Make tsan tests more portable (take 2)

Using stderr more uniformily, avoiding potential races when scanning stdout
and stderr output.

Patch by Maxim Kuvyrkov.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@266294 91177308-0d34-0410-b5e6-96231b3b80d8

51 files changed, 63 insertions, 63 deletions

diff --git a/test/tsan/Linux/user_malloc.cc b/test/tsan/Linux/user_malloc.cc
index c671bfcdd..9c3ce681d 100644
--- a/test/tsan/Linux/user_malloc.cc
+++ b/test/tsan/Linux/user_malloc.cc
@@ -8,7 +8,7 @@ extern "C" void __interceptor_free(void *p);
 extern "C" void *malloc(unsigned long size) {
   static int first = 0;
   if (__sync_lock_test_and_set(&first, 1) == 0)
-    printf("user malloc\n");
+    fprintf(stderr, "user malloc\n");
   return __interceptor_malloc(size);
 }
 
diff --git a/test/tsan/aligned_vs_unaligned_race.cc b/test/tsan/aligned_vs_unaligned_race.cc
index 5c1189f34..61f73ba69 100644
--- a/test/tsan/aligned_vs_unaligned_race.cc
+++ b/test/tsan/aligned_vs_unaligned_race.cc
@@ -28,7 +28,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("Pass\n");
+  fprintf(stderr, "Pass\n");
   // CHECK: ThreadSanitizer: data race
   // CHECK: Pass
   return 0;
diff --git a/test/tsan/benign_race.cc b/test/tsan/benign_race.cc
index 2f72fe186..90722aa93 100644
--- a/test/tsan/benign_race.cc
+++ b/test/tsan/benign_race.cc
@@ -33,7 +33,7 @@ int main() {
   Global = 43;
   WTFGlobal = 143;
   pthread_join(t, 0);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/blacklist.cc b/test/tsan/blacklist.cc
index d6ca383cb..c1bcca60d 100644
--- a/test/tsan/blacklist.cc
+++ b/test/tsan/blacklist.cc
@@ -23,7 +23,7 @@ int main() {
   pthread_create(&t[1], NULL, Blacklisted_Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/blacklist2.cc b/test/tsan/blacklist2.cc
index 629b58821..bf6c4eb75 100644
--- a/test/tsan/blacklist2.cc
+++ b/test/tsan/blacklist2.cc
@@ -44,6 +44,6 @@ int main() {
   pthread_create(&t[1], NULL, Blacklisted_Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
diff --git a/test/tsan/dl_iterate_phdr.cc b/test/tsan/dl_iterate_phdr.cc
index b9ce615f8..3c9821bf4 100644
--- a/test/tsan/dl_iterate_phdr.cc
+++ b/test/tsan/dl_iterate_phdr.cc
@@ -47,7 +47,7 @@ int main(int argc, char *argv[]) {
     dlclose(lib);
   }
   pthread_join(th, 0);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return 0;
 }
 
diff --git a/test/tsan/fd_close_norace.cc b/test/tsan/fd_close_norace.cc
index 1b52c20f9..7d9d491f1 100644
--- a/test/tsan/fd_close_norace.cc
+++ b/test/tsan/fd_close_norace.cc
@@ -25,7 +25,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_close_norace2.cc b/test/tsan/fd_close_norace2.cc
index bf94fd551..382ae5f34 100644
--- a/test/tsan/fd_close_norace2.cc
+++ b/test/tsan/fd_close_norace2.cc
@@ -23,7 +23,7 @@ int main() {
   while (write(pipes[1], &t, 1) != 1) {
   }
   pthread_join(t, 0);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_dup_norace.cc b/test/tsan/fd_dup_norace.cc
index 5045325b2..e5995175b 100644
--- a/test/tsan/fd_dup_norace.cc
+++ b/test/tsan/fd_dup_norace.cc
@@ -28,7 +28,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_dup_norace2.cc b/test/tsan/fd_dup_norace2.cc
index 662c686f3..31aaed9d3 100644
--- a/test/tsan/fd_dup_norace2.cc
+++ b/test/tsan/fd_dup_norace2.cc
@@ -53,7 +53,7 @@ int main() {
     exit(printf("close failed\n"));
   if (close(fd2) == -1)
     exit(printf("close failed\n"));
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_dup_race.cc b/test/tsan/fd_dup_race.cc
index a1aee5500..d665eebff 100644
--- a/test/tsan/fd_dup_race.cc
+++ b/test/tsan/fd_dup_race.cc
@@ -27,7 +27,7 @@ int main() {
     exit(printf("dup2 failed\n"));
   barrier_wait(&barrier);
   pthread_join(th, 0);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
 }
 
