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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 3AEB9C433DB for ; Mon, 21 Dec 2020 16:40:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF57422C9C for ; Mon, 21 Dec 2020 16:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725841AbgLUQkK (ORCPT ); Mon, 21 Dec 2020 11:40:10 -0500 Received: from gate.crashing.org ([63.228.1.57]:51030 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725777AbgLUQkJ (ORCPT ); Mon, 21 Dec 2020 11:40:09 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 0BLGVbM9009946; Mon, 21 Dec 2020 10:31:37 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 0BLGVULx009932; Mon, 21 Dec 2020 10:31:30 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 21 Dec 2020 10:31:30 -0600 From: Segher Boessenkool To: Christophe Leroy Cc: Xiaoming Ni , linux-kernel@vger.kernel.org, benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, yanaijie@huawei.com, npiggin@gmail.com, ravi.bangoria@linux.ibm.com, mikey@neuling.org, aneesh.kumar@linux.ibm.com, haren@linux.ibm.com, wangle6@huawei.com Subject: Re: [PATCH] powerpc:Don't print raw EIP/LR hex values in dump_stack() and show_regs() Message-ID: <20201221163130.GZ2672@gate.crashing.org> References: <20201221032758.12143-1-nixiaoming@huawei.com> <2279fc96-1f10-0c3f-64d9-734f18758620@csgroup.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2279fc96-1f10-0c3f-64d9-734f18758620@csgroup.eu> User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 21, 2020 at 04:17:21PM +0100, Christophe Leroy wrote: > Le 21/12/2020 à 04:27, Xiaoming Ni a écrit : > >Since the commit 2b0e86cc5de6 ("powerpc/fsl_booke/32: implement KASLR > >infrastructure"), the powerpc system is ready to support KASLR. > >To reduces the risk of invalidating address randomization, don't print the > >EIP/LR hex values in dump_stack() and show_regs(). > I think your change is not enough to hide EIP address, see below a dump > with you patch, you get "Faulting instruction address: 0xc03a0c14" As far as I can see the patch does nothing to the GPR printout. Often GPRs contain code addresses. As one example, the LR is moved via a GPR (often GPR0, but not always) for storing on the stack. So this needs more work. Segher