Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758853Ab0GPSar (ORCPT ); Fri, 16 Jul 2010 14:30:47 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:57943 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757696Ab0GPSaq (ORCPT ); Fri, 16 Jul 2010 14:30:46 -0400 MIME-Version: 1.0 In-Reply-To: <4C40A1BD.4040507@redhat.com> References: <20100714154923.947138065@efficios.com> <20100714155804.252253097@efficios.com> <4C405078.20707@redhat.com> <20100716144927.GA22516@Krystal> <4C408D0C.5050709@redhat.com> <20100716165855.GA3836@Krystal> <4C409CBA.1050709@redhat.com> <4C409F62.6030303@zytor.com> <4C40A1BD.4040507@redhat.com> Date: Fri, 16 Jul 2010 11:25:19 -0700 Message-ID: Subject: Re: [patch 2/2] x86 NMI-safe INT3 and Page Fault From: Linus Torvalds To: Avi Kivity Cc: "H. Peter Anvin" , Mathieu Desnoyers , LKML , Andrew Morton , Ingo Molnar , Peter Zijlstra , Steven Rostedt , Steven Rostedt , Frederic Weisbecker , Thomas Gleixner , Christoph Hellwig , Li Zefan , Lai Jiangshan , Johannes Berg , Masami Hiramatsu , Arnaldo Carvalho de Melo , Tom Zanussi , KOSAKI Motohiro , Andi Kleen , Jeremy Fitzhardinge , "Frank Ch. Eigler" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 960 Lines: 21 On Fri, Jul 16, 2010 at 11:15 AM, Avi Kivity wrote: > > I think the concern here is about an NMI handler's code running in vmalloc > space, or is it something else? I think the concern was also potentially doing things like backtraces etc that may need access to the module data structures (I think the ELF headers end up all being in vmalloc space too, for example). The whole debugging thing is also an issue. Now, I obviously am not a big fan of remote debuggers, but everybody tells me I'm wrong. And putting a breakpoint on NMI is certainly not insane if you are doing debugging in the first place. So it's not necessarily always about the page faults. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/