linux-kernel - Re: [RFC][PATCH 2/8] sched/rtmutex/deadline: Fix a PI crash for deadline tasks

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Message-ID: <20160614163948.GN5981@e106622-lin>
Date:	Tue, 14 Jun 2016 17:39:48 +0100
From:	Juri Lelli <juri.lelli@....com>
To:	xlpang@...hat.com
Cc:	Peter Zijlstra <peterz@...radead.org>, mingo@...nel.org,
	tglx@...utronix.de, rostedt@...dmis.org,
	linux-kernel@...r.kernel.org, mathieu.desnoyers@...icios.com,
	jdesfossez@...icios.com, bristot@...hat.com,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: [RFC][PATCH 2/8] sched/rtmutex/deadline: Fix a PI crash for
 deadline tasks

On 14/06/16 14:07, Juri Lelli wrote:
> On 14/06/16 20:53, Xunlei Pang wrote:
> > On 2016/06/14 at 18:21, Juri Lelli wrote:
> > > Hi,
> > >
> > > On 07/06/16 21:56, Peter Zijlstra wrote:
> > >> From: Xunlei Pang <xlpang@...hat.com>
> > >>

[...]

> > > The idea of this fix makes sense to me. But, I would like to be able to
> > > see the BUG and test the fix. What I have is a test in which I create N
> > > DEADLINE workers that share a PI mutex. They get migrated around and
> > > seem to stress PI code. But I couldn't hit the BUG yet. Maybe I let it
> > > run for some more time.
> > 
> > You can use this reproducer attached(gcc crash_deadline_pi.c -lpthread -lrt ).
> > Start multiple instances, then it will hit the bug very soon.
> > 
> 
> Great, thanks! I'll use it.
> 

OK. I could reproduce and also test that I can't see the BUG anymore
with the fix.