hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hemanth Yamijala (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MAPREDUCE-1342) Potential JT deadlock in faulty TT tracking
Date Tue, 19 Jan 2010 09:38:54 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-1342?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12802161#action_12802161
] 

Hemanth Yamijala commented on MAPREDUCE-1342:
---------------------------------------------

I verified the changes in the patch for Branch 0.21 to see the shared data structures are
accessed under the JT lock. Also the patch for 21 seems similar to the patch for trunk. Will
commit the changes to branch 0.21 to unblock other patches.

> Potential JT deadlock in faulty TT tracking
> -------------------------------------------
>
>                 Key: MAPREDUCE-1342
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1342
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>          Components: jobtracker
>    Affects Versions: 0.20.1
>            Reporter: Todd Lipcon
>            Assignee: Amareshwari Sriramadasu
>             Fix For: 0.21.0
>
>         Attachments: cycle0.png, mapreduce-1342-1.patch, mapreduce-1342-2.patch, patch-1342-0.21.txt,
patch-1342-1.txt, patch-1342-2-ydist.txt, patch-1342-2.txt, patch-1342-3-ydist.txt, patch-1342-3.txt,
patch-1342-ydist.txt, patch-1342.txt
>
>
> JT$FaultyTrackersInfo.incrementFaults first locks potentiallyFaultyTrackers, and then
calls blackListTracker, which calls removeHostCapacity, which locks JT.taskTrackers
> On the other hand, JT.blacklistedTaskTrackers() locks taskTrackers, then calls faultyTrackers.isBlacklisted()
which goes on to lock potentiallyFaultyTrackers.
> I haven't produced such a deadlock, but the lock ordering here is inverted and therefore
could deadlock.
> Not sure if this goes back to 0.21 or just in trunk.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message