[HADOOP-9932] Improper synchronization in RetryCache

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 2.1.1-beta
• Target Version/s: 2.1.1-beta
• Hadoop Flags: Reviewed
• Assignee: Kihwal Lee
• Reporter: Kihwal Lee
• Created: 04/Sep/13 16:40
• Updated: 03/Sep/14 23:49
• Resolved: 04/Sep/13 20:01

Description

In LightWeightCache#evictExpiredEntries(), the precondition check can fail. patwhitey2007 ran a HA failover test and it occurred while the SBN was catching up with edits during a transition to active. This caused NN to terminate.

Here is my theory: If an RPC handler calls waitForCompletion() and it happens to remove the head of the queue in get(), it will race with evictExpiredEntries() frrom put().