From c0440f69ebf051ff2ffdc00de51005a040014462 Mon Sep 17 00:00:00 2001
From: Andreas Gampe <agampe@google.com>
Date: Thu, 22 Jan 2015 19:48:51 -0800
Subject: [PATCH] ART: On shutdown, only warn on mutex contention

Do not abort, as daemon threads may still be active.

Bug: 17894429
Change-Id: I7c1d50ff8d4a5e150279e703a69c8f2f1d423e6b
---
 runtime/base/mutex.cc                        | 24 ++++++++-----
 test/132-daemon-locks-shutdown/expected.txt  |  0
 test/132-daemon-locks-shutdown/info.txt      |  1 +
 test/132-daemon-locks-shutdown/src/Main.java | 53 ++++++++++++++++++++++++++++
 4 files changed, 70 insertions(+), 8 deletions(-)
 create mode 100644 test/132-daemon-locks-shutdown/expected.txt
 create mode 100644 test/132-daemon-locks-shutdown/info.txt
 create mode 100644 test/132-daemon-locks-shutdown/src/Main.java

diff --git a/runtime/base/mutex.cc b/runtime/base/mutex.cc
index 495ea5c10..3f015de6f 100644
--- a/runtime/base/mutex.cc
+++ b/runtime/base/mutex.cc
@@ -276,16 +276,26 @@ Mutex::Mutex(const char* name, LockLevel level, bool recursive)
   exclusive_owner_ = 0;
 }
 
+// Helper to ignore the lock requirement.
+static bool IsShuttingDown() NO_THREAD_SAFETY_ANALYSIS {
+  Runtime* runtime = Runtime::Current();
+  return runtime == nullptr || runtime->IsShuttingDownLocked();
+}
+
 Mutex::~Mutex() {
+  bool shutting_down = IsShuttingDown();
 #if ART_USE_FUTEXES
   if (state_.LoadRelaxed() != 0) {
-    Runtime* runtime = Runtime::Current();
-    bool shutting_down = runtime == nullptr || runtime->IsShuttingDown(Thread::Current());
-    LOG(shutting_down ? WARNING : FATAL) << "destroying mutex with owner: " << exclusive_owner_;
+    LOG(shutting_down ? WARNING : FATAL) << "destroying mutex with owner: "
+                                                 << exclusive_owner_;
   } else {
-    CHECK_EQ(exclusive_owner_, 0U)  << "unexpectedly found an owner on unlocked mutex " << name_;
-    CHECK_EQ(num_contenders_.LoadSequentiallyConsistent(), 0)
-        << "unexpectedly found a contender on mutex " << name_;
+    if (exclusive_owner_ != 0) {
+      LOG(shutting_down ? WARNING : FATAL) << "unexpectedly found an owner on unlocked mutex "
+                                           << name_;
+    }
+    if (num_contenders_.LoadSequentiallyConsistent() != 0) {
+      LOG(shutting_down ? WARNING : FATAL) << "unexpectedly found a contender on mutex " << name_;
+    }
   }
 #else
   // We can't use CHECK_MUTEX_CALL here because on shutdown a suspended daemon thread
@@ -295,8 +305,6 @@ Mutex::~Mutex() {
     errno = rc;
     // TODO: should we just not log at all if shutting down? this could be the logging mutex!
     MutexLock mu(Thread::Current(), *Locks::runtime_shutdown_lock_);
-    Runtime* runtime = Runtime::Current();
-    bool shutting_down = (runtime == NULL) || runtime->IsShuttingDownLocked();
     PLOG(shutting_down ? WARNING : FATAL) << "pthread_mutex_destroy failed for " << name_;
   }
 #endif
diff --git a/test/132-daemon-locks-shutdown/expected.txt b/test/132-daemon-locks-shutdown/expected.txt
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/132-daemon-locks-shutdown/info.txt b/test/132-daemon-locks-shutdown/info.txt
new file mode 100644
index 000000000..f8040643d
--- /dev/null
+++ b/test/132-daemon-locks-shutdown/info.txt
@@ -0,0 +1 @@
+Tests that we can shut down the runtime with daemons still looping over locks.
diff --git a/test/132-daemon-locks-shutdown/src/Main.java b/test/132-daemon-locks-shutdown/src/Main.java
new file mode 100644
index 000000000..b5bbc8cbe
--- /dev/null
+++ b/test/132-daemon-locks-shutdown/src/Main.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+/**
+ * Test that daemon threads still contending for a lock don't make the runtime abort on shutdown.
+ */
+public class Main {
+
+    public final static int THREAD_COUNT = 32;
+
+    public static void main(String[] args) throws Exception {
+        Object sync = new Object();
+
+        for (int i = 0; i < THREAD_COUNT; i++) {
+            Thread t = new Thread(new Wait(sync));
+            t.setDaemon(true);
+            t.start();
+        }
+    }
+
+    private static class Wait implements Runnable {
+        private Object obj;
+
+        public Wait(Object obj) {
+            this.obj = obj;
+        }
+
+        public void run() {
+            for (;;) {
+                synchronized(obj) {
+                    try {
+                        obj.wait(1);
+                    } catch (Exception exc) {
+                        exc.printStackTrace(System.out);
+                    }
+                }
+            }
+        }
+    }
+}
-- 
2.11.0