 // CHECK: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_pipe_norace.cc b/test/tsan/fd_pipe_norace.cc
index b434703d7..01c4490c6 100644
--- a/test/tsan/fd_pipe_norace.cc
+++ b/test/tsan/fd_pipe_norace.cc
@@ -27,7 +27,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_socket_connect_norace.cc b/test/tsan/fd_socket_connect_norace.cc
index ab2a950f1..b9fb4340a 100644
--- a/test/tsan/fd_socket_connect_norace.cc
+++ b/test/tsan/fd_socket_connect_norace.cc
@@ -38,7 +38,7 @@ int main() {
   pthread_join(t, 0);
   close(c);
   close(s);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_socket_norace.cc b/test/tsan/fd_socket_norace.cc
index 0f41c4357..07b0cb356 100644
--- a/test/tsan/fd_socket_norace.cc
+++ b/test/tsan/fd_socket_norace.cc
@@ -45,7 +45,7 @@ int main() {
   close(c);
   close(s);
   pthread_join(t, 0);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/fd_socketpair_norace.cc b/test/tsan/fd_socketpair_norace.cc
index a455d44a3..bee030dd3 100644
--- a/test/tsan/fd_socketpair_norace.cc
+++ b/test/tsan/fd_socketpair_norace.cc
@@ -31,7 +31,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/ignore_race.cc b/test/tsan/ignore_race.cc
index cc33b66b2..e410006dd 100644
--- a/test/tsan/ignore_race.cc
+++ b/test/tsan/ignore_race.cc
@@ -25,7 +25,7 @@ int main() {
   barrier_wait(&barrier);
   Global = 43;
   pthread_join(t, 0);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/inlined_memcpy_race.cc b/test/tsan/inlined_memcpy_race.cc
index 720f2bfca..4d5de8852 100644
--- a/test/tsan/inlined_memcpy_race.cc
+++ b/test/tsan/inlined_memcpy_race.cc
@@ -24,7 +24,7 @@ int main() {
   pthread_create(&t[1], NULL, MemSetThread, x);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/inlined_memcpy_race2.cc b/test/tsan/inlined_memcpy_race2.cc
index 2c63dc665..bf33c3014 100644
--- a/test/tsan/inlined_memcpy_race2.cc
+++ b/test/tsan/inlined_memcpy_race2.cc
@@ -25,7 +25,7 @@ int main() {
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
 
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/interface_atomic_test.c b/test/tsan/interface_atomic_test.c
index 18d860ea0..99f6074df 100644
--- a/test/tsan/interface_atomic_test.c
+++ b/test/tsan/interface_atomic_test.c
@@ -9,7 +9,7 @@ int main() {
   int res = __tsan_atomic32_load(&a, __tsan_memory_order_acquire);
   if (res == 100) {
     // CHECK: PASS
-    printf("PASS\n");
+    fprintf(stderr, "PASS\n");
     return 0;
   }
   return 1;
diff --git a/test/tsan/java_alloc.cc b/test/tsan/java_alloc.cc
index 4a606f794..94919a437 100644
--- a/test/tsan/java_alloc.cc
+++ b/test/tsan/java_alloc.cc
@@ -26,10 +26,10 @@ int main() {
   stress(jheap);
   pthread_join(th, 0);
   if (__tsan_java_fini() != 0) {
-    printf("FAILED\n");
+    fprintf(stderr, "FAILED\n");
     return 1;
   }
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return 0;
 }
 
