From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756077AbbDIQBO (ORCPT ); Thu, 9 Apr 2015 12:01:14 -0400 Received: from lb2-smtp-cloud2.xs4all.net ([194.109.24.25]:47837 "EHLO lb2-smtp-cloud2.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024AbbDIQBL (ORCPT ); Thu, 9 Apr 2015 12:01:11 -0400 Message-ID: <1428595267.13881.6.camel@x220> Subject: Re: [PATCH] kasan: Makefile: shut up warnings if CONFIG_COMPILE_TEST=y From: Paul Bolle To: Andrey Ryabinin Cc: Andrew Morton , Michal Marek , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 09 Apr 2015 18:01:07 +0200 In-Reply-To: <55267431.7030304@samsung.com> References: <20150407160213.8f66c90ca812c30f362dd543@linux-foundation.org> <1428507505-4015-1-git-send-email-a.ryabinin@samsung.com> <1428577598.14000.31.camel@x220> <55267431.7030304@samsung.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2015-04-09 at 15:44 +0300, Andrey Ryabinin wrote: > On 04/09/2015 02:06 PM, Paul Bolle wrote: > > On Wed, 2015-04-08 at 18:38 +0300, Andrey Ryabinin wrote: > >> It might be annoying to constantly see this: > >> > >> scripts/Makefile.kasan:16: Cannot use CONFIG_KASAN: -fsanitize=kernel-address is not supported by compiler > >> > >> while performing allmodconfig/allyesconfig build tests. > > > > That warning might be seen - once per build - because allmodconfig and > > allyesconfig enable both CONFIG_KASAN and CONFIG_COMPILE_TEST, right? > > > > It might be seen once per build because all*config enables CONFIG_KASAN. > There was no dependency on CONFIG_COMPILE_TEST before this patch. Yes, of course. > >> Disable this warning if CONFIG_COMPILE_TEST=y. > > > > Do we expect that some people want to enable both KASAN and COMPILE_TEST > > manually (ie, not as a result of allmodconfig or allyesconfig)? If so, > > those people might now be in for some head-scratching if their compiler > > lacks what's apparently needed to run kasan. > > > > I think this shouldn't be a problem. > CONFIG_COMPILE_TEST used for building drivers that cannot be loaded on > platform used for compiling these drivers. > So it's unlikely that such kernel will be used for runtime testing. It would be nice if there would at least be a comment explaining what's being done here (ie, assuming that if CONFIG_COMPILE_TEST equals 'y' we're doing a allmodconfig or an allyesconfig and that people using either of those make targets don't care whether their compiler supports kasan). Because I'd be surprised if people figure that out by looking at this Makefile. > >> Signed-off-by: Andrey Ryabinin > >> --- > >> scripts/Makefile.kasan | 8 ++++++-- > >> 1 file changed, 6 insertions(+), 2 deletions(-) > >> > >> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan > >> index 631619b..3f874d2 100644 > >> --- a/scripts/Makefile.kasan > >> +++ b/scripts/Makefile.kasan > >> @@ -13,12 +13,16 @@ CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \ > >> --param asan-instrumentation-with-call-threshold=$(call_threshold)) > >> > >> ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),) > >> + ifneq ($(CONFIG_COMPILE_TEST),y) > >> $(warning Cannot use CONFIG_KASAN: \ > >> -fsanitize=kernel-address is not supported by compiler) > >> + endif > >> else > >> ifeq ($(CFLAGS_KASAN),) > >> - $(warning CONFIG_KASAN: compiler does not support all options.\ > >> - Trying minimal configuration) > >> + ifneq ($(CONFIG_COMPILE_TEST),y) > >> + $(warning CONFIG_KASAN: compiler does not support all options.\ > >> + Trying minimal configuration) > > > > (Side note: in this case the compiler supports that minimal > > configuration, doesn't it? So shouldn't the second warning end in > > Running with minimal configuration) > > > > or something to that effect?) > > > > It should and it does. > CFLAGS_KASAN reassigned to minimal set of options below. Which makes "Trying" ambiguous, but anyway, it's just a side note. > >> + endif > >> CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL) > >> endif > >> endif Thanks, Paul Bolle