tree: https://android.googlesource.com/kernel/common android-4.19-stable head: d8a2d7d9141fa875f4ce185507764d58ba4437ed commit: 3d88b138f0cbafac10e4eaec4c5377827fe7bd8b [1/3] ANDROID: extcon: Export symbol of `extcon_get_edev_name` config: arm-cns3420vb_defconfig (attached as .config) compiler: arm-linux-gnueabi-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 3d88b138f0cbafac10e4eaec4c5377827fe7bd8b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>, old ones prefixed by <<): In file included from include/linux/usb/phy.h:13, from include/linux/usb/otg.h:14, from include/linux/usb/of.h:12, from drivers/usb/phy/of.c:9: 316 | EXPORT_SYMBOL_GPU(extcon_get_edev_name); | ^~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +316 include/linux/extcon.h 311 312 static inline const char *extcon_get_edev_name(struct extcon_dev *edev) 313 { 314 return NULL; 315 } 317 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org