From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754093AbeDCXPj (ORCPT ); Tue, 3 Apr 2018 19:15:39 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:44116 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753305AbeDCXPi (ORCPT ); Tue, 3 Apr 2018 19:15:38 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04446;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0T-dXevc_1522797320; Subject: Re: [RFC] prctl: Deprecate non PR_SET_MM_MAP operations To: Cyrill Gorcunov , LKML Cc: Andrey Vagin , Andrew Morton , Pavel Emelyanov , Michael Kerrisk , Michal Hocko References: <20180403223722.GA15783@uranus.lan> From: Yang Shi Message-ID: <48bcd917-4eb8-9da6-ec4b-e76a654695c4@linux.alibaba.com> Date: Tue, 3 Apr 2018 16:15:20 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180403223722.GA15783@uranus.lan> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/3/18 3:37 PM, Cyrill Gorcunov wrote: > An ability to manipulate mm_struct fields was introduced in > sake of CRIU in first place. Later we provide more suitable > and safe operation PR_SET_MM_MAP where all fields to be modifed > are passed in one structure which allows us to make more detailed > verification. > > Still old interface remains present for compatibility reason > though CRIU itself already switched to PR_SET_MM_MAP on its > own long ago. > > Googling didn't reveal some other users of this operation > so I think it should be safe to issue deprecation warning > first time and get rid of this interface after a couple > of releases. > > CC: Andrey Vagin > CC: Andrew Morton > CC: Pavel Emelyanov > CC: Michael Kerrisk > CC: Yang Shi > CC: Michal Hocko > Signed-off-by: Cyrill Gorcunov > --- > Or we can simply drop it off because PR_SET_MM_MAP covers all needs, > and I would rather prefer to do that asap. Thanks for making it deprecated. I'd prefer just drop it off if nobody objects. The change will get soaked in linux-next for a while , we will know if it breaks compatibility (it sounds very unlikely). Yang > > kernel/sys.c | 2 ++ > 1 file changed, 2 insertions(+) > > Index: linux-ml.git/kernel/sys.c > =================================================================== > --- linux-ml.git.orig/kernel/sys.c > +++ linux-ml.git/kernel/sys.c > @@ -2052,6 +2052,8 @@ static int prctl_set_mm(int opt, unsigne > if (!capable(CAP_SYS_RESOURCE)) > return -EPERM; > > + pr_warn_once("Non PR_SET_MM_MAP operations are deprecated\n"); > + > if (opt == PR_SET_MM_EXE_FILE) > return prctl_set_mm_exe_file(mm, (unsigned int)addr); >