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https://issues.apache.org/jira/browse/AMQ-7154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16776784#comment-16776784
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Christopher L. Shannon commented on AMQ-7154:
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[~gtully] - what do you think about this? I looked at this a bit and the
simplest thing is to acquire the sendLock before the messagesLock in
doPageInForDispatch but I am not sure what that will do for performance plus
that seems like overkill because the lock is only needed if a message is
expired and if the DLQ is even active. This is the line I am talking about:
[https://github.com/apache/activemq/blob/bcad7e1f6a6dd078d87787a03b56560e995ef773/activemq-broker/src/main/java/org/apache/activemq/broker/region/Queue.java#L1996]
Another option could be to queue up the messages to be expired to a list (up to
some max of course) and then expire them after the page in is finished and the
lock is released but this could get more tricky.
> Broker Deadlock while processing expired DLQ messages
> -----------------------------------------------------
>
> Key: AMQ-7154
> URL: https://issues.apache.org/jira/browse/AMQ-7154
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.12.0
> Reporter: Kestutis Gedminas
> Priority: Major
> Attachments: amq.svg, threaddump.zip
>
>
> We get a deadlock on AMQ. After analysis, it looks like in case if expired
> messages thread is processing DLQ queue at the same moment when poisonAck is
> received we run into preexisting racing condition in code due to inconsistent
> lock acquiring order.
> [ !amq.svg|width=1000!|^amq.svg]
>
> [^threaddump.zip]
> [^amq.svg]
>
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