xref: /llvm-project/compiler-rt/test/tsan/write_in_reader_lock.cpp (revision bcaeed49cb063de9fe504aa29e1cadff8a7be710)
1*bcaeed49SFangrui Song // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
2*bcaeed49SFangrui Song #include "test.h"
3*bcaeed49SFangrui Song 
4*bcaeed49SFangrui Song pthread_rwlock_t rwlock;
5*bcaeed49SFangrui Song int GLOB;
6*bcaeed49SFangrui Song 
Thread1(void * p)7*bcaeed49SFangrui Song void *Thread1(void *p) {
8*bcaeed49SFangrui Song   (void)p;
9*bcaeed49SFangrui Song   pthread_rwlock_rdlock(&rwlock);
10*bcaeed49SFangrui Song   barrier_wait(&barrier);
11*bcaeed49SFangrui Song   // Write under reader lock.
12*bcaeed49SFangrui Song   GLOB++;
13*bcaeed49SFangrui Song   pthread_rwlock_unlock(&rwlock);
14*bcaeed49SFangrui Song   return 0;
15*bcaeed49SFangrui Song }
16*bcaeed49SFangrui Song 
main(int argc,char * argv[])17*bcaeed49SFangrui Song int main(int argc, char *argv[]) {
18*bcaeed49SFangrui Song   barrier_init(&barrier, 2);
19*bcaeed49SFangrui Song   pthread_rwlock_init(&rwlock, NULL);
20*bcaeed49SFangrui Song   pthread_rwlock_rdlock(&rwlock);
21*bcaeed49SFangrui Song   pthread_t t;
22*bcaeed49SFangrui Song   pthread_create(&t, 0, Thread1, 0);
23*bcaeed49SFangrui Song   volatile int x = GLOB;
24*bcaeed49SFangrui Song   (void)x;
25*bcaeed49SFangrui Song   pthread_rwlock_unlock(&rwlock);
26*bcaeed49SFangrui Song   barrier_wait(&barrier);
27*bcaeed49SFangrui Song   pthread_join(t, 0);
28*bcaeed49SFangrui Song   pthread_rwlock_destroy(&rwlock);
29*bcaeed49SFangrui Song   return 0;
30*bcaeed49SFangrui Song }
31*bcaeed49SFangrui Song 
32*bcaeed49SFangrui Song // CHECK: WARNING: ThreadSanitizer: data race
33*bcaeed49SFangrui Song // CHECK:   Write of size 4 at {{.*}} by thread T1{{.*}}:
34*bcaeed49SFangrui Song // CHECK:     #0 Thread1(void*) {{.*}}write_in_reader_lock.cpp:12
35*bcaeed49SFangrui Song // CHECK:   Previous read of size 4 at {{.*}} by main thread{{.*}}:
36*bcaeed49SFangrui Song // CHECK:     #0 main {{.*}}write_in_reader_lock.cpp:23
37