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Amar Kamat commented on MAPREDUCE-1342: --------------------------------------- Wouldnt simply making JobTracker.FaultyTrackerInfo.potentiallyFaultyTrackers a concurrent HashMap and removing the *synchronized* block in JobTracker.FaultyTrackerInfo.isBlacklisted() solve the deadlock issue? > 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: 0.22.0 > Reporter: Todd Lipcon > Attachments: cycle0.png, mapreduce-1342-1.patch > > > 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.