Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965842AbbKEODB (ORCPT ); Thu, 5 Nov 2015 09:03:01 -0500 Received: from vserver.eikelenboom.it ([84.200.39.61]:38345 "EHLO smtp.eikelenboom.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965213AbbKEOC7 (ORCPT ); Thu, 5 Nov 2015 09:02:59 -0500 Date: Thu, 5 Nov 2015 15:02:52 +0100 From: Sander Eikelenboom Organization: Eikelenboom IT services X-Priority: 3 (Normal) Message-ID: <1565834186.20151105150252@eikelenboom.it> To: Boris Ostrovsky CC: Stephen Smalley , linux-kernel@vger.kernel.org, , David Vrabel , , Subject: Re: [Xen-devel] Linux 4.4 MW: Boot under Xen fails with CONFIG_DEBUG_WX enabled: RIP: ptdump_walk_pgd_level_core In-Reply-To: <563B5F64.1010806@oracle.com> References: <9184aedc84bf5274c290183fa60b48e9@eikelenboom.it> <563A29C4.7020400@tycho.nsa.gov> <60febac0220bd2b5df2fd0d86c8d40ae@eikelenboom.it> <563A52CD.5030903@tycho.nsa.gov> <8bbf050578e9254ac3bf1d941dc0fb19@eikelenboom.it> <563A910F.7060008@oracle.com> <80b3ed527b208d28ee05fb627bc28d91@eikelenboom.it> <563B5F64.1010806@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1412 Lines: 48 Thursday, November 5, 2015, 2:53:40 PM, you wrote: > On 11/05/2015 04:13 AM, Sander Eikelenboom wrote: >> >> It makes "cat /sys/kernel/debug/kernel_page_tables" work and >> prevents a kernel with CONFIG_DEBUG_WX=y from crashing at boot. > Great. Our nightly runs also failed spectacularly due to this bug. >> >> It now does give a warning about an insecure W+X mapping, so >> CONFIG_DEBUG_WX=y >> seems to be working. No idea how to interpret it though (and if it's a >> legit >> warning). >> >> -- >> Sander >> >> [ 19.034706] Freeing unused kernel memory: 1104K (ffffffff822fc000 - >> ffffffff82410000) >> [ 19.041339] Write protecting the kernel read-only data: 18432k >> [ 19.052596] Freeing unused kernel memory: 1144K (ffff880001ae2000 - >> ffff880001c00000) >> [ 19.060285] Freeing unused kernel memory: 1560K (ffff88000207a000 - >> ffff880002200000) >> [ 19.067079] ------------[ cut here ]------------ >> [ 19.073931] WARNING: CPU: 5 PID: 1 at >> arch/x86/mm/dump_pagetables.c:225 note_page+0x619/0x7e0() > Yes, this apparently is a known issue: https://lkml.org/lkml/2015/11/4/476 > -boris Ah thx for the pointer :) -- Sander -- 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/