Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935561AbYCFSK4 (ORCPT ); Thu, 6 Mar 2008 13:10:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935293AbYCFSKf (ORCPT ); Thu, 6 Mar 2008 13:10:35 -0500 Received: from dspnet.fr.eu.org ([213.186.44.138]:3098 "EHLO dspnet.fr.eu.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935226AbYCFSKe (ORCPT ); Thu, 6 Mar 2008 13:10:34 -0500 Date: Thu, 6 Mar 2008 19:10:30 +0100 From: Olivier Galibert To: Joe Buck Cc: 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: <20080306181029.GA42904@dspnet.fr.eu.org> Mail-Followup-To: Olivier Galibert , Joe Buck , Paolo Bonzini , "H. Peter Anvin" , Chris Lattner , Michael Matz , Richard Guenther , Jan Hubicka , Aurelien Jarno , linux-kernel@vger.kernel.org, gcc@gcc.gnu.org References: <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> <20080306175841.GI17267@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080306175841.GI17267@synopsys.com> 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: 936 Lines: 19 On Thu, Mar 06, 2008 at 09:58:41AM -0800, Joe Buck wrote: > 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. I don't think that it is relevant in your case. If you have the signal handler in something that does not share the VM with the interrupted thread, you will have a context switch which is supposed to store the direction flag and restore the one from the handling thread. If you share the VM there is no context switch but you have access to the exact same memory with the exact same rights, making the leak irrelevant. OG. -- 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/