diff --git a/test/tsan/java_heap_init.cc b/test/tsan/java_heap_init.cc
index bb7357c25..47ec5dbad 100644
--- a/test/tsan/java_heap_init.cc
+++ b/test/tsan/java_heap_init.cc
@@ -20,7 +20,7 @@ int main() {
     return printf("second mmap failed with %d\n", errno);
   __tsan_java_init(jheap, kHeapSize);
   __tsan_java_move(jheap + 16, jheap, 16);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_lock_move.cc b/test/tsan/java_lock_move.cc
index fe5491dc2..66599f8b7 100644
--- a/test/tsan/java_lock_move.cc
+++ b/test/tsan/java_lock_move.cc
@@ -35,7 +35,7 @@ int main() {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr2, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_lock_rec.cc b/test/tsan/java_lock_rec.cc
index f0bf40196..aa8de97a1 100644
--- a/test/tsan/java_lock_rec.cc
+++ b/test/tsan/java_lock_rec.cc
@@ -10,14 +10,14 @@ void *Thread(void *p) {
   *(int*)varaddr = 42;
   int rec = __tsan_java_mutex_unlock_rec(lockaddr);
   if (rec != 2) {
-    printf("FAILED 0 rec=%d\n", rec);
+    fprintf(stderr, "FAILED 0 rec=%d\n", rec);
     exit(1);
   }
   barrier_wait(&barrier);
   barrier_wait(&barrier);
   __tsan_java_mutex_lock_rec(lockaddr, rec);
   if (*(int*)varaddr != 43) {
-    printf("FAILED 3 var=%d\n", *(int*)varaddr);
+    fprintf(stderr, "FAILED 3 var=%d\n", *(int*)varaddr);
     exit(1);
   }
   __tsan_java_mutex_unlock(lockaddr);
@@ -40,7 +40,7 @@ int main() {
   barrier_wait(&barrier);
   __tsan_java_mutex_lock(lockaddr);
   if (*(int*)varaddr != 42) {
-    printf("FAILED 1 var=%d\n", *(int*)varaddr);
+    fprintf(stderr, "FAILED 1 var=%d\n", *(int*)varaddr);
     exit(1);
   }
   *(int*)varaddr = 43;
@@ -48,7 +48,7 @@ int main() {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_lock_rec_race.cc b/test/tsan/java_lock_rec_race.cc
index 3da8ad076..b6c7ccb7e 100644
--- a/test/tsan/java_lock_rec_race.cc
+++ b/test/tsan/java_lock_rec_race.cc
@@ -10,7 +10,7 @@ void *Thread(void *p) {
   __tsan_java_mutex_lock(lockaddr);
   int rec = __tsan_java_mutex_unlock_rec(lockaddr);
   if (rec != 3) {
-    printf("FAILED 0 rec=%d\n", rec);
+    fprintf(stderr, "FAILED 0 rec=%d\n", rec);
     exit(1);
   }
   *(int*)varaddr = 42;
@@ -42,7 +42,7 @@ int main() {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_move_overlap.cc b/test/tsan/java_move_overlap.cc
index 7ed98ef1a..bf8d1e155 100644
--- a/test/tsan/java_move_overlap.cc
+++ b/test/tsan/java_move_overlap.cc
@@ -66,7 +66,7 @@ int main(int argc, char **argv) {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr1_new, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_move_overlap_race.cc b/test/tsan/java_move_overlap_race.cc
index 874b90b26..2887fd3fe 100644
--- a/test/tsan/java_move_overlap_race.cc
+++ b/test/tsan/java_move_overlap_race.cc
@@ -46,7 +46,7 @@ int main(int argc, char **argv) {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(varaddr1_new, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/java_rwlock.cc b/test/tsan/java_rwlock.cc
index a4cc92a13..aa77273a4 100644
--- a/test/tsan/java_rwlock.cc
+++ b/test/tsan/java_rwlock.cc
@@ -29,7 +29,7 @@ int main() {
   barrier_wait(&barrier);
   pthread_join(th, 0);
   __tsan_java_free(jheap, kBlockSize);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return __tsan_java_fini();
 }
 
