Wei-Chiu Chuang created HDFS-12279:
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Summary: TestPipelinesFailover#testPipelineRecoveryStress fails
due to race condition
Key: HDFS-12279
URL: https://issues.apache.org/jira/browse/HDFS-12279
Project: Hadoop HDFS
Issue Type: Bug
Components: namenode, test
Reporter: Wei-Chiu Chuang
Saw a test failure in a precommit test
https://builds.apache.org/job/PreCommit-HDFS-Build/20600/testReport/org.apache.hadoop.hdfs.server.namenode.ha/TestPipelinesFailover/testPipelineRecoveryStress/
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Error Message
Deferred
Stacktrace
java.lang.RuntimeException: Deferred
at
org.apache.hadoop.test.MultithreadedTestUtil$TestContext.checkException(MultithreadedTestUtil.java:130)
at
org.apache.hadoop.test.MultithreadedTestUtil$TestContext.stop(MultithreadedTestUtil.java:166)
at
org.apache.hadoop.hdfs.server.namenode.ha.HAStressTestHarness.shutdown(HAStressTestHarness.java:154)
at
org.apache.hadoop.hdfs.server.namenode.ha.TestPipelinesFailover.testPipelineRecoveryStress(TestPipelinesFailover.java:493)
Caused by: java.lang.AssertionError: null
at
org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.addBlocksToBeInvalidated(DatanodeDescriptor.java:641)
at
org.apache.hadoop.hdfs.server.blockmanagement.InvalidateBlocks.invalidateWork(InvalidateBlocks.java:299)
at
org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.invalidateWorkForOneNode(BlockManager.java:4236)
at
org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.computeInvalidateWork(BlockManager.java:1736)
at
org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil.computeInvalidationWork(BlockManagerTestUtil.java:169)
at
org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil.computeAllPendingWork(BlockManagerTestUtil.java:185)
at
org.apache.hadoop.hdfs.server.namenode.ha.HAStressTestHarness$1.doAnAction(HAStressTestHarness.java:102)
at
org.apache.hadoop.test.MultithreadedTestUtil$RepeatingTestThread.doWork(MultithreadedTestUtil.java:222)
at
org.apache.hadoop.test.MultithreadedTestUtil$TestingThread.run(MultithreadedTestUtil.java:189)
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Studying the code, the assert can only fail due to a race condition that only
happens in the test.
Specifically, the test uses BlockManagerTestUtil to call
{{BlockManager#computeInvalidateWork}}, which gets
{{invalidateBlocks.getDatanodes()}}. Afterwards, use the list to perform block
invalidation via {{InvalidateBlocks#invalidateWork}}, which calls
{{DatanodeDesriptor#addBlocksToBeInvalidated}} and there is an assertion to
ensure the invalidation list is not empty. However, if the BlockManager
performs block invalidation before
{{DatanodeDesriptor#addBlocksToBeInvalidated}}, the invalidation list can be
empty, because there's no proper lock to ensure atomicity.
This is not a problem for real cluster, because there is only one BlockManager
per NameNode process, so the potential race condition is not exposed.
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