tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing head: b61c8bf4694b5115766849378dcb8787ff54e65e commit: b61c8bf4694b5115766849378dcb8787ff54e65e [218/218] tty: serial: Add UART driver for Cortina-Access platform config: m68k-allmodconfig (attached as .config) compiler: m68k-linux-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 # https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?id... git remote add tty https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git git fetch --no-tags tty tty-testing git checkout b61c8bf4694b5115766849378dcb8787ff54e65e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 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 >>): 76 | struct cortina_uart_port *cortina_uart_get_port(unsigned int index) | ^~~~~~~~~~~~~~~~~~~~~ vim +/cortina_uart_get_port +76 drivers/tty/serial/serial_cortina-access.c 74 75 /* Return uart_port pointer base on index */ 77 { 78 struct cortina_uart_port *pca_port = cortina_uart_ports; 79 80 if (index >= UART_NR) { 81 /* return 1st element if invalid index */ 82 index = 0; 83 } 84 85 pca_port += index; 86 87 return pca_port; 88 } 89 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org