QPID-3697: SortedQueue synchronisation can cause deadlock

Sorted queue enqueue() should lock on a private rather than the lock of the object to avoid the possibility of
a deadlock with a thread performing subscription operations.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@1231095 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 86 insertions, 3 deletions

diff --git a/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueue.java b/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueue.java
index 3f02442704..865b3d1f48 100644
--- a/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueue.java
+++ b/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueue.java
@@ -1,3 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
 package org.apache.qpid.server.queue;
 
 import java.util.Map;
@@ -7,7 +26,11 @@ import org.apache.qpid.server.virtualhost.VirtualHost;
 
 public class SortedQueue extends OutOfOrderQueue
 {
-    private String _sortedPropertyName;
+    //Lock object to synchronize enqueue. Used instead of the object
+    //monitor to prevent lock order issues with subscription sendLocks
+    //and consumer updates in the super classes
+    private final Object _sortedQueueLock = new Object();
+    private final String _sortedPropertyName;
 
     protected SortedQueue(final String name, final boolean durable,
                             final String owner, final boolean autoDelete, final boolean exclusive,
@@ -23,8 +46,11 @@ public class SortedQueue extends OutOfOrderQueue
         return _sortedPropertyName;
     }
 
-    public synchronized void enqueue(ServerMessage message, PostEnqueueAction action) throws AMQException
+    public void enqueue(ServerMessage message, PostEnqueueAction action) throws AMQException
     {
-        super.enqueue(message, action);
+        synchronized (_sortedQueueLock)
+        {
+            super.enqueue(message, action);
+        }
     }
 }
\ No newline at end of file
diff --git a/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueueEntryListFactory.java b/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueueEntryListFactory.java
index 7a70795e77..87c79178f0 100644
--- a/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueueEntryListFactory.java
+++ b/java/broker/src/main/java/org/apache/qpid/server/queue/SortedQueueEntryListFactory.java
@@ -1,3 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
 package org.apache.qpid.server.queue;
 
 public class SortedQueueEntryListFactory implements QueueEntryListFactory
diff --git a/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryImplTest.java b/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryImplTest.java
index 43fb5b4cb3..99e05851ca 100644
--- a/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryImplTest.java
+++ b/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryImplTest.java
@@ -1,3 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
 package org.apache.qpid.server.queue;
 
 import org.apache.qpid.AMQException;
diff --git a/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryListTest.java b/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryListTest.java
index 34ad0e5668..d177993886 100644
--- a/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryListTest.java
+++ b/java/broker/src/test/java/org/apache/qpid/server/queue/SortedQueueEntryListTest.java
@@ -1,3 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
 package org.apache.qpid.server.queue;
 
 import org.apache.qpid.server.message.AMQMessage;