From: Tejun Heo <tj@kernel.org>
To: Jeff Layton <jlayton@poochiereds.net>
Cc: Chris Worley <chris.worley@primarydata.com>,
linux-kernel@vger.kernel.org, bfields@fieldses.org,
Michael Skralivetsky <michael.skralivetsky@primarydata.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
Shaohua Li <shli@fb.com>
Subject: Re: timer code oops when calling mod_delayed_work
Date: Tue, 3 Nov 2015 17:54:05 -0500 [thread overview]
Message-ID: <20151103225405.GG5749@mtj.duckdns.org> (raw)
In-Reply-To: <20151103125504.6649138f@tlielax.poochiereds.net>
Hello, Jeff.
On Tue, Nov 03, 2015 at 12:55:04PM -0500, Jeff Layton wrote:
> > Ok, I built a kernel with that patch reverted and that seems to fix the
> > problem.
> >
> > Looking at the patch, I guess the main difference is that we're no
> > longer using add_timer for unbound workqueue tasks. That said, we
> > should have possession of the PENDING bit before calling add_timer_on.
> >
> > So...I'm a little stumped. Any thoughts as to where the race could be?
>
> Ok, I've been able to reproduce this with a small module that I wrote
> as a reproducer:
I think I know what's going on. Looks like a bug in timer code when
timers are queued on a different cpu than before. Will experiment
with it a bit and report back.
Thanks.
--
tejun
next prev parent reply other threads:[~2015-11-03 22:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 14:31 timer code oops when calling mod_delayed_work Jeff Layton
2015-10-29 17:58 ` Jeff Layton
2015-10-31 2:00 ` Tejun Heo
2015-10-31 11:34 ` Jeff Layton
2015-10-31 21:31 ` Tejun Heo
2015-10-31 21:54 ` Jeff Layton
2015-11-02 19:48 ` Chris Worley
2015-11-02 19:56 ` Jeff Layton
2015-11-03 1:33 ` Jeff Layton
2015-11-03 17:55 ` Jeff Layton
2015-11-03 22:54 ` Tejun Heo [this message]
2015-11-04 0:06 ` Tejun Heo
2015-11-04 11:48 ` Jeff Layton
2015-11-04 17:15 ` [PATCH] timer: add_timer_on() should perform proper migration Tejun Heo
2015-11-04 19:27 ` [tip:timers/urgent] timers: Use proper base migration in add_timer_on() tip-bot for Tejun Heo
2015-11-04 19:35 ` [PATCH] timer: add_timer_on() should perform proper migration Thomas Gleixner
2015-11-04 19:43 ` Tejun Heo
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