[jira] [Created] (YUNIKORN-3540) Application.GetAllPlaceholderData() returns the internal PlaceholderData objects

["YUNG_CHENG (Jira)" <ji...@apache.org>]

YUNG_CHENG created YUNIKORN-3540:
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             Summary: Application.GetAllPlaceholderData() returns the internal PlaceholderData objects
                 Key: YUNIKORN-3540
                 URL: https://issues.apache.org/jira/browse/YUNIKORN-3540
             Project: Apache YuniKorn
          Issue Type: Bug
          Components: core - scheduler
            Reporter: YUNG_CHENG
            Assignee: YUNG_CHENG



{{Application.GetAllPlaceholderData()}} in {{pkg/scheduler/objects/application.go}} takes the application read lock and returns the {{*PlaceholderData}} pointers stored in the application. The lock is released when the method returns, but the caller still holds the internal objects.

The REST handler {{getPlaceholderDAO()}} in {{pkg/webservice/handlers.go}} reads {{Count}}, {{Replaced}} and {{TimedOut}} from these objects without the application lock. The scheduler changes the same fields under the application lock in {{addPlaceholderData()}}, {{removeAllocationInternal()}}, {{RemoveAllAllocations()}}, {{timeoutPlaceholderProcessing()}} and {{SetTimedOutPlaceholder()}}. This is a data race: a test that adds placeholder asks while it reads the data the same way as the REST handler fails with {{-race}}.

The impact is low. The REST response can show counts from the middle of an update, and the race detector reports the race. Because the caller gets the internal objects, a write through the returned pointer would also change the application state. No caller writes to it today.

The test variable in {{TestAddAllocAsk}} is called {{clonePlaceholderData}}, which suggests that the method was meant to return a copy.

*Proposed change*
Return a copy of each {{PlaceholderData}}. A shallow copy is enough: {{MinResource}} is cloned when the entry is created and is not changed afterwards. Update {{TestAddAllocAsk}} to compare the values instead of the pointers, and check that the result is a copy.




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