[kbuild-all] ERROR: modpost: "max_low_pfn" undefined!

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 18445bf405cb331117bc98427b1ba6f12418ad17 commit: 521fd61c84a19b31dfbaa8dde3d2577e4e115d12 security/keys: rewrite big_key crypto to use library interface date: 3 months ago config: ia64-randconfig-r034-20200820 (attached as .config) compiler: ia64-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 521fd61c84a19b31dfbaa8dde3d2577e4e115d12 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 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 >>, old ones prefixed by <<): --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org