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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, kernel test robot <lkp@intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Subject: [PATCH 4.9 02/20] ARM: 9134/1: remove duplicate memcpy() definition
Date:   Mon,  1 Nov 2021 10:17:11 +0100
Message-Id: <20211101082444.650245644@linuxfoundation.org>
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From: Arnd Bergmann <arnd@arndb.de>

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.

Link: https://lore.kernel.org/linux-arm-kernel/CACRpkdZYJogU_SN3H9oeVq=zJkRgRT1gDz3xp59gdqWXxw-B=w@mail.gmail.com/
Link: https://lore.kernel.org/lkml/202105091112.F5rmd4By-lkp@intel.com/

Fixes: d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan")
Fixes: a7f464f3db93 ("ARM: 7001/2: Wire up support for the XZ decompressor")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm/boot/compressed/decompress.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/arm/boot/compressed/decompress.c
+++ b/arch/arm/boot/compressed/decompress.c
@@ -46,7 +46,10 @@ extern char * strstr(const char * s1, co
 #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