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Date: Thu, 20 Nov 2014 08:45:02 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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Subject: Re: [PATCH v3 3/3] sched, x86: Check that we're on the right stack
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* Andy Lutomirski <luto@amacapital.net> wrote:

> On Wed, Nov 19, 2014 at 3:59 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> > On Wed, Nov 19, 2014 at 3:49 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> >>
> >> My only real objection is that it's going to be ugly and 
> >> error prone. It'll have to be something like:
> >
> > No.
> >
> >> because the whole point of this series is to make the IST 
> >> entries not be atomic when they come from userspace.
> >
> > Andy, you need to lay off the drugs.
> >
> 
> No drugs, just imprecision.  This series doesn't change NMI 
> handling at all.  It only changes machine_check int3, debug, 
> and stack_segment. (Why is #SS using IST stacks anyway?)

We made most of those preemptible in -rt and changed it away from 
the IST. I never got a good explanation from anyone for why they 
were IST in the first place - histeric accident or such.

Feel free to clean this up too!

Thanks,

	Ingo