[Gluster-devel] Regression caused to gfapi applications with enabling client-io-threads by default

[Pranith Kumar Karampuri]

On Wed, Oct 5, 2016 at 2:00 PM, Soumya Koduri <skoduri at redhat.com> wrote:

> Hi,
>
> With http://review.gluster.org/#/c/15051/, performace/client-io-threads
> is enabled by default. But with that we see regression caused to
> nfs-ganesha application trying to un/re-export any glusterfs volume. This
> shall be the same case with any gfapi application using glfs_fini().
>
> More details and the RCA can be found at [1].
>
> In short, iot-worker threads spawned  (when the above option is enabled)
> are not cleaned up as part of io-threads-xlator->fini() and those threads
> could end up accessing invalid/freed memory post glfs_fini().
>
> The actual fix is to address io-threads-xlator->fini() to cleanup those
> threads before exiting. But since those threads' IDs are currently not
> stored, the fix could be very intricate and take a while. So till then to
> avoid all existing applications crash, I suggest to keep this option
> disabled by default and update this known_issue with enabling this option
> in the release-notes.
>
> I sent a patch to revert the commit - http://review.gluster.org/#/c/15616/
> [2]
>

Good catch! I think the correct fix would be to make sure all threads die
as part of PARENT_DOWN then?


> Comments/Suggestions are welcome.
>
> Thanks,
> Soumya
>
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1380619#c11
> [2] http://review.gluster.org/#/c/15616/
>



-- 
Pranith
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