Hi Dexuan, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on tip/x86/core] [also build test WARNING on tip/auto-latest v5.7-rc7 next-20200529] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Dexuan-Cui/x86-apic-flat64-Add-b... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 9cb1fd0efd195590b828b9b865421ad345a4a145 config: x86_64-defconfig (attached as .config) compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 2388a096e7865c043e83ece4e26654bd3d1a20d5) 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 # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): The function flat_acpi_madt_oem_check() references the variable __initdata disable_timer_pin_1. This is often because flat_acpi_madt_oem_check lacks a __initdata annotation or the annotation of disable_timer_pin_1 is wrong. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org