Maybe the KASan folk can look into this, it isn't obvious how to fix
this, since XZ needs memcpy/memmove #defined to avoid using its own
version. Having KASan override these with a #define is all very well,
but it makes the behaviour of lib/decompress_unxz.c indeterminant if
we get rid of the definitions the XZ support added.

On Sun, May 09, 2021 at 11:32:17AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   b741596468b010af2846b75f5e75a842ce344a6e
> commit: 421015713b306e47af95d4d61cdfbd96d462e4cb ARM: 9017/2: Enable KASan for ARM
> date:   6 months ago
> config: arm-randconfig-r015-20210509 (attached as .config)
> compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=421015713b306e47af95d4d61cdfbd96d462e4cb
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 421015713b306e47af95d4d61cdfbd96d462e4cb
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=arm 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
> >> arch/arm/boot/compressed/decompress.c:50: warning: "memmove" redefined
>       50 | #define memmove memmove
>          | 
>    In file included from arch/arm/boot/compressed/decompress.c:8:
>    arch/arm/include/asm/string.h:59: note: this is the location of the previous definition
>       59 | #define memmove(dst, src, len) __memmove(dst, src, len)
>          | 
>    arch/arm/boot/compressed/decompress.c:51: warning: "memcpy" redefined
>       51 | #define memcpy memcpy
>          | 
>    In file included from arch/arm/boot/compressed/decompress.c:8:
>    arch/arm/include/asm/string.h:58: note: this is the location of the previous definition
>       58 | #define memcpy(dst, src, len) __memcpy(dst, src, len)
>          | 
>    arch/arm/boot/compressed/decompress.c:59:5: warning: no previous prototype for 'do_decompress' [-Wmissing-prototypes]
>       59 | int do_decompress(u8 *input, int len, u8 *output, void (*error)(char *x))
>          |     ^~~~~~~~~~~~~
> 
> 
> vim +/memmove +50 arch/arm/boot/compressed/decompress.c
> 
> 6e8699f7d68589 Albin Tonnerre 2010-04-03  48  
> a7f464f3db93ae Imre Kaloz     2012-01-26  49  #ifdef CONFIG_KERNEL_XZ
> a7f464f3db93ae Imre Kaloz     2012-01-26 @50  #define memmove memmove
> a7f464f3db93ae Imre Kaloz     2012-01-26  51  #define memcpy memcpy
> a7f464f3db93ae Imre Kaloz     2012-01-26  52  #include "../../../../lib/decompress_unxz.c"
> a7f464f3db93ae Imre Kaloz     2012-01-26  53  #endif
> a7f464f3db93ae Imre Kaloz     2012-01-26  54  
> 
> :::::: The code at line 50 was first introduced by commit
> :::::: a7f464f3db93ae5492bee6f6e48939fd8a45fa99 ARM: 7001/2: Wire up support for the XZ decompressor
> 
> :::::: TO: Imre Kaloz <kaloz@openwrt.org>
> :::::: CC: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org



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