From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758927Ab1DZHjS (ORCPT ); Tue, 26 Apr 2011 03:39:18 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:49436 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758444Ab1DZHjP convert rfc822-to-8bit (ORCPT ); Tue, 26 Apr 2011 03:39:15 -0400 Subject: Re: [BUG] perf and kmemcheck : fatal combination From: Peter Zijlstra To: Eric Dumazet Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Paul Mackerras , Pekka Enberg , Vegard Nossum , linux-kernel , Mathieu Desnoyers In-Reply-To: <1303747731.2747.182.camel@edumazet-laptop> References: <1303747731.2747.182.camel@edumazet-laptop> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 26 Apr 2011 09:38:45 +0200 Message-ID: <1303803525.20212.20.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-04-25 at 18:08 +0200, Eric Dumazet wrote: > Hi guys > > Just got a panic on a kmemcheck kernel, latest linux-2.6 tree. > > I forgot I had kmemcheck enabled, and started "perf top" just because my > machine was damn slow... Oh well... > > Crash in do_nmi -> nmi_enter() -> BUG_ON(in_nmi()); Hmm,. I bet because kmemcheck triggers faults from nmi context because it messes about with the page protection bits a lot to track things. Can't really think of anything except not making perf available on kmemcheck kernels. --- init/Kconfig | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 32745bf..94735b4 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1125,6 +1125,7 @@ config PERF_EVENTS bool "Kernel performance events and counters" default y if (PROFILING || PERF_COUNTERS) depends on HAVE_PERF_EVENTS + depends on !KMEMCHECK select ANON_INODES select IRQ_WORK help