[compiler-rt] [rtsan][compiler-rt] Prevent UB hang in rtsan lock unit tests (PR #104733)

[Chris Apple via llvm-commits]

================
@@ -328,26 +328,64 @@ TEST(TestRtsanInterceptors, PthreadCreateDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(Func);
 }
 
-TEST(TestRtsanInterceptors, PthreadMutexLockDiesWhenRealtime) {
-  auto Func = []() {
-    pthread_mutex_t mutex{};
+class PthreadMutexLockTest : public ::testing::Test {
+protected:
+  void SetUp() override {
+    pthread_mutex_init(&mutex, nullptr);
+    is_locked = false;
+  }
+
+  void TearDown() override {
+    if (is_locked) {
+      Unlock();
+    }
+    pthread_mutex_destroy(&mutex);
+  }
+
+  void Lock() {
+    ASSERT_TRUE(!is_locked);
     pthread_mutex_lock(&mutex);
-  };
+    is_locked = true;
+  }
+
+  void Unlock() {
+    ASSERT_TRUE(is_locked);
+    pthread_mutex_unlock(&mutex);
+    is_locked = false;
+  }
+
+private:
+  pthread_mutex_t mutex;
+  bool is_locked;
+};
+
+TEST_F(PthreadMutexLockTest, PthreadMutexLockDiesWhenRealtime) {
+  auto Func = [this]() { Lock(); };
 
   ExpectRealtimeDeath(Func, "pthread_mutex_lock");
+}
+
+TEST_F(PthreadMutexLockTest, PthreadMutexLockSurvivesWhenNotRealtime) {
+  auto Func = [this]() { Lock(); };
+
   ExpectNonRealtimeSurvival(Func);
 }
 
-TEST(TestRtsanInterceptors, PthreadMutexUnlockDiesWhenRealtime) {
-  auto Func = []() {
-    pthread_mutex_t mutex{};
-    pthread_mutex_unlock(&mutex);
----------------
cjappl wrote:

Unlocking an uninited, and not-locked lock

https://github.com/llvm/llvm-project/pull/104733