llvm-project/compiler-rt/test/tsan/mutexset1.cc

// RUN: %clangxx_tsan -O1 %s -o %t && not %t 2>&1 | FileCheck %s
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>

int Global;
pthread_mutex_t mtx;

void *Thread1(void *x) {
  sleep(1);
  pthread_mutex_lock(&mtx);
  Global++;
  pthread_mutex_unlock(&mtx);
  return NULL;
}

void *Thread2(void *x) {
  Global--;
  return NULL;
}

int main() {
  // CHECK: WARNING: ThreadSanitizer: data race
  // CHECK:   Write of size 4 at {{.*}} by thread T1
  // CHECK:                         (mutexes: write [[M1:M[0-9]+]]):
  // CHECK:   Previous write of size 4 at {{.*}} by thread T2:
  // CHECK:   Mutex [[M1]] (0x{{.*}}) created at:
  // CHECK:     #0 pthread_mutex_init
  // CHECK:     #1 main {{.*}}/mutexset1.cc:[[@LINE+1]]
  pthread_mutex_init(&mtx, 0);
  pthread_t t[2];
  pthread_create(&t[0], NULL, Thread1, NULL);
  pthread_create(&t[1], NULL, Thread2, NULL);
  pthread_join(t[0], NULL);
  pthread_join(t[1], NULL);
  pthread_mutex_destroy(&mtx);
}