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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 CA549C433B4 for ; Tue, 6 Apr 2021 18:01:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 915C5613D4 for ; Tue, 6 Apr 2021 18:01:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236992AbhDFSCA (ORCPT ); Tue, 6 Apr 2021 14:02:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:34992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236643AbhDFSB6 (ORCPT ); Tue, 6 Apr 2021 14:01:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BC282613D4; Tue, 6 Apr 2021 18:01:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617732109; bh=wcmJmM32XVNM7FM06Y3fkyzjESD0AfDNqmejJzodirk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fDGdNFrZiBxgLjN8FYEVewZdlthRjl5VmDMn9/HqVYkoQg8M/FzeBMOQnXmpi+alj 4NkK0WgOCCkSNBD4ygedZJqhwVdMoqphPjRrp2xe4uQFc/XKdO6LZo+LOQLlVOAxVG +Oqi9Apd6pRs5uy3mvKsk08yft4IdKDnGBumePpv8QtnQWPfMVtrZoOTRWnZvy50VD AqY8UMgGbvT64zMmdz3rWu0uQ3UQyGcFqjnSsboSbuOlj7yNWfoIzJd0e/yUTAkJVX xORFe/0qoINHGreKqSnwxSncmdWUgL4IyvsO+c0muAbwMM2IB9RiitK6glRj7QJ/GG U2winEWJOcdCQ== Date: Tue, 6 Apr 2021 14:01:48 -0400 From: Sasha Levin To: Paolo Bonzini Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Peter Feiner , Ben Gardon Subject: Re: [PATCH 5.10 096/126] KVM: x86/mmu: Use atomic ops to set SPTEs in TDP MMU map Message-ID: References: <20210405085031.040238881@linuxfoundation.org> <20210405085034.229578703@linuxfoundation.org> <98478382-23f8-57af-dc17-23c7d9899b9a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 06, 2021 at 05:48:50PM +0200, Paolo Bonzini wrote: >On 06/04/21 15:49, Sasha Levin wrote: >>Yup. Is there anything wrong with those patches? > >The big issue, and the one that you ignoredz every time we discuss >this topic, is that this particular subset of 17 has AFAIK never been >tested by anyone. Few of the CI systems that run on stable(-rc) releases run kvm-unit-tests, which passed. So yes, this was tested. >There's plenty of locking changes in here, one patch that you didn't >backport has this in its commit message: > > This isn't technically a bug fix in the current code [...] but that > is all very, very subtle, and will break at the slightest sneeze, > >meaning that the locking in 5.10 and 5.11 was also less robust to >changes elsewhere in the code. > >Let's also talk about the process and the timing. I got the "failed >to apply" automated message last Friday and I was going to work on the >backport today since yesterday was a holiday here. I was *never* CCed There are a few more "FAILED:" mails that need attention that are older than this one, I hope they're also in the queue. >on a post of this backport for maintainers to review; you guys You're looking at it, this is the -rc cycle for stable kernels. >*literally* took random subsets of patches from a feature that is new >and in active development, and hoped that they worked on a past >release. Right, I looked at what needed to be backported, took it back to 5.4, and ran kvm-unit-tests on it. What other hoops should we jump through so we won't need to "hope" anymore? >I could be happy because you just provided me with a perfect example >of why to use my employer's franken-kernel instead of upstream stable >kernels... ;) but this is not how a world-class operating system is >developed. Who cares if a VM breaks or even if my laptop panics; but >I'd seriously fear for my data if you applied the same attitude to XFS >or ext4fs. > >For now, please drop all 17 patches from 5.10 and 5.11. I'll send a >tested backport as soon as possible. Sure, I'll drop them. Please let us know when a backport is available. -- Thanks, Sasha