From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8489DC43381 for ; Fri, 8 Mar 2019 19:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FCD620857 for ; Fri, 8 Mar 2019 19:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726864AbfCHTdM (ORCPT ); Fri, 8 Mar 2019 14:33:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37444 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726546AbfCHTdM (ORCPT ); Fri, 8 Mar 2019 14:33:12 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ED587A4053; Fri, 8 Mar 2019 19:33:11 +0000 (UTC) Received: from treble (ovpn-120-61.rdu2.redhat.com [10.10.120.61]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 43CD360856; Fri, 8 Mar 2019 19:33:08 +0000 (UTC) Date: Fri, 8 Mar 2019 13:33:05 -0600 From: Josh Poimboeuf To: Peter Zijlstra Cc: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net, mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, valentin.schneider@arm.com, brgerst@gmail.com, luto@kernel.org, bp@alien8.de, dvlasenk@redhat.com, linux-kernel@vger.kernel.org, dvyukov@google.com, rostedt@goodmis.org Subject: Re: [PATCH 15/20] objtool: Add --backtrace support Message-ID: <20190308193305.ccivol3axwvcuc5p@treble> References: <20190307114511.870090179@infradead.org> <20190307115200.419834588@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190307115200.419834588@infradead.org> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 08 Mar 2019 19:33:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 07, 2019 at 12:45:26PM +0100, Peter Zijlstra wrote: > For when you want to know the path that reached your fail state. > > $ ./objtool check --no-fp --backtrace arch/x86/lib/usercopy_64.o > arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0x3: UACCESS disable without MEMOPs: __clear_user() > arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x3a: (alt) > arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x2e: (branch) > arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x18: (branch) > arch/x86/lib/usercopy_64.o: warning: objtool: .altinstr_replacement+0xffffffffffffffff: (branch) > arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x5: (alt) > arch/x86/lib/usercopy_64.o: warning: objtool: __clear_user()+0x0: <=== (func) We should have done this a long time ago. Thank you for this! -- Josh