Re: [PATCH] x86, kasan: Fix build failure on KASAN=y && KMEMCHECK=y kernels

From: Borislav Petkov
Date: Mon Oct 19 2015 - 12:53:43 EST


On Fri, Oct 16, 2015 at 02:28:53PM +0300, Andrey Ryabinin wrote:
> Declaration of memcpy is hidden under #ifndef CONFIG_KMEMCHECK.
> In asm/efi.h we under #ifdef CONFIG_KASAN we #undef memcpy
> thus following happens:
>
> In file included from arch/x86/kernel/setup.c:96:0:
> ./arch/x86/include/asm/desc.h: In function ânative_write_idt_entryâ:
> ./arch/x86/include/asm/desc.h:122:2: error: implicit declaration of function âmemcpyâ [-Werror=implicit-function-declaration]
> memcpy(&idt[entry], gate, sizeof(*gate));
> ^
> cc1: some warnings being treated as errors
> make[2]: *** [arch/x86/kernel/setup.o] Error 1
>
> We will get rid of that #undef in asm/efi.h eventually.
> But in the meanwhile move memcpy() declaration out ifdefs
> to fix build.
>

Looks ok to me. I guess this should go together with the efi.h fix.

> Reported-by: Borislav Petkov <bp@xxxxxxxxx>

...-and-tested-by: me

> Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/string_64.h | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
> index e466119..ff8b9a1 100644
> --- a/arch/x86/include/asm/string_64.h
> +++ b/arch/x86/include/asm/string_64.h
> @@ -27,12 +27,11 @@ static __always_inline void *__inline_memcpy(void *to, const void *from, size_t
> function. */
>
> #define __HAVE_ARCH_MEMCPY 1
> +extern void *memcpy(void *to, const void *from, size_t len);
> extern void *__memcpy(void *to, const void *from, size_t len);
>
> #ifndef CONFIG_KMEMCHECK
> -#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4
> -extern void *memcpy(void *to, const void *from, size_t len);
> -#else
> +#if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
> #define memcpy(dst, src, len) \
> ({ \
> size_t __len = (len); \
> --
> 2.4.9

Thanks.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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