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https://issues.apache.org/jira/browse/ARTEMIS-3622?focusedWorklogId=920214&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-920214
]
ASF GitHub Bot logged work on ARTEMIS-3622:
-------------------------------------------
Author: ASF GitHub Bot
Created on: 21/May/24 13:33
Start Date: 21/May/24 13:33
Worklog Time Spent: 10m
Work Description: jbertram commented on code in PR #4909:
URL: https://github.com/apache/activemq-artemis/pull/4909#discussion_r1608344664
##########
artemis-protocols/artemis-mqtt-protocol/src/main/java/org/apache/activemq/artemis/core/protocol/mqtt/MQTTConnectionManager.java:
##########
@@ -176,33 +174,27 @@ ServerSessionImpl createServerSession(String username,
String password, String v
return (ServerSessionImpl) serverSession;
}
- void disconnect(boolean failure) {
+ synchronized void disconnect(boolean failure) {
if (session == null || session.getStopped()) {
return;
}
- synchronized (session.getState()) {
Review Comment:
I've looked through it carefully and I don't see any potential problems. The
relevant changes to the state are performed by `connect` and `disconnect` which
are themselves now use `synchronized`.
Issue Time Tracking
-------------------
Worklog Id: (was: 920214)
Time Spent: 0.5h (was: 20m)
> MQTT can deadlock on client connection / disconnection
> ------------------------------------------------------
>
> Key: ARTEMIS-3622
> URL: https://issues.apache.org/jira/browse/ARTEMIS-3622
> Project: ActiveMQ Artemis
> Issue Type: Bug
> Components: MQTT
> Affects Versions: 2.19.0
> Environment: Using the latest java 17 and artemis 2.19 but looking at
> the code, it should affect 2.20 as well.
> Reporter: Marcelo Takeshi Fukushima
> Assignee: Justin Bertram
> Priority: Major
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> It seems that the {{MQTTProtocolHandler}} and {{MQTTConnectionManager}} are
> on a racing condition and can deadlock themselves on misbehaving clients. I'm
> including the relevant stack trace (ignore thread 11 that is just waiting for
> the lock).
> Looking at the relevant code, it seems that the clean-up thread (88 on the
> {{{}MQTTFailureListener{}}}) starts cleaning up the session state and then
> the session, but when {{MQTTSession.stop}} calls
> {{{}MQTTSessionState.clear{}}}, the session state is no longer the same (a
> racy connection has replaced the session state with a brand new under the
> same client-id).
> I think the methods connect and disconnect on the {{MQTTConnectionManager}}
> could be marked as synchronized as a whole, to prevent racy connects /
> disconnects (but since I don't know all the ins and outs of the code, you
> guys might have a better fix).
> {noformat}
> Found one Java-level deadlock:
> =============================
> "Thread-11
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)":
> waiting to lock monitor 0x00007f6d003368c0 (object 0x000000045f29f240, a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState),
> which is held by "Thread-24
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)"
> "Thread-24
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)":
> waiting to lock monitor 0x00007f6d00336a80 (object 0x000000045f2a1068, a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession),
> which is held by "Thread-88
> (ActiveMQ-remoting-threads-ActiveMQServerImpl::name=0.0.0.0-212232499)"
> "Thread-88
> (ActiveMQ-remoting-threads-ActiveMQServerImpl::name=0.0.0.0-212232499)":
> waiting to lock monitor 0x00007f6d003368c0 (object 0x000000045f29f240, a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState),
> which is held by "Thread-24
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)"
> Java stack information for the threads listed above:
> ===================================================
> "Thread-11
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)":
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTConnectionManager.disconnect(MQTTConnectionManager.java:150)
> - waiting to lock <0x000000045f29f240> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTFailureListener.connectionFailed(MQTTFailureListener.java:37)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTConnection.fail(MQTTConnection.java:150)
> at
> org.apache.activemq.artemis.core.remoting.server.impl.RemotingServiceImpl$FailureCheckAndFlushThread$2.run(RemotingServiceImpl.java:780)
> at
> org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:42)
> at
> org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:31)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase.executePendingTasks(ProcessorBase.java:65)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase$$Lambda$137/0x0000000800e01dc8.run(Unknown
> Source)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@17.0.1/ThreadPoolExecutor.java:1136)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@17.0.1/ThreadPoolExecutor.java:635)
> at
> org.apache.activemq.artemis.utils.ActiveMQThreadFactory$1.run(ActiveMQThreadFactory.java:118)
> "Thread-24
> (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6@640f11a1)":
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession.start(MQTTSession.java:87)
> - waiting to lock <0x000000045f2a1068> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTConnectionManager.connect(MQTTConnectionManager.java:111)
> - locked <0x000000045f29f240> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTProtocolHandler.handleConnect(MQTTProtocolHandler.java:185)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTProtocolHandler.act(MQTTProtocolHandler.java:133)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTProtocolHandler$$Lambda$382/0x0000000801034000.onMessage(Unknown
> Source)
> at org.apache.activemq.artemis.utils.actors.Actor.doTask(Actor.java:33)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase.executePendingTasks(ProcessorBase.java:65)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase$$Lambda$137/0x0000000800e01dc8.run(Unknown
> Source)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@17.0.1/ThreadPoolExecutor.java:1136)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@17.0.1/ThreadPoolExecutor.java:635)
> at
> org.apache.activemq.artemis.utils.ActiveMQThreadFactory$1.run(ActiveMQThreadFactory.java:118)
> "Thread-88
> (ActiveMQ-remoting-threads-ActiveMQServerImpl::name=0.0.0.0-212232499)":
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState.clear(MQTTSessionState.java:59)
> - waiting to lock <0x000000045f29f240> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession.clean(MQTTSession.java:200)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession.stop(MQTTSession.java:115)
> - locked <0x000000045f2a1068> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSession)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTConnectionManager.disconnect(MQTTConnectionManager.java:155)
> - locked <0x00000002223bc2d0> (a
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTSessionState)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTFailureListener.connectionFailed(MQTTFailureListener.java:37)
> at
> org.apache.activemq.artemis.core.protocol.mqtt.MQTTConnection.fail(MQTTConnection.java:150)
> at
> org.apache.activemq.artemis.core.remoting.server.impl.RemotingServiceImpl.issueFailure(RemotingServiceImpl.java:606)
> at
> org.apache.activemq.artemis.core.remoting.server.impl.RemotingServiceImpl.connectionDestroyed(RemotingServiceImpl.java:587)
> at
> org.apache.activemq.artemis.core.remoting.impl.netty.NettyAcceptor$Listener.connectionDestroyed(NettyAcceptor.java:951)
> at
> org.apache.activemq.artemis.core.remoting.impl.netty.ActiveMQChannelHandler.lambda$channelInactive$0(ActiveMQChannelHandler.java:89)
> at
> org.apache.activemq.artemis.core.remoting.impl.netty.ActiveMQChannelHandler$$Lambda$419/0x0000000801103b48.run(Unknown
> Source)
> at
> org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:42)
> at
> org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:31)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase.executePendingTasks(ProcessorBase.java:65)
> at
> org.apache.activemq.artemis.utils.actors.ProcessorBase$$Lambda$137/0x0000000800e01dc8.run(Unknown
> Source)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@17.0.1/ThreadPoolExecutor.java:1136)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@17.0.1/ThreadPoolExecutor.java:635)
> at
> org.apache.activemq.artemis.utils.ActiveMQThreadFactory$1.run(ActiveMQThreadFactory.java:118)
> Found 1 deadlock.{noformat}
>
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