1 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
2 #include "test.h"
3 
4 pthread_rwlock_t rwlock;
5 int GLOB;
6 
Thread1(void * p)7 void *Thread1(void *p) {
8   (void)p;
9   pthread_rwlock_rdlock(&rwlock);
10   barrier_wait(&barrier);
11   // Write under reader lock.
12   GLOB++;
13   pthread_rwlock_unlock(&rwlock);
14   return 0;
15 }
16 
main(int argc,char * argv[])17 int main(int argc, char *argv[]) {
18   barrier_init(&barrier, 2);
19   pthread_rwlock_init(&rwlock, NULL);
20   pthread_rwlock_rdlock(&rwlock);
21   pthread_t t;
22   pthread_create(&t, 0, Thread1, 0);
23   volatile int x = GLOB;
24   (void)x;
25   pthread_rwlock_unlock(&rwlock);
26   barrier_wait(&barrier);
27   pthread_join(t, 0);
28   pthread_rwlock_destroy(&rwlock);
29   return 0;
30 }
31 
32 // CHECK: WARNING: ThreadSanitizer: data race
33 // CHECK:   Write of size 4 at {{.*}} by thread T1{{.*}}:
34 // CHECK:     #0 Thread1(void*) {{.*}}write_in_reader_lock.cc:12
35 // CHECK:   Previous read of size 4 at {{.*}} by main thread{{.*}}:
36 // CHECK:     #0 main {{.*}}write_in_reader_lock.cc:23
37