[jira] [Resolved] (KAFKA-4409) ZK consumer shutdown/topic event deadlock

["Jiangjie Qin (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-4409?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jiangjie Qin resolved KAFKA-4409.
---------------------------------
    Resolution: Fixed
      Assignee: Joel Koshy
      Reviewer: Jiangjie Qin

> ZK consumer shutdown/topic event deadlock
> -----------------------------------------
>
>                 Key: KAFKA-4409
>                 URL: https://issues.apache.org/jira/browse/KAFKA-4409
>             Project: Kafka
>          Issue Type: Bug
>            Reporter: Joel Koshy
>            Assignee: Joel Koshy
>
> This only applies to the old zookeeper consumer. It is trivial enough to fix.
> The consumer can deadlock on shutdown if a topic event fires during shutdown. The shutdown acquires the rebalance lock and then the topic-event-watcher lock. The topic event watcher acquires these in the reverse order. Shutdown should not need to acquire the topic-event-watcher’s lock - all it does is unsubscribes from topic events.
> Stack trace:
> {noformat}
> "mirrormaker-thread-0":
>         at kafka.consumer.ZookeeperTopicEventWatcher.shutdown(ZookeeperTopicEventWatcher.scala:50)
>         - waiting to lock <0x000000072a65d508> (a java.lang.Object)
>         at kafka.consumer.ZookeeperConsumerConnector.shutdown(ZookeeperConsumerConnector.scala:216)
>         - locked <0x00000007103c69c0> (a java.lang.Object)
>         at kafka.tools.MirrorMaker$MirrorMakerOldConsumer.cleanup(MirrorMaker.scala:519)
>         at kafka.tools.MirrorMaker$MirrorMakerThread$$anonfun$run$3.apply$mcV$sp(MirrorMaker.scala:441)
>         at kafka.utils.CoreUtils$.swallow(CoreUtils.scala:76)
>         at kafka.utils.Logging$class.swallowWarn(Logging.scala:92)
>         at kafka.utils.CoreUtils$.swallowWarn(CoreUtils.scala:47)
>         at kafka.utils.Logging$class.swallow(Logging.scala:94)
>         at kafka.utils.CoreUtils$.swallow(CoreUtils.scala:47)
>         at kafka.tools.MirrorMaker$MirrorMakerThread.run(MirrorMaker.scala:441)
> "ZkClient-EventThread-58-<zkconnect>":
>         at kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener.syncedRebalance(ZookeeperConsumerConnector.scala:639)
>         - waiting to lock <0x00000007103c69c0> (a java.lang.Object)
>         at kafka.consumer.ZookeeperConsumerConnector.kafka$consumer$ZookeeperConsumerConnector$$reinitializeConsumer(ZookeeperConsumerConnector.scala:982)
>         at kafka.consumer.ZookeeperConsumerConnector$WildcardStreamsHandler.handleTopicEvent(ZookeeperConsumerConnector.scala:1048)
>         at kafka.consumer.ZookeeperTopicEventWatcher$ZkTopicEventListener.liftedTree1$1(ZookeeperTopicEventWatcher.scala:69)
>         at kafka.consumer.ZookeeperTopicEventWatcher$ZkTopicEventListener.handleChildChange(ZookeeperTopicEventWatcher.scala:65)
>         - locked <0x000000072a65d508> (a java.lang.Object)
>         at org.I0Itec.zkclient.ZkClient$10.run(ZkClient.java:842)
>         at org.I0Itec.zkclient.ZkEventThread.run(ZkEventThread.java:71)
> Found one Java-level deadlock:
> =============================
> "mirrormaker-thread-0":
>   waiting to lock monitor 0x00007f1f38029748 (object 0x000000072a65d508, a java.lang.Object),
>   which is held by "ZkClient-EventThread-58-<zkconnect>"
> "ZkClient-EventThread-58-<zkconnect>":
>   waiting to lock monitor 0x00007f1e900249a8 (object 0x00000007103c69c0, a java.lang.Object),
>   which is held by "mirrormaker-thread-0"
> {noformat}



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