Re: [PATCH v2 5/5] kasan: add compiler support for clang

[Andrey Ryabinin]

On 11/30/2017 12:50 AM, Paul Lawrence wrote:
> For now we can hard-code ASAN ABI level 5, since historical clang builds
> can't build the kernel anyway.  We also need to emulate gcc's
> __SANITIZE_ADDRESS__ flag, or memset() calls won't be instrumented.
> 
> Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
> Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx>
> 
> ---
>  include/linux/compiler-clang.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index 3b609edffa8f..d02a4df3f473 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -19,3 +19,11 @@
>  
>  #define randomized_struct_fields_start	struct {
>  #define randomized_struct_fields_end	};
> +
> +/* all clang versions usable with the kernel support KASAN ABI version 5 */
> +#define KASAN_ABI_VERSION 5
> +

This patch should be earlier in this series. Patch 4/5 breaks clang-built kernel, because
we start using globals instrumentation with wrong KASAN_ABI_VERSION.

> +/* emulate gcc's __SANITIZE_ADDRESS__ flag */
> +#if __has_feature(address_sanitizer)
> +#define __SANITIZE_ADDRESS__
> +#endif
>