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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D461C04AA6 for ; Tue, 30 Apr 2019 09:11:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2776220652 for ; Tue, 30 Apr 2019 09:11:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726953AbfD3JLp (ORCPT ); Tue, 30 Apr 2019 05:11:45 -0400 Received: from relay.sw.ru ([185.231.240.75]:39018 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726165AbfD3JLo (ORCPT ); Tue, 30 Apr 2019 05:11:44 -0400 Received: from [172.16.25.169] by relay.sw.ru with esmtp (Exim 4.91) (envelope-from ) id 1hLOnZ-0007Uk-Vy; Tue, 30 Apr 2019 12:11:38 +0300 Subject: Re: [PATCH 3/3] prctl_set_mm: downgrade mmap_sem to read lock To: Cyrill Gorcunov Cc: =?UTF-8?Q?Michal_Koutn=c3=bd?= , akpm@linux-foundation.org, arunks@codeaurora.org, brgl@bgdev.pl, geert+renesas@glider.be, ldufour@linux.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mguzik@redhat.com, mhocko@kernel.org, rppt@linux.ibm.com, vbabka@suse.cz References: <20190418182321.GJ3040@uranus.lan> <20190430081844.22597-1-mkoutny@suse.com> <20190430081844.22597-4-mkoutny@suse.com> <20190430090808.GC2673@uranus.lan> From: Kirill Tkhai Message-ID: <0a48e0a2-a282-159e-a56e-201fbc0faa91@virtuozzo.com> Date: Tue, 30 Apr 2019 12:11:37 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190430090808.GC2673@uranus.lan> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30.04.2019 12:08, Cyrill Gorcunov wrote: > On Tue, Apr 30, 2019 at 11:55:45AM +0300, Kirill Tkhai wrote: >>> - up_write(&mm->mmap_sem); >>> + spin_unlock(&mm->arg_lock); >>> + up_read(&mm->mmap_sem); >>> return error; >> >> Hm, shouldn't spin_lock()/spin_unlock() pair go as a fixup to existing code >> in a separate patch? >> >> Without them, the existing code has a problem at least in get_mm_cmdline(). > > Seems reasonable to merge it into patch 1. Sounds sensibly.