From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756942AbaHHOfu (ORCPT ); Fri, 8 Aug 2014 10:35:50 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:37981 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756678AbaHHOft (ORCPT ); Fri, 8 Aug 2014 10:35:49 -0400 Message-ID: <53E4E042.1070300@canonical.com> Date: Fri, 08 Aug 2014 16:35:46 +0200 From: Stefan Bader User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: David Vrabel , "xen-devel@lists.xensource.com" , Linux Kernel Mailing List CC: Kees Cook Subject: Re: [Xen-devel] Xen PV domain regression with KASLR enabled (kernel 3.16) References: <53E4B281.5050302@canonical.com> <53E4C5D5.2090103@citrix.com> In-Reply-To: <53E4C5D5.2090103@citrix.com> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="x0qLLSxA4EmVvK2TwaoNQoOHNIAXJ7Tbs" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --x0qLLSxA4EmVvK2TwaoNQoOHNIAXJ7Tbs Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 08.08.2014 14:43, David Vrabel wrote: > On 08/08/14 12:20, Stefan Bader wrote: >> Unfortunately I have not yet figured out why this happens, but can con= firm by >> compiling with or without CONFIG_RANDOMIZE_BASE being set that without= KASLR all >> is ok, but with it enabled there are issues (actually a dom0 does not = even boot >> as a follow up error). >> >> Details can be seen in [1] but basically this is always some portion o= f a >> vmalloc allocation failing after hitting a freshly allocated PTE space= not being >> PTE_NONE (usually from a module load triggered by systemd-udevd). In t= he >> non-dom0 case this repeats many times but ends in a guest that allows = login. In >> the dom0 case there is a more fatal error at some point causing a cras= h. >> >> I have not tried this for a normal PV guest but for dom0 it also does = not help >> to add "nokaslr" to the kernel command-line. >=20 > Maybe it's overlapping with regions of the virtual address space > reserved for Xen? What the the VA that fails? >=20 > David >=20 Yeah, there is some code to avoid some regions of memory (like initrd). M= aybe missing p2m tables? I probably need to add debugging to find the failing = VA (iow not sure whether it might be somewhere in the stacktraces in the report).= The kernel-command line does not seem to be looked at. It should put some= thing into dmesg and that never shows up. Also today's random feature is other = PV guests crashing after a bit somewhere in the check_for_corruption area...= -Stefan --x0qLLSxA4EmVvK2TwaoNQoOHNIAXJ7Tbs Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJT5OBCAAoJEOhnXe7L7s6jhp4QANCkgwd5l8hgydbxAQSla3B1 oxH9CHRngjqicYSgaV74TsLNSavyoG0vM7gw2b0GUXWT0jv3Bq/ouXjAE+Scy3Ic ZWUcWsxfEVeU3OTTmmFiyXuCPoW8ZhETyxsAncQnWZtuY7c/ciXlcWnxmyzIpt2J QXZEYNND1+iMgQz4Z40zaEJVEoxnSKIdU5GEAne4vgELr9qVnNjzVD/vsvMGXkoB j1LnKiLHTE1YQt27G/GuPMlJA5iDXwCzgGleSbsFIYxc3idUxmhfu9k0OW9HpwFb 9q1hUTTNQja3KSnauAyjZMDa/Vv9mpEkg7pJ6q7/qUFLzUVZ4QJEVSsNnk2ejb9S AIXXogiUSNEVih/qHtBn5JpqTNlse9blUZKVPpzLQMb/v9Mr8CIG58XdXu9GHMLy qwOttEMbbC5WiYxz8nXqFWMjrjsIGW/u577J4dB1ZrUm5Bcr2Ru+CYm5gZosKrUS tBR+OGlFNI/VjfeQyO0i4if5CwhcxSxGHHhl4QFXRil1Pzkl/9v3TUJC93qGAW19 NGglrSae9L/AzuodF/67TDhlqp4yib5xjni1q2mZJoBaCxNkuOlY9BulYsnrcOKY SB6H9rhWCvNxM5RibaacLiiDz3KNJ/ceyctI5d9iJful2wVSidHHcmYPS0AUkMxA lUzt9mun0httOWv3VyV0 =ZmHC -----END PGP SIGNATURE----- --x0qLLSxA4EmVvK2TwaoNQoOHNIAXJ7Tbs--