diff --git a/test/tsan/longjmp.cc b/test/tsan/longjmp.cc
index d64206739..61d285c11 100644
--- a/test/tsan/longjmp.cc
+++ b/test/tsan/longjmp.cc
@@ -14,11 +14,11 @@ int foo(jmp_buf env) {
 int main() {
   jmp_buf env;
   if (setjmp(env) == 42) {
-    printf("JUMPED\n");
+    fprintf(stderr, "JUMPED\n");
     return 0;
   }
   foo(env);
-  printf("FAILED\n");
+  fprintf(stderr, "FAILED\n");
   return 0;
 }
 
diff --git a/test/tsan/longjmp2.cc b/test/tsan/longjmp2.cc
index eee423dc5..2b2775a8c 100644
--- a/test/tsan/longjmp2.cc
+++ b/test/tsan/longjmp2.cc
@@ -16,11 +16,11 @@ int main() {
   sigjmp_buf env;
   printf("env=%p\n", env);
   if (sigsetjmp(env, 1) == 42) {
-    printf("JUMPED\n");
+    fprintf(stderr, "JUMPED\n");
     return 0;
   }
   foo(env);
-  printf("FAILED\n");
+  fprintf(stderr, "FAILED\n");
   return 0;
 }
 
diff --git a/test/tsan/longjmp3.cc b/test/tsan/longjmp3.cc
index 79965c419..f4f9c2b31 100644
--- a/test/tsan/longjmp3.cc
+++ b/test/tsan/longjmp3.cc
@@ -34,7 +34,7 @@ void mymain() {
     return;
   }
   foo(env);
-  printf("FAILED\n");
+  fprintf(stderr, "FAILED\n");
 }
 
 int main() {
diff --git a/test/tsan/longjmp4.cc b/test/tsan/longjmp4.cc
index c85839973..2b15435a1 100644
--- a/test/tsan/longjmp4.cc
+++ b/test/tsan/longjmp4.cc
@@ -37,7 +37,7 @@ void mymain() {
     return;
   }
   foo(env);
-  printf("FAILED\n");
+  fprintf(stderr, "FAILED\n");
 }
 
