[jira] [Updated] (YARN-2608) FairScheduler: Potential deadlocks in loading alloc files and clock access

["Karthik Kambatla (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YARN-2608?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Karthik Kambatla updated YARN-2608:
-----------------------------------
    Summary: FairScheduler: Potential deadlocks in loading alloc files and clock access  (was: FairScheduler: Potential deadlocks in loading alloc files and clock)

> FairScheduler: Potential deadlocks in loading alloc files and clock access
> --------------------------------------------------------------------------
>
>                 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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