From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753655AbcHBKpo (ORCPT ); Tue, 2 Aug 2016 06:45:44 -0400 Received: from foss.arm.com ([217.140.101.70]:38106 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753206AbcHBKpf (ORCPT ); Tue, 2 Aug 2016 06:45:35 -0400 Date: Tue, 2 Aug 2016 10:50:41 +0100 From: Mark Rutland To: Kees Cook Cc: Linus Torvalds , Arnd Bergmann , Greg Kroah-Hartman , LKML Subject: Re: [PATCH] lkdtm: Fix targets for objcopy usage Message-ID: <20160802095040.GC19251@leverpostej> References: <20160729023039.GA15900@www.outflux.net> <20160729093757.GA21580@leverpostej> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 On Mon, Aug 01, 2016 at 02:25:48PM -0700, Kees Cook wrote: > On Fri, Jul 29, 2016 at 2:37 AM, Mark Rutland wrote: > > Hi, > > > > On Thu, Jul 28, 2016 at 07:30:39PM -0700, Kees Cook wrote: > >> The targets for lkdtm's objcopy were missing which caused them to always > >> be rebuilt. This corrects the problem. > >> > >> Additionally, commit f8fa70f392fa ("arm64: localise Image objcopy flags") > >> has landed now, so this removes the work-around for the global OBJCOPY > >> flag setting. > >> > >> Reported-by: Linus Torvalds > >> Signed-off-by: Kees Cook > > > > With this applied, LKDTM builds fine for me on arm64, the redundant > > rebuilds are gone, and the result appears to work. So FWIW: > > > > Tested-by: Mark Rutland > > Argh, it looks like ARM suffers the same global OBJCOPY problem, so > I'm going to leave that change out. :( :( FWIW, I dropped a patch for ARM [1] in Russell's patch system [2]. Hopefully that will be picked up during the v4.9 merge window. Looking again, it appears a number of other arches might be affected: [mark@leverpostej:~/src/linux]% git grep 'OBJCOPYFLAGS\s\+:=' -- arch/*/Makefile arch/arm/Makefile:OBJCOPYFLAGS :=-O binary -R .comment -S arch/blackfin/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -S arch/cris/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -S arch/ia64/Makefile:OBJCOPYFLAGS := --strip-all arch/m32r/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -S arch/metag/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -S arch/mn10300/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -R .GCC-command-line -R .note.gnu.build-id -S arch/openrisc/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .comment -S arch/s390/Makefile:OBJCOPYFLAGS := -O binary arch/sh/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .note.gnu.build-id -R .comment \ arch/unicore32/Makefile:OBJCOPYFLAGS := -O binary -R .note -R .note.gnu.build-id -R .comment -S ... so we probably need to fix up these first, regardless. In the mean time, can we add the targets dependency, but leave the flags work-around intact? Thanks, Mark. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-July/442974.html [2] http://www.armlinux.org.uk/developer/patches/viewpatch.php?id=8588/1