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From: Avi Kivity <avi@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.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>,
	akpm@osdl.org, Jeremy Fitzhardinge <jeremy@goop.org>,
	"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [patch 2/2] x86 NMI-safe INT3 and Page Fault
Date: Fri, 16 Jul 2010 22:32:13 +0300	[thread overview]
Message-ID: <4C40B3BD.7030101@redhat.com> (raw)
In-Reply-To: <20100716192847.GC7338@basil.fritz.box>

On 07/16/2010 10:28 PM, Andi Kleen wrote:
>
>> I really hope noone ever gets the idea of touching user space from an
>> NMI handler, though, and expecting it to work...
>>      
> It can make sense for a backtrace in a profiler.
>
> In fact perf is nearly doing it I believe, but moves
> it to the self IPI handler in most cases.
>    

Interesting, is the self IPI guaranteed to execute synchronously after 
the NMI's IRET?  Or can the core IRET faster than the APIC and so we get 
the backtrace at the wrong place?

(and does it matter? the NMI itself is not always accurate)

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.


  reply	other threads:[~2010-07-16 19:32 UTC|newest]

Thread overview: 168+ 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
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 [this message]
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
  -- strict thread matches above, loose matches on Subject: below --
2010-07-16 22:02 [patch 2/2] x86 NMI-safe INT3 and Page Fault Jeffrey Merkey
2010-07-16 22:22 ` Linus Torvalds
2010-07-16 22:48   ` Jeffrey Merkey
2010-07-16 22:53     ` Jeffrey Merkey
2010-07-16 22:50   ` Jeffrey Merkey

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