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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Thu, 13 Jul 2023 12:33:33 +0800
Message-ID: <CAAhV-H4nuwBJHE3VPj6yE2HUw3tDaLtgeRQ5mj0SRV6RoD8-9Q@mail.gmail.com>
Subject: Re: [PATCH] kasan: Fix tests by removing -ffreestanding
To:     Andrey Konovalov <andreyknvl@gmail.com>
Cc:     Huacai Chen <chenhuacai@loongson.cn>,
        Marco Elver <elver@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
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Hi, Andrey,

On Thu, Jul 13, 2023 at 12:12=E2=80=AFAM Andrey Konovalov <andreyknvl@gmail=
.com> wrote:
>
> On Wed, Jul 12, 2023 at 12:14=E2=80=AFPM Huacai Chen <chenhuacai@loongson=
.cn> wrote:
> >
> > CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX hopes -fbuiltin for memset()/
> > memcpy()/memmove() if instrumentation is needed. This is the default
> > behavior but some archs pass -ffreestanding which implies -fno-builtin,
> > and then causes some kasan tests fail. So we remove -ffreestanding for
> > kasan tests.
>
> Could you clarify on which architecture you observed tests failures?
Observed on LoongArch [1], KASAN for LoongArch was planned to be
merged in 6.5, but at the last minute I found some tests fail with
GCC14 (CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) so the patches are
dropped. After some debugging we found the root cause is
-ffreestanding.

[1] https://github.com/chenhuacai/linux/commit/af2da91541a8899b502bece9b1fd=
e225b71f37a8

Huacai
>
> >
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> >  mm/kasan/Makefile | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
> > index 7634dd2a6128..edd1977a6b88 100644
> > --- a/mm/kasan/Makefile
> > +++ b/mm/kasan/Makefile
> > @@ -45,7 +45,9 @@ CFLAGS_KASAN_TEST +=3D -fno-builtin
> >  endif
> >
> >  CFLAGS_kasan_test.o :=3D $(CFLAGS_KASAN_TEST)
> > +CFLAGS_REMOVE_kasan_test.o :=3D -ffreestanding
> >  CFLAGS_kasan_test_module.o :=3D $(CFLAGS_KASAN_TEST)
> > +CFLAGS_REMOVE_kasan_test_module.o :=3D -ffreestanding
> >
> >  obj-y :=3D common.o report.o
> >  obj-$(CONFIG_KASAN_GENERIC) +=3D init.o generic.o report_generic.o sha=
dow.o quarantine.o
> > --
> > 2.39.3
>
> +Marco