Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757296AbYBEQiT (ORCPT ); Tue, 5 Feb 2008 11:38:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752451AbYBEQiL (ORCPT ); Tue, 5 Feb 2008 11:38:11 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:37131 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750864AbYBEQiK (ORCPT ); Tue, 5 Feb 2008 11:38:10 -0500 Date: Tue, 5 Feb 2008 17:37:24 +0100 From: Ingo Molnar To: Pavel Machek Cc: Jakub Jelinek , Jiri Kosina , Andrew Morton , "Rafael J. Wysocki" , kernel list , Abel Bernabeu , Hugh Dickins , Arjan van de Ven Subject: Re: [regression] Re: brk randomization breaks columns Message-ID: <20080205163724.GA31286@elte.hu> References: <20080204122837.GA1647@elf.ucw.cz> <20080205110632.GB3758@elf.ucw.cz> <20080205125426.GA27724@elte.hu> <20080205130546.GF30691@devserv.devel.redhat.com> <20080205161810.GF24331@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080205161810.GF24331@elf.ucw.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1559 Lines: 39 * Pavel Machek wrote: > > > > I am still not completely sure. It might be a regression, but it > > > > also might just trigger the bug in ancient version in libc.so.5 > > > > which might be fixed in some later version [...] > > > > > > which too is a regression ... > > > > > > really, lets add a sysctl for this, and a .config option that > > > either disables or enables it. Then we will default to disabled. > > > (but users can enable it - and distros can build their kernels > > > with this .config option enabled) > > > > I don't think kernel should care about programs which are buggy and > > make invalid assumptions, and that's the case here. I remember we > > have been > > Those "invalid assumptions" crept into documentation. Everybody knew > heap starts at the end of bss in 1995. what matters most isnt really any documentation but what programs really do, and how it affects users. in this case i think we should offer a .config option to set the randomization behavior, and should perhaps make the more conservative one the default. New distros (with 10,000+ binaries that work just fine with randomization) will turn on max randomization by default, while people like you who mix 1996 binaries with a 2008 kernel will use a more conservative default. Ingo -- 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/