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 57220C05027 for ; Fri, 10 Feb 2023 17:15:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232577AbjBJRPi (ORCPT ); Fri, 10 Feb 2023 12:15:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232475AbjBJRPg (ORCPT ); Fri, 10 Feb 2023 12:15:36 -0500 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE3F5222FE for ; Fri, 10 Feb 2023 09:15:32 -0800 (PST) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1pQWzd-0005Kj-2N; Fri, 10 Feb 2023 18:15:25 +0100 Message-ID: <82db210b-c23d-1e59-e3c8-73e1b27cb945@leemhuis.info> Date: Fri, 10 Feb 2023 18:15:22 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v10 2/5] sched: Use user_cpus_ptr for saving user provided cpumask in sched_setaffinity() Content-Language: en-US, de-DE From: "Linux kernel regression tracking (#update)" To: Will Deacon , Waiman Long Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Tejun Heo , Zefan Li , Johannes Weiner , linux-kernel@vger.kernel.org, Linus Torvalds , Lai Jiangshan , qperret@google.com Reply-To: Linux regressions mailing list , Linux regressions mailing list References: <20220922180041.1768141-1-longman@redhat.com> <20220922180041.1768141-3-longman@redhat.com> <20230117160825.GA17756@willie-the-truck> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1676049332;2e9cbe57; X-HE-SMSGID: 1pQWzd-0005Kj-2N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [TLDR: This mail in primarily relevant for Linux kernel regression tracking. There afaics is a fix for the regression discussed in this thread, but it did not use a Link: tag to point to the report, as Linus and the documentation call for. Things happen, no worries -- but it forces me to write this mail to make the regression tracking bot aware of the fix. See link in footer if these mails annoy you.] On 26.01.23 13:52, Linux kernel regression tracking (#adding) wrote: > On 17.01.23 17:08, Will Deacon wrote: >> >> On Thu, Sep 22, 2022 at 02:00:38PM -0400, Waiman Long wrote: >>> The user_cpus_ptr field is added by commit b90ca8badbd1 ("sched: >>> Introduce task_struct::user_cpus_ptr to track requested affinity"). It >>> is currently used only by arm64 arch due to possible asymmetric CPU >>> setup. This patch extends its usage to save user provided cpumask >>> when sched_setaffinity() is called for all arches. With this patch >>> applied, user_cpus_ptr, once allocated after a successful call to >>> sched_setaffinity(), will only be freed when the task exits. >> [...] >> We've tracked this down as the cause of an arm64 regression in Android and I've >> reproduced the issue with mainline. >> >> Basically, if an arm64 system is booted with "allow_mismatched_32bit_el0" on >> the command-line, then the arch code will (amongst other things) call >> force_compatible_cpus_allowed_ptr() and relax_compatible_cpus_allowed_ptr() >> when exec()'ing a 32-bit or a 64-bit task respectively. >> [...] > > Thanks for the report. To be sure the issue doesn't fall through the > cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression > tracking bot: > > #regzbot ^introduced 8f9ea86fdf99 #regzbot fix: 3fb906e7fabbb5b76c3c #regzbot ignore-activity Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr That page also explains what to do if mails like this annoy you.