Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754900Ab3JDNvN (ORCPT ); Fri, 4 Oct 2013 09:51:13 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:18594 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754016Ab3JDNvJ (ORCPT ); Fri, 4 Oct 2013 09:51:09 -0400 X-IronPort-AV: E=Sophos;i="4.90,1033,1371081600"; d="scan'208";a="57748334" Message-ID: <524EC3C1.4010304@citrix.com> Date: Fri, 4 Oct 2013 14:33:53 +0100 From: Andrew Cooper User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130827 Icedove/17.0.8 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: Frediano Ziglio , Boris Ostrovsky , David Vrabel , , Subject: Re: [Xen-devel] [PATCH] xen: Fix possible user space selector corruption References: <1380788677.30462.1.camel@hamster.uk.xensource.com> <524D4132.3000809@citrix.com> <1380804692.30462.3.camel@hamster.uk.xensource.com> <20131004132033.GA26673@phenom.dumpdata.com> In-Reply-To: <20131004132033.GA26673@phenom.dumpdata.com> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1519 Lines: 39 On 04/10/13 14:20, Konrad Rzeszutek Wilk wrote: > On Thu, Oct 03, 2013 at 01:51:32PM +0100, Frediano Ziglio wrote: >> On Thu, 2013-10-03 at 11:04 +0100, Andrew Cooper wrote: >>> On 03/10/13 09:24, Frediano Ziglio wrote: >>>> >>>> Bisecting the code commit 7076aada1040de4ed79a5977dbabdb5e5ea5e249 appears >>>> to be the first one that have this issue. >>>> >>>> Signed-off-by: Frediano Ziglio >>> In terms of the correctness of the fix, >>> >>> Reviewed-by: Andrew Cooper > Should this also go in stable tree? Very much so. The change which exposed it for us was from 3.7 iirc, but I believe it has been a latent bug for as long as the native early boot code uses __USER_DS. >>> However, I am not sure the comment is necessary. The prevailing style >>> is for no justification of loads of segment selectors on boot, and the >>> comment itself refers simply to an interaction issue of 32bit on Xen >>> when making use of sysenter. >>> >> Suggestion for the comment ?? >> >> Frediano My suggestion was to omit the comment entirely, or simplify it to just: /* Xen starts us with XEN_FLAT_RING1_DS, but linux code expects __USER_DS */ Anyone who wants the full explanation can read the patch description. ~Andrew -- 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/