From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756868Ab2DSXCD (ORCPT ); Thu, 19 Apr 2012 19:02:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61764 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932602Ab2DSXCC (ORCPT ); Thu, 19 Apr 2012 19:02:02 -0400 Date: Fri, 20 Apr 2012 00:29:50 +0200 From: Oleg Nesterov To: Konstantin Khlebnikov Cc: Cyrill Gorcunov , "akpm@linux-foundation.org" , "keescook@chromium.org" , "kosaki.motohiro@jp.fujitsu.com" , "matthltc@us.ibm.com" , "tj@kernel.org" , Pavel Emelianov , "linux-kernel@vger.kernel.org" Subject: Re: + c-r-prctl-add-ability-to-set-new-mm_struct-exe_file-update-after-mm- num_exe_file_vmas-removal.patch added to -mm tree Message-ID: <20120419222950.GA5807@redhat.com> References: <20120419185221.E8ED6A055E@akpm.mtv.corp.google.com> <20120419192005.GA13558@redhat.com> <20120419210033.GO1893@moon> <20120419211216.GA2200@redhat.com> <20120419213204.GP1893@moon> <4F908CEB.8090606@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F908CEB.8090606@openvz.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/20, Konstantin Khlebnikov wrote: > >>> My question is: unless I missed something "it can't be changed again" >>> is not actually true. A task does PR_SET_MM_EXE_FILE, then it forks >>> the new child. The child can do PR_SET_MM_EXE_FILE again. Is this >>> by design? >> >> Hmm, not sure, Konstantin? > > Why not? It has new pid, why it cannot change exe_file? OK, if you do not see a problem - I agree with this patch. I don't really understand what PR_SET_MM_EXE_FILE buys us if parent/child can have different /proc/pid/exe links without exec, but > Actually I don't care too. same here ;) and at least this addresses the "establishes a bound on how frequently the symlink can change" from Matt. Oleg.