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From:   Alexander Potapenko <glider@google.com>
Date:   Thu, 2 Mar 2023 15:27:47 +0100
Message-ID: <CAG_fn=U9H2bmUxkJA6vyD15j+=GJTkSgKuMRbd=CWVZsRwR7TQ@mail.gmail.com>
Subject: Re: [PATCH 1/4] x86: kmsan: Don't rename memintrinsics in
 uninstrumented files
To:     Marco Elver <elver@google.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org,
        dave.hansen@linux.intel.com, hpa@zytor.com,
        akpm@linux-foundation.org, dvyukov@google.com, nathan@kernel.org,
        ndesaulniers@google.com, kasan-dev@googlegroups.com,
        Kees Cook <keescook@chromium.org>
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On Thu, Mar 2, 2023 at 12:14=E2=80=AFPM Marco Elver <elver@google.com> wrot=
e:
>
> On Wed, 1 Mar 2023 at 15:39, Alexander Potapenko <glider@google.com> wrot=
e:
> >
> > KMSAN should be overriding calls to memset/memcpy/memmove and their
>
> You mean that the compiler will override calls?
> All supported compilers that have fsanitize=3Dkernel-memory replace
> memintrinsics with __msan_mem*() calls, right?

Right. Changed to:

KMSAN already replaces calls to to memset/memcpy/memmove and their
__builtin_ versions with __msan_memset/__msan_memcpy/__msan_memmove in
instrumented files, so there is no need to override them.


>
> > __builtin_ versions in instrumented files, so there is no need to
> > override them. In non-instrumented versions we are now required to
> > leave memset() and friends intact, so we cannot replace them with
> > __msan_XXX() functions.
> >
> > Cc: Kees Cook <keescook@chromium.org>
> > Suggested-by: Marco Elver <elver@google.com>
> > Signed-off-by: Alexander Potapenko <glider@google.com>
>
> Other than that,
>
> Reviewed-by: Marco Elver <elver@google.com>
Thanks!