Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760137AbYCFR7B (ORCPT ); Thu, 6 Mar 2008 12:59:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754938AbYCFR6u (ORCPT ); Thu, 6 Mar 2008 12:58:50 -0500 Received: from us02smtp1.synopsys.com ([198.182.60.75]:34490 "EHLO vaxjo.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754725AbYCFR6u (ORCPT ); Thu, 6 Mar 2008 12:58:50 -0500 Date: Thu, 6 Mar 2008 09:58:41 -0800 From: Joe Buck To: Olivier Galibert , Paolo Bonzini , "H. Peter Anvin" , Chris Lattner , Michael Matz , Richard Guenther , Jan Hubicka , Aurelien Jarno , linux-kernel@vger.kernel.org, gcc@gcc.gnu.org Subject: Re: RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction flag Message-ID: <20080306175841.GI17267@synopsys.com> References: <47CF11D6.7070901@zytor.com> <738B72DB-A1D6-43F8-813A-E49688D05771@apple.com> <2F47E21A-9055-4EC3-99CF-B666BBC045C3@apple.com> <47CF3F09.4080606@zytor.com> <578FCA7D-D7A6-44F6-9310-4A97C13CDCBE@apple.com> <47CF44E7.3020106@zytor.com> <20080306135139.GA5236@dspnet.fr.eu.org> <47CFF9A3.30309@gnu.org> <20080306141221.GC5236@dspnet.fr.eu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080306141221.GC5236@dspnet.fr.eu.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 33 On Thu, Mar 06, 2008 at 03:12:21PM +0100, Olivier Galibert wrote: > On Thu, Mar 06, 2008 at 03:03:15PM +0100, Paolo Bonzini wrote: > > Olivier Galibert wrote: > > >On Wed, Mar 05, 2008 at 05:12:07PM -0800, H. Peter Anvin wrote: > > >>It's a kernel bug, and it needs to be fixed. > > > > > >I'm not convinced. It's been that way for 15 years, it's that way in > > >the BSD kernels, at that point it's a feature. The bug is in the > > >documentation, nowhere else. And in gcc for blindly trusting the > > >documentation. > > > > No, the bug *in the kernel* was already present (if you had a signal > > raised during a call to memmove). It's just more visible with GCC 4.3. > > I'm curious, since when paper documentation became the Truth and > reality became a bug? If the kernel allows state to leak from one process to another, for example from a process running as root to a process running as an ordinary user, it's a bug, with possible security implications. In this particular case not much can be communicated through a one-bit flag, so it would only be relevant in those situations where you want to forbid any communication channels from a given process. So the kernel developers might consider it a trivial bug. Or, they could just fix it, which I understand is the plan. -- 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/