Hi Piotr, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 18445bf405cb331117bc98427b1ba6f12418ad17 commit: ec4ba01e894d3165e4d1ccbef782ef5593b708b4 mtd: rawnand: Add new Cadence NAND driver to MTD subsystem date: 11 months ago config: microblaze-randconfig-r031-20200819 (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 ec4ba01e894d3165e4d1ccbef782ef5593b708b4 # 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 >>): ERROR: "min_low_pfn" [drivers/mtd/nand/raw/nand.ko] undefined! ERROR: "min_low_pfn" [drivers/media/common/videobuf2/videobuf2-dma-contig.ko] undefined! --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org