[HADOOP-791] deadlock issue in taskstracker.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.1
• Fix Version/s: 0.9.2
• Assignee: Mahadev Konar
• Reporter: Mahadev Konar
• Created: 07/Dec/06 04:37
• Updated: 08/Jul/09 16:52
• Resolved: 15/Dec/06 22:12

Description

the stack trace--
"main":
at org.apache.hadoop.mapred.TaskTracker$TaskInProgress.createStatus(TaskTracker.java:880)

• waiting to lock <0xea101658> (a org.apache.hadoop.mapred.TaskTracker$TaskInProgress)
  at org.apache.hadoop.mapred.TaskTracker.transmitHeartBeat(TaskTracker.java:489)
• locked <0x75505f00> (a org.apache.hadoop.mapred.TaskTracker)
  at org.apache.hadoop.mapred.TaskTracker.offerService(TaskTracker.java:442)
  at org.apache.hadoop.mapred.TaskTracker.run(TaskTracker.java:720)
  at org.apache.hadoop.mapred.TaskTracker.main(TaskTracker.java:1374)
  "taskCleanup":
  at org.apache.hadoop.mapred.TaskTracker$TaskInProgress.cleanup(TaskTracker.java:1072)
• waiting to lock <0x75505f00> (a org.apache.hadoop.mapred.TaskTracker)
  at org.apache.hadoop.mapred.TaskTracker$TaskInProgress.jobHasFinished(TaskTracker.java:1013)
• locked <0xea101658> (a org.apache.hadoop.mapred.TaskTracker$TaskInProgress)
  at org.apache.hadoop.mapred.TaskTracker$1.run(TaskTracker.java:144)
  at java.lang.Thread.run(Thread.java:595)
  Found 1 deadlock.

The jobhasfinished method and transmitHeart beat lock the tasktracker and tip in a different order. Also , before emitting HeartBeat we should be updating the status and removing entries from runningtasks. Currently this is done after the heartbeat.