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=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,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 3E1F5C433DB for ; Thu, 4 Feb 2021 10:36:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08DEA64E34 for ; Thu, 4 Feb 2021 10:36:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235635AbhBDKfz (ORCPT ); Thu, 4 Feb 2021 05:35:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235527AbhBDKeS (ORCPT ); Thu, 4 Feb 2021 05:34:18 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2DE0C0613D6 for ; Thu, 4 Feb 2021 02:33:38 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: gtucker) with ESMTPSA id 4BB081F44AE3 Subject: Re: next/master bisection: baseline.login on rk3288-rock2-square To: Ard Biesheuvel , Russell King - ARM Linux admin Cc: Geert Uytterhoeven , Linux Kernel Mailing List , Linus Walleij , Linux ARM , Nicolas Pitre , "kernelci-results@groups.io" References: <601b773a.1c69fb81.9f381.a32a@mx.google.com> <6c65bcef-d4e7-25fa-43cf-2c435bb61bb9@collabora.com> <20210204100601.GT1463@shell.armlinux.org.uk> From: Guillaume Tucker Message-ID: Date: Thu, 4 Feb 2021 10:33:33 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/2021 10:27, Ard Biesheuvel wrote: > On Thu, 4 Feb 2021 at 11:06, Russell King - ARM Linux admin > wrote: >> >> On Thu, Feb 04, 2021 at 10:07:58AM +0100, Ard Biesheuvel wrote: >>> On Thu, 4 Feb 2021 at 09:43, Guillaume Tucker >>> wrote: >>>> >>>> Hi Ard, >>>> >>>> Please see the bisection report below about a boot failure on >>>> rk3288 with next-20210203. It was also bisected on >>>> imx6q-var-dt6customboard with next-20210202. >>>> >>>> Reports aren't automatically sent to the public while we're >>>> trialing new bisection features on kernelci.org but this one >>>> looks valid. >>>> >>>> The kernel is most likely crashing very early on, so there's >>>> nothing in the logs. Please let us know if you need some help >>>> with debugging or trying a fix on these platforms. >>>> >>> >>> Thanks for the report. >> >> Ard, >> >> I want to send my fixes branch today which includes your regression >> fix that caused this regression. >> >> As this is proving difficult to fix, I can only drop your fix from >> my fixes branch - and given that this seems to be problematical, I'm >> tempted to revert the original change at this point which should fix >> both of these regressions - and then we have another go at getting rid >> of the set/way instructions during the next cycle. >> >> Thoughts? >> > > Hi Russell, > > If Guillaume is willing to do the experiment, and it fixes the issue, Yes, I'm running some tests with that fix now and should have some results shortly. > it proves that rk3288 is relying on the flush before the MMU is > disabled, and so in that case, the fix is trivial, and we can just > apply it. > > If the experiment fails (which would mean rk3288 does not tolerate the > cache maintenance being performed after cache off), it is going to be > hairy, and so it will definitely take more time. > > So in the latter case (or if Guillaume does not get back to us), I > think reverting my queued fix is the only sane option. But in that > case, may I suggest that we queue the revert of the original by-VA > change for v5.12 so it gets lots of coverage in -next, and allows us > an opportunity to come up with a proper fix in the same timeframe, and > backport the revert and the subsequent fix as a pair? Otherwise, we'll > end up in the situation where v5.10.x until today has by-va, v5.10.x-y > has set/way, and v5.10y+ has by-va again. (I don't think we care about > anything before that, given that v5.4 predates any of this) > > But in the end, I'm happy to go along with whatever works best for you. Thanks, Guillaume