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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9CF84C76195 for ; Tue, 28 Mar 2023 04:59:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232025AbjC1E7U (ORCPT ); Tue, 28 Mar 2023 00:59:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229611AbjC1E7S (ORCPT ); Tue, 28 Mar 2023 00:59:18 -0400 Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 21EC02121 for ; Mon, 27 Mar 2023 21:59:15 -0700 (PDT) Received: (from willy@localhost) by mail.home.local (8.17.1/8.17.1/Submit) id 32S4x8Z6026649; Tue, 28 Mar 2023 06:59:08 +0200 Date: Tue, 28 Mar 2023 06:59:08 +0200 From: Willy Tarreau To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: Alexey Dobriyan , "Paul E. McKenney" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/8] tools/nolibc: tests: add test for -fstack-protector Message-ID: References: <89a960c7-0c9b-43ab-9fc8-a68405f7ed6a@p183> <8e156377-e7d9-48ec-a7ee-292aba002201@t-8ch.de> <162bc469-1654-4636-bf22-e929170ff092@t-8ch.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <162bc469-1654-4636-bf22-e929170ff092@t-8ch.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, On Mon, Mar 27, 2023 at 11:20:32PM +0000, Thomas Weißschuh wrote: > On 2023-03-27 17:54:11+0200, Willy Tarreau wrote: > > On Mon, Mar 27, 2023 at 06:32:51PM +0300, Alexey Dobriyan wrote: > > > On Sun, Mar 26, 2023 at 09:42:29PM +0200, Willy Tarreau wrote: > > > > On Sun, Mar 26, 2023 at 10:38:39PM +0300, Alexey Dobriyan wrote: > > > > > > I'm not seeing any issue with your approach instead, let's > > > > > > keep it as-is for now (also it does what the stack protector is supposed > > > > > > to catch anyway). > > > > > > > > > > There are no guarantess about stack layout and dead writes. > > > > > The test doesn't corrupt stack reliably, just 99.99% reliably. > > > > > > > > Sure but it's for a regtest which can easily be adjusted and its > > > > posrtability and ease of maintenance outweights its reliability, > > > > especially when in practice what the code does is what we want to > > > > test for. And if an extra zero needs to be added to the loop, it > > > > can be at a lower cost than maintaining arch-specific asm code. > > > > > > For the record, I disagree. Use volatile writes at least. > > > > Yeah I agree on the volatile one. > > Sounds good. > > How do we proceed? > > Do I send a new revision? > Will you fix up the series? > Will someone create a new patch? If so who? Please just send an additional patch to be applied on top of the existing series that turns this to volatile, and add a Reported-by: with Alexey's e-mail. You may even verify that once you do this it's safe to remove the optimize attributes. Thank you! Willy