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https://issues.apache.org/jira/browse/AMQ-7106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Gary Tully resolved AMQ-7106.
-----------------------------
Resolution: Fixed
The same fix pattern could be applied to the stop/stopping choreography however
that problem goes deeper due to the interaction with the service stopper state
etc. It gets very involved quickly. This is a small step with specific intent
and scope.
> TransportConnection pendingStop support during start is broken
> --------------------------------------------------------------
>
> Key: AMQ-7106
> URL: https://issues.apache.org/jira/browse/AMQ-7106
> Project: ActiveMQ
> Issue Type: Bug
> Components: Transport
> Affects Versions: 5.15.0
> Environment: mqtt nio ssl
> Reporter: Gary Tully
> Assignee: Gary Tully
> Priority: Major
> Fix For: 5.16.0
>
>
> If start blocks, the inactivity monitor can kick in. The intent is that it
> can see the starting state and initiate a pending stop and complete.
> The current synchronization breaks this b/c the start code holds a lock for
> its duration, which requires the stopAsync code to block in error.
> This means there is a blocked inactivity monitor thread per blocked starting
> connection... very quickly too many threads.
> A blocked ssl handshake can demonstrate.
> {code:java}
> "MQTTInactivityMonitor Async Task:
> java.util.concurrent.ThreadPoolExecutor$Worker@7c1745f4[State = -1, empty
> queue]" #4412 daemon prio=5 os_prio=0 tid=0x00007fd524f2c800 nid=0x622d
> waiting for monitor entry [0x00007fd393776000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.activemq.broker.TransportConnection.stopAsync(TransportConnection.java:1136)
> - waiting to lock <0x00000004dc8059b0> (a
> org.apache.activemq.broker.jmx.ManagedTransportConnection)
> at
> org.apache.activemq.broker.jmx.ManagedTransportConnection.stopAsync(ManagedTransportConnection.java:66)
> at
> org.apache.activemq.broker.TransportConnection.stopAsync(TransportConnection.java:1131)
> at
> org.apache.activemq.broker.TransportConnection.serviceTransportException(TransportConnection.java:235)
> at
> org.apache.activemq.broker.TransportConnection$1.onException(TransportConnection.java:206)
> at
> org.apache.activemq.transport.TransportFilter.onException(TransportFilter.java:101)
> at
> org.apache.activemq.transport.mqtt.MQTTInactivityMonitor.onException(MQTTInactivityMonitor.java:196)
> at
> org.apache.activemq.transport.mqtt.MQTTInactivityMonitor$1$1.run(MQTTInactivityMonitor.java:81)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> Locked ownable synchronizers:
> - <0x00000004d7803c60> (a
> java.util.concurrent.ThreadPoolExecutor$Worker)
> {code}
> {code:java}
> "ActiveMQ BrokerService[BB] Task-51959" #4414527 daemon prio=5 os_prio=0
> tid=0x00007fd5f83b9800 nid=0x1846 runnable [0x00007fd3873b3000]
> java.lang.Thread.State: RUNNABLE
> at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
> at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
> at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
> at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
> - locked <0x00000004dc805830> (a sun.nio.ch.Util$3)
> - locked <0x00000004dc805820> (a
> java.util.Collections$UnmodifiableSet)
> - locked <0x00000004dc805840> (a sun.nio.ch.EPollSelectorImpl)
> at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
> at
> org.apache.activemq.transport.nio.NIOSSLTransport.doHandshake(NIOSSLTransport.java:380)
> at
> org.apache.activemq.transport.nio.NIOSSLTransport.initializeStreams(NIOSSLTransport.java:137)
> at
> org.apache.activemq.transport.mqtt.MQTTNIOSSLTransport.initializeStreams(MQTTNIOSSLTransport.java:46)
> at
> org.apache.activemq.transport.tcp.TcpTransport.connect(TcpTransport.java:519)
> at
> org.apache.activemq.transport.nio.NIOTransport.doStart(NIOTransport.java:160)
> at
> org.apache.activemq.transport.nio.NIOSSLTransport.doStart(NIOSSLTransport.java:412)
> at
> org.apache.activemq.util.ServiceSupport.start(ServiceSupport.java:55)
> at
> org.apache.activemq.transport.TransportFilter.start(TransportFilter.java:58)
> at
> org.apache.activemq.transport.mqtt.MQTTTransportFilter.start(MQTTTransportFilter.java:157)
> at
> org.apache.activemq.transport.mqtt.MQTTInactivityMonitor.start(MQTTInactivityMonitor.java:148)
> at
> org.apache.activemq.transport.TransportFilter.start(TransportFilter.java:58)
> at
> org.apache.activemq.broker.TransportConnection.start(TransportConnection.java:1066)
> - locked <0x00000004dc8059b0> (a
> org.apache.activemq.broker.jmx.ManagedTransportConnection)
> at
> org.apache.activemq.broker.TransportConnector$1$1.run(TransportConnector.java:218)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> Locked ownable synchronizers:
> - <0x00000004dc805a78> (a
> java.util.concurrent.ThreadPoolExecutor$Worker){code}
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