 int main() {
diff --git a/test/tsan/malloc_overflow.cc b/test/tsan/malloc_overflow.cc
index b2f9b0f57..3db412978 100644
--- a/test/tsan/malloc_overflow.cc
+++ b/test/tsan/malloc_overflow.cc
@@ -6,17 +6,17 @@
 int main() {
   void *p = malloc((size_t)-1);
   if (p != 0)
-    printf("FAIL malloc(-1) = %p\n", p);
+    fprintf(stderr, "FAIL malloc(-1) = %p\n", p);
   p = malloc((size_t)-1 / 2);
   if (p != 0)
-    printf("FAIL malloc(-1/2) = %p\n", p);
+    fprintf(stderr, "FAIL malloc(-1/2) = %p\n", p);
   p = calloc((size_t)-1, (size_t)-1);
   if (p != 0)
-    printf("FAIL calloc(-1, -1) = %p\n", p);
+    fprintf(stderr, "FAIL calloc(-1, -1) = %p\n", p);
   p = calloc((size_t)-1 / 2, (size_t)-1 / 2);
   if (p != 0)
-    printf("FAIL calloc(-1/2, -1/2) = %p\n", p);
-  printf("OK\n");
+    fprintf(stderr, "FAIL calloc(-1/2, -1/2) = %p\n", p);
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: FAIL
diff --git a/test/tsan/race_on_speculative_load.cc b/test/tsan/race_on_speculative_load.cc
index dd40daeb5..89b162116 100644
--- a/test/tsan/race_on_speculative_load.cc
+++ b/test/tsan/race_on_speculative_load.cc
@@ -24,7 +24,7 @@ int main() {
   g = 1;
   barrier_wait(&barrier);
   pthread_join(t, 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   // CHECK-NOT: ThreadSanitizer: data race
   // CHECK: PASS
 }
diff --git a/test/tsan/static_init1.cc b/test/tsan/static_init1.cc
index 3e5fb14ba..3e6e4f9df 100644
--- a/test/tsan/static_init1.cc
+++ b/test/tsan/static_init1.cc
@@ -21,7 +21,7 @@ int main() {
   pthread_create(&t[1], 0, Thread, 0);
   pthread_join(t[0], 0);
   pthread_join(t[1], 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/static_init2.cc b/test/tsan/static_init2.cc
index 667aed134..ca2300ae6 100644
--- a/test/tsan/static_init2.cc
+++ b/test/tsan/static_init2.cc
@@ -27,7 +27,7 @@ int main() {
   pthread_create(&t[1], 0, Thread, 0);
   pthread_join(t[0], 0);
   pthread_join(t[1], 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/static_init4.cc b/test/tsan/static_init4.cc
index 85835a252..c8da78364 100644
--- a/test/tsan/static_init4.cc
+++ b/test/tsan/static_init4.cc
@@ -31,7 +31,7 @@ int main() {
   pthread_create(&t[1], 0, Thread1, 0);
   pthread_join(t[0], 0);
   pthread_join(t[1], 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/static_init5.cc b/test/tsan/static_init5.cc
index 961e3a3b6..b334981e8 100644
--- a/test/tsan/static_init5.cc
+++ b/test/tsan/static_init5.cc
@@ -36,7 +36,7 @@ int main() {
   pthread_create(&t[1], 0, Thread1, 0);
   pthread_join(t[0], 0);
   pthread_join(t[1], 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/static_init6.cc b/test/tsan/static_init6.cc
index 0bfefe345..fd22e0a02 100644
--- a/test/tsan/static_init6.cc
+++ b/test/tsan/static_init6.cc
@@ -36,7 +36,7 @@ int main() {
   pthread_create(&t[1], 0, Thread1, 0);
   pthread_join(t[0], 0);
   pthread_join(t[1], 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/sunrpc.cc b/test/tsan/sunrpc.cc
index 579816d64..5cfb5344e 100644
--- a/test/tsan/sunrpc.cc
+++ b/test/tsan/sunrpc.cc
@@ -19,7 +19,7 @@ int main(int argc, char *argv[]) {
   pthread_create(&th[1], 0, thr, 0);
   pthread_join(th[0], 0);
   pthread_join(th[1], 0);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   // CHECK: DONE
   return 0;
 }
diff --git a/test/tsan/suppressions_global.cc b/test/tsan/suppressions_global.cc
index 8928162cf..282d261c1 100644
--- a/test/tsan/suppressions_global.cc
+++ b/test/tsan/suppressions_global.cc
@@ -20,7 +20,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
   return 0;
 }
 
diff --git a/test/tsan/suppressions_race.cc b/test/tsan/suppressions_race.cc
index 7a88434db..d0aeeda95 100644
--- a/test/tsan/suppressions_race.cc
+++ b/test/tsan/suppressions_race.cc
@@ -22,7 +22,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
   return 0;
 }
 
diff --git a/test/tsan/suppressions_race2.cc b/test/tsan/suppressions_race2.cc
index b6566a801..6f8ca736d 100644
--- a/test/tsan/suppressions_race2.cc
+++ b/test/tsan/suppressions_race2.cc
@@ -22,7 +22,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
   return 0;
 }
 
