From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751423AbWF3QKS (ORCPT ); Fri, 30 Jun 2006 12:10:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751462AbWF3QKR (ORCPT ); Fri, 30 Jun 2006 12:10:17 -0400 Received: from ccerelbas03.cce.hp.com ([161.114.21.106]:4802 "EHLO ccerelbas03.cce.hp.com") by vger.kernel.org with ESMTP id S1751423AbWF3QKP (ORCPT ); Fri, 30 Jun 2006 12:10:15 -0400 Date: Fri, 30 Jun 2006 09:02:03 -0700 From: Stephane Eranian To: Andi Kleen Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/17] 2.6.17.1 perfmon2 patch for review: PMU context switch Message-ID: <20060630160203.GH22381@frankl.hpl.hp.com> Reply-To: eranian@hpl.hp.com References: <200606230913.k5N9D73v032387@frankl.hpl.hp.com> <200606301541.22928.ak@suse.de> <20060630141248.GC22381@frankl.hpl.hp.com> <200606301633.35818.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200606301633.35818.ak@suse.de> User-Agent: Mutt/1.4.1i Organisation: HP Labs Palo Alto Address: HP Labs, 1U-17, 1501 Page Mill road, Palo Alto, CA 94304, USA. E-mail: eranian@hpl.hp.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi, As a first step, I am looking at implementing a TIF_DEBUG for x86-64. AFAIK, debug registers must not be inherited on fork(). In copy_thread(), I do not see the place where the child's debug registers (or just debugreg7) are cleared to avoid reloading the parents values in __switch_to() if debugreg7 is not 0. I believe the debug registers values are copied in dup_task_struct(). Am I missing something? -- -Stephane