Fix issue with RawMonitors around thread suspension.

Investigation of real-world JVMTI agents revealed that some rely on
the RawMonitorEnter function acting as a Java suspend point. If it
fails to act as one the agent could end up deadlocked.

Test: ./test.py --host -j50
Bug: 62821960
Bug: 34415266

Change-Id: I3daf5c49c1c9870e1f69eebfd4c6f2ad15224510
diff --git a/test/1921-suspend-native-recursive-monitor/native_suspend_recursive_monitor.cc b/test/1921-suspend-native-recursive-monitor/native_suspend_recursive_monitor.cc
new file mode 100644
index 0000000..b39f590
--- /dev/null
+++ b/test/1921-suspend-native-recursive-monitor/native_suspend_recursive_monitor.cc
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <atomic>
+
+#include "android-base/logging.h"
+#include "jni.h"
+#include "scoped_local_ref.h"
+#include "scoped_primitive_array.h"
+
+#include "jvmti.h"
+
+// Test infrastructure
+#include "jvmti_helper.h"
+#include "test_env.h"
+
+namespace art {
+namespace Test1921NativeSuspendMonitorRecursive {
+
+std::atomic<bool> should_pause(false);
+std::atomic<bool> paused(false);
+std::atomic<bool> done(false);
+std::atomic<bool> started(false);
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1921_nativeSpin(JNIEnv* env, jclass) {
+  jrawMonitorID mon;
+  if (JvmtiErrorToException(
+      env, jvmti_env, jvmti_env->CreateRawMonitor("Test1921 monitor", &mon))) {
+    return;
+  }
+  if (JvmtiErrorToException(env, jvmti_env, jvmti_env->RawMonitorEnter(mon))) {
+    return;
+  }
+  while (!done.load()) {
+    while (should_pause.load()) {
+      paused.store(true);
+    }
+    paused.store(false);
+    if (JvmtiErrorToException(env, jvmti_env, jvmti_env->RawMonitorEnter(mon))) {
+      return;
+    }
+    started.store(true);
+    if (JvmtiErrorToException(env, jvmti_env, jvmti_env->RawMonitorExit(mon))) {
+      return;
+    }
+  }
+  if (JvmtiErrorToException(env, jvmti_env, jvmti_env->RawMonitorExit(mon))) {
+    return;
+  }
+}
+
+extern "C" JNIEXPORT jboolean JNICALL Java_art_Test1921_isNativeThreadSpinning(JNIEnv*, jclass) {
+  return started.load();
+}
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1921_pause(JNIEnv*, jclass) {
+  should_pause.store(true);
+  paused.store(false);
+  while (!paused.load()) { }
+}
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1921_resume(JNIEnv*, jclass) {
+  should_pause.store(false);
+  while (paused.load()) { }
+}
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1921_reset(JNIEnv*, jclass) {
+  started.store(false);
+}
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1921_nativeFinish(JNIEnv*, jclass) {
+  done.store(true);
+}
+
+}  // namespace Test1921NativeSuspendMonitorRecursive
+}  // namespace art