From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH RT 4/8] rtmutex: use a trylock for waiter lock in trylock Date: Fri, 31 Jan 2014 23:07:37 +0100 Message-ID: <20140131220737.GF21238@linutronix.de> References: <20140116015824.201732155@goodmis.org> <20140116020324.637491369@goodmis.org> <1389841737.5418.14.camel@marge.simpson.net> <20140116232228.0f3cfb89@gandalf.local.home> <1389935832.5449.23.camel@marge.simpson.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Steven Rostedt , linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , John Kacur To: Mike Galbraith Return-path: Content-Disposition: inline In-Reply-To: <1389935832.5449.23.camel@marge.simpson.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org * Mike Galbraith | 2014-01-17 06:17:12 [+0100]: >On Thu, 2014-01-16 at 23:22 -0500, Steven Rostedt wrote: >> On Thu, 16 Jan 2014 04:08:57 +0100 >> Mike Galbraith wrote: >> >> > On Wed, 2014-01-15 at 20:58 -0500, Steven Rostedt wrote: >> > >> > >> > > 3.2.53-rt76-rc1 stable review patch. >> > > If anyone has any objections, please let me know. >> > >> > Not sure this is needed without the tglx don't unconditionally raise >> > timer softirq patch, and with that patch applied in the form it exists >> > in 3.12-rt9, as well as this one, you'll still eventually deadlock. >> >> Hmm, I'll have to take a look. This sounds to be missing from all the >> stable -rt kernels. I'll be pulling in the latest updates from 3.12-rt >> soon. > >Below are the two deadlocks I encountered with 3.12-rt9, which has both >$subject and timers-do-not-raise-softirq-unconditionally.patch applied. This patch was introduced because we had a deadlock in run_local_timers() which took a sleeping lock in hardirq context. This seem not to be the case in v3.2 therefore I would suggest not to take this patch here because it does not fix anything. Mike, do you see these deadlocks with 3.12.*-rt11 as well? Sebastian