From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261190AbTJQWmK (ORCPT ); Fri, 17 Oct 2003 18:42:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261159AbTJQWmK (ORCPT ); Fri, 17 Oct 2003 18:42:10 -0400 Received: from ns.suse.de ([195.135.220.2]:10187 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S261162AbTJQWmH (ORCPT ); Fri, 17 Oct 2003 18:42:07 -0400 To: "Luck, Tony" Cc: "Bjorn Helgaas" , , Subject: Re: [RFC] prevent "dd if=/dev/mem" crash References: From: Andreas Schwab X-Yow: I'm ZIPPY the PINHEAD and I'm totally committed to the festive mode. Date: Sat, 18 Oct 2003 00:40:48 +0200 In-Reply-To: (Tony Luck's message of "Fri, 17 Oct 2003 15:19:49 -0700") Message-ID: User-Agent: Gnus/5.1002 (Gnus v5.10.2) Emacs/21.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "Luck, Tony" writes: >> I expect there are probably different opinions about the idea >> that "dd if=/dev/mem" exits without doing anything. Sparc and >> 68K have nearby code that bit-buckets writes and returns zeroes >> for reads of page zero. We could do that, too, but it seems like >> kind of a hack, and holes on ia64 can be BIG (on the order of >> 256GB for one box). > > Filling in the holes does seem like a bad idea, but so does returning > EOF when you hit a hole (which is what I think your patch is doing). > > Would ENODEV be better? EIO would probably fit better. Andreas. -- Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."