[ https://issues.apache.org/jira/browse/SPARK-1769?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Aaron Davidson reassigned SPARK-1769: ------------------------------------- Assignee: Aaron Davidson > Executor loss can cause race condition in Pool > ---------------------------------------------- > > Key: SPARK-1769 > URL: https://issues.apache.org/jira/browse/SPARK-1769 > Project: Spark > Issue Type: Bug > Components: Spark Core > Affects Versions: 1.0.0 > Reporter: Aaron Davidson > Assignee: Aaron Davidson > > Loss of executors (in this case due to OOMs) exposes a race condition in > Pool.scala, evident from this stack trace: > {code} > 14/05/08 22:41:48 ERROR OneForOneStrategy: > java.lang.NullPointerException > at > org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87) > at > org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87) > at > scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) > at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) > at org.apache.spark.scheduler.Pool.executorLost(Pool.scala:87) > at > org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87) > at > org.apache.spark.scheduler.Pool$$anonfun$executorLost$1.apply(Pool.scala:87) > at > scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59) > at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47) > at org.apache.spark.scheduler.Pool.executorLost(Pool.scala:87) > at > org.apache.spark.scheduler.TaskSchedulerImpl.removeExecutor(TaskSchedulerImpl.scala:412) > at > org.apache.spark.scheduler.TaskSchedulerImpl.executorLost(TaskSchedulerImpl.scala:385) > at > org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor.removeExecutor(CoarseGrainedSchedulerBackend.scala:160) > at > org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1$$anonfun$applyOrElse$5.apply(CoarseGrainedSchedulerBackend.scala:123) > at > org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1$$anonfun$applyOrElse$5.apply(CoarseGrainedSchedulerBackend.scala:123) > at scala.Option.foreach(Option.scala:236) > at > org.apache.spark.scheduler.cluster.CoarseGrainedSchedulerBackend$DriverActor$$anonfun$receive$1.applyOrElse(CoarseGrainedSchedulerBackend.scala:123) > at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498) > at akka.actor.ActorCell.invoke(ActorCell.scala:456) > at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237) > at akka.dispatch.Mailbox.run(Mailbox.scala:219) > at > akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386) > at > scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) > at > scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) > at > scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) > at > scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) > {code} > Note that the line of code that throws this exception is here: > {code} > schedulableQueue.foreach(_.executorLost(executorId, host)) > {code} > By the stack trace, it's not schedulableQueue that is null, but an element > therein. As far as I could tell, we never add a null element to this queue. > Rather, I could see that removeSchedulable() and executorLost() were called > at about the same time (via log messages), and suspect that since this > ArrayBuffer is in no way synchronized, that we iterate through the list while > it's in an incomplete state. -- This message was sent by Atlassian JIRA (v6.2#6252)