From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbaB1QXV (ORCPT ); Fri, 28 Feb 2014 11:23:21 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.229]:14374 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751447AbaB1QXU (ORCPT ); Fri, 28 Feb 2014 11:23:20 -0500 Date: Fri, 28 Feb 2014 11:23:17 -0500 From: Steven Rostedt To: "H. Peter Anvin" Cc: Jiri Olsa , Peter Zijlstra , linux-kernel@vger.kernel.org, Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , Seiji Aguchi , Vince Weaver Subject: Re: [PATCHv2] x86 trace: Fix page fault tracing bug Message-ID: <20140228112317.59b63a04@gandalf.local.home> In-Reply-To: <5310B54F.3000709@zytor.com> References: <1393601620-13117-1-git-send-email-jolsa@redhat.com> <20140228154708.GI9987@twins.programming.kicks-ass.net> <20140228160526.GD1133@krava.brq.redhat.com> <5310B54F.3000709@zytor.com> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 28 Feb 2014 08:11:59 -0800 "H. Peter Anvin" wrote: > If so, do we need to hoist the reading of %cr2 all the way into assembly > or something else? Function tracing code should not fault. Peter and Jiri were discussing on IRC to make sure that perf could not enable userspace stack tracing for function tracing. At this point, I would say, lets get rid of any users of function tracing callbacks that can fault. There callbacks are limited in context even more so than any other context (faults, interrupts, and NMIs). -- Steve