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https://issues.apache.org/jira/browse/YARN-2608?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14148496#comment-14148496
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Hadoop QA commented on YARN-2608:
---------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest 
attachment 
  http://issues.apache.org/jira/secure/attachment/12671328/YARN-2608-3.patch
  against trunk revision 8269bfa.

    {color:green}+1 @author{color}.  The patch does not contain any @author 
tags.

    {color:red}-1 tests included{color}.  The patch doesn't appear to include 
any new or modified tests.
                        Please justify why no new tests are needed for this 
patch.
                        Also please list what manual steps were performed to 
verify this patch.

    {color:green}+1 javac{color}.  The applied patch does not increase the 
total number of javac compiler warnings.

    {color:green}+1 javadoc{color}.  There were no new javadoc warning messages.

    {color:green}+1 eclipse:eclipse{color}.  The patch built with 
eclipse:eclipse.

    {color:green}+1 findbugs{color}.  The patch does not introduce any new 
Findbugs (version 2.0.3) warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase 
the total number of release audit warnings.

    {color:green}+1 core tests{color}.  The patch passed unit tests in 
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager.

    {color:green}+1 contrib tests{color}.  The patch passed contrib unit tests.

Test results: 
https://builds.apache.org/job/PreCommit-YARN-Build/5136//testReport/
Console output: https://builds.apache.org/job/PreCommit-YARN-Build/5136//console

This message is automatically generated.

> FairScheduler may hung due to two potential deadlocks
> -----------------------------------------------------
>
>                 Key: YARN-2608
>                 URL: https://issues.apache.org/jira/browse/YARN-2608
>             Project: Hadoop YARN
>          Issue Type: Bug
>            Reporter: Wei Yan
>            Assignee: Wei Yan
>         Attachments: YARN-2608-1.patch, YARN-2608-2.patch, YARN-2608-3.patch
>
>
> Two potential deadlocks exist inside the FairScheduler.
> 1. AllocationFileLoaderService would reload the queue configuration, which 
> calls FairScheduler.AllocationReloadListener.onReload() function. And require 
> *FairScheduler's lock*; 
> {code}
>   public void onReload(AllocationConfiguration queueInfo) {
>       synchronized (FairScheduler.this) {
>           ....
>       }
>   }
> {code}
> after that, it would require the *QueueManager's queues lock*.
> {code}
>   private FSQueue getQueue(String name, boolean create, FSQueueType 
> queueType) {
>       name = ensureRootPrefix(name);
>       synchronized (queues) {
>           ....
>       }
>   }
> {code}
> Another thread FairScheduler.assignToQueue may also need to create a new 
> queue when a new job submitted. This thread would hold the *QueueManager's 
> queues lock* firstly, and then would like to hold the *FairScheduler's lock* 
> as it needs to call FairScheduler.getClock() function when creating a new 
> FSLeafQueue. Deadlock may happen here.
> 2. The AllocationFileLoaderService holds  *AllocationFileLoaderService's 
> lock* first, and then waits for *FairScheduler's lock*. Another thread (like 
> AdminService.refreshQueues) may call FairScheduler's reinitialize function, 
> which holds *FairScheduler's lock* first, and then waits for 
> *AllocationFileLoaderService's lock*. Deadlock may happen here.



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