On Wed, Jul 07, 2021 at 01:15:28AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y
> head:   3909e2374335335c9504467caabc906d3f7487e4
> commit: defcc2b5e54a4724fb5733f802edf5dd596018b6 [7045/7049] lib/lz4: explicitly support in-place decompression
> config: mips-randconfig-r036-20210706 (attached as .config)
> compiler: mipsel-linux-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/stable/linux-stable-rc.git/commit/?id=defcc2b5e54a4724fb5733f802edf5dd596018b6
>         git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
>         git fetch --no-tags linux-stable-rc linux-5.4.y
>         git checkout defcc2b5e54a4724fb5733f802edf5dd596018b6
>         # save the attached .config to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>

Which is weird, does the preboot environment miss memmove() on mipsel?
Just a guess, I may look into that myself later...

Thanks,
Gao Xiang

> 
> All errors (new ones prefixed by >>):
> 
>    mipsel-linux-ld: arch/mips/boot/compressed/decompress.o: in function `LZ4_decompress_safe_withSmallPrefix':
>    decompress.c:(.text+0x220): undefined reference to `memmove'
>    mipsel-linux-ld: arch/mips/boot/compressed/decompress.o: in function `LZ4_decompress_fast_extDict':
>    decompress.c:(.text+0x694): undefined reference to `memmove'
> >> mipsel-linux-ld: decompress.c:(.text+0x774): undefined reference to `memmove'
>    mipsel-linux-ld: arch/mips/boot/compressed/decompress.o: in function `LZ4_decompress_safe':
>    decompress.c:(.text+0xb88): undefined reference to `memmove'
>    mipsel-linux-ld: arch/mips/boot/compressed/decompress.o: in function `LZ4_decompress_safe_partial':
>    decompress.c:(.text+0x1078): undefined reference to `memmove'
>    mipsel-linux-ld: arch/mips/boot/compressed/decompress.o:decompress.c:(.text+0x12f8): more undefined references to `memmove' follow
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org