Subject: Re: [BUG: NULL pointer dereference] cgroups and RT
	scheduling	interact badly.
From: Peter Zijlstra <peterz@infradead.org>
To: "Daniel K." <dk@uw.no>
Cc: mingo@elte.hu, menage@google.com,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <1213624312.16944.104.camel@twins>
References: <485445AE.2010602@uw.no> <1213612447.16944.99.camel@twins>
	 <4856671B.1020304@uw.no>  <1213624312.16944.104.camel@twins>
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Date: Mon, 16 Jun 2008 16:39:08 +0200
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On Mon, 2008-06-16 at 15:51 +0200, Peter Zijlstra wrote:
> On Mon, 2008-06-16 at 15:14 +0200, Daniel K. wrote:
> > Peter Zijlstra wrote:
> > > Does the below work for you?
> > > 
> > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > > ---
> > > Index: linux-2.6/kernel/sched.c
> > > ===================================================================
> > > --- linux-2.6.orig/kernel/sched.c
> > > +++ linux-2.6/kernel/sched.c
> > > @@ -7784,7 +7784,6 @@ static void init_tg_rt_entry(struct task
> > >  	else
> > >  		rt_se->rt_rq = parent->my_q;
> > >  
> > > -	rt_se->rt_rq = &rq->rt;
> > >  	rt_se->my_q = rt_rq;
> > >  	rt_se->parent = parent;
> > >  	INIT_LIST_HEAD(&rt_se->run_list);
> > 
> > Although this patch seems to be correct, this is what shows up on my
> > netconsole, when applying it -- with an offset, do you have other fixes
> > applied as well?
> 
> I had indeed, although nothing touching the rt scheduler. I popped all
> my patches and pulled an update from Linus, but I fail to reproduce the
> below.
> 
> /me goes look for that burnp6 thing, I used a simple while (1); loop.

found it, still seems to work for me. do you have a funny number of
cpus? or anything else noteworthy?

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