Hi, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on staging/staging-testing] url: https://github.com/0day-ci/linux/commits/ameynarkhede03-gmail-com/staging-gdm724x-Fix-DMA-from-stack/20210209-225530 base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git 06b0c0dce88e2aa2f01343db0f26d214d7f264a0 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://github.com/0day-ci/linux/commit/d793f4f05736924fc2207a0f8c338115523930da git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review ameynarkhede03-gmail-com/staging-gdm724x-Fix-DMA-from-stack/20210209-225530 git checkout d793f4f05736924fc2207a0f8c338115523930da # 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 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:12, from drivers/staging/gdm724x/gdm_usb.c:6: include/linux/scatterlist.h: In function 'sg_set_buf': arch/m68k/include/asm/page_mm.h:174:49: warning: ordered comparison of pointer with null pointer [-Wextra] 174 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory) | ^~ include/linux/compiler.h:78:42: note: in definition of macro 'unlikely' 78 | # define unlikely(x) __builtin_expect(!!(x), 0) | ^ include/linux/scatterlist.h:137:2: note: in expansion of macro 'BUG_ON' 137 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~ include/linux/scatterlist.h:137:10: note: in expansion of macro 'virt_addr_valid' 137 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~~~~~~~~~~ drivers/staging/gdm724x/gdm_usb.c: In function 'request_mac_address': >> drivers/staging/gdm724x/gdm_usb.c:60:21: warning: 'buf' is used uninitialized in this function [-Wuninitialized] 60 | struct hci_packet *hci = (struct hci_packet *)buf; | ^~~ vim +/buf +60 drivers/staging/gdm724x/gdm_usb.c 61e12104764512 Won Kang 2013-07-25 50 61e12104764512 Won Kang 2013-07-25 51 static int gdm_usb_recv(void *priv_dev, 35db0350c5ef0d Aybuke Ozdemir 2014-03-14 52 int (*cb)(void *cb_data, 35db0350c5ef0d Aybuke Ozdemir 2014-03-14 53 void *data, int len, int context), 61e12104764512 Won Kang 2013-07-25 54 void *cb_data, 61e12104764512 Won Kang 2013-07-25 55 int context); 61e12104764512 Won Kang 2013-07-25 56 61e12104764512 Won Kang 2013-07-25 57 static int request_mac_address(struct lte_udev *udev) 61e12104764512 Won Kang 2013-07-25 58 { d793f4f0573692 Amey Narkhede 2021-02-09 59 u8 *buf; 61e12104764512 Won Kang 2013-07-25 @60 struct hci_packet *hci = (struct hci_packet *)buf; 61e12104764512 Won Kang 2013-07-25 61 struct usb_device *usbdev = udev->usbdev; 61e12104764512 Won Kang 2013-07-25 62 int actual; 61e12104764512 Won Kang 2013-07-25 63 int ret = -1; 61e12104764512 Won Kang 2013-07-25 64 1b5e56ece3f501 Quytelda Kahja 2018-02-22 65 hci->cmd_evt = gdm_cpu_to_dev16(udev->gdm_ed, LTE_GET_INFORMATION); 1b5e56ece3f501 Quytelda Kahja 2018-02-22 66 hci->len = gdm_cpu_to_dev16(udev->gdm_ed, 1); 61e12104764512 Won Kang 2013-07-25 67 hci->data[0] = MAC_ADDRESS; 61e12104764512 Won Kang 2013-07-25 68 d793f4f0573692 Amey Narkhede 2021-02-09 69 buf = kmalloc(16, GFP_KERNEL); d793f4f0573692 Amey Narkhede 2021-02-09 70 if (!buf) d793f4f0573692 Amey Narkhede 2021-02-09 71 return -ENOMEM; d793f4f0573692 Amey Narkhede 2021-02-09 72 61e12104764512 Won Kang 2013-07-25 73 ret = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 2), buf, 5, 61e12104764512 Won Kang 2013-07-25 74 &actual, 1000); 61e12104764512 Won Kang 2013-07-25 75 61e12104764512 Won Kang 2013-07-25 76 udev->request_mac_addr = 1; 61e12104764512 Won Kang 2013-07-25 77 61e12104764512 Won Kang 2013-07-25 78 return ret; 61e12104764512 Won Kang 2013-07-25 79 } 61e12104764512 Won Kang 2013-07-25 80 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org