Actually, I see it now, the message delivery lock is obtained in the dispatcher run method.
So createTextMessage is doing: 1. Obtain message delivery lock. 2. Obtain failover mutex. And the main thread calling close is doing: 1. Obtain failover mutex. 2. Obtain message delivery lock. Just swap the lock ordering as I suggested. Unless this conflicts with other orderings... On 17/09/2007, Rupert Smith <[EMAIL PROTECTED]> wrote: > > It looks to me that the message delivery lock is the more fundamental > cause of the dead lock. I can't figure out from the stack trace why the > dispatcher thread is holding that one (I suppose I should look at what the > test is doing to figure that out). > > Can we swap the order of obtaining the locks in AMQSession.close(long > timeout) from > > synchronized(_messageDeliveryLock) > synchronized (_connection.getFailoverMutex()) > > to > > synchronized (_connection.getFailoverMutex()) > synchronized(_messageDeliveryLock) > > ? > > Unless that causes a different dead lock, it looks like it will fix the > problem. > > Also, it looks to me that removing the failover mutex acquisition from > createTextMessage will be harmless enough. > > Rupert > > > On 15/09/2007, Rajith Attapattu <[EMAIL PROTECTED]> wrote: > > > > Hi All, > > > > When I run the latest version of trunk I get a hang on > > org.apache.qpid.test.unit.client.forwardall.CombinedTest > > kill -3 (thread dump) provides information to say there is a deadlock. > > > > I also noted that all AMQSession.createXXXMessage contains > > synchronization > > code. > > (in this case the deadlock happens inn AMQSession.createTextMessagetrying > > to obtain the failover mutex) > > > > Do we really need this synchronization code when creating messages? I am > > not > > really convinced it is needed. > > Can someody explain the reason for that code block? > > > > Regard, > > > > Rajith > > > > I have attached the trace below. > > > > Found one Java-level deadlock: > > ============================= > > "Dispatcher-Channel-1": > > waiting to lock monitor 0x09ff950c (object 0x8b85a1a0, a > > java.lang.Object > > ), > > which is held by "main" > > "main": > > waiting to lock monitor 0x09ff964c (object 0x88ff0240, a > > java.lang.Object > > ), > > which is held by "Dispatcher-Channel-1" > > > > Java stack information for the threads listed above: > > =================================================== > > "Dispatcher-Channel-1": > > at org.apache.qpid.client.AMQSession.createTextMessage( > > AMQSession.java:1057) > > - waiting to lock <0x8b85a1a0> (a java.lang.Object) > > at org.apache.qpid.client.AMQSession.createTextMessage ( > > AMQSession.java:1068) > > at org.apache.qpid.test.unit.client.forwardall.Service.onMessage > > ( > > Service.java:59) > > at org.apache.qpid.client.BasicMessageConsumer.notifyMessage( > > BasicMessageConsumer.java :628) > > at org.apache.qpid.client.BasicMessageConsumer.notifyMessage( > > BasicMessageConsumer.java:583) > > at org.apache.qpid.client.AMQSession$Dispatcher.dispatchMessage( > > AMQSession.java:2579) > > at org.apache.qpid.client.AMQSession$Dispatcher.run( > > AMQSession.java > > :2502) > > - locked <0x88ff0240> (a java.lang.Object) > > - locked <0x88ff0238> (a java.lang.Object) > > "main": > > at org.apache.qpid.client.AMQSession.close(AMQSession.java:462) > > - waiting to lock <0x88ff0240> (a java.lang.Object) > > at org.apache.qpid.client.AMQConnection.closeAllSessions( > > AMQConnection.java:752) > > at org.apache.qpid.client.AMQConnection.close(AMQConnection.java > > :673) > > - locked <0x8b85a1a0> (a java.lang.Object) > > at org.apache.qpid.client.AMQConnection.close(AMQConnection.java > > :659) > > at org.apache.qpid.test.unit.client.forwardall.Service.close( > > Service.java:71) > > at > > org.apache.qpid.test.unit.client.forwardall.ServiceCreator.closeSC( > > ServiceCreator.java:57) > > at > > org.apache.qpid.test.unit.client.forwardall.ServiceCreator.closeAll( > > ServiceCreator.java:66) > > at > > org.apache.qpid.test.unit.client.forwardall.CombinedTest.tearDown > > (CombinedTest.java:44) > > at junit.framework.TestCase.runBare (TestCase.java:130) > > at junit.framework.TestResult$1.protect(TestResult.java:106) > > at junit.framework.TestResult.runProtected(TestResult.java:124) > > at junit.framework.TestResult.run(TestResult.java :109) > > at junit.framework.TestCase.run(TestCase.java:118) > > at junit.framework.TestSuite.runTest(TestSuite.java:208) > > at junit.framework.TestSuite.run(TestSuite.java:203) > > at junit.extensions.TestDecorator.basicRun (TestDecorator.java > > :22) > > > >
