// https://syzkaller.appspot.com/bug?id=126ab667f003eed2434b03214c5fda3edafc0edb // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } uint64_t current_time_ms() { 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 thread_start(void* (*fn)(void*), void* arg) { pthread_t th; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); if (pthread_create(&th, &attr, fn, arg)) exit(1); pthread_attr_destroy(&attr); } typedef struct { pthread_mutex_t mu; pthread_cond_t cv; int state; } event_t; static void event_init(event_t* ev) { if (pthread_mutex_init(&ev->mu, 0)) exit(1); if (pthread_cond_init(&ev->cv, 0)) exit(1); ev->state = 0; } static void event_reset(event_t* ev) { ev->state = 0; } static void event_set(event_t* ev) { pthread_mutex_lock(&ev->mu); if (ev->state) exit(1); ev->state = 1; pthread_mutex_unlock(&ev->mu); pthread_cond_broadcast(&ev->cv); } static void event_wait(event_t* ev) { pthread_mutex_lock(&ev->mu); while (!ev->state) pthread_cond_wait(&ev->cv, &ev->mu); pthread_mutex_unlock(&ev->mu); } static int event_isset(event_t* ev) { pthread_mutex_lock(&ev->mu); int res = ev->state; pthread_mutex_unlock(&ev->mu); return res; } static int event_timedwait(event_t* ev, uint64_t timeout) { uint64_t start = current_time_ms(); uint64_t now = start; pthread_mutex_lock(&ev->mu); for (;;) { if (ev->state) break; uint64_t remain = timeout - (now - start); struct timespec ts; ts.tv_sec = remain / 1000; ts.tv_nsec = (remain % 1000) * 1000 * 1000; pthread_cond_timedwait(&ev->cv, &ev->mu, &ts); now = current_time_ms(); if (now - start > timeout) break; } int res = ev->state; pthread_mutex_unlock(&ev->mu); return res; } struct thread_t { int created, call; event_t ready, done; }; 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 (;;) { event_wait(&th->ready); event_reset(&th->ready); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); event_set(&th->done); } return 0; } static void loop() { int call, thread; int collide = 0; again: for (call = 0; call < 2; call++) { for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; event_init(&th->ready); event_init(&th->done); event_set(&th->done); thread_start(thr, th); } if (!event_isset(&th->done)) continue; event_reset(&th->done); th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); event_set(&th->ready); if (collide && (call % 2) == 0) break; event_timedwait(&th->done, 25); if (__atomic_load_n(&running, __ATOMIC_RELAXED)) sleep_ms((call == 2 - 1) ? 10 : 2); break; } } if (!collide) { collide = 1; goto again; } } void execute_call(int call) { switch (call) { case 0: memcpy((void*)0x20000100, "./file0", 8); memcpy((void*)0x20000140, "./file0/file0", 14); syscall(SYS_nunmount, 0x20000100, 8, 0x20000140, 0xe); break; case 1: memcpy((void*)0x20000780, "./file0", 8); memcpy((void*)0x200007c0, "./file0", 8); syscall(SYS_symlink, 0x20000780, 8, 0x200007c0, 8); break; } } int main() { syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); loop(); return 0; }