Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932167Ab0KSUQo (ORCPT ); Fri, 19 Nov 2010 15:16:44 -0500 Received: from 1wt.eu ([62.212.114.60]:47490 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756633Ab0KSUQn (ORCPT ); Fri, 19 Nov 2010 15:16:43 -0500 Date: Fri, 19 Nov 2010 21:16:14 +0100 From: Willy Tarreau To: Linus Torvalds Cc: david@lang.hm, Sarah Sharp , Marcus Meissner , linux-kernel@vger.kernel.org, tj@kernel.org, akpm@linux-foundation.org, hpa@zytor.com, mingo@elte.hu, alan@lxorguk.ukuu.org.uk Subject: Re: [PATCH] kernel: make /proc/kallsyms mode 400 to reduce ease of attacking Message-ID: <20101119201614.GB19329@1wt.eu> References: <20101116104600.GA24015@suse.de> <20101119191906.GA31760@xanatos> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1306 Lines: 31 On Fri, Nov 19, 2010 at 12:04:47PM -0800, Linus Torvalds wrote: > On Fri, Nov 19, 2010 at 11:58 AM, wrote: > > > > how far back do we need to maintain compatibility with userspace? > > > > Is this something that we can revisit in a few years and lock it down then? > > The rule is basically "we never break user space". > > But the "out" to that rule is that "if nobody notices, it's not > broken". In a few years? Who knows? > > So breaking user space is a bit like trees falling in the forest. If > there's nobody around to see it, did it really break? FWIW, I appreciate a lot that non-breaking rule. I have some testing machines which boot from PXE or USB on a file-system with some old tools and libc, that are both 2.4 and 2.6 compatible. Everything works like a charm, the only point of care was to have both module-init-tools and modutils (obviously) but even that integrates smoothly. I know quite a lot of people who never replace user-space but only kernels on their systems, so this non-breaking rule is much welcome ! Willy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/