From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754789AbYCJRO4 (ORCPT ); Mon, 10 Mar 2008 13:14:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751445AbYCJROd (ORCPT ); Mon, 10 Mar 2008 13:14:33 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:58313 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751388AbYCJROc (ORCPT ); Mon, 10 Mar 2008 13:14:32 -0400 Date: Mon, 10 Mar 2008 18:14:09 +0100 From: Ingo Molnar To: Jan Beulich Cc: tglx@linutronix.de, hpa@zytor.com, markus.t.metzger@intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: prevent unconditional writes to DebugCtl MSR Message-ID: <20080310171409.GA24133@elte.hu> References: <47D54185.76E4.0078.0@novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47D54185.76E4.0078.0@novell.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0046] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jan Beulich wrote: > Otherwise, enabling (or better, subsequent disabling) of single > stepping would cause a kernel oops on CPUs not having this MSR. > > The patch could have been added a conditional to the MSR write in > user_disable_single_step(), but centralizing the updates seems safer > and (looking forward) better manageable. thanks Jan, applied. Ingo