[jira] [Updated] (SLING-2990) race condition in scheduler could cause tasks to be lost

["Carsten Ziegeler (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SLING-2990?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Carsten Ziegeler updated SLING-2990:
------------------------------------

    Fix Version/s: Commons Scheduler 2.4.0
    
> race condition in scheduler could cause tasks to be lost
> --------------------------------------------------------
>
>                 Key: SLING-2990
>                 URL: https://issues.apache.org/jira/browse/SLING-2990
>             Project: Sling
>          Issue Type: Bug
>          Components: Commons
>    Affects Versions: Commons Scheduler 2.3.4
>            Reporter: Amichai Rothman
>             Fix For: Commons Scheduler 2.4.0
>
>
> In QuartzScheduler.java, binding a task/job checks if the scheduler is null and then either registers the service reference or adds it to a list for later registration. When the scheduler is activated all items on the list are registered and the list is cleared.
> All accesses to the list are properly synchronized, but the scheduler null check is not, so they are not done atomically together - there may be a race condition here that can cause a task to be lost: if the scheduler is checked and found to be null, then a context switch occurs and the scheduler is activated and processes the list, and then the original thread resumes and adds the task to the list, then the task will remain unprocessed in the list and never be registered.
> The same thing might happen inversed with unbinding tasks/jobs.
> btw the bind/unbind methods are duplicated for jobs and tasks, so it might be nicer to extract the common implementation and delegate to it with a job/task parameter. Then there will be less places to apply the fix in :-)

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira