From: Aaron Tomlin <atomlin@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
bmr@redhat.com, jcastillo@redhat.com, mguzik@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] fs: Use a seperate wq for do_sync_work() to avoid a potential deadlock
Date: Fri, 19 Sep 2014 16:44:23 +0100 [thread overview]
Message-ID: <20140919154423.GH25400@atomlin.usersys.redhat.com> (raw)
In-Reply-To: <20140917211613.GU4322@dastard>
On Thu, Sep 18, 2014 at 07:16:13AM +1000, Dave Chinner wrote:
> > - Both lru_add_drain and do_sync_work work items are added to
> > the same global system_wq
> >
> > - The current work fn on the system_wq is do_sync_work and is
> > blocked waiting to aquire an sb's s_umount for reading
> >
> > - The umount task is the current owner of the s_umount in
> > question but is waiting for do_sync_work to continue.
> > Thus we hit a deadlock situation.
>
> What kernel did you see this deadlock on?
Sorry for the noise. This deadlock was produced under a kernel whereby
the workqueue implementation is significantly less sophisticated.
--
Aaron Tomlin
next prev parent reply other threads:[~2014-09-19 15:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-17 11:39 [RFC PATCH] fs: Use a seperate wq for do_sync_work() to avoid a potential deadlock Aaron Tomlin
2014-09-17 18:22 ` Oleg Nesterov
2014-09-17 20:46 ` Aaron Tomlin
2014-09-17 21:16 ` Dave Chinner
2014-09-19 15:44 ` Aaron Tomlin [this message]
2014-09-17 21:42 ` Oleg Nesterov
2014-09-19 9:35 ` Aaron Tomlin
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