Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S942923AbcJSOms (ORCPT ); Wed, 19 Oct 2016 10:42:48 -0400 Received: from mail-lf0-f46.google.com ([209.85.215.46]:36373 "EHLO mail-lf0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S942490AbcJSOm0 (ORCPT ); Wed, 19 Oct 2016 10:42:26 -0400 Date: Wed, 19 Oct 2016 10:06:46 +0100 From: Lorenzo Stoakes To: Michal Hocko Cc: Jan Kara , linux-mm@kvack.org, Linus Torvalds , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Message-ID: <20161019090646.GA24243@lucifer> References: <20161013002020.3062-1-lstoakes@gmail.com> <20161013002020.3062-9-lstoakes@gmail.com> <20161019075903.GP29967@quack2.suse.cz> <20161019081352.GB7562@dhcp22.suse.cz> <20161019084045.GA19441@lucifer> <20161019085204.GD7517@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161019085204.GD7517@dhcp22.suse.cz> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 692 Lines: 15 On Wed, Oct 19, 2016 at 10:52:05AM +0200, Michal Hocko wrote: > yes this is the desirable and expected behavior. > > > wonder if this is desirable behaviour or whether this ought to be limited to > > ptrace system calls. Regardless, by making the flag more visible it makes it > > easier to see that this is happening. > > mem_open already enforces PTRACE_MODE_ATTACH Ah I missed this, that makes a lot of sense, thanks! I still wonder whether other invocations of access_remote_vm() in fs/proc/base.c (the principle caller of this function) need FOLL_FORCE, for example the various calls that simply read data from other processes, so I think the point stands about keeping this explicit.