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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6B55C433F5 for ; Sat, 2 Oct 2021 17:17:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C4F561B00 for ; Sat, 2 Oct 2021 17:17:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4C4F561B00 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 8A0266B006C; Sat, 2 Oct 2021 13:17:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 84EB8900002; Sat, 2 Oct 2021 13:17:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 73D0B6B0072; Sat, 2 Oct 2021 13:17:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0022.hostedemail.com [216.40.44.22]) by kanga.kvack.org (Postfix) with ESMTP id 609B46B006C for ; Sat, 2 Oct 2021 13:17:10 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 1395232616 for ; Sat, 2 Oct 2021 17:17:10 +0000 (UTC) X-FDA: 78652153020.24.F1EABDB Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf13.hostedemail.com (Postfix) with ESMTP id CE0041037558 for ; Sat, 2 Oct 2021 17:17:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bqShy79e/Z6K5vfk14zyDLtX0I5IPDlQiZpIZhz37d8=; b=GcMWFnNkUKLx/mRl8xq1PX+bU5 EDLMvoLX89jugtardbhC1/9q6x/xHccn1pK6+RpNG48SSwRchXjKo22uklJMATbzE4j17dDHSGUD9 ozMLLgnboaT9CjjiCa21/qIJcktW/4pO9Q/gL+s2jE5Vf4yhvsSMgCYBBDglLnclLhpVHmYUg+SvR f3FwSu8h22ioKbLZ/S4UQJYkpWgn2HxOEUOiTTJ8YyWrAvXb+aAFNEd1Q1KlcPzNgDWMDiNwfEoLd rR+MnH5pRFDcijbBI4RqeGoAipy1eRLYKgdQXWP++ojX3S62bpAx7KXgmogdNOJdUtW2bBbp6iWZk JCLBgM/A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mWicA-00FEXG-Av; Sat, 02 Oct 2021 17:16:10 +0000 Date: Sat, 2 Oct 2021 18:15:58 +0100 From: Matthew Wilcox To: Eric Dumazet Cc: Andrew Morton , Eric Dumazet , linux-kernel , linux-mm , syzbot , "Huang, Ying" , Mel Gorman Subject: Re: [PATCH v2] mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind() Message-ID: References: <20211001215630.810592-1-eric.dumazet@gmail.com> <20211001154949.98956c092734590e781ce672@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: CE0041037558 X-Stat-Signature: ghh4mt7735rofqeqyfibeqfk9mxztdhg Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=GcMWFnNk; dmarc=none; spf=none (imf13.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-HE-Tag: 1633195029-548212 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 01, 2021 at 04:37:40PM -0700, Eric Dumazet wrote: > > > Issue came with commit bda420b98505 ("numa balancing: migrate on > > > fault among multiple bound nodes") > > > > No cc:stable? What's the worst-case user-visible impact here? > > I added the more precise tag : Fixes: bda420b98505 ("numa balancing: > migrate on fault among multiple bound nodes") > I only put Fixes: tag, so that stable teams can use their automation just fine. > > worst-case impact, I am not sure if any application ever used this > undocumented combinations of flags ? > Also, it is generally advised that accessing garbage values has > undocumented behavior. > A host could for example crash (it certainly does with KMSAN) mm has special stable rules; fixes only get backported if explicitly requested instead of automatically like most of the rest of the kernel.