Jobs stalling forever

[Nathan Marz]

Every now and then, I have jobs that stall forever with one map task  
remaining. The last map task remaining says it is at "100%" and in the  
logs, it says it is in the process of committing. However, the task  
never times out, and the job just sits there forever. Has anyone else  
seen this? Is there a JIRA ticket open for it already?