diff --git a/test/tsan/thread_detach.c b/test/tsan/thread_detach.c
index 802d8ded0..2a95742b7 100644
--- a/test/tsan/thread_detach.c
+++ b/test/tsan/thread_detach.c
@@ -12,7 +12,7 @@ int main() {
   pthread_create(&t, 0, Thread, 0);
   barrier_wait(&barrier);
   pthread_detach(t);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/thread_detach2.c b/test/tsan/thread_detach2.c
index 8133980ba..5ee94e9a9 100644
--- a/test/tsan/thread_detach2.c
+++ b/test/tsan/thread_detach2.c
@@ -20,7 +20,7 @@ int main() {
   pthread_create(&t, 0, Thread, 0);
   pthread_detach(t);
   barrier_wait(&barrier);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/thread_leak.c b/test/tsan/thread_leak.c
index 9b850dd4b..9b42b16b7 100644
--- a/test/tsan/thread_leak.c
+++ b/test/tsan/thread_leak.c
@@ -10,7 +10,7 @@ int main() {
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   pthread_join(t, 0);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/thread_leak2.c b/test/tsan/thread_leak2.c
index fc2942b2a..c3cac7a49 100644
--- a/test/tsan/thread_leak2.c
+++ b/test/tsan/thread_leak2.c
@@ -10,7 +10,7 @@ int main() {
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
   pthread_detach(t);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
   return 0;
 }
 
diff --git a/test/tsan/thread_leak4.c b/test/tsan/thread_leak4.c
index 1ebca5887..1d0636f1a 100644
--- a/test/tsan/thread_leak4.c
+++ b/test/tsan/thread_leak4.c
@@ -9,7 +9,7 @@ void *Thread(void *x) {
 int main() {
   pthread_t t;
   pthread_create(&t, 0, Thread, 0);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
   return 0;
 }
 
diff --git a/test/tsan/tsan-vs-gvn.cc b/test/tsan/tsan-vs-gvn.cc
index 950f5d30d..efd81ef50 100644
--- a/test/tsan/tsan-vs-gvn.cc
+++ b/test/tsan/tsan-vs-gvn.cc
@@ -31,7 +31,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("PASS\n");
+  fprintf(stderr, "PASS\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/unaligned_norace.cc b/test/tsan/unaligned_norace.cc
index 94df1cf74..7e360cf87 100644
--- a/test/tsan/unaligned_norace.cc
+++ b/test/tsan/unaligned_norace.cc
@@ -77,7 +77,7 @@ int main() {
   pthread_create(&th, 0, Thread, 0);
   Test(true);
   pthread_join(th, 0);
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer:
diff --git a/test/tsan/vfork.cc b/test/tsan/vfork.cc
index 5ae1dd1ab..2d669b305 100644
--- a/test/tsan/vfork.cc
+++ b/test/tsan/vfork.cc
@@ -26,7 +26,7 @@ int main() {
   pipe(fds);
   int pid = vfork();
   if (pid < 0) {
-    printf("FAIL to vfork\n");
+    fprintf(stderr, "FAIL to vfork\n");
     exit(1);
   }
   if (pid == 0) {  // child
@@ -43,7 +43,7 @@ int main() {
   pthread_create(&t[1], NULL, Thread2, NULL);
   pthread_join(t[0], NULL);
   pthread_join(t[1], NULL);
-  printf("DONE\n");
+  fprintf(stderr, "DONE\n");
 }
 
 // CHECK-NOT: WARNING: ThreadSanitizer: data race
diff --git a/test/tsan/virtual_inheritance_compile_bug.cc b/test/tsan/virtual_inheritance_compile_bug.cc
index 7da581d80..3b1e08b16 100644
--- a/test/tsan/virtual_inheritance_compile_bug.cc
+++ b/test/tsan/virtual_inheritance_compile_bug.cc
@@ -10,6 +10,6 @@ struct DDD: CCC, BBB { DDD(); };  // NOLINT
 DDD::DDD()  { }
 int main() {
   DDD d;
-  printf("OK\n");
+  fprintf(stderr, "OK\n");
 }
 // CHECK: OK