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Posted to derby-dev@db.apache.org by "Diogo Sousa (JIRA)" <ji...@apache.org> on 2014/07/29 09:57:38 UTC

[jira] [Updated] (DERBY-6679) Possible Atomicity Violation in BaseMonitor.shutdown()

     [ https://issues.apache.org/jira/browse/DERBY-6679?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Diogo Sousa updated DERBY-6679:
-------------------------------

    Description: 
In org.apache.derby.impl.services.monitor.BaseMonitor there might be an atomicity violation in method shutdown(), lines 181-206:

{{monospaced}}
> 		for (;;) {
> 			synchronized (this) {
>   181:    		position = services.size()  - 1;
> 				if (position == 0)
> 					break;
>                                 ...
> 			}
>                         ...
> 		}
> 		...
>  206:	((TopService) services.get(0)).shutdown();
{{monospaced}}

Between the execution of lines 181 and 206 a concurrent thread may remove the only remaining service, causing the access to "services" in line 206 to fail.

  was:
In org.apache.derby.impl.services.monitor.BaseMonitor there might be an atomicity violation in method shutdown(), lines 181-206:

> 		for (;;) {
> 			synchronized (this) {
>   181:    		position = services.size()  - 1;
> 				if (position == 0)
> 					break;
>                                 ...
> 			}
>                         ...
> 		}
> 		...
>  206:	((TopService) services.get(0)).shutdown();

Between the execution of lines 181 and 206 a concurrent thread may remove the only remaining service, causing the access to "services" in line 206 to fail.


> Possible Atomicity Violation in BaseMonitor.shutdown()
> ------------------------------------------------------
>
>                 Key: DERBY-6679
>                 URL: https://issues.apache.org/jira/browse/DERBY-6679
>             Project: Derby
>          Issue Type: Bug
>          Components: Services
>    Affects Versions: 10.10.2.0
>         Environment: all
>            Reporter: Diogo Sousa
>            Priority: Minor
>
> In org.apache.derby.impl.services.monitor.BaseMonitor there might be an atomicity violation in method shutdown(), lines 181-206:
> {{monospaced}}
> > 		for (;;) {
> > 			synchronized (this) {
> >   181:    		position = services.size()  - 1;
> > 				if (position == 0)
> > 					break;
> >                                 ...
> > 			}
> >                         ...
> > 		}
> > 		...
> >  206:	((TopService) services.get(0)).shutdown();
> {{monospaced}}
> Between the execution of lines 181 and 206 a concurrent thread may remove the only remaining service, causing the access to "services" in line 206 to fail.



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