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[195.135.220.15]) by mx.google.com with ESMTPS id z6si7450183edp.370.2019.06.16.23.33.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 16 Jun 2019 23:33:21 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id AF6EDAFC9; Mon, 17 Jun 2019 06:33:20 +0000 (UTC) Date: Mon, 17 Jun 2019 08:33:19 +0200 From: Michal Hocko To: Shakeel Butt Cc: syzbot , Andrew Morton , "Eric W. Biederman" , Roman Gushchin , Johannes Weiner , =?iso-8859-1?B?Suly9G1l?= Glisse , LKML , Linux MM , Tetsuo Handa , syzkaller-bugs , yuzhoujian@didichuxing.com Subject: Re: general protection fault in oom_unkillable_task Message-ID: <20190617063319.GB30420@dhcp22.suse.cz> References: <0000000000004143a5058b526503@google.com> <20190615134955.GA28441@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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 Sat 15-06-19 09:11:37, Shakeel Butt wrote: > On Sat, Jun 15, 2019 at 6:50 AM Michal Hocko wrote: [...] > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > index 5a58778c91d4..43eb479a5dc7 100644 > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -161,8 +161,8 @@ static bool oom_unkillable_task(struct task_struct *p, > > return true; > > > > /* When mem_cgroup_out_of_memory() and p is not member of the group */ > > - if (memcg && !task_in_mem_cgroup(p, memcg)) > > - return true; > > + if (memcg) > > + return false; > > This will break the dump_tasks() usage of oom_unkillable_task(). We > can change dump_tasks() to traverse processes like > mem_cgroup_scan_tasks() for memcg OOMs. Right you are. Doing a similar trick to the oom victim selection is indeed better. We should really strive to not doing a global process iteration when we can do a targeted scan. Care to send a patch? Thanks! -- Michal Hocko SUSE Labs