Hi Prabhat, FYI, the error/warning still remains. tree: https://github.com/intel/linux-intel-lts.git 4.19/android_r head: 71dbe8b787e34f3ce300217fc6ca5a2ec4aef447 commit: 77896075c455635a9e8c59ade5e30b75711cc099 [18601/23451] usb: xhci: dbc: DbC TTY driver to use new interface config: h8300-randconfig-r031-20210622 (attached as .config) compiler: h8300-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://github.com/intel/linux-intel-lts/commit/77896075c455635a9e8c59ade... 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 77896075c455635a9e8c59ade5e30b75711cc099 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=h8300 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 >>): In file included from include/linux/kernel.h:10, from include/linux/list.h:9, from include/linux/module.h:9, from drivers/usb/host/xhci-dbgtty.c:10: include/linux/scatterlist.h: In function 'sg_set_buf': include/asm-generic/page.h:93:50: warning: ordered comparison of pointer with null pointer [-Wextra] 93 | #define virt_addr_valid(kaddr) (((void *)(kaddr) >= (void *)PAGE_OFFSET) && \ | ^~ include/linux/compiler.h:77:42: note: in definition of macro 'unlikely' 77 | # define unlikely(x) __builtin_expect(!!(x), 0) | ^ include/linux/scatterlist.h:143:2: note: in expansion of macro 'BUG_ON' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~ include/linux/scatterlist.h:143:10: note: in expansion of macro 'virt_addr_valid' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~~~~~~~~~~ drivers/usb/host/xhci-dbgtty.c: At top level: 497 | void xhci_dbc_tty_unregister_device(struct xhci_hcd *xhci) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/xhci_dbc_tty_unregister_device +497 drivers/usb/host/xhci-dbgtty.c dfba2174dc421e Lu Baolu 2017-12-08 496 dfba2174dc421e Lu Baolu 2017-12-08 @497 void xhci_dbc_tty_unregister_device(struct xhci_hcd *xhci) dfba2174dc421e Lu Baolu 2017-12-08 498 { dfba2174dc421e Lu Baolu 2017-12-08 499 struct xhci_dbc *dbc = xhci->dbc; dfba2174dc421e Lu Baolu 2017-12-08 500 struct dbc_port *port = &dbc->port; 77896075c45563 Prabhat Chand Pandey 2019-01-30 501 struct tty_driver *dbc_tty_driver = 77896075c45563 Prabhat Chand Pandey 2019-01-30 502 (struct tty_driver *) dbc->func_priv; dfba2174dc421e Lu Baolu 2017-12-08 503 dfba2174dc421e Lu Baolu 2017-12-08 504 tty_unregister_device(dbc_tty_driver, 0); dfba2174dc421e Lu Baolu 2017-12-08 505 xhci_dbc_tty_exit_port(port); dfba2174dc421e Lu Baolu 2017-12-08 506 port->registered = false; dfba2174dc421e Lu Baolu 2017-12-08 507 dfba2174dc421e Lu Baolu 2017-12-08 508 kfifo_free(&port->write_fifo); dfba2174dc421e Lu Baolu 2017-12-08 509 xhci_dbc_free_requests(get_out_ep(xhci), &port->read_pool); dfba2174dc421e Lu Baolu 2017-12-08 510 xhci_dbc_free_requests(get_out_ep(xhci), &port->read_queue); dfba2174dc421e Lu Baolu 2017-12-08 511 xhci_dbc_free_requests(get_in_ep(xhci), &port->write_pool); dfba2174dc421e Lu Baolu 2017-12-08 512 } 77896075c45563 Prabhat Chand Pandey 2019-01-30 513 :::::: The code at line 497 was first introduced by commit :::::: dfba2174dc421ecad8dc50741054a305cd3ba681 usb: xhci: Add DbC support in xHCI driver :::::: TO: Lu Baolu <baolu.lu(a)linux.intel.com&gt; :::::: CC: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org