Repository: spark Updated Branches: refs/heads/master 1f29d502e -> affc8a887
[SPARK-10125] [STREAMING] Fix a potential deadlock in JobGenerator.stop Because `lazy val` uses `this` lock, if JobGenerator.stop and JobGenerator.doCheckpoint (JobGenerator.shouldCheckpoint has not yet been initialized) run at the same time, it may hang. Here are the stack traces for the deadlock: ```Java "pool-1-thread-1-ScalaTest-running-StreamingListenerSuite" #11 prio=5 os_prio=31 tid=0x00007fd35d094800 nid=0x5703 in Object.wait() [0x000000012ecaf000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) at java.lang.Thread.join(Thread.java:1245) - locked <0x00000007b5d8d7f8> (a org.apache.spark.util.EventLoop$$anon$1) at java.lang.Thread.join(Thread.java:1319) at org.apache.spark.util.EventLoop.stop(EventLoop.scala:81) at org.apache.spark.streaming.scheduler.JobGenerator.stop(JobGenerator.scala:155) - locked <0x00000007b5d8cea0> (a org.apache.spark.streaming.scheduler.JobGenerator) at org.apache.spark.streaming.scheduler.JobScheduler.stop(JobScheduler.scala:95) - locked <0x00000007b5d8ced8> (a org.apache.spark.streaming.scheduler.JobScheduler) at org.apache.spark.streaming.StreamingContext.stop(StreamingContext.scala:687) "JobGenerator" #67 daemon prio=5 os_prio=31 tid=0x00007fd35c3b9800 nid=0x9f03 waiting for monitor entry [0x0000000139e4a000] java.lang.Thread.State: BLOCKED (on object monitor) at org.apache.spark.streaming.scheduler.JobGenerator.shouldCheckpoint$lzycompute(JobGenerator.scala:63) - waiting to lock <0x00000007b5d8cea0> (a org.apache.spark.streaming.scheduler.JobGenerator) at org.apache.spark.streaming.scheduler.JobGenerator.shouldCheckpoint(JobGenerator.scala:63) at org.apache.spark.streaming.scheduler.JobGenerator.doCheckpoint(JobGenerator.scala:290) at org.apache.spark.streaming.scheduler.JobGenerator.org$apache$spark$streaming$scheduler$JobGenerator$$processEvent(JobGenerator.scala:182) at org.apache.spark.streaming.scheduler.JobGenerator$$anon$1.onReceive(JobGenerator.scala:83) at org.apache.spark.streaming.scheduler.JobGenerator$$anon$1.onReceive(JobGenerator.scala:82) at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:48) ``` I can use this patch to produce this deadlock: https://github.com/zsxwing/spark/commit/8a88f28d1331003a65fabef48ae3d22a7c21f05f And a timeout build in Jenkins due to this deadlock: https://amplab.cs.berkeley.edu/jenkins/job/NewSparkPullRequestBuilder/1654/ This PR initializes `checkpointWriter` before `eventLoop` uses it to avoid this deadlock. Author: zsxwing <zsxw...@gmail.com> Closes #8326 from zsxwing/SPARK-10125. Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/affc8a88 Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/affc8a88 Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/affc8a88 Branch: refs/heads/master Commit: affc8a887ede9fdc2ca6051833954cd10918c869 Parents: 1f29d50 Author: zsxwing <zsxw...@gmail.com> Authored: Wed Aug 19 19:43:09 2015 -0700 Committer: Tathagata Das <tathagata.das1...@gmail.com> Committed: Wed Aug 19 19:43:09 2015 -0700 ---------------------------------------------------------------------- .../org/apache/spark/streaming/scheduler/JobGenerator.scala | 4 ++++ 1 file changed, 4 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/affc8a88/streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala ---------------------------------------------------------------------- diff --git a/streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala b/streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala index 9f2117a..2de035d 100644 --- a/streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala +++ b/streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala @@ -79,6 +79,10 @@ class JobGenerator(jobScheduler: JobScheduler) extends Logging { def start(): Unit = synchronized { if (eventLoop != null) return // generator has already been started + // Call checkpointWriter here to initialize it before eventLoop uses it to avoid a deadlock. + // See SPARK-10125 + checkpointWriter + eventLoop = new EventLoop[JobGeneratorEvent]("JobGenerator") { override protected def onReceive(event: JobGeneratorEvent): Unit = processEvent(event) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@spark.apache.org For additional commands, e-mail: commits-h...@spark.apache.org