From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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 09:49:10 -0700 [thread overview]
Message-ID: <AANLkTik4mdj3h16CU2GUQAQuG4yeAWFuZsqbPC0ra6Id@mail.gmail.com> (raw)
In-Reply-To: <20100715164450.GC30989@Krystal>
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.
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.
Linus
next prev parent reply other threads:[~2010-07-15 16:49 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 [this message]
2010-07-15 17:38 ` Mathieu Desnoyers
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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