Hi Andrew,
After merging the akpm-current tree, today's linux-next build (x86-64
allmodconfig) failed like this:
scripts/Makefile.kasan:21: CONFIG_KASAN: compiler does not support all options. Trying minimal configuration
scripts/Makefile.kasan:21: CONFIG_KASAN: compiler does not support all options. Trying minimal configuration
x86_64-linux-gcc: warning: unrecognized argument to -fsanitize= option: 'kernel-address'
lots and lots of this last message ...
Caused by the commits that added the kernel address sanitizer.
gcc version 4.9.0 cross compiling from Powerpc64.
I have added the following patch for today (after which I only got one
of the "compiler does not support all options" messages).
From: Stephen Rothwell <[email protected]>
Date: Wed, 4 Feb 2015 18:43:52 +1100
Subject: [PATCH] disable CONFIG_KASAN for now
Signed-off-by: Stephen Rothwell <[email protected]>
---
lib/Kconfig.kasan | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 4fecaedc80a2..4301bb56e3ce 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -1,7 +1,7 @@
config HAVE_ARCH_KASAN
bool
-if HAVE_ARCH_KASAN
+if HAVE_ARCH_KASAN && BROKEN
config KASAN
bool "KASan: runtime memory debugger"
--
2.1.4
--
Cheers,
Stephen Rothwell [email protected]
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 <[email protected]>
Reported-by: Stephen Rothwell <[email protected]>
---
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
--
2.2.2
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 <[email protected]>
> Reported-by: Stephen Rothwell <[email protected]>
> ---
>
> 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 <[email protected]>
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 <[email protected]>
Reported-by: Stephen Rothwell <[email protected]>
Cc: Michal Marek <[email protected]>
---
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
On 2015-02-04 13:05, Andrey Ryabinin wrote:
> Or maybe it would be be better always use -Werror in cc-option?
Please don't do it. A couple of Makefiles call cc-option after we have
added the user-supplied KCFLAGS to KBUILD_CFLAGS.
Michal