[AMQ-1108] Deadlock in PrefetchSubscription

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 5.0.0
• Fix Version/s: 5.0.0
• Component/s: Broker
• Assignee: Robert Davies
• Reporter: Robert Davies
• Created: 23/Dec/06 12:51
• Updated: 24/Dec/06 08:58
• Resolved: 24/Dec/06 08:58

Description

see: http://www.nabble.com/Another-deadlock-showing-up-tf2874106.html#a8033006

The deadlock is as follows:

Found one Java-level deadlock:
=============================
"ActiveMQ Task":
waiting to lock monitor 0x080e4f3c (object 0x92b60db0, a
java.util.LinkedList),
which is held by "ActiveMQ Transport: tcp:///127.0.0.1:37496"
"ActiveMQ Transport: tcp:///127.0.0.1:37496":
waiting to lock monitor 0x080e4f7c (object 0x92b60d98, a
org.apache.activemq.broker.region.cursors.VMPendingMessageCursor),
which is held by "ActiveMQ Task"

Java stack information for the threads listed above:
===================================================
"ActiveMQ Task":
at
org.apache.activemq.broker.region.PrefetchSubscription.dispatch(PrefetchSubscription.java:414)

• waiting to lock <0x92b60db0> (a java.util.LinkedList)
  at
  org.apache.activemq.broker.region.QueueSubscription.dispatch(QueueSubscription.java:172)
  at
  org.apache.activemq.broker.region.PrefetchSubscription.dispatchMatched(PrefetchSubscription.java:397)
• locked <0x92b60d98> (a
  org.apache.activemq.broker.region.cursors.VMPendingMessageCursor)
  at
  org.apache.activemq.broker.region.PrefetchSubscription.onDispatch(PrefetchSubscription.java:451)
  at
  org.apache.activemq.broker.region.QueueSubscription.onDispatch(QueueSubscription.java:192)
  at
  org.apache.activemq.broker.region.PrefetchSubscription$3.run(PrefetchSubscription.java:429)
  at
  org.apache.activemq.broker.TransportConnection.processDispatch(TransportConnection.java:778)
  at
  org.apache.activemq.broker.TransportConnection.iterate(TransportConnection.java:791)
  at
  org.apache.activemq.thread.PooledTaskRunner.runTask(PooledTaskRunner.java:111)
  at
  org.apache.activemq.thread.PooledTaskRunner.access$100(PooledTaskRunner.java:26)
  at
  org.apache.activemq.thread.PooledTaskRunner$1.run(PooledTaskRunner.java:44)
  at
  java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
  at
  java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
  at java.lang.Thread.run(Thread.java:595)
  "ActiveMQ Transport: tcp:///127.0.0.1:37496":
  at
  org.apache.activemq.broker.region.PrefetchSubscription.dispatchMatched(PrefetchSubscription.java:383)
• waiting to lock <0x92b60d98> (a
  org.apache.activemq.broker.region.cursors.VMPendingMessageCursor)
  at
  org.apache.activemq.broker.region.PrefetchSubscription.acknowledge(PrefetchSubscription.java:219)
• locked <0x92b60db0> (a java.util.LinkedList)
  at
  org.apache.activemq.broker.region.AbstractRegion.acknowledge(AbstractRegion.java:299)
  at
  org.apache.activemq.broker.region.RegionBroker.acknowledge(RegionBroker.java:397)
  at
  org.apache.activemq.broker.TransactionBroker.acknowledge(TransactionBroker.java:177)
  at
  org.apache.activemq.broker.BrokerFilter.acknowledge(BrokerFilter.java:74)
  at
  org.apache.activemq.broker.BrokerFilter.acknowledge(BrokerFilter.java:74)
  at
  org.apache.activemq.broker.MutableBrokerFilter.acknowledge(MutableBrokerFilter.java:88)
  at
  org.apache.activemq.broker.TransportConnection.processMessageAck(TransportConnection.java:491)
  at org.apache.activemq.command.MessageAck.visit(MessageAck.java:179)
  at
  org.apache.activemq.broker.TransportConnection.service(TransportConnection.java:287)
  at
  org.apache.activemq.broker.TransportConnection$1.onCommand(TransportConnection.java:178)
  at
  org.apache.activemq.transport.TransportFilter.onCommand(TransportFilter.java:65)
  at
  org.apache.activemq.transport.WireFormatNegotiator.onCommand(WireFormatNegotiator.java:133)
  at
  org.apache.activemq.transport.InactivityMonitor.onCommand(InactivityMonitor.java:122)
  at
  org.apache.activemq.transport.TransportSupport.doConsume(TransportSupport.java:84)
  at
  org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:137)
  at java.lang.Thread.run(Thread.java:595)

Found 1 deadlock.