[YARN-10642] Race condition: AsyncDispatcher can get stuck by the changes introduced in YARN-8995

• Type: Sub-task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.2.1
• Fix Version/s: 3.4.0, 3.3.1, 3.2.3
• Component/s: resourcemanager
• Target Version/s: 3.4.0
• External issue ID: YARN-8995
• Assignee: Chenyu Zheng
• Reporter: Chenyu Zheng
• Created: 20/Feb/21 12:47
• Updated: 10/Jun/21 08:15
• Resolved: 11/May/21 13:19

Description

In our cluster, ResouceManager stuck twice within twenty days. Yarn client can't submit application. I got jstack info at second time, then found the reason.
I analyze all the jstack, I found many thread stuck because can't get LinkedBlockingQueue.putLock. (Note: Sorry for limited space , omit the analytical process)
The reason is that one thread hold the putLock all the time, printEventQueueDetails will called forEachRemaining, then hold putLock and readLock. The AsyncDispatcher will stuck.

Thread 6526 (IPC Server handler 454 on default port 8030):
  State: RUNNABLE
  Blocked count: 29988
  Waited count: 2035029
  Stack:
    java.util.concurrent.LinkedBlockingQueue$LBQSpliterator.forEachRemaining(LinkedBlockingQueue.java:926)
    java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
    java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
    java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
    java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
    org.apache.hadoop.yarn.event.AsyncDispatcher$GenericEventHandler.printEventQueueDetails(AsyncDispatcher.java:270)
    org.apache.hadoop.yarn.event.AsyncDispatcher$GenericEventHandler.handle(AsyncDispatcher.java:295)
    org.apache.hadoop.yarn.server.resourcemanager.DefaultAMSProcessor.handleProgress(DefaultAMSProcessor.java:408)
    org.apache.hadoop.yarn.server.resourcemanager.DefaultAMSProcessor.allocate(DefaultAMSProcessor.java:215)
    org.apache.hadoop.yarn.server.resourcemanager.scheduler.constraint.processor.DisabledPlacementProcessor.allocate(DisabledPlacementProcessor.java:75)
    org.apache.hadoop.yarn.server.resourcemanager.AMSProcessingChain.allocate(AMSProcessingChain.java:92)
    org.apache.hadoop.yarn.server.resourcemanager.ApplicationMasterService.allocate(ApplicationMasterService.java:432)
    org.apache.hadoop.yarn.api.impl.pb.service.ApplicationMasterProtocolPBServiceImpl.allocate(ApplicationMasterProtocolPBServiceImpl.java:60)
    org.apache.hadoop.yarn.proto.ApplicationMasterProtocol$ApplicationMasterProtocolService$2.callBlockingMethod(ApplicationMasterProtocol.java:99)
    org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:528)
    org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1070)
    org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:1040)
    org.apache.hadoop.ipc.Server$RpcCall.run(Server.java:958)
    java.security.AccessController.doPrivileged(Native Method)

I analyze LinkedBlockingQueue's source code. I found forEachRemaining in LinkedBlockingQueue.LBQSpliterator may stuck, when forEachRemaining and take are called in different thread.
YARN-8995 introduce printEventQueueDetails method, "eventQueue.stream().collect" will called forEachRemaining method.

Let's see why？ "put.png" shows that how to put("a"), "take.png" shows that how to take()。Specical Node: The removed Node will point itself for help gc!!!
The key point code is in forEachRemaining, we see LBQSpliterator use forEachRemaining to visit all Node. But when got item value from Node, will release the lock. If at this time, take() will be called.
The variable 'p' in forEachRemaining may point a Node which point itself, then forEachRemaining will be in dead loop. You can see it in "deadloop.png"

Let's see a simple uni-test, Let's forEachRemaining called more slow than take, the problem will reproduction。uni-test is MockForDeadLoop.java.

I debug MockForDeadLoop.java, and see a Node point itself. You can see pic "debugfornode.png"

Environment:
OS: CentOS Linux release 7.5.1804 (Core)
JDK: jdk1.8.0_281

Issue Links

• is duplicated by: YARN-10643 Fix the race condition introduced by YARN-8995.
• relates to: YARN-10643 Fix the race condition introduced by YARN-8995.