On Wed, Mar 25, 2020 at 5:13 PM <glider@xxxxxxxxxx> wrote:
>
> __no_sanitize_memory is a function attribute that makes KMSAN
> ignore the uninitialized values coming from the function's
> inputs, and initialize the function's outputs.
>
> Functions marked with this attribute can't be inlined into functions
> not marked with it, and vice versa.
>
> __SANITIZE_MEMORY__ is a macro that's defined iff the file is
> instrumented with KMSAN. This is not the same as CONFIG_KMSAN, which is
> defined for every file.
>
> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
> To: Alexander Potapenko <glider@xxxxxxxxxx>
> Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: Marco Elver <elver@xxxxxxxxxx>
> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Acked-by: Marco Elver <elver@xxxxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
>
> ---
>
> v4:
> - dropped an unnecessary comment as requested by Marco Elver
>
> Change-Id: I1f1672652c8392f15f7ca8ac26cd4e71f9cc1e4b
> ---
> include/linux/compiler-clang.h | 7 +++++++
> include/linux/compiler-gcc.h | 5 +++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index 2cb42d8bdedc6..d4f929b4a6705 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -33,6 +33,13 @@
> #define __no_sanitize_thread
> #endif
>
> +#if __has_feature(memory_sanitizer)
> +# define __SANITIZE_MEMORY__
> +# define __no_sanitize_memory __attribute__((no_sanitize("kernel-memory")))
> +#else
> +# define __no_sanitize_memory
> +#endif
> +
> /*
> * Not all versions of clang implement the the type-generic versions
> * of the builtin overflow checkers. Fortunately, clang implements
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index cf294faec2f87..1121557252f88 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -151,6 +151,11 @@
> #define __no_sanitize_thread
> #endif
>
> +/*
> + * GCC doesn't support KMSAN.
> + */
> +#define __no_sanitize_memory
> +
> #if GCC_VERSION >= 50100
> #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
> #endif
> --
> 2.25.1.696.g5e7596f4ac-goog
>
