From: Andrey Ryabinin <a.ryabinin@samsung.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>
Cc: linux-next@vger.kernel.org,
open list <linux-kernel@vger.kernel.org>,
Michal Marek <mmarek@suse.cz>,
linux-kbuild@vger.kernel.org
Subject: Re: [PATCH] kasan: fix build warnings
Date: Wed, 04 Feb 2015 15:05:28 +0300 [thread overview]
Message-ID: <54D20B08.7010508@samsung.com> (raw)
In-Reply-To: <1423050231-1701-1-git-send-email-a.ryabinin@samsung.com>
On 02/04/2015 02:43 PM, Andrey Ryabinin wrote:
> Some versions of gcc produce warning instead of error when
> -fsanitize flag uses unsupported argument:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61065
>
> This breaks our detection of whether -fsanitize=kernel-address
> is supported by compiler or not. Thus we have tons of build
> warnings like this:
> x86_64-linux-gcc: warning: unrecognized argument to -fsanitize= option: 'kernel-address'
>
> Passing -Werror into $(call cc-option) will fix this problem
> as gcc will error out now.
>
> Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> ---
>
> Hi Andrew, this patch applies on top kasan patch set.
> We can't just fix add-kernel-address-sanitizer-infrastructure.patch
> as patch kasan-enable-instrumentation-of-global-variables.patch
> depends on it.
>
> Let me know if your prefer to update all needed patches instead
> of this fix.
>
> scripts/Makefile.kasan | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index df302f8..72a40bb 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -5,15 +5,14 @@ else
> call_threshold := 0
> endif
>
> -CFLAGS_KASAN_MINIMAL := $(call cc-option, -fsanitize=kernel-address \
> - --param asan-globals=1)
> +CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address --param asan-globals=1
>
> CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
> -fasan-shadow-offset=$(CONFIG_KASAN_SHADOW_OFFSET) \
> --param asan-stack=1 --param asan-globals=1 \
> --param asan-instrumentation-with-call-threshold=$(call_threshold))
>
> -ifeq ($(CFLAGS_KASAN_MINIMAL),)
> +ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
> $(warning Cannot use CONFIG_KASAN: \
> -fsanitize=kernel-address is not supported by compiler)
> else
>
Or maybe it would be be better always use -Werror in cc-option?
---
From: Andrey Ryabinin <a.ryabinin@samsung.com>
Subject: [PATCH] kbuild: always use -Werror in 'call cc-option'
Some versions of gcc produce warning instead of error when
-fsanitize flag uses unsupported argument:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61065
This breaks our detection of whether -fsanitize=kernel-address
is supported by compiler or not. Thus we have tons of build
warnings like this:
x86_64-linux-gcc: warning: unrecognized argument to -fsanitize= option: 'kernel-address'
To workaround this compiler bug we could always use -Werror
with 'call cc-option' forcing gcc to produce error instead of
warnings.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Michal Marek <mmarek@suse.cz>
---
scripts/Kbuild.include | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index d3437b8..6bc4e3e 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -111,12 +111,12 @@ as-instr = $(call try-run,\
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
cc-option = $(call try-run,\
- $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
+ $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -Werror -c -x c /dev/null -o "$$TMP",$(1),$(2))
# cc-option-yn
# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
cc-option-yn = $(call try-run,\
- $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
+ $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -Werror -c -x c /dev/null -o "$$TMP",y,n)
# cc-option-align
# Prefix align with either -falign or -malign
next prev parent reply other threads:[~2015-02-04 12:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-04 7:53 linux-next: build failure after merge of the akpm-current tree Stephen Rothwell
2015-02-04 11:43 ` [PATCH] kasan: fix build warnings Andrey Ryabinin
2015-02-04 12:05 ` Andrey Ryabinin [this message]
2015-02-04 12:23 ` Michal Marek
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