Hi "Stefan, I love your patch! Yet something to improve: [auto build test ERROR on cbe8cd7d83e251bff134a57ea4b6378db992ad82] url: https://github.com/0day-ci/linux/commits/Stefan-M-tje/can-esd-add-support... base: cbe8cd7d83e251bff134a57ea4b6378db992ad82 config: arm64-randconfig-r033-20210911 (attached as .config) compiler: aarch64-linux-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/0day-ci/linux/commit/f2b8372d3e4a1cb2ece97f52560d0a598... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Stefan-M-tje/can-esd-add-support-for-esd-GmbH-PCIe-402-CAN-interface/20210909-004948 git checkout f2b8372d3e4a1cb2ece97f52560d0a598b36cb6b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm64 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: "__aarch64_ldadd4_acq_rel" [drivers/net/can/esd/esd_402_pci.ko] undefined!