Sungwoo created TEZ-4334:
----------------------------
Summary: Fix deadlock in ShuffleScheduler
Key: TEZ-4334
URL: https://issues.apache.org/jira/browse/TEZ-4334
Project: Apache Tez
Issue Type: Bug
Reporter: Sungwoo
Deadlock can be generated between a thread calling ShuffleScheduler.close() and
the ShufflePenaltyReferee thread.
Example (produced with an earlier version):
{code}
"Fetcher_O { attempt_1611850856294_0026_1_03_000000_0_10344 Reducer_3} #13"
#2669 daemon prio=5 os_prio=0 tid=0x00002b9de869d000 nid=0xf99 in Object.wait()
[0x00002b9de4983000]
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler.close(ShuffleScheduler.java:481)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.Shuffle.cleanupShuffleScheduler(Shuffle.java:352)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.Shuffle.cleanupShuffleSchedulerIgnoreErrors(Shuffle.java:343)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.Shuffle.reportException(Shuffle.java:407)
- locked <0x00002b96bbb9d7a8> (a
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.Shuffle)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler.isShuffleHealthy(ShuffleScheduler.java:1033)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler.copyFailed(ShuffleScheduler.java:781)
- locked <0x00002b96b98a7860> (a
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.FetcherOrderedGrouped.setupConnection(FetcherOrderedGrouped.java:414)
"ShufflePenaltyReferee {Reducer_3}" #2645 daemon prio=5 os_prio=0
tid=0x00002b9560fae800 nid=0xf7d waiting for monitor entry [0x00002b9de733b000]
java.lang.Thread.State: BLOCKED (on object monitor)
at
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler$Referee.run(ShuffleScheduler.java:1322)
- waiting to lock <0x00002b96b98a7860> (a
org.apache.tez.runtime.library.common.shuffle.orderedgrouped.ShuffleScheduler)
{/code}
We can fix the deadlock with:
1) do not hold ShuffleScheduler.this when calling
exceptionReporter.reportException()
2) remove synchronized in copyFailed()
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