Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751991AbbLIAK0 (ORCPT ); Tue, 8 Dec 2015 19:10:26 -0500 Received: from arcturus.aphlor.org ([188.246.204.175]:54628 "EHLO arcturus.aphlor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751184AbbLIAKZ (ORCPT ); Tue, 8 Dec 2015 19:10:25 -0500 Date: Tue, 8 Dec 2015 19:10:12 -0500 From: Dave Jones To: Kees Cook Cc: Mihai =?utf-8?B?RG9uyJt1?= , Pavel Machek , LKML , Stephen Smalley Subject: Re: 4.4-rc0: 5 W+X pages found Message-ID: <20151209001012.GA17123@codemonkey.org.uk> Mail-Followup-To: Dave Jones , Kees Cook , Mihai =?utf-8?B?RG9uyJt1?= , Pavel Machek , LKML , Stephen Smalley References: <20151115070022.GA15417@amd> <20151123163714.00f06010@mdontu-l.dsd.bitdefender.biz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Spam-Score: -2.9 (--) X-Spam-Report: Spam report generated by SpamAssassin on "arcturus.aphlor.org" Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4630 Lines: 94 On Tue, Dec 08, 2015 at 01:19:32PM -0800, Kees Cook wrote: > On Mon, Nov 23, 2015 at 6:37 AM, Mihai Donțu wrote: > > On Sun, 15 Nov 2015 08:00:22 +0100 Pavel Machek wrote: > >> Kernel complains: > >> > >> [ 5.256044] ------------[ cut here ]------------ > >> [ 5.259267] WARNING: CPU: 0 PID: 1 at > >> arch/x86/mm/dump_pagetables.c:225 note_page+0x5ec/0x790() > >> [ 5.262668] x86/mm: Found insecure W+X mapping at address > >> ffe69000/0xffe69000 > >> [ 5.267109] Modules linked in: > >> [ 5.271403] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.3.0+ #122 > >> [ 5.275679] Hardware name: LENOVO 17097HU/17097HU, BIOS 7BETD8WW > >> (2.19 ) 03/31/2011 > >> [ 5.279957] 00000000 00000000 f5cffeac c42b9f18 f5cffed8 f5cffec8 > >> c404062b 000000e1 > >> [ 5.284387] c403ca9c f5cfff50 00000163 00000000 f5cffee0 c4040686 > >> 00000009 f5cffed8 > >> [ 5.288815] c4d268ac f5cffef4 f5cfff1c c403ca9c c4d1f494 000000e1 > >> c4d268ac ffe69000 > >> [ 5.293314] Call Trace: > >> [ 5.297602] [] dump_stack+0x41/0x59 > >> [ 5.301864] [] warn_slowpath_common+0x6b/0xa0 > >> [ 5.306054] [] ? note_page+0x5ec/0x790 > >> [ 5.310209] [] warn_slowpath_fmt+0x26/0x30 > >> [ 5.314358] [] note_page+0x5ec/0x790 > >> [ 5.318440] [] ptdump_walk_pgd_level_core+0x14f/0x230 > >> [ 5.322578] [] ptdump_walk_pgd_level_checkwx+0x11/0x20 > >> [ 5.326632] [] mark_rodata_ro+0xcd/0xf0 > >> [ 5.330625] [] kernel_init+0x17/0xc0 > >> [ 5.334585] [] ret_from_kernel_thread+0x21/0x38 > >> [ 5.338585] [] ? rest_init+0xa0/0xa0 > >> [ 5.342583] ---[ end trace bc9ac0874ad9a058 ]--- > >> [ 5.346630] x86/mm: Checked W+X mappings: FAILED, 5 W+X pages > >> found. > >> > >> ...I'm not quite sure why it does backtrace, or how to debug this > >> one... > > > > That is a modest number. > > > > [ 2.493559] ------------[ cut here ]------------ > > [ 2.493563] WARNING: CPU: 2 PID: 1 at arch/x86/mm/dump_pagetables.c:225 note_page+0x5e1/0x780() > > [ 2.493565] x86/mm: Found insecure W+X mapping at address ffff88000009d000/0xffff88000009d000 > > [ 2.493565] Modules linked in: > > [ 2.493568] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.4.0-rc2 #2 > > [ 2.493569] Hardware name: Dell Inc. Latitude E7440/07F3F4, BIOS A15 05/19/2015 > > [ 2.493570] 0000000000000000 00000000c03551f4 ffff88040c7cbd48 ffffffffaa54851c > > [ 2.493572] ffff88040c7cbd90 ffff88040c7cbd80 ffffffffaa13a662 ffff88040c7cbe90 > > [ 2.493573] 8000000000000163 0000000000000004 0000000000000000 0000000000000000 > > [ 2.493575] Call Trace: > > [ 2.493579] [] dump_stack+0x4e/0x82 > > [ 2.493582] [] warn_slowpath_common+0x82/0xc0 > > [ 2.493583] [] warn_slowpath_fmt+0x5c/0x80 > > [ 2.493585] [] note_page+0x5e1/0x780 > > [ 2.493587] [] ptdump_walk_pgd_level_core+0x2c4/0x3f0 > > [ 2.493588] [] ptdump_walk_pgd_level_checkwx+0x17/0x20 > > [ 2.493591] [] mark_rodata_ro+0xef/0x100 > > [ 2.493594] [] ? rest_init+0x90/0x90 > > [ 2.493595] [] kernel_init+0x1d/0xe0 > > [ 2.493596] [] ret_from_fork+0x3f/0x70 > > [ 2.493598] [] ? rest_init+0x90/0x90 > > [ 2.493599] ---[ end trace e2aec56d15b94609 ]--- > > [ 2.498994] x86/mm: Checked W+X mappings: FAILED, 104640 W+X pages found. > > > > All the while I have: > > > > $ zgrep NX /proc/config.gz > > CONFIG_DEBUG_SET_MODULE_RONX=y > > > > I added to CC the people involved in pushing this feature to mainline, > > maybe they can point me to a possible cause. > > If you enable CONFIG_X86_PTDUMP, see if you can find out what exists > in /sys/kernel/debug/kernel_page_tables at ffff88000009d000 ? Is this not likely the EFI stuff mentioned in commit 54727e6e950aacd14ec9cd4260e9fe498322828c ? I saw some patches that reorg'd a lot of the EFI memory code, but afaik they didn't get merged yet. sidenote: # cat /sys/kernel/debug/kernel_page_tables cat: /sys/kernel/debug/kernel_page_tables: Cannot allocate memory Dave -- 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/