From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A58842580EA; Fri, 2 May 2025 16:12:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746202334; cv=none; b=nM3NZeG6dzWtIizpXbHKd5jrXV/S4L8b1nKsY6NXaGznhrMyyuv3oyQ2xfoc19ouiwPvLgGG3AIpl9r2+Ewm2jys99CVR5/lXgFhihMCAnFwUBsLWBS1DZmp2T2Odh/ewgjwlAXfBz01b8CSgGDqiK/OP2D1oGfthwz5XdgNQB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746202334; c=relaxed/simple; bh=oIBoHhr4ygbJf9Q+KP535Pj4mKXpGFceRyolVWXj4HA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pmMf4SVswafm8yIenlHpyWixNPrAGOle+XrHxHOMPnb9MXe/G+YzsdWXwsDAf8Lrntt4NPc/meWkVbpQrnRf37PuL+EliQ8KF2cHWzH6qbBQBou0nCaaJ46YHyJGPM45oSiz4D0+Gquv2Elk0ayXozqmuvcW8TNwJLpQoIaRb64= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ilrraeZl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ilrraeZl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A9ACC4CEE4; Fri, 2 May 2025 16:12:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746202334; bh=oIBoHhr4ygbJf9Q+KP535Pj4mKXpGFceRyolVWXj4HA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ilrraeZlcDUAQ/GSbU7RteYAGpWdWZLitu4sOfw/srjuMVxWYq5pD5dIo1mAimLnx qlW8HwK0dy4y2dg4v3QnU4hKF8uZiR7jm1f3bxu3hil08qrv+wrPwRlH5MtfqQ6Xrp BqOZdNIpAHowgPPpwb4toDRF75B8zLY1wD+C2GcxHaUN/1sklXb3eg2ppF/vtuZuic oU5p3VWXemkQbHfwJagFnDuC0MG8FmP5dvtQNERqZ3aaDMHxUtqPVZlTRUmuT57HAg ntijOf3pYY5Rk+sKjxQUfErmj+vnNgNzOlA2mwt0BL9EZQji9GhfV8s1FU8vhfp3Lf kil+ZxwZ25c6A== Date: Fri, 2 May 2025 09:12:09 -0700 From: Nathan Chancellor To: Kees Cook Cc: Masahiro Yamada , Nicolas Schier , Petr Pavlu , Sebastian Andrzej Siewior , linux-kbuild@vger.kernel.org, Justin Stitt , Marco Elver , Andrey Konovalov , Andrey Ryabinin , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, kasan-dev@googlegroups.com Subject: Re: [PATCH 2/3] randstruct: Force full rebuild when seed changes Message-ID: <20250502161209.GA2850065@ax162> References: <20250501193839.work.525-kees@kernel.org> <20250501194826.2947101-2-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250501194826.2947101-2-kees@kernel.org> Hi Kees, On Thu, May 01, 2025 at 12:48:17PM -0700, Kees Cook wrote: > While the randstruct GCC plugin was being rebuilt if the randstruct > seed changed, Clangs build did not notice the change. Include the hash > header directly so that it becomes a universal build dependency and full > rebuilds will happen if it changes. > > Signed-off-by: Kees Cook > --- > Cc: Masahiro Yamada > Cc: Nathan Chancellor > Cc: Nicolas Schier > Cc: Petr Pavlu > Cc: Sebastian Andrzej Siewior > Cc: > --- > include/linux/vermagic.h | 1 - > scripts/Makefile.randstruct | 3 ++- > scripts/basic/Makefile | 11 ++++++----- > 3 files changed, 8 insertions(+), 7 deletions(-) > > diff --git a/include/linux/vermagic.h b/include/linux/vermagic.h > index 939ceabcaf06..335c360d4f9b 100644 > --- a/include/linux/vermagic.h > +++ b/include/linux/vermagic.h > @@ -33,7 +33,6 @@ > #define MODULE_VERMAGIC_MODVERSIONS "" > #endif > #ifdef RANDSTRUCT > -#include > #define MODULE_RANDSTRUCT "RANDSTRUCT_" RANDSTRUCT_HASHED_SEED > #else > #define MODULE_RANDSTRUCT > diff --git a/scripts/Makefile.randstruct b/scripts/Makefile.randstruct > index 24e283e89893..ab87219c6149 100644 > --- a/scripts/Makefile.randstruct > +++ b/scripts/Makefile.randstruct > @@ -12,6 +12,7 @@ randstruct-cflags-y \ > += -frandomize-layout-seed-file=$(objtree)/scripts/basic/randstruct.seed > endif > > -export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y) > +export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y) \ > + -include $(objtree)/scripts/basic/randstruct_hash.h As the kernel test robot points out (on a report that you weren't included on for some reason...), this breaks the build in several places on next-20250502. https://lore.kernel.org/202505021409.yC9C70lH-lkp@intel.com/ $ make -skj"$(nproc)" ARCH=arm LLVM=1 clean allmodconfig arch/arm/vdso/vgettimeofday.o clang: error: cannot specify -o when generating multiple output files There are places in the kernel that filter out RANDSTRUCT_CFLAGS and this appears to cause other '-include' flags to be filtered out as well, such as the one in the efistub that includes hidden.h. > KBUILD_CFLAGS += $(RANDSTRUCT_CFLAGS) > diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile > index dd289a6725ac..31637ce4dc5c 100644 > --- a/scripts/basic/Makefile > +++ b/scripts/basic/Makefile > @@ -8,9 +8,10 @@ hostprogs-always-y += fixdep > # before running a Clang kernel build. > gen-randstruct-seed := $(srctree)/scripts/gen-randstruct-seed.sh > quiet_cmd_create_randstruct_seed = GENSEED $@ > -cmd_create_randstruct_seed = \ > - $(CONFIG_SHELL) $(gen-randstruct-seed) \ > - $@ $(objtree)/include/generated/randstruct_hash.h > -$(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE > + cmd_create_randstruct_seed = $(CONFIG_SHELL) $(gen-randstruct-seed) \ > + $(obj)/randstruct.seed $(obj)/randstruct_hash.h > + > +$(obj)/randstruct_hash.h $(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE > $(call if_changed,create_randstruct_seed) > -always-$(CONFIG_RANDSTRUCT) += randstruct.seed > + > +always-$(CONFIG_RANDSTRUCT) += randstruct.seed randstruct_hash.h > -- > 2.34.1 >