From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Steven Rostedt <rostedt@rostedt.homelinux.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>, Li Zefan <lizf@cn.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Johannes Berg <johannes.berg@intel.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Tom Zanussi <tzanussi@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Andi Kleen <andi@firstfloor.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
Tejun Heo <htejun@gmail.com>
Subject: Re: [patch 1/2] x86_64 page fault NMI-safe
Date: Thu, 15 Jul 2010 13:38:36 -0400 [thread overview]
Message-ID: <20100715173836.GA17376@Krystal> (raw)
In-Reply-To: <AANLkTik4mdj3h16CU2GUQAQuG4yeAWFuZsqbPC0ra6Id@mail.gmail.com>
* Linus Torvalds (torvalds@linux-foundation.org) wrote:
> On Thu, Jul 15, 2010 at 9:44 AM, Mathieu Desnoyers
> <mathieu.desnoyers@efficios.com> wrote:
> >
> > The first thing that strikes me is that we could be interrupted by a standard
> > interrupt on top of the iret instruction below.
>
> No, that can never happen.
>
> Why? Simple: regular interrupts aren't ever enabled in eflags. So the
> only kinds of traps we can get are NMI's (that don't follow the normal
> rules), and exceptions.
Ah, you're right, since NMIs are an intr gate, IF is disabled in the EFLAGS all
along.
>
> Of course, if there is some trap that re-enables interrupts even if
> the trap happened in an interrupt-disabled region, then that would
> change things, but that would be a bad bug regardless (and totally
> independently of any NMI issues). So in that sense it's a "could
> happen", but it's something that would be a totally separate bug.
Yep, this kind of scenario would therefore be a bug that does not belong to the
specific realm of nmis.
Thanks,
Mathieu
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2010-07-15 17:38 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-14 15:49 [patch 0/2] x86: NMI-safe trap handlers Mathieu Desnoyers
2010-07-14 15:49 ` [patch 1/2] x86_64 page fault NMI-safe Mathieu Desnoyers
2010-07-14 16:28 ` Linus Torvalds
2010-07-14 17:06 ` Mathieu Desnoyers
2010-07-14 18:10 ` Linus Torvalds
2010-07-14 18:46 ` Ingo Molnar
2010-07-14 19:14 ` Linus Torvalds
2010-07-14 19:36 ` Frederic Weisbecker
2010-07-14 19:54 ` Linus Torvalds
2010-07-14 20:17 ` Mathieu Desnoyers
2010-07-14 20:55 ` Linus Torvalds
2010-07-14 21:18 ` Ingo Molnar
2010-07-14 22:14 ` Frederic Weisbecker
2010-07-14 22:31 ` Mathieu Desnoyers
2010-07-14 22:48 ` Frederic Weisbecker
2010-07-14 23:11 ` Mathieu Desnoyers
2010-07-14 23:38 ` Frederic Weisbecker
2010-07-15 16:26 ` Mathieu Desnoyers
2010-08-03 17:18 ` Peter Zijlstra
2010-08-03 18:25 ` Mathieu Desnoyers
2010-08-04 6:46 ` Peter Zijlstra
2010-08-04 7:14 ` Ingo Molnar
2010-08-04 14:45 ` Mathieu Desnoyers
2010-08-04 14:56 ` Peter Zijlstra
2010-08-06 1:49 ` Mathieu Desnoyers
2010-08-06 9:51 ` Peter Zijlstra
2010-08-06 13:46 ` Mathieu Desnoyers
2010-08-06 6:18 ` Masami Hiramatsu
2010-08-06 9:50 ` Peter Zijlstra
2010-08-06 13:37 ` Mathieu Desnoyers
2010-08-07 9:51 ` Masami Hiramatsu
2010-08-09 16:53 ` Frederic Weisbecker
2010-08-03 18:56 ` Linus Torvalds
2010-08-03 19:45 ` Mathieu Desnoyers
2010-08-03 20:02 ` Linus Torvalds
2010-08-03 20:10 ` Ingo Molnar
2010-08-03 20:21 ` Ingo Molnar
2010-08-03 21:16 ` Mathieu Desnoyers
2010-08-03 20:54 ` Mathieu Desnoyers
2010-08-04 6:27 ` Peter Zijlstra
2010-08-04 14:06 ` Mathieu Desnoyers
2010-08-04 14:50 ` Peter Zijlstra
2010-08-06 1:42 ` Mathieu Desnoyers
2010-08-06 10:11 ` Peter Zijlstra
2010-08-06 11:14 ` Peter Zijlstra
2010-08-06 14:15 ` Mathieu Desnoyers
2010-08-06 14:13 ` Mathieu Desnoyers
2010-08-11 14:44 ` Steven Rostedt
2010-08-11 14:34 ` Steven Rostedt
2010-08-15 13:35 ` Mathieu Desnoyers
2010-08-15 16:33 ` Avi Kivity
2010-08-15 16:44 ` Mathieu Desnoyers
2010-08-15 16:51 ` Avi Kivity
