Bug#723180: [PATCH] Revert "x86: Disable IST stacks for debug/int 3/stack fault for PREEMPT_RT"
- 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: Bug#723180: [PATCH] Revert "x86: Disable IST stacks for debug/int 3/stack fault for PREEMPT_RT"
- From: Andi Kleen <andi@firstfloor.org>
- Date: Sun, 5 Jan 2014 19:04:47 +0100
- Message-id: <[🔎] 20140105180446.GX20765@two.firstfloor.org>
- Reply-to: Andi Kleen <andi@firstfloor.org>, 723180@bugs.debian.org
- In-reply-to: <[🔎] 1388897147.5342.36.camel@marge.simpson.net>
- References: <20130917061329.4872.51468.reportbug@dell-inspiron-linux.dlinkrouter> <1379427451.23881.48.camel@deadeye.wl.decadent.org.uk> <CAP01z6LVxoA6kDJeL8NuO2aA22BjMvXSk9ZY7z9cOK1=k56vpg@mail.gmail.com> <1379905562.3913.8.camel@deadeye.wl.decadent.org.uk> <CAP01z6+j6moUio9pc3G3iz+ebJCdKEvngddxnxazRP+NXwLkyg@mail.gmail.com> <1380115449.4430.21.camel@deadeye.wl.decadent.org.uk> <52AE0419.3050103@linutronix.de> <[🔎] 20140103135548.GA6327@linutronix.de> <[🔎] 20140104181807.GS20765@two.firstfloor.org> <[🔎] 1388897147.5342.36.camel@marge.simpson.net>
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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