tree: https://github.com/intel/linux-intel-lts.git 4.19/android_r head: 4a6aef8d991e7c47e5da39927e0ad28ec90cd01b commit: b652a52d36a85d1b731921ba08e701d7150ce200 [19120/20689] Merge branch 'aosp/android-4.19-stable' into android_r config: arm-randconfig-r015-20201210 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 5ff35356f1af2bb92785b38c657463924d9ec386) 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 arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://github.com/intel/linux-intel-lts/commit/b652a52d36a85d1b731921ba0... git remote add intel-linux-intel-lts https://github.com/intel/linux-intel-lts.git git fetch --no-tags intel-linux-intel-lts 4.19/android_r git checkout b652a52d36a85d1b731921ba08e701d7150ce200 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang 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 warnings (new ones prefixed by >>): void xhci_dbc_flush_requests(struct xhci_dbc *dbc) ^ drivers/usb/host/xhci-dbgcap.c:191:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void xhci_dbc_flush_requests(struct xhci_dbc *dbc) ^ static 1 warning generated. drivers/usb/host/xhci-dbgcap.c:18: warning: cannot understand function prototype: 'struct dbc_function *dbc_registered_func; ' ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected vim +/xhci_dbc_flush_requests +191 drivers/usb/host/xhci-dbgcap.c dfba2174dc421e Lu Baolu 2017-12-08 189 b88d999a5b9ae9 Prabhat Chand Pandey 2019-05-22 190 b88d999a5b9ae9 Prabhat Chand Pandey 2019-05-22 @191 void xhci_dbc_flush_requests(struct xhci_dbc *dbc) dfba2174dc421e Lu Baolu 2017-12-08 192 { dfba2174dc421e Lu Baolu 2017-12-08 193 xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]); dfba2174dc421e Lu Baolu 2017-12-08 194 xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]); dfba2174dc421e Lu Baolu 2017-12-08 195 } b88d999a5b9ae9 Prabhat Chand Pandey 2019-05-22 196 EXPORT_SYMBOL_GPL(xhci_dbc_flush_requests); dfba2174dc421e Lu Baolu 2017-12-08 197 :::::: The code at line 191 was first introduced by commit :::::: b88d999a5b9ae9022e12e1a5810b12b21cb77996 usb: xhci: dbc: make DbC modular, introducing dbc_function structure :::::: TO: Prabhat Chand Pandey <prabhat.chand.pandey(a)intel.com&gt; :::::: CC: Pan, Kris <kris.pan(a)intel.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org