From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 19 Oct 2016 11:24:04 +0200 (CEST) Received: from mail-wm0-f65.google.com ([74.125.82.65]:34050 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23991986AbcJSJX5gKBOu (ORCPT ); Wed, 19 Oct 2016 11:23:57 +0200 Received: by mail-wm0-f65.google.com with SMTP id d199so3033964wmd.1 for ; Wed, 19 Oct 2016 02:23:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=++FvlNLVYzOp8+DkPkQd2fkTJ+ESt47iJEedHbRBZLk=; b=JWLyutsMcRRTFKlpi6fY5KqJE6gnerhl3XqcFBUtbArWnKOJ1hptOmY04sPBJZd6hQ ae5zDMRBROFhSExbLvZOU4727XzIziFCY53D3DbQ1JIk6jKzhl4f1kskIrrJEBf2eleW JpscWq13ySqLX2RZZkeQqnQLl1Ynchh/RQvNzIZdUbSJdYkAVkuxaosu6pAyGR/9Wfae 08HOZmr//1jOfu7Hxcu94DaJa/qwvaP3TvwLD7D6BY7mdaDkQQ2xlpj/wcnBODxY6bVC ykUY2uV68nU6Bvi1Rsh6XNGYcjvbDsvUagV8sozZKkNfvyD5rY796VipA2dkpEZumTpl 07iw== X-Gm-Message-State: AA6/9RnTfv6aTv8ulTxzFVZNlL5BpQYEX/lQnPNlUrb+6YQDIpWJvrk9pXcA5UOmf9BcnA== X-Received: by 10.194.188.37 with SMTP id fx5mr3621591wjc.170.1476869032188; Wed, 19 Oct 2016 02:23:52 -0700 (PDT) Received: from localhost ([213.151.95.130]) by smtp.gmail.com with ESMTPSA id ct1sm67516236wjd.13.2016.10.19.02.23.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 19 Oct 2016 02:23:51 -0700 (PDT) Date: Wed, 19 Oct 2016 11:23:51 +0200 From: Michal Hocko 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 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> User-Agent: Mutt/1.6.0 (2016-04-01) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 55507 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: mhocko@kernel.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 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