Hi Rishi, I love your patch! Yet something to improve: [auto build test ERROR on tty/tty-testing] [also build test ERROR on robh/for-next usb/usb-testing linus/master v5.5-rc5 next-20200106] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Rishi-Gupta/Add-virtual-serial-null-modem-emulation-driver/20200106-155424 base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing config: ia64-allmodconfig (attached as .config) compiler: ia64-linux-gcc (GCC) 7.5.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree GCC_VERSION=7.5.0 make.cross ARCH=ia64 If you fix the issue, kindly add following tag Reported-by: kbuild test robot All errors (new ones prefixed by >>): drivers//tty/ttyvs.c: In function 'vs_get_serinfo': >> drivers//tty/ttyvs.c:1012:8: error: implicit declaration of function 'copy_to_user'; did you mean 'cpu_to_mem'? [-Werror=implicit-function-declaration] ret = copy_to_user((void __user *)arg, &info, ^~~~~~~~~~~~ cpu_to_mem drivers//tty/ttyvs.c: In function 'vs_card_write': >> drivers//tty/ttyvs.c:1996:7: error: implicit declaration of function 'copy_from_user'; did you mean 'copy_creds'? [-Werror=implicit-function-declaration] if (copy_from_user(data, buf, length) != 0) ^~~~~~~~~~~~~~ copy_creds cc1: some warnings being treated as errors vim +1012 drivers//tty/ttyvs.c 985 986 /* Provides information as a repsonse to TIOCGSERIAL IOCTL */ 987 static int vs_get_serinfo(struct tty_struct *tty, unsigned long arg) 988 { 989 int ret; 990 struct serial_struct info; 991 struct vs_dev *local_vsdev = db[tty->index].vsdev; 992 struct serial_struct serial = local_vsdev->serial; 993 994 if (!arg) 995 return -EFAULT; 996 997 memset(&info, 0, sizeof(info)); 998 999 info.type = PORT_UNKNOWN; 1000 info.line = serial.line; 1001 info.port = tty->index; 1002 info.irq = 0; 1003 info.flags = tty->port->flags; 1004 info.xmit_fifo_size = 0; 1005 info.baud_base = 0; 1006 info.close_delay = tty->port->close_delay; 1007 info.closing_wait = tty->port->closing_wait; 1008 info.custom_divisor = 0; 1009 info.hub6 = 0; 1010 info.io_type = SERIAL_IO_MEM; 1011 > 1012 ret = copy_to_user((void __user *)arg, &info, 1013 sizeof(struct serial_struct)); 1014 1015 return ret ? -EFAULT : 0; 1016 } 1017 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation