From 32e3df31c2dacb8af8af198c82881f42fee285dc Mon Sep 17 00:00:00 2001
From: Robert Gemmell <robbie@apache.org>
Date: Fri, 6 Apr 2012 10:51:21 +0000
Subject: QPID-3911: Fix deadlock on concurrent invocation of
 MessageConsumer#close() and Session#rollback() from consumer MessageListener

This patch contains the following changes:
- Add synchronization on AMSession#_messageDeliveryLock into MessageConsumer#close() in order to block until message listener in progress has completed(as required in JMS javadoc for MessageConsumer#close()).
- Change the session dispatcher to stop messages delivery into consumer local message queue if the consumer in the process of closing. This eliminates the need to stop the dispatcher on rejecting pending messages for closing consumer.
- Remove the synchronization on the dispatcher lock from AMQSession.Dispatcher#rejectPending and code to stop the dispatcher, as we are synchronizing on the deliveryLock now and incoming messages are not dispatched into closing consumers anymore.
- Add a system test to reproduce the deadlock and verify its resolution.

Applied patch from Oleksandr Rudyy <orudyy@gmail.com>

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1310275 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/qpid/client/AMQSession.java    | 27 ++++++----------------
 .../apache/qpid/client/BasicMessageConsumer.java   |  5 +++-
 2 files changed, 11 insertions(+), 21 deletions(-)

(limited to 'qpid/java/client/src')

diff --git a/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java b/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
index ce624cb91b..55d3ccb6e7 100644
--- a/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
+++ b/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
@@ -3212,28 +3212,15 @@ public abstract class AMQSession<C extends BasicMessageConsumer, P extends Basic
 
         public void rejectPending(C consumer)
         {
-            synchronized (_lock)
-            {
-                boolean stopped = connectionStopped();
+            // Reject messages on pre-receive queue
+            consumer.rollbackPendingMessages();
 
-                if (!stopped)
-                {
-                    setConnectionStopped(true);
-                }
+            // Reject messages on pre-dispatch queue
+            rejectMessagesForConsumerTag(consumer.getConsumerTag(), true, false);
 
-                // Reject messages on pre-receive queue
-                consumer.rollbackPendingMessages();
+            // closeConsumer
+            consumer.markClosed();
 
-                // Reject messages on pre-dispatch queue
-                rejectMessagesForConsumerTag(consumer.getConsumerTag(), true, false);
-                //Let the dispatcher deal with this when it gets to them.
-
-                // closeConsumer
-                consumer.markClosed();
-
-                setConnectionStopped(stopped);
-
-            }
         }
 
         public void rollback()
@@ -3425,7 +3412,7 @@ public abstract class AMQSession<C extends BasicMessageConsumer, P extends Basic
         {
             final C consumer = _consumers.get(message.getConsumerTag());
 
-            if ((consumer == null) || consumer.isClosed())
+            if ((consumer == null) || consumer.isClosed() || consumer.isClosing())
             {
                 if (_dispatcherLogger.isInfoEnabled())
                 {
diff --git a/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java b/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
index 0d717a3216..0f8b5717d6 100644
--- a/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
+++ b/qpid/java/client/src/main/java/org/apache/qpid/client/BasicMessageConsumer.java
@@ -593,7 +593,10 @@ public abstract class BasicMessageConsumer<U> extends Closeable implements Messa
                         // no point otherwise as the connection will be gone
                         if (!_session.isClosed() || _session.isClosing())
                         {
-                            sendCancel();
+                            synchronized(_session.getMessageDeliveryLock())
+                            {
+                                sendCancel();
+                            }
                             cleanupQueue();
                         }
                     }
-- 
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