From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752879AbdJGCvq (ORCPT ); Fri, 6 Oct 2017 22:51:46 -0400 Received: from gum.cmpxchg.org ([85.214.110.215]:53632 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752392AbdJGCvp (ORCPT ); Fri, 6 Oct 2017 22:51:45 -0400 Date: Fri, 6 Oct 2017 22:51:31 -0400 From: Johannes Weiner To: Tetsuo Handa Cc: Andrew Morton , Michal Hocko , Alan Cox , Christoph Hellwig , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 1/2] Revert "vmalloc: back off when the current task is killed" Message-ID: <20171007025131.GA12944@cmpxchg.org> References: <20171003225504.GA966@cmpxchg.org> <20171004185813.GA2136@cmpxchg.org> <20171004185906.GB2136@cmpxchg.org> <20171004153245.2b08d831688bb8c66ef64708@linux-foundation.org> <20171004231821.GA3610@cmpxchg.org> <20171005075704.enxdgjteoe4vgbag@dhcp22.suse.cz> <55d8bf19-3f29-6264-f954-8749ea234efd@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 07, 2017 at 11:21:26AM +0900, Tetsuo Handa wrote: > On 2017/10/05 19:36, Tetsuo Handa wrote: > > I don't want this patch backported. If you want to backport, > > "s/fatal_signal_pending/tsk_is_oom_victim/" is the safer way. > > If you backport this patch, you will see "complete depletion of memory reserves" > and "extra OOM kills due to depletion of memory reserves" using below reproducer. > > ---------- > #include > #include > #include > > static char *buffer; > > static int __init test_init(void) > { > set_current_oom_origin(); > buffer = vmalloc((1UL << 32) - 480 * 1048576); That's not a reproducer, that's a kernel module. It's not hard to crash the kernel from within the kernel.