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https://issues.apache.org/jira/browse/SPARK-19870?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15958894#comment-15958894
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Eyal Farago commented on SPARK-19870:
-------------------------------------
[~stevenruppert] can you attach traces?
[~joshrosen], a glance at the torrent broadcast code shows that it explicitly
[releases the
read-lock|https://github.com/apache/spark/blob/d009fb369bbea0df81bbcf9c8028d14cfcaa683b/core/src/main/scala/org/apache/spark/broadcast/TorrentBroadcast.scala#L214]
on the block even though the [iterator obtained from the
BlockResult|https://github.com/apache/spark/blob/d009fb369bbea0df81bbcf9c8028d14cfcaa683b/core/src/main/scala/org/apache/spark/storage/BlockManager.scala#L497]
is a completion iterator that releases locks (read lock in this scenario) upon
completion.
is it possible that the torrent code 'double-releases' the read lock on the
relevant block putting it in some inconsistent state that prevents the next
read from obtaining the lock (or somehow not notify on release)?
[~joshrosen], seems at least part of this is related to your work on
SPARK-12757, hence tagging you.
> Repeatable deadlock on BlockInfoManager and TorrentBroadcast
> ------------------------------------------------------------
>
> Key: SPARK-19870
> URL: https://issues.apache.org/jira/browse/SPARK-19870
> Project: Spark
> Issue Type: Bug
> Components: Block Manager, Shuffle
> Affects Versions: 2.0.2, 2.1.0
> Environment: ubuntu linux 14.04 x86_64 on ec2, hadoop cdh 5.10.0,
> yarn coarse-grained.
> Reporter: Steven Ruppert
> Attachments: stack.txt
>
>
> Running what I believe to be a fairly vanilla spark job, using the RDD api,
> with several shuffles, a cached RDD, and finally a conversion to DataFrame to
> save to parquet. I get a repeatable deadlock at the very last reducers of one
> of the stages.
> Roughly:
> {noformat}
> "Executor task launch worker-6" #56 daemon prio=5 os_prio=0
> tid=0x00007fffd88d3000 nid=0x1022b9 waiting for monitor entry
> [0x00007fffb95f3000]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.spark.broadcast.TorrentBroadcast$$anonfun$readBroadcastBlock$1.apply(TorrentBroadcast.scala:207)
> - waiting to lock <0x00000005445cfc00> (a
> org.apache.spark.broadcast.TorrentBroadcast$)
> at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1269)
> at
> org.apache.spark.broadcast.TorrentBroadcast.readBroadcastBlock(TorrentBroadcast.scala:206)
> at
> org.apache.spark.broadcast.TorrentBroadcast._value$lzycompute(TorrentBroadcast.scala:66)
> - locked <0x00000005b12f2290> (a
> org.apache.spark.broadcast.TorrentBroadcast)
> at
> org.apache.spark.broadcast.TorrentBroadcast._value(TorrentBroadcast.scala:66)
> at
> org.apache.spark.broadcast.TorrentBroadcast.getValue(TorrentBroadcast.scala:96)
> at org.apache.spark.broadcast.Broadcast.value(Broadcast.scala:70)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:86)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
> at org.apache.spark.scheduler.Task.run(Task.scala:99)
> at
> org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> and
> {noformat}
> "Executor task launch worker-5" #55 daemon prio=5 os_prio=0
> tid=0x00007fffd88d0000 nid=0x1022b8 in Object.wait() [0x00007fffb96f4000]
> java.lang.Thread.State: WAITING (on object monitor)
> at java.lang.Object.wait(Native Method)
> at java.lang.Object.wait(Object.java:502)
> at
> org.apache.spark.storage.BlockInfoManager.lockForReading(BlockInfoManager.scala:202)
> - locked <0x0000000545736b58> (a
> org.apache.spark.storage.BlockInfoManager)
> at
> org.apache.spark.storage.BlockManager.getLocalValues(BlockManager.scala:444)
> at
> org.apache.spark.broadcast.TorrentBroadcast$$anonfun$readBroadcastBlock$1.apply(TorrentBroadcast.scala:210)
> - locked <0x00000005445cfc00> (a
> org.apache.spark.broadcast.TorrentBroadcast$)
> at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1269)
> at
> org.apache.spark.broadcast.TorrentBroadcast.readBroadcastBlock(TorrentBroadcast.scala:206)
> at
> org.apache.spark.broadcast.TorrentBroadcast._value$lzycompute(TorrentBroadcast.scala:66)
> - locked <0x000000059711eb10> (a
> org.apache.spark.broadcast.TorrentBroadcast)
> at
> org.apache.spark.broadcast.TorrentBroadcast._value(TorrentBroadcast.scala:66)
> at
> org.apache.spark.broadcast.TorrentBroadcast.getValue(TorrentBroadcast.scala:96)
> at org.apache.spark.broadcast.Broadcast.value(Broadcast.scala:70)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:86)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
> at org.apache.spark.scheduler.Task.run(Task.scala:99)
> at
> org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> {noformat}
> A full stack trace is attached, but those seem to be the offending threads.
> This happens across several different executors, and has persisted through
> several runs of the same job across spark 2.1.0 and 2.0.2. I also tried
> killing individual executors to "unstick" the job, to no avail.
> I haven't yet narrowed down the job itself to something publicly repeatable,
> but hopefully the stacktraces are enough to start debugging.
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