From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id AD2B66B2BC6 for ; Thu, 23 Aug 2018 16:06:42 -0400 (EDT) Received: by mail-pf1-f199.google.com with SMTP id c8-v6so4068190pfn.2 for ; Thu, 23 Aug 2018 13:06:42 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id o8-v6sor1958549plk.132.2018.08.23.13.06.41 for (Google Transport Security); Thu, 23 Aug 2018 13:06:41 -0700 (PDT) Date: Thu, 23 Aug 2018 13:06:38 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry(). In-Reply-To: <804b50cb-0b17-201a-790b-18604396f826@i-love.sakura.ne.jp> Message-ID: References: <9158a23e-7793-7735-e35c-acd540ca59bf@i-love.sakura.ne.jp> <20180730144647.GX24267@dhcp22.suse.cz> <20180730145425.GE1206094@devbig004.ftw2.facebook.com> <0018ac3b-94ee-5f09-e4e0-df53d2cbc925@i-love.sakura.ne.jp> <20180730154424.GG1206094@devbig004.ftw2.facebook.com> <20180730185110.GB24267@dhcp22.suse.cz> <20180730191005.GC24267@dhcp22.suse.cz> <6f433d59-4a56-b698-e119-682bb8bf6713@i-love.sakura.ne.jp> <20180731050928.GA4557@dhcp22.suse.cz> <20180803061653.GB27245@dhcp22.suse.cz> <804b50cb-0b17-201a-790b-18604396f826@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: Michal Hocko , Tejun Heo , Roman Gushchin , Johannes Weiner , Vladimir Davydov , Andrew Morton , Linus Torvalds , linux-mm , LKML On Wed, 22 Aug 2018, Tetsuo Handa wrote: > On 2018/08/03 15:16, Michal Hocko wrote: > > On Fri 03-08-18 07:05:54, Tetsuo Handa wrote: > >> On 2018/07/31 14:09, Michal Hocko wrote: > >>> On Tue 31-07-18 06:01:48, Tetsuo Handa wrote: > >>>> On 2018/07/31 4:10, Michal Hocko wrote: > >>>>> Since should_reclaim_retry() should be a natural reschedule point, > >>>>> let's do the short sleep for PF_WQ_WORKER threads unconditionally in > >>>>> order to guarantee that other pending work items are started. This will > >>>>> workaround this problem and it is less fragile than hunting down when > >>>>> the sleep is missed. E.g. we used to have a sleeping point in the oom > >>>>> path but this has been removed recently because it caused other issues. > >>>>> Having a single sleeping point is more robust. > >>>> > >>>> linux.git has not removed the sleeping point in the OOM path yet. Since removing the > >>>> sleeping point in the OOM path can mitigate CVE-2016-10723, please do so immediately. > >>> > >>> is this an {Acked,Reviewed,Tested}-by? > >>> > >>> I will send the patch to Andrew if the patch is ok. > >>> > >>>> (And that change will conflict with Roman's cgroup aware OOM killer patchset. But it > >>>> should be easy to rebase.) > >>> > >>> That is still a WIP so I would lose sleep over it. > >>> > >> > >> Now that Roman's cgroup aware OOM killer patchset will be dropped from linux-next.git , > >> linux-next.git will get the sleeping point removed. Please send this patch to linux-next.git . > > > > I still haven't heard any explicit confirmation that the patch works for > > your workload. Should I beg for it? Or you simply do not want to have > > your stamp on the patch? If yes, I can live with that but this playing > > hide and catch is not really a lot of fun. > > > > I noticed that the patch has not been sent to linux-next.git yet. > Please send to linux-next.git without my stamp on the patch. > For those of us who are tracking CVE-2016-10723 which has peristently been labeled as "disputed" and with no clear indication of what patches address it, I am assuming that commit 9bfe5ded054b ("mm, oom: remove sleep from under oom_lock") and this patch are the intended mitigations? A list of SHA1s for merged fixed and links to proposed patches to address this issue would be appreciated.