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

[Nathan Chancellor]

On Tue, Apr 18, 2023 at 02:23:35PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> 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@xxxxxxxxxxxxxx/
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>

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
>