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Date: Thu, 19 Mar 2015 10:42:18 -0600
From: Thavatchai Makphaibulchoke <thavatchai.makpahibulchoke@hp.com>
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To: Steven Rostedt <rostedt@goodmis.org>,
        Mike Galbraith <umgwanakikbuti@gmail.com>
CC: linux-kernel@vger.kernel.org,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Carsten Emde <C.Emde@osadl.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        John Kacur <jkacur@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>
Subject: Re: [PATCH RT 2/4] Revert "timers: do not raise softirq unconditionally"
References: <20150317163541.080310081@goodmis.org>	<20150317163617.218582800@goodmis.org>	<20150317163551.3093b6c2@gandalf.local.home>	<1426753029.4168.80.camel@gmail.com> <20150319122611.0d002d48@gandalf.local.home>
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On 03/19/2015 10:26 AM, Steven Rostedt wrote:
> On Thu, 19 Mar 2015 09:17:09 +0100
> Mike Galbraith <umgwanakikbuti@gmail.com> wrote:
> 
> 
>> (aw crap, let's go shopping)... so why is the one in timer.c ok?
> 
> It's not. Sebastian, you said there were no other cases of rt_mutexes
> being taken in hard irq context. Looks like timer.c has one.
> 
> So perhaps the real fix is to get that special case of ownership in
> hard interrupt context?
> 
> -- Steve
> 

Steve, I'm still working on the fix we discussed using dummy irq_task.
I should be able to submit some time next week, if still interested.

Either that, or I think we should remove the function
spin_do_trylock_in_interrupt() to prevent any possibility of running
into similar problems in the future.

Thanks,
Mak.