From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932364AbaGWG6d (ORCPT ); Wed, 23 Jul 2014 02:58:33 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:50300 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932267AbaGWG6a (ORCPT ); Wed, 23 Jul 2014 02:58:30 -0400 Date: Wed, 23 Jul 2014 08:58:22 +0200 From: Peter Zijlstra To: Adrian Hunter Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, David Ahern , Frederic Weisbecker , Jiri Olsa , Namhyung Kim , Paul Mackerras , Stephane Eranian Subject: Re: [PATCH 01/52] perf tools: Fix jump label always changing during tracing Message-ID: <20140723065822.GN3935@laptop> References: <1406035081-14301-1-git-send-email-adrian.hunter@intel.com> <1406035081-14301-2-git-send-email-adrian.hunter@intel.com> <20140722140034.GE20303@kernel.org> <20140722141135.GF3935@laptop> <53CF5124.2090901@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53CF5124.2090901@intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 23, 2014 at 09:07:32AM +0300, Adrian Hunter wrote: > On 07/22/2014 05:11 PM, Peter Zijlstra wrote: > > On Tue, Jul 22, 2014 at 11:00:34AM -0300, Arnaldo Carvalho de Melo wrote: > >> Em Tue, Jul 22, 2014 at 04:17:10PM +0300, Adrian Hunter escreveu: > >>> Intel PT decoding walks the object code to reconstruct > >>> the trace. A jump label change during tracing causes > >>> decoding errors. > > > > You'd better fix that, jump_labels can change any time and they're all > > over the frigging place. > > > > Perhaps a general method is needed to be able to deal with kernel > self-modifying code. I know people are looking at doing the same to userspace, is that also a problem?