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https://issues.apache.org/jira/browse/QPID-7399?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16222358#comment-16222358
]
Lorenz Quack commented on QPID-7399:
------------------------------------
My analysis (current revision is 626666a) is as follows:
# The selector thread detects acceptable keys and puts the Runnable on line 196
onto the {{_workQueue}}.
# In the meantime something closes the AmqpPort which calls
{{AmqpPortImpl#onClose}} -> {{TCPandSSLTransport#close}} ->
{{NetworkConnectionScheduler#close}} -> {{SelectorThread#close}} which sets
{{_closed}} to {{true}}.
# The selector thread now reaches the end of the while loop in
{{SelectionTask#performSelect}} and calls {{SelectionTask#closeSelector}} which
closes the {{_selector}}.
# Now a different IO-Thread picks up the Runnable from step 1. from the
{{_workQueue}} and starts executing it. Notice that the Runnable is a closure
around the former selector thread's {{SelectorTask}} (the one who's
{{_selector}} was closed in step 3.).
# When trying to use the {{_selector}} in line 210 we get the above
{{ClosedSelectorException}}
For now I will simply catch the exception which seems to occur rarely.
Since {{Selector#close}} is synchronized on the selector itself (see
Concurrency section of [the
docs|https://docs.oracle.com/javase/8/docs/api/java/nio/channels/Selector.html])
we could alternatively synchronize a block around the call to
{{channel.register}} in line 210.
> [Java Broker] ClosedSelectorException during shutdown
> -----------------------------------------------------
>
> Key: QPID-7399
> URL: https://issues.apache.org/jira/browse/QPID-7399
> Project: Qpid
> Issue Type: Bug
> Components: Java Broker
> Reporter: Lorenz Quack
> Priority: Minor
> Fix For: qpid-java-broker-7.0.0
>
> Attachments:
> TEST-org.apache.qpid.transport.MaxFrameSizeTest.testTooLargeFrameSize.txt
>
>
> Today the Jenkins mms.0-9-1 job on trunk failed the test
> {{MaxFrameSizeTest.testTooSmallFrameSize}} but the actual problem seems to
> have been during shutdown of {{MaxFrameSizeTest.testTooLargeFrameSize}}.
> There the following exception occurred:
> {code}
> 2016-08-23 20:26:34,118 ERROR [IO-pool-Port-amqp-2]
> o.a.q.t.u.InternalBrokerHolder Uncaught exception from thread
> IO-pool-Port-amqp-2
> java.nio.channels.ClosedSelectorException: null
> at sun.nio.ch.EPollSelectorImpl.putEventOps(EPollSelectorImpl.java:185)
> ~[na:1.7.0_80]
> at
> sun.nio.ch.ServerSocketChannelImpl.translateAndSetInterestOps(ServerSocketChannelImpl.java:361)
> ~[na:1.7.0_80]
> at
> sun.nio.ch.SelectionKeyImpl.nioInterestOps(SelectionKeyImpl.java:105)
> ~[na:1.7.0_80]
> at sun.nio.ch.SelectionKeyImpl.interestOps(SelectionKeyImpl.java:83)
> ~[na:1.7.0_80]
> at
> java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSelectableChannel.java:201)
> ~[na:1.7.0_80]
> at
> org.apache.qpid.server.transport.SelectorThread$SelectionTask$1.run(SelectorThread.java:197)
> ~[qpid-broker-core-6.1.0-SNAPSHOT.jar:6.1.0-SNAPSHOT]
> at
> org.apache.qpid.server.transport.SelectorThread.run(SelectorThread.java:462)
> ~[qpid-broker-core-6.1.0-SNAPSHOT.jar:6.1.0-SNAPSHOT]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> ~[na:1.7.0_80]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> ~[na:1.7.0_80]
> at java.lang.Thread.run(Thread.java:745) ~[na:1.7.0_80]
> {code}
> The full log is attached.
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