Date: Sun, 5 Jan 2014 19:04:47 +0100
From: Andi Kleen <andi@firstfloor.org>
To: Mike Galbraith <bitbucket@online.de>
Cc: Andi Kleen <andi@firstfloor.org>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Ben Hutchings <ben@decadent.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Steven Rostedt <rostedt@rostedt.homelinux.com>, 723180@bugs.debian.org,
        Brian Silverman <bsilver16384@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-rt-users@vger.kernel.org
Subject: Re: [PATCH] Revert "x86: Disable IST stacks for debug/int 3/stack
 fault for PREEMPT_RT"
Message-ID: <20140105180446.GX20765@two.firstfloor.org>
References: <20130917061329.4872.51468.reportbug@dell-inspiron-linux.dlinkrouter>
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 <1380115449.4430.21.camel@deadeye.wl.decadent.org.uk>
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On Sun, Jan 05, 2014 at 05:45:47AM +0100, Mike Galbraith wrote:
> On Sat, 2014-01-04 at 19:18 +0100, Andi Kleen wrote: 
> > On Fri, Jan 03, 2014 at 02:55:48PM +0100, Sebastian Andrzej Siewior wrote:
> > > where do I start. Let me explain what is going on here. The code
> > > sequence
> > 
> > Yes the IST stacks are needed for correctness, even in more cases than
> > the example below. You cannot just disable them, just because you don't
> > like them.
> 
> You had a better reason than dislike.

Ah true it was me. Good point. I forgot all about that.

Probably it needs some form of the NMI style paranoid_* switch.

-Andi
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