[rtsan] Add test for pthread_cond_wait segfault

compiler-rt/test/rtsan/pthread_cond_wait.cpp

@@ -0,0 +1,46 @@
+// RUN: %clangxx -fsanitize=realtime %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s
+
+// UNSUPPORTED: ios
+
+// Intent: Ensures that pthread_cond_signal does not segfault under rtsan
+// See issue #146120
+
+#include <condition_variable>
+#include <future>
+#include <mutex>
+#include <thread>
+
+#include <iostream>
+
+int main() {
+  std::cout << "Entry to main!" << std::endl;
+  std::mutex mut;
+  std::condition_variable cv;
+  bool go{false};
+
+  const auto fut = std::async(std::launch::async, [&] {
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    {
+      std::unique_lock<std::mutex> lock(mut);
+      go = true;
+    }
+    cv.notify_one();
+  });
+
+  std::unique_lock<std::mutex> lock(mut);
+  // normal wait is fine
+  // cv.wait(lock, [&] { return go; });
+  // but timed wait could segfault
+
+  // NOTE: If this test segfaults on a test runner, please comment
+  //       out this line and submit the patch.
+  //       I will follow up with a fix of the underlying problem,
+  //       but first I need to understand if it fails a test runner
+  cv.wait_for(lock, std::chrono::milliseconds(200), [&] { return go; });
+
+  std::cout << "Exit from main!" << std::endl;
+}
+
+// CHECK: Entry to main!
+// CHECK-NEXT: Exit from main!