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https://issues.apache.org/jira/browse/DIRMINA-1021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15401781#comment-15401781
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Emmanuel Lecharny commented on DIRMINA-1021:
--------------------------------------------

Actually, I was reviewing the various close methods in IoSession. I found that 
when teh {{closeNow()}} method was called, the underlying connection was not 
closed immediately, something that would potentially have some side effect, as 
some messages may be processed between the moment the {{closeNow()}} method was 
called, and the moment the effective closure is done.

But this is not the bottom of my review : I still have to check what's going on 
when an exception occurs somewhere, because it ends with a close being done, 
and I think this is where you have some issue.

I hope to get to the bottom of this problem soon, and to cut a 2.0.14 release, 
so bear with me in teh coming days...

> MINA-CORE does not remove sessions if exceptions occur while closing
> --------------------------------------------------------------------
>
>                 Key: DIRMINA-1021
>                 URL: https://issues.apache.org/jira/browse/DIRMINA-1021
>             Project: MINA
>          Issue Type: Bug
>    Affects Versions: 2.0.8
>         Environment: mina-ssh 0.14.0 
> mina-core 2.0.8 
> Multiple OSes / Java configurations: 
> * Mac OS X El Capitan on Java 8 (1.8.0_60) 
> * CentOS 6.4 on Java 8 (1.8.0_60) 
> * CentOS 6.5 on Java 8 (1.8.0_20-b26).
>            Reporter: Doug Kelly
>         Attachments: attempt-removing-sessions-closing.patch, 
> mina-core-2.0.14-SNAPSHOT.jar
>
>
> MINA SSHD isn't removing sessions when using the MINA/NIO backend if an 
> exception as received as the session is closing (such as a connection reset 
> is received with data still in the write buffer). When this case happens, it 
> seems that {{NioProcessor.getState}} returns the state as {{CLOSING}} (I'm 
> assuming since the underlying channel is now closed), which means that the 
> {{AbstractPollingIoProcessor.removeSessions()}} won't ever prune the session, 
> since a {{CLOSING}} state is simply ignored. The result is a resource leak 
> over time, since these sessions are never pruned (it's a slow leak, since 
> entering this condition is racy – on my workstation, I can produce it through 
> randomly interrupting connections anywhere from 1/6 to 1/10th of the time). 
> (This may either be major or critical; reprioritize as necessary.)
> I specifically see this error with Gerrit 2.10.4 and Gerrit 2.11.5 (using 
> mina-sshd 0.14.0 / mina-core 2.0.8), and it looks like the code path is 
> unchanged in mina-sshd 1.0.0 / mina-core 2.0.9. I was unsure if this is 
> specifically a bug in mina-core or, if it's something unique to mina-sshd. My 
> local development system runs Mac OS X El Capitan on Java 8 (1.8.0_60), but 
> I've also seen this on Linux (CentOS 6.4, again Java 1.8.0_60 and CentOS 6.5 
> on Java 1.8.0_20-b26).
> The fix may be as simple as attempting to remove the session if {{OPENED}} or 
> {{CLOSING}}, but I'm unsure what side-effects this may have with other 
> backends. I'll be happy to test it locally, but I'm fairly ignorant when it 
> comes to MINA's code.
> The attached patch (to mina-core) seems to resolve the issue by following the 
> reproduction case I have on the [Gerrit issue 
> tracker|https://code.google.com/p/gerrit/issues/detail?id=3685].



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