Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761489Ab2FHIFH (ORCPT ); Fri, 8 Jun 2012 04:05:07 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:41600 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760459Ab2FHIE6 (ORCPT ); Fri, 8 Jun 2012 04:04:58 -0400 Date: Fri, 8 Jun 2012 17:04:49 +0900 From: Greg KH To: Josh Boyer Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ulrich Obergfell , Andrea Arcangeli , Mel Gorman , Hugh Dickins , Larry Woodman , Petr Matousek , Rik van Riel Subject: Re: [ 08/82] mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition Message-ID: <20120608080449.GC24167@kroah.com> References: <20120607041406.GA13233@kroah.com> <20120607040337.622672845@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1254 Lines: 35 On Thu, Jun 07, 2012 at 09:42:55AM -0400, Josh Boyer wrote: > On Thu, Jun 7, 2012 at 12:03 AM, Greg KH wrote: > > 3.4-stable review patch. ?If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Andrea Arcangeli > > > > commit 26c191788f18129af0eb32a358cdaea0c7479626 upstream. > > > > When holding the mmap_sem for reading, pmd_offset_map_lock should only > > run on a pmd_t that has been read atomically from the pmdp pointer, > > otherwise we may read only half of it leading to this crash. > > This one is important, but it can break Xen apparently: > > http://permalink.gmane.org/gmane.comp.emulators.xen.devel/132522 > https://bugzilla.redhat.com/show_bug.cgi?id=829016 > > Not sure if you want to hold off on it or see if Andrea comes up with > a follow up fix? Ok, for now, I'll drop it. When Andrea gets this fixed up, can someone let me know so I can apply this one again, and the fixup? thanks, greg k-h -- 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/