Return-Path: linux-nfs-owner@vger.kernel.org Received: from bombadil.infradead.org ([198.137.202.9]:33896 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752687AbaDVGXi (ORCPT ); Tue, 22 Apr 2014 02:23:38 -0400 Date: Mon, 21 Apr 2014 23:23:38 -0700 From: Christoph Hellwig To: Chuck Lever Cc: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH V2 10/17] xprtrdma: Add CONFIG setting that can disable ALLPHYSICAL Message-ID: <20140422062338.GA23311@infradead.org> References: <20140421214442.12569.8950.stgit@manet.1015granger.net> <20140421220214.12569.23157.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20140421220214.12569.23157.stgit@manet.1015granger.net> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Apr 21, 2014 at 06:02:14PM -0400, Chuck Lever wrote: > ALLPHYSICAL is not a safe memory registration mode because it > permits NFS servers to write anywhere in a client's memory. NFS > server bugs could result in client memory being overwritten. > > This can be useful for embedded systems which do not support more > surgical RDMA memory registration and protection methods, or for > bring-up of new HCA hardware. > > However, enterprise Linux distributions have expressed a desire to > disable it in production environments. It's just as unsafe in embedded devices. I think it should go