Re: [PATCH 5.10 03/77] ARM: 9134/1: remove duplicate memcpy() definition

Pavel Machek
2021-11-12T22:22:57Z

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Hi!

> commit eaf6cc7165c9c5aa3c2f9faa03a98598123d0afb upstream.
>
> Both the decompressor code and the kasan logic try to override
> the memcpy() and memmove() definitions, which leading to a clash
> in a KASAN-enabled kernel with XZ decompression:
>
> arch/arm/boot/compressed/decompress.c:50:9: error: 'memmove' macro redefined [-Werror,-Wmacro-redefined]
> #define memmove memmove
> ^
> arch/arm/include/asm/string.h:59:9: note: previous definition is here
> #define memmove(dst, src, len) __memmove(dst, src, len)
> ^
> arch/arm/boot/compressed/decompress.c:51:9: error: 'memcpy' macro redefined [-Werror,-Wmacro-redefined]
> #define memcpy memcpy
> ^
> arch/arm/include/asm/string.h:58:9: note: previous definition is here
> #define memcpy(dst, src, len) __memcpy(dst, src, len)
> ^
>
> Here we want the set of functions from the decompressor, so undefine
> the other macros before the override.

AFAICT the conflicting defines are not present in v4.4 or v5.10, so
warnings should not be there and #undefs are not needed.

Best regards,
Pavel

> +++ b/arch/arm/boot/compressed/decompress.c
> @@ -47,7 +47,10 @@ extern char * strchrnul(const char *, in
> #endif
>
> #ifdef CONFIG_KERNEL_XZ
> +/* Prevent KASAN override of string helpers in decompressor */
> +#undef memmove
> #define memmove memmove
> +#undef memcpy
> #define memcpy memcpy
> #include "../../../../lib/decompress_unxz.c"
> #endif
>

--
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