From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757554Ab3AYRWh (ORCPT ); Fri, 25 Jan 2013 12:22:37 -0500 Received: from mail-bk0-f48.google.com ([209.85.214.48]:43767 "EHLO mail-bk0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755243Ab3AYRWd (ORCPT ); Fri, 25 Jan 2013 12:22:33 -0500 Date: Fri, 25 Jan 2013 17:22:24 +0000 From: Dave Martin To: Steven Rostedt Cc: Arnd Bergmann , linux-kernel@vger.kernel.org, sahara , Russell King , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 19/19] [INCOMPLETE] ARM: make return_address available for ARM_UNWIND Message-ID: <20130125172224.GA1961@linaro.org> References: <1359123276-15833-1-git-send-email-arnd@arndb.de> <1359123276-15833-20-git-send-email-arnd@arndb.de> <20130125162608.GD2069@linaro.org> <1359132254.21576.230.camel@gandalf.local.home> <20130125165934.GE2069@linaro.org> <1359133703.21576.233.camel@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1359133703.21576.233.camel@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 25, 2013 at 12:08:23PM -0500, Steven Rostedt wrote: > On Fri, 2013-01-25 at 16:59 +0000, Dave Martin wrote: > > > Cool. Are you aware of return_address being used elsewhere? Currently > > I'm not aware of anything else which uses it, and grep is not finding > > any calls outside ftrace.h that I can see. > > softirq.c has a trace_preempt_off() use of CALLER_ADDR1. > > kernel/sched/core.c has CALLER_ADDR1, 2 an 3. These cases look safe to me ... sched/core.c:get_parent_ip() looks like it uses notrace purely to avoid the spurious extra frame which it would otherwise insert, and the code in softirq.c doesn't appear to be in a notrace context. Am I being too optimistic, or does that match your understanding? Cheers ---Dave