tree: https://github.com/luxis1999/iommufd iommufd-v5.17-rc1 head: ebf68af0385d0d5c209e63e8065d31db938275d8 commit: 92b20d75d7b30d1c70dd13b1be97a7bb00d5910b [14/28] vifo_platform: Use vfio_alloc/put_device() config: arm-allmodconfig (https://download.01.org/0day-ci/archive/20220210/202202100548.m45ZFnHj-lk...) compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0 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://github.com/luxis1999/iommufd/commit/92b20d75d7b30d1c70dd13b1be97a... git remote add luxis1999-iommufd https://github.com/luxis1999/iommufd git fetch --no-tags luxis1999-iommufd iommufd-v5.17-rc1 git checkout 92b20d75d7b30d1c70dd13b1be97a7bb00d5910b # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm SHELL=/bin/bash 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 <<): ERROR: modpost: "vfio_platform_ops" [drivers/vfio/platform/vfio-platform.ko] undefined! --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org