[HADOOP-6939] Inconsistent lock ordering in AbstractDelegationTokenSecretManager

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.22.0
• Fix Version/s: 0.23.0
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 03/Sep/10 22:48
• Updated: 15/Nov/11 00:50
• Resolved: 03/Dec/10 23:02

Description

AbstractDelegationTokenSecretManager.startThreads() is synchronized, which calls updateCurrentKey(), which calls logUpdateMasterKey. logUpdateMasterKey's implementation for HDFS's manager calls namesystem.logUpdateMasterKey() which is synchronized. Thus the lock order is ADTSM -> FSN. In FSN.saveNamespace, though, it calls DTSM.saveSecretManagerState(), so the lock order is FSN -> ADTSM.

I don't think this deadlock occurs in practice since saveNamespace won't occur until after the ADTSM has started its threads, but should be fixed anyway.