2010-08-15 18:31 ` Mathieu Desnoyers
2010-08-16 10:49 ` Avi Kivity
2010-08-16 11:29 ` Avi Kivity
2010-08-04 6:46 ` Dave Chinner
2010-08-04 7:21 ` Ingo Molnar
2010-07-14 23:40 ` Steven Rostedt
2010-07-14 19:41 ` Linus Torvalds
2010-07-14 19:56 ` Andi Kleen
2010-07-14 20:05 ` Mathieu Desnoyers
2010-07-14 20:07 ` Andi Kleen
2010-07-14 20:08 ` H. Peter Anvin
2010-07-14 23:32 ` Tejun Heo
2010-07-14 22:31 ` Frederic Weisbecker
2010-07-14 22:56 ` Linus Torvalds
2010-07-14 23:09 ` Andi Kleen
2010-07-14 23:22 ` Linus Torvalds
2010-07-15 14:11 ` Frederic Weisbecker
2010-07-15 14:35 ` Andi Kleen
2010-07-16 11:21 ` Frederic Weisbecker
2010-07-15 14:46 ` Steven Rostedt
2010-07-16 10:47 ` Frederic Weisbecker
2010-07-16 11:43 ` Steven Rostedt
2010-07-15 14:51 ` Linus Torvalds
2010-07-15 15:38 ` Linus Torvalds
2010-07-16 12:00 ` Frederic Weisbecker
2010-07-16 12:54 ` Steven Rostedt
2010-07-14 20:39 ` Mathieu Desnoyers
2010-07-14 21:23 ` Linus Torvalds
2010-07-14 21:45 ` Maciej W. Rozycki
2010-07-14 21:52 ` Linus Torvalds
2010-07-14 22:31 ` Maciej W. Rozycki
2010-07-14 22:21 ` Mathieu Desnoyers
2010-07-14 22:37 ` Linus Torvalds
2010-07-14 22:51 ` Jeremy Fitzhardinge
2010-07-14 23:02 ` Linus Torvalds
2010-07-14 23:54 ` Jeremy Fitzhardinge
2010-07-15 1:23 ` Linus Torvalds
2010-07-15 1:45 ` Linus Torvalds
2010-07-15 18:31 ` Mathieu Desnoyers
2010-07-15 18:43 ` Linus Torvalds
2010-07-15 18:48 ` Linus Torvalds
2010-07-15 22:01 ` Mathieu Desnoyers
2010-07-15 22:16 ` Linus Torvalds
2010-07-15 22:24 ` H. Peter Anvin
2010-07-15 22:26 ` Linus Torvalds
2010-07-15 22:46 ` H. Peter Anvin
2010-07-15 22:58 ` Andi Kleen
2010-07-15 23:20 ` H. Peter Anvin
2010-07-15 23:23 ` Linus Torvalds
2010-07-15 23:41 ` H. Peter Anvin
2010-07-15 23:44 ` Linus Torvalds
2010-07-15 23:46 ` H. Peter Anvin
2010-07-15 23:48 ` Andi Kleen
2010-07-15 22:30 ` Mathieu Desnoyers
2010-07-16 19:13 ` Mathieu Desnoyers
2010-07-15 16:44 ` Mathieu Desnoyers
2010-07-15 16:49 ` Linus Torvalds
2010-07-15 17:38 ` Mathieu Desnoyers [this message]
2010-07-15 20:44 ` H. Peter Anvin
2010-07-18 11:03 ` Avi Kivity
2010-07-18 17:36 ` Linus Torvalds
2010-07-18 18:04 ` Avi Kivity
2010-07-18 18:22 ` Linus Torvalds
2010-07-19 7:32 ` Avi Kivity
2010-07-18 18:17 ` Linus Torvalds
2010-07-18 18:43 ` Steven Rostedt
2010-07-18 19:26 ` Linus Torvalds
2010-07-14 15:49 ` [patch 2/2] x86 NMI-safe INT3 and Page Fault Mathieu Desnoyers
2010-07-14 16:42 ` Maciej W. Rozycki
2010-07-14 18:12 ` Mathieu Desnoyers
2010-07-14 19:21 ` Maciej W. Rozycki
2010-07-14 19:58 ` Mathieu Desnoyers
2010-07-14 20:36 ` Maciej W. Rozycki
2010-07-16 12:28 ` Avi Kivity
2010-07-16 14:49 ` Mathieu Desnoyers
2010-07-16 15:34 ` Andi Kleen
2010-07-16 15:40 ` Mathieu Desnoyers
2010-07-16 16:47 ` Avi Kivity
2010-07-16 16:58 ` Mathieu Desnoyers
2010-07-16 17:54 ` Avi Kivity
2010-07-16 18:05 ` H. Peter Anvin
2010-07-16 18:15 ` Avi Kivity
2010-07-16 18:17 ` H. Peter Anvin
2010-07-16 18:28 ` Avi Kivity
2010-07-16 18:37 ` Linus Torvalds
2010-07-16 19:26 ` Avi Kivity
2010-07-16 21:39 ` Linus Torvalds
2010-07-16 22:07 ` Andi Kleen
2010-07-16 22:26 ` Linus Torvalds
2010-07-16 22:41 ` Andi Kleen
2010-07-17 1:15 ` Linus Torvalds
2010-07-16 22:40 ` Mathieu Desnoyers
2010-07-18 9:23 ` Avi Kivity
2010-07-16 18:22 ` Mathieu Desnoyers
2010-07-16 18:32 ` Avi Kivity
2010-07-16 19:29 ` H. Peter Anvin
2010-07-16 19:39 ` Avi Kivity
2010-07-16 19:32 ` Andi Kleen
2010-07-16 18:25 ` Linus Torvalds
2010-07-16 19:30 ` Andi Kleen
2010-07-18 9:26 ` Avi Kivity
2010-07-16 19:28 ` Andi Kleen
2010-07-16 19:32 ` Avi Kivity
2010-07-16 19:34 ` Andi Kleen
2010-08-04 9:46 ` Peter Zijlstra
2010-08-04 20:23 ` H. Peter Anvin
2010-07-14 17:06 ` [patch 0/2] x86: NMI-safe trap handlers Andi Kleen
2010-07-14 17:08 ` Mathieu Desnoyers
2010-07-14 18:56 ` Andi Kleen
2010-07-14 23:29 ` Tejun Heo
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