From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756458AbbKDXjn (ORCPT ); Wed, 4 Nov 2015 18:39:43 -0500 Received: from arcturus.aphlor.org ([188.246.204.175]:50534 "EHLO arcturus.aphlor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756335AbbKDXjk (ORCPT ); Wed, 4 Nov 2015 18:39:40 -0500 Date: Wed, 4 Nov 2015 18:39:07 -0500 From: Dave Jones To: Linus Torvalds Cc: Ingo Molnar , Linux Kernel Mailing List , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov , Andrew Morton , Andy Lutomirski , Denys Vlasenko Subject: Re: [GIT PULL] x86/mm changes for v4.4 Message-ID: <20151104233907.GA25925@codemonkey.org.uk> Mail-Followup-To: Dave Jones , Linus Torvalds , Ingo Molnar , Linux Kernel Mailing List , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov , Andrew Morton , Andy Lutomirski , Denys Vlasenko References: <20151103111649.GA3477@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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] X-Authenticated-User: davej@codemonkey.org.uk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 04, 2015 at 11:26:12AM -0800, Linus Torvalds wrote: > On Tue, Nov 3, 2015 at 3:16 AM, Ingo Molnar wrote: > > > > The new CONFIG_DEBUG_WX=y warning is marked default-y if CONFIG_DEBUG_RODATA=y is > > already eanbled, as a special exception, as these bugs are hard to notice and this > > check already found several live bugs. > > So this seems to be not very useful. > > ... > Freeing unused kernel memory: 1068K (ffffffff8bcc0000 - > ffffffff8bdcb000) > Write protecting the kernel read-only data: 12288k > Freeing unused kernel memory: 1944K (ffff88000b61a000 - ffff88000b800000) > Freeing unused kernel memory: 1372K (ffff88000baa9000 - ffff88000bc00000) > ------------[ cut here ]------------ > WARNING: CPU: 7 PID: 1 at arch/x86/mm/dump_pagetables.c:225 > note_page+0x5dc/0x780() > x86/mm: Found insecure W+X mapping at address > ffff88000005f000/0xffff88000005f000 > ... > x86/mm: Checked W+X mappings: FAILED, 165660 W+X pages found. > ... > > because it doesn't seem to give you any idea where to look for the > issue. Those 165660 pages come out to 647MB. Odd number. > > Is this *supposed* to come out clean? FWIW I'm seeing this too. [ 3.293503] x86/mm: Found insecure W+X mapping at address ffff880000800000/0xffff880000800000 Looking further up the dmesg I see that range is.. [ 0.468368] ---[ Low Kernel Mapping ]--- [ 0.468381] 0xffff880000000000-0xffff880000800000 8M RW GLB NX pte [ 0.468391] 0xffff880000800000-0xffff880000900000 1M RW GLB x pte Linus, does that match your trace too ? The 2nd low kernel mapping? Dave