From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933578AbXCEQBF (ORCPT ); Mon, 5 Mar 2007 11:01:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933582AbXCEQBA (ORCPT ); Mon, 5 Mar 2007 11:01:00 -0500 Received: from mail.tmr.com ([64.65.253.246]:58295 "EHLO gaimboi.tmr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933578AbXCEQAt (ORCPT ); Mon, 5 Mar 2007 11:00:49 -0500 Message-ID: <45EC3F25.5060308@tmr.com> Date: Mon, 05 Mar 2007 11:02:45 -0500 From: Bill Davidsen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061105 SeaMonkey/1.0.6 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel To: Ingo Molnar CC: Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [patch] disable NMI watchdog by default References: <20070114092926.GA14465@elte.hu> In-Reply-To: <20070114092926.GA14465@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > From: Ingo Molnar > Subject: [patch] disable NMI watchdog by default > > there's a new NMI watchdog related problem: KVM crashes on certain > bzImages because ... we enable the NMI watchdog by default (even if the > user does not ask for it) , and no other OS on this planet does that so > KVM doesnt have emulation for that yet. So KVM injects a #GP, which > crashes the Linux guest: > > general protection fault: 0000 [#1] > PREEMPT SMP > Modules linked in: > CPU: 0 > EIP: 0060:[] Not tainted VLI > EFLAGS: 00000246 (2.6.20-rc5-rt0 #3) > EIP is at setup_apic_nmi_watchdog+0x26d/0x3d3 > > and no, i did /not/ request an nmi_watchdog on the boot command line! > > Solution: turn off that darn thing! It's a debug tool, not a 'make life > harder' tool!! > > with this patch the KVM guest boots up just fine. > > And with this my laptop (Lenovo T60) also stops its sporadic hard > hanging (sometimes in acpi_init(), sometimes later during bootup, > sometimes much later during actual use) as well. It hung with both > nmi_watchdog=1 and nmi_watchdog=2, so it's generally the fact of NMI > injection that is causing problems, not the NMI watchdog variant, nor > any particular bootup code. > > The patch is unintrusive. I'm missing something, what limits this to systems running under kvm? -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot