[jira] [Commented] (TEZ-3297) Deadlock scenario in AM during ShuffleVertexManager auto reduce

["Zhiyuan Yang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TEZ-3297?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16076050#comment-16076050 ] 

Zhiyuan Yang commented on TEZ-3297:
-----------------------------------

Add 0.8.4 and 0.9.0 to 'Fix Version' since patch was committed to these branch also.

> Deadlock scenario in AM during ShuffleVertexManager auto reduce
> ---------------------------------------------------------------
>
>                 Key: TEZ-3297
>                 URL: https://issues.apache.org/jira/browse/TEZ-3297
>             Project: Apache Tez
>          Issue Type: Bug
>            Reporter: Zhiyuan Yang
>            Assignee: Rajesh Balamohan
>            Priority: Critical
>             Fix For: 0.7.2, 0.9.0, 0.8.4
>
>         Attachments: am_log, TEZ-3297.1.patch, TEZ-3297.2.branch-0.7.patch, TEZ-3297.2.patch, thread_dump
>
>
> Here is what's happening in the attached thread dump.
> App Pool thread #9 does the auto reduce on V2 and initializes the new edge manager, it holds the V2 write lock and wants read lock of source vertex V1. 
> At the same time, another App Pool thread #2 schedules a task of V1 and gets the output spec, so it holds the V1 read lock and wants V2 read lock. 
> Also, dispatcher thread wants the V1 write lock to begin the state machine transition. Since dispatcher thread is at the head of V1 ReadWriteLock queue, thread #9 cannot get V1 read lock even thread #2 is holding V1 read lock. 
> This is a circular lock scenario. #2 blocks dispatcher, dispatcher blocks #9, and #9 blocks #2.
> There is no problem with ReadWriteLock behavior in this case. Please see this java bug report, http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6816565.



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