[KAFKA-4409] ZK consumer shutdown/topic event deadlock

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.1.0
• Fix Version/s: 0.10.1.1
• Component/s: consumer, core
• Assignee: Joel Jacob Koshy
• Reporter: Joel Jacob Koshy
• Reviewer: Jiangjie Qin
• Created: 14/Nov/16 17:42
• Updated: 15/Nov/16 00:47
• Resolved: 14/Nov/16 18:08

Description

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:

"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"

Issue Links

• links to: GitHub Pull Request #2129