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[198.145.29.99]) by mx.google.com with ESMTPS id y6si12303910pgv.210.2019.06.17.18.45.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 Jun 2019 18:45:49 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=yNs5c0Qr; spf=pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from localhost.localdomain (c-73-223-200-170.hsd1.ca.comcast.net [73.223.200.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 606D22082C; Tue, 18 Jun 2019 01:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560822349; bh=oSzNYEyekhj/NlwHW0X2pXMLHkV8SDK6JssH3xf5sKg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=yNs5c0QrkZ+OIgygnIUxK1vdNmaCS4P0DJmYxw82YOS8uUEUaNn7eElyjXdJTD7e6 AfBWK397l1VTwpLOKs0GssDSAozZx2a+g3IrfRp4gA0WGzszrWdzhMeqc4VaY4cRJc ay+PycslEeYEG8Qr0sSGPmcGs7WwRl+eZQ6k8OdY= Date: Mon, 17 Jun 2019 18:45:47 -0700 From: Andrew Morton To: Shakeel Butt Cc: Tetsuo Handa , Michal Hocko , syzbot , "Eric W. Biederman" , Roman Gushchin , Johannes Weiner , =?ISO-8859-1?Q?J=E9r=F4me?= Glisse , LKML , Linux MM , syzkaller-bugs , yuzhoujian@didichuxing.com Subject: Re: general protection fault in oom_unkillable_task Message-Id: <20190617184547.5b81f7df81af46e86441ba8c@linux-foundation.org> In-Reply-To: References: <0000000000004143a5058b526503@google.com> <20190615134955.GA28441@dhcp22.suse.cz> <5bb1fe5d-f0e1-678b-4f64-82c8d5d81f61@i-love.sakura.ne.jp> <791594c6-45a3-d78a-70b5-901aa580ed9f@i-love.sakura.ne.jp> <840fa9f1-07e2-e206-2fc0-725392f96baf@i-love.sakura.ne.jp> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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 Mon, 17 Jun 2019 06:23:07 -0700 Shakeel Butt wrote: > > Here is a patch to use CSS_TASK_ITER_PROCS. > > > > From 415e52cf55bc4ad931e4f005421b827f0b02693d Mon Sep 17 00:00:00 2001 > > From: Tetsuo Handa > > Date: Mon, 17 Jun 2019 00:09:38 +0900 > > Subject: [PATCH] mm: memcontrol: Use CSS_TASK_ITER_PROCS at mem_cgroup_scan_tasks(). > > > > Since commit c03cd7738a83b137 ("cgroup: Include dying leaders with live > > threads in PROCS iterations") corrected how CSS_TASK_ITER_PROCS works, > > mem_cgroup_scan_tasks() can use CSS_TASK_ITER_PROCS in order to check > > only one thread from each thread group. > > > > Signed-off-by: Tetsuo Handa > > Reviewed-by: Shakeel Butt > > Why not add the reproducer in the commit message? That would be nice. More nice would be, as always, a descriptoin of the user-visible impact of the patch. As I understand it, it's just a bit of a cleanup against current mainline but without this patch in place, Shakeel's "mm, oom: refactor dump_tasks for memcg OOMs" will cause kernel crashes. Correct?