Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753371AbaAQTSE (ORCPT ); Fri, 17 Jan 2014 14:18:04 -0500 Received: from mail-vc0-f181.google.com ([209.85.220.181]:58246 "EHLO mail-vc0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752778AbaAQTR7 (ORCPT ); Fri, 17 Jan 2014 14:17:59 -0500 MIME-Version: 1.0 In-Reply-To: <52D971FE.9030008@hp.com> References: <20140110200603.GJ7572@laptop.programming.kicks-ass.net> <52D971FE.9030008@hp.com> From: Andy Lutomirski Date: Fri, 17 Jan 2014 11:17:38 -0800 Message-ID: Subject: Re: [tip:perf/core] x86, mm, perf: Allow recursive faults from interrupts To: Waiman Long Cc: Ingo Molnar , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , Linus Torvalds , Peter Zijlstra , Arnaldo Carvalho de Melo , Andrew Morton , Thomas Gleixner , Scott J Norton , Aswin Chandramouleeswaran , tip-bot for Peter Zijlstra , linux-tip-commits@vger.kernel.org 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 On Fri, Jan 17, 2014 at 10:10 AM, Waiman Long wrote: > On 01/16/2014 08:39 AM, tip-bot for Peter Zijlstra wrote: >> >> Commit-ID: c026b3591e4f2a4993df773183704bb31634e0bd >> Gitweb: >> http://git.kernel.org/tip/c026b3591e4f2a4993df773183704bb31634e0bd >> Author: Peter Zijlstra >> AuthorDate: Fri, 10 Jan 2014 21:06:03 +0100 >> Committer: Ingo Molnar >> CommitDate: Thu, 16 Jan 2014 09:19:48 +0100 >> >> x86, mm, perf: Allow recursive faults from interrupts >> >> Waiman managed to trigger a PMI while in a emulate_vsyscall() fault, >> the PMI in turn managed to trigger a fault while obtaining a stack >> trace. This triggered the sig_on_uaccess_error recursive fault logic >> and killed the process dead. >> >> Fix this by explicitly excluding interrupts from the recursive fault >> logic. >> >> Reported-and-Tested-by: Waiman Long >> Fixes: e00b12e64be9 ("perf/x86: Further optimize copy_from_user_nmi()") >> Cc: Aswin Chandramouleeswaran >> Cc: Scott J Norton >> Cc: Linus Torvalds >> Cc: Andy Lutomirski >> Cc: Arnaldo Carvalho de Melo >> Cc: Andrew Morton >> Signed-off-by: Peter Zijlstra >> Link: >> http://lkml.kernel.org/r/20140110200603.GJ7572@laptop.programming.kicks-ass.net >> Signed-off-by: Ingo Molnar >> --- >> arch/x86/mm/fault.c | 18 ++++++++++++++++++ >> 1 file changed, 18 insertions(+) >> >> > > Will that be picked up by Linus as it is a 3.13 regression? Does anyone actually know why this regressed recently? The buggy code has been there for quite a while. --Andy -- 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/