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https://issues.apache.org/jira/browse/DIRMINA-1021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15028369#comment-15028369
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Emmanuel Lecharny commented on DIRMINA-1021:
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What I mean is that the {{removeSessions()}} function role is just to close
opened sessions scheduled for closing. When you actually want to close a
session, you push the session to this least, whatever its status is (OPENING,
OPENED or CLOSING). This is not the place where we actually close the sessions,
except when they are oepned. It means that if the session is in CLOSING state,
then it was already closed somewhere else.
I'm currently looking where this close could have happened (and that includes
exceptions).
> 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 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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