[rtsan] Ensure pthread is initialized in test

[cjappl]

From #107988 One of the reports was:

I use Red Hat Enterprise Linux 9.0 (Plow) and Ubuntu 22.04 LTS, and the following code will work fine with Ubuntu and will segment fault for the redhat.

#include <pthread.h>
int main() {
pthread_t thread{};
pthread_join(thread, nullptr);
return 0;

I think this could be that we are trying to join a null thread that was never created.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Chris Apple (cjappl)

Changes

From #107988 One of the reports was:

>
> I use Red Hat Enterprise Linux 9.0 (Plow) and Ubuntu 22.04 LTS, and the following code will work fine with Ubuntu and will segment fault for the redhat.
>
> #include <pthread.h>
> int main() {
> pthread_t thread{};
> pthread_join(thread, nullptr);
> return 0;
>

I think this could be that we are trying to join a null thread that was never created.

---

Full diff: https://github.com/llvm/llvm-project/pull/108040.diff

1 Files Affected:

• (modified) compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp (+6-5)

diff --git a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
index 0eeaf9da67098e..1ef4c66a28de88 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
@@ -472,11 +472,12 @@ TEST_F(PthreadMutexLockTest, PthreadMutexUnlockSurvivesWhenNotRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
-TEST(TestRtsanInterceptors, PthreadMutexJoinDiesWhenRealtime) {
-  auto Func = []() {
-    pthread_t thread{};
-    pthread_join(thread, nullptr);
-  };
+TEST(TestRtsanInterceptors, PthreadJoinDiesWhenRealtime) {
+  pthread_t thread{};
+  ASSERT_EQ(0,
+            pthread_create(&thread, nullptr, &FakeThreadEntryPoint, nullptr));
+
+  auto Func = [&thread]() { pthread_join(thread, nullptr); };
 
   ExpectRealtimeDeath(Func, "pthread_join");
   ExpectNonRealtimeSurvival(Func);

[cjappl]

CC @davidtrevelyan for review

@yingcong-wu could you apply this patch and make sure that it fixes that crash for you?

[mgorny]

This fixes the SEGV for me, thanks!

[davidtrevelyan]

LGTM!

[yingcong-wu]

This fix works for me too. Thank you.