If usb_set_interface() failed, iface->cur_altsetting will not be assigned and it will be used in flexcop_usb_transfer_init() It may lead a NULL pointer dereference. Check usb_set_interface() return value in flexcop_usb_init() and return failed to avoid using this NULL pointer. Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> --- drivers/media/usb/b2c2/flexcop-usb.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/b2c2/flexcop-usb.c b/drivers/media/usb/b2c2/flexcop-usb.c index 1826ff8..4bf85e9 100644 --- a/drivers/media/usb/b2c2/flexcop-usb.c +++ b/drivers/media/usb/b2c2/flexcop-usb.c @@ -504,7 +504,13 @@ static int flexcop_usb_transfer_init(struct flexcop_usb *fc_usb) static int flexcop_usb_init(struct flexcop_usb *fc_usb) { /* use the alternate setting with the larges buffer */ - usb_set_interface(fc_usb->udev,0,1); + int ret = usb_set_interface(fc_usb->udev, 0, 1); + + if (ret) { + err("set interface failed."); + return ret; + } + switch (fc_usb->udev->speed) { case USB_SPEED_LOW: err("cannot handle USB speed because it is too slow."); -- 1.8.3