Hi Michal, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: fc4f28bb3daf3265d6bc5f73b497306985bb23ab commit: 2602276d3d3811b1a48c48113042cd75fcbfc27d microblaze: Wire CMA allocator date: 7 months ago config: microblaze-randconfig-r025-20200913 (attached as .config) compiler: microblaze-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 git checkout 2602276d3d3811b1a48c48113042cd75fcbfc27d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): microblaze-linux-ld: mm/page_alloc.o: in function `alloc_contig_range': microblaze-linux-ld: (.text+0xbd44): undefined reference to `undo_isolate_page_range' microblaze-linux-ld: (.text+0xbd88): undefined reference to `undo_isolate_page_range' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org