test/tsan/race_on_mutex.c

   1 // RUN: %clang_tsan -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <stddef.h>
   5 #include <unistd.h>
   6
   7 pthread_mutex_t Mtx;
   8 int Global;
   9
  10 void *Thread1(void *x) {
  11   pthread_mutex_init(&Mtx, 0);
  12   pthread_mutex_lock(&Mtx);
  13   Global = 42;
  14   pthread_mutex_unlock(&Mtx);
  15   return NULL;
  16 }
  17
  18 void *Thread2(void *x) {
  19   sleep(1);
  20   pthread_mutex_lock(&Mtx);
  21   Global = 43;
  22   pthread_mutex_unlock(&Mtx);
  23   return NULL;
  24 }
  25
  26 int main() {
  27   pthread_t t[2];
  28   pthread_create(&t[0], NULL, Thread1, NULL);
  29   pthread_create(&t[1], NULL, Thread2, NULL);
  30   pthread_join(t[0], NULL);
  31   pthread_join(t[1], NULL);
  32   pthread_mutex_destroy(&Mtx);
  33   return 0;
  34 }
  35
  36 // CHECK:      WARNING: ThreadSanitizer: data race
  37 // CHECK-NEXT:   Atomic read of size 1 at {{.*}} by thread T2:
  38 // CHECK-NEXT:     #0 pthread_mutex_lock
  39 // CHECK-NEXT:     #1 Thread2{{.*}} {{.*}}race_on_mutex.c:20{{(:3)?}} ({{.*}})
  40 // CHECK:        Previous write of size 1 at {{.*}} by thread T1:
  41 // CHECK-NEXT:     #0 pthread_mutex_init {{.*}} ({{.*}})
  42 // CHECK-NEXT:     #1 Thread1{{.*}} {{.*}}race_on_mutex.c:11{{(:3)?}} ({{.*}})