[MAPREDUCE-4359] Potential deadlock in Counters

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.3
• Fix Version/s: 1.2.0
• Target Version/s: 1.0.3
• Hadoop Flags: Reviewed
• Assignee: Thomas White
• Reporter: Todd Lipcon
• Created: 21/Jun/12 17:27
• Updated: 15/May/13 05:16
• Resolved: 05/Jul/12 19:46

Description

jcarder identified this deadlock in branch-1 (though it may also be present in trunk):

• Counters.size() is synchronized and locks Counters before Group
• Counters.Group.getCounterForName() is synchronized and calls through to Counters.size()

This creates a potential cycle which could cause a deadlock (though probably quite rare in practice)