From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: Kent Overstreet <kmo@daterainc.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
RT <linux-rt-users@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH V2] rt/aio: fix rcu garbage collection might_sleep() splat
Date: Wed, 11 Jun 2014 06:10:04 +0200 [thread overview]
Message-ID: <1402459804.5195.19.camel@marge.simpson.net> (raw)
In-Reply-To: <20140610175001.GF27015@kvack.org>
On Tue, 2014-06-10 at 13:50 -0400, Benjamin LaHaise wrote:
> On Tue, Jun 10, 2014 at 05:47:28AM +0200, Mike Galbraith wrote:
> > On Mon, 2014-06-09 at 10:08 +0800, Lai Jiangshan wrote:
> > > Hi, rt-people
> > >
> > > I don't think it is the correct direction.
> > > Softirq (including local_bh_disable()) in RT kernel should be preemptible.
> >
> > How about the below then?
> >
> > I was sorely tempted to post a tiny variant that dropped taking ctx_lock
> > in free_ioctx_users() entirely, as someone diddling with no reference
> > didn't make sense. Cc Ben, he would know.
>
> That should be okay... Let's ask Kent to chime in on whether this looks
> safe to him on the percpu ref front as well, since he's the one who wrote
> this code.
Looking at the gizzard of our in-tree user of kiocb_set_cancel_fn()
(gadget), cancel() leads to dequeue() methods, which take other sleeping
locks, so tiniest variant is not an option, patchlet stands.
-Mike
next prev parent reply other threads:[~2014-06-11 4:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-08 8:35 [RFC PATCH] rt/aio: fix rcu garbage collection might_sleep() splat Mike Galbraith
2014-06-09 2:08 ` Lai Jiangshan
2014-06-09 3:17 ` Mike Galbraith
2014-06-09 6:22 ` Mike Galbraith
2014-06-09 9:04 ` Pavel Vasilyev
2014-06-10 3:47 ` [RFC PATCH V2] " Mike Galbraith
2014-06-10 17:50 ` Benjamin LaHaise
2014-06-11 4:10 ` Mike Galbraith [this message]
2014-06-12 20:26 ` Kent Overstreet
2014-06-25 15:24 ` Benjamin LaHaise
2014-06-26 7:37 ` Mike Galbraith
2014-06-26 16:42 ` Benjamin LaHaise
2015-02-16 17:59 ` Sebastian Andrzej Siewior
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