1 files changed, 9 insertions, 8 deletions
diff --git a/test/tsan/aligned_vs_unaligned_race.cc b/test/tsan/aligned_vs_unaligned_race.cc
index f82542ed2b85..5c1189f34a4b 100644
--- a/test/tsan/aligned_vs_unaligned_race.cc
+++ b/test/tsan/aligned_vs_unaligned_race.cc
@@ -1,34 +1,35 @@
-// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
 // Race between an aligned access and an unaligned access, which
 // touches the same memory region.
-// This is a real race which is not detected by tsan.
-// https://code.google.com/p/thread-sanitizer/issues/detail?id=17
-#include <pthread.h>
-#include <stdio.h>
+#include "test.h"
 #include <stdint.h>
 
 uint64_t Global[2];
 
 void *Thread1(void *x) {
   Global[1]++;
+  barrier_wait(&barrier);
   return NULL;
 }
 
 void *Thread2(void *x) {
+  barrier_wait(&barrier);
   char *p1 = reinterpret_cast<char *>(&Global[0]);
-  uint64_t *p4 = reinterpret_cast<uint64_t *>(p1 + 1);
-  (*p4)++;
+  struct __attribute__((packed, aligned(1))) u_uint64_t { uint64_t val; };
+  u_uint64_t *p4 = reinterpret_cast<u_uint64_t *>(p1 + 1);
+  (*p4).val++;
   return NULL;
 }
 
 int main() {
+  barrier_init(&barrier, 2);
   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);
   printf("Pass\n");
-  // CHECK-NOT: ThreadSanitizer: data race
+  // CHECK: ThreadSanitizer: data race
   // CHECK: Pass
   return 0;
 }