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https://issues.apache.org/jira/browse/MAPREDUCE-1499?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12838131#action_12838131
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Matei Zaharia commented on MAPREDUCE-1499:
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The problem in MAPREDUCE-1436 only happened with a backport of the trunk fair
scheduler to 0.20. It probably won't happen with the 0.20 fair scheduler.
However, anyone packaging a distribution that includes a backport of the fair
scheduler should look into it. As I mentioned in MAPREDUCE-1436, the fix
(adding a lock around the TaskTrackerManager in update() is simple and is
unlikely to have a major impact on performance.
> JobTracker.finalizeJob inverts lock order and causes potential deadlock
> -----------------------------------------------------------------------
>
> Key: MAPREDUCE-1499
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1499
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobtracker
> Affects Versions: 0.20.1, 0.20.2
> Reporter: Todd Lipcon
> Assignee: Aaron Kimball
> Priority: Critical
> Attachments: jcarder_result_1.dot.png, jcarder_result_8.dot.png,
> MAPREDUCE-1499.patch
>
>
> This issue was brought up by Matei in MAPREDUCE-1436 as a fairsched bug, but
> it turns out it's a JT bug even with the fifo scheduler in unpatched 0.20.2.
> JobTracker.finalizeJob locks JT.jobs, JT.taskScheduler, etc, having gotten
> the JIP log before the JT lock.
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