2023-04-18 12:25:26

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] [v2] kasan: remove hwasan-kernel-mem-intrinsic-prefix=1 for clang-14

From: Arnd Bergmann <[email protected]>

Some unknown -mllvm options (i.e. those starting with the letter "h")
don't cause an error to be returned by clang, so the cc-option helper
adds the unknown hwasan-kernel-mem-intrinsic-prefix=1 flag to CFLAGS
with compilers that are new enough for hwasan but too old for this option.

This causes a rather unreadable build failure:

fixdep: error opening file: scripts/mod/.empty.o.d: No such file or directory
make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:252: scripts/mod/empty.o] Error 2
fixdep: error opening file: scripts/mod/.devicetable-offsets.s.d: No such file or directory
make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 2

Add a version check to only allow this option with clang-15, gcc-13
or later versions.

Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics")
Link: https://lore.kernel.org/all/CANpmjNMwYosrvqh4ogDO8rgn+SeDHM2b-shD21wTypm_6MMe=g@mail.gmail.com/
Signed-off-by: Arnd Bergmann <[email protected]>
---
v2: use one-line version check for both clang and gcc, clarify changelog text
---
scripts/Makefile.kasan | 2 ++
1 file changed, 2 insertions(+)

diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index c186110ffa20..390658a2d5b7 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -69,7 +69,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
$(instrumentation_flags)

# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
+ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+endif

endif # CONFIG_KASAN_SW_TAGS

--
2.39.2


2023-04-18 13:12:54

by Marco Elver

[permalink] [raw]
Subject: Re: [PATCH] [v2] kasan: remove hwasan-kernel-mem-intrinsic-prefix=1 for clang-14

On Tue, 18 Apr 2023 at 14:24, Arnd Bergmann <[email protected]> wrote:
>
> From: Arnd Bergmann <[email protected]>
>
> Some unknown -mllvm options (i.e. those starting with the letter "h")
> don't cause an error to be returned by clang, so the cc-option helper
> adds the unknown hwasan-kernel-mem-intrinsic-prefix=1 flag to CFLAGS
> with compilers that are new enough for hwasan but too old for this option.
>
> This causes a rather unreadable build failure:
>
> fixdep: error opening file: scripts/mod/.empty.o.d: No such file or directory
> make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:252: scripts/mod/empty.o] Error 2
> fixdep: error opening file: scripts/mod/.devicetable-offsets.s.d: No such file or directory
> make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 2
>
> Add a version check to only allow this option with clang-15, gcc-13
> or later versions.
>
> Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics")
> Link: https://lore.kernel.org/all/CANpmjNMwYosrvqh4ogDO8rgn+SeDHM2b-shD21wTypm_6MMe=g@mail.gmail.com/
> Signed-off-by: Arnd Bergmann <[email protected]>

Reviewed-by: Marco Elver <[email protected]>

Thanks!

> ---
> v2: use one-line version check for both clang and gcc, clarify changelog text
> ---
> scripts/Makefile.kasan | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index c186110ffa20..390658a2d5b7 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -69,7 +69,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> $(instrumentation_flags)
>
> # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
> +ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
> CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
> +endif
>
> endif # CONFIG_KASAN_SW_TAGS
>
> --
> 2.39.2
>
>

2023-04-18 16:19:33

by Nathan Chancellor

[permalink] [raw]
Subject: Re: [PATCH] [v2] kasan: remove hwasan-kernel-mem-intrinsic-prefix=1 for clang-14

On Tue, Apr 18, 2023 at 02:23:35PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> Some unknown -mllvm options (i.e. those starting with the letter "h")
> don't cause an error to be returned by clang, so the cc-option helper
> adds the unknown hwasan-kernel-mem-intrinsic-prefix=1 flag to CFLAGS
> with compilers that are new enough for hwasan but too old for this option.
>
> This causes a rather unreadable build failure:
>
> fixdep: error opening file: scripts/mod/.empty.o.d: No such file or directory
> make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:252: scripts/mod/empty.o] Error 2
> fixdep: error opening file: scripts/mod/.devicetable-offsets.s.d: No such file or directory
> make[4]: *** [/home/arnd/arm-soc/scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 2
>
> Add a version check to only allow this option with clang-15, gcc-13
> or later versions.
>
> Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics")
> Link: https://lore.kernel.org/all/CANpmjNMwYosrvqh4ogDO8rgn+SeDHM2b-shD21wTypm_6MMe=g@mail.gmail.com/
> Signed-off-by: Arnd Bergmann <[email protected]>

Reviewed-by: Nathan Chancellor <[email protected]>

Kudos to Marco for figuring out the 'starting with the letter "h"' part
of this issue :)

> ---
> v2: use one-line version check for both clang and gcc, clarify changelog text
> ---
> scripts/Makefile.kasan | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index c186110ffa20..390658a2d5b7 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -69,7 +69,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> $(instrumentation_flags)
>
> # Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
> +ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
> CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
> +endif
>
> endif # CONFIG_KASAN_SW_TAGS
>
> --
> 2.39.2
>