From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 21DDD6B0263 for ; Wed, 19 Oct 2016 05:23:54 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id g16so11962956wmg.3 for ; Wed, 19 Oct 2016 02:23:54 -0700 (PDT) Received: from mail-wm0-f66.google.com (mail-wm0-f66.google.com. [74.125.82.66]) by mx.google.com with ESMTPS id rj13si53123641wjb.152.2016.10.19.02.23.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 19 Oct 2016 02:23:52 -0700 (PDT) Received: by mail-wm0-f66.google.com with SMTP id o81so3022621wma.3 for ; Wed, 19 Oct 2016 02:23:52 -0700 (PDT) Date: Wed, 19 Oct 2016 11:23:51 +0200 From: Michal Hocko Subject: Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Message-ID: <20161019092350.GF7517@dhcp22.suse.cz> 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> <20161019090646.GA24243@lucifer> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161019090646.GA24243@lucifer> Sender: owner-linux-mm@kvack.org List-ID: To: Lorenzo Stoakes 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 On Wed 19-10-16 10:06:46, Lorenzo Stoakes wrote: > 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. I do agree. Making them explicit will help to clean them up later, should there be a need. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org