)

#define BITMASK_LEN_OFF(type, bf_off, bf_len)                                  \
  (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))

#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)                      \
  if ((bf_off) == 0 && (bf_len) == 0) {                                        \
    *(type*)(addr) = (type)(val);                                              \
  } else {                                                                     \
    type new_val = *(type*)(addr);                                             \
    new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));                     \
    new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off);          \
    *(type*)(addr) = new_val;                                                  \
  }

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 int collide;

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);
        if (collide && call % 2)
          break;
        struct timespec ts;
        ts.tv_sec = 0;
        ts.tv_nsec = 20 * 1000 * 1000;
        syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
        if (running)
          usleep((call == num_calls - 1) ? 10000 : 1000);
        break;
      }
    }
  }
}

uint64_t r[10] = {
    0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xffffffffffffffff,
    0xffffffffffffffff, 0x0};
void execute_call(int call)
{
  long res;
  switch (call) {
  case 0:
    memcpy((void*)0x20000000, "cpuset.effective_mems", 22);
    res = syscall(__NR_openat, 0xffffff9c, 0x20000000, 0, 0);
    if (res != -1)
      r[0] = res;
    break;
  case 1:
    *(uint32_t*)0x20000080 = 4;
    syscall(__NR_getsockopt, r[0], 0x29, 0x13, 0x20000040, 0x20000080);
    break;
  case 2:
    res = syscall(__NR_getpgid, -1);
    if (res != -1)
      r[1] = res;
    break;
  case 3:
    syscall(__NR_sched_getaffinity, r[1], 8, 0x200000c0);
    break;
  case 4:
    syscall(__NR_waitid, 2, r[1], 0x20000100, 0x1000002, 0x20000140);
    break;
  case 5:
    *(uint32_t*)0x20000400 = 0xe8;
    syscall(__NR_getsockopt, r[0], 0x29, 0x22, 0x20000300, 0x20000400);
    break;
  case 6:
    res = syscall(__NR_getresgid, 0x20000440, 0x20000480, 0x200004c0);
    if (res != -1)
      r[2] = *(uint32_t*)0x20000440;
    break;
  case 7:
    memcpy((void*)0x20000500, "./file0", 8);
    res = syscall(__NR_lstat, 0x20000500, 0x20000540);
    if (res != -1) {
      r[3] = *(uint32_t*)0x2000054c;
      r[4] = *(uint32_t*)0x20000550;
    }
    break;
  case 8:
    syscall(__NR_getresgid, 0x200005c0, 0x20000600, 0x20000640);
    break;
  case 9:
    memcpy((void*)0x20000680, "./file0", 8);
    syscall(__NR_lstat, 0x20000680, 0x200006c0);
    break;
  case 10:
    syscall(__NR_getresgid, 0x20000740, 0x20000780, 0x200007c0);
    break;
  case 11:
    memcpy((void*)0x20000800, "./file0", 8);
    syscall(__NR_stat, 0x20000800, 0x20000840);
    break;
  case 12:
    syscall(__NR_getegid);
    break;
  case 13:
    *(uint32_t*)0x20000900 = 0xc;
    res = syscall(__NR_getsockopt, r[0], 1, 0x11, 0x200008c0, 0x20000900);
    if (res != -1)
      r[5] = *(uint32_t*)0x200008c0;
    break;
  case 14:
    *(uint32_t*)0x20000980 = 0xc;
    res = syscall(__NR_getsockopt, r[0], 1, 0x11, 0x20000940, 0x20000980);
    if (res != -1)
      r[6] = *(uint32_t*)0x20000944;
    break;
  case 15:
    *(uint32_t*)0x20000b40 = 0;
    *(uint32_t*)0x20000b44 = 0x20000800;
    *(uint32_t*)0x20000b48 = 0x400;
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 0x2d, 0, 1);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 1, 1, 2);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 9, 3, 1);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 0x8001, 4, 1);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 0xe26c, 5, 1);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 7, 6, 1);
    STORE_BY_BITMASK(uint32_t, 0x20000b4c, 0x9c7, 7, 1);
    syscall(__NR_modify_ldt, 0x11, 0x20000b40, 0x10);
    break;
  case 16:
    syscall(__NR_ioctl, r[0], 0x5441, 9);
    break;
  case 17:
    syscall(__NR_clock_getres, 3, 0x20000b80);
    break;
  case 18:
    res = syscall(__NR_socketpair, 0xa, 1, 0, 0x20000bc0);
    if (res != -1) {
      r[7] = *(uint32_t*)0x20000bc0;
      r[8] = *(uint32_t*)0x20000bc4;
    }
    break;
  case 19:
    syscall(__NR_fcntl, r[8], 0x10, 0x20000c00);
    break;
  case 20:
    *(uint32_t*)0x20000c40 = r[5];
    syscall(__NR_ioctl, r[7], 0x8901, 0x20000c40);
    break;
  case 21:
    res = syscall(__NR_semget, 0x798e2633, 6, 0x240);
    if (res != -1)
      r[9] = res;
    break;
  case 22:
    *(uint32_t*)0x20000c80 = 0x101;
    *(uint32_t*)0x20000c84 = r[6];
    *(uint32_t*)0x20000c88 = r[4];
    *(uint32_t*)0x20000c8c = r[3];
    *(uint32_t*)0x20000c90 = r[2];
    *(uint32_t*)0x20000c94 = 0x40;
    *(uint16_t*)0x20000c98 = 7;
    *(uint16_t*)0x20000c9a = 0;
    *(uint64_t*)0x20000ca0 = 0;
    *(uint64_t*)0x20000ca8 = 0;
    *(uint64_t*)0x20000cb0 = 8;
    *(uint64_t*)0x20000cb8 = 3;
    *(uint64_t*)0x20000cc0 = 9;
    *(uint64_t*)0x20000cc8 = 0;
    *(uint64_t*)0x20000cd0 = 0;
    syscall(__NR_semctl, r[9], 0, 1, 0x20000c80);
    break;
  }
}

void execute_one()
{
  execute(23);
  collide = 1;
  execute(23);
}

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