1// Test that the deadlock detector can find a deadlock that actually happened.
2// Currently we will fail to report such a deadlock because we check for
3// cycles in lock-order graph after pthread_mutex_lock.
4
5// RUN: %clangxx_tsan %s -o %t
6// RUN: not %run %t 2>&1 | FileCheck %s
7// XFAIL: *
8#include <pthread.h>
9#include <stdio.h>
10#include <unistd.h>
11
12pthread_mutex_t mu1, mu2;
13pthread_barrier_t barrier;
14
15void *Thread(void *p) {
16  // mu2 => mu1
17  pthread_mutex_lock(&mu2);
18  pthread_barrier_wait(&barrier);
19  pthread_mutex_lock(&mu1);
20  // CHECK: ThreadSanitizer: lock-order-inversion (potential deadlock)
21  pthread_mutex_unlock(&mu1);
22  pthread_mutex_unlock(&mu2);
23  return p;
24}
25
26int main() {
27  pthread_mutex_init(&mu1, NULL);
28  pthread_mutex_init(&mu2, NULL);
29  pthread_barrier_init(&barrier, 0, 2);
30
31  fprintf(stderr, "This test is going to deadlock and die in 3 seconds\n");
32  alarm(3);
33
34  pthread_t t;
35  pthread_create(&t, 0, Thread, 0);
36
37  // mu1 => mu2
38  pthread_mutex_lock(&mu1);
39  pthread_barrier_wait(&barrier);
40  pthread_mutex_lock(&mu2);
41  pthread_mutex_unlock(&mu2);
42  pthread_mutex_unlock(&mu1);
43
44  pthread_join(t, 0);
45
46  pthread_mutex_destroy(&mu1);
47  pthread_mutex_destroy(&mu2);
48  pthread_barrier_destroy(&barrier);
49  fprintf(stderr, "FAILED\n");
50}
51