4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit e33eab9ded328ccc14308afa51b5be7cbe78d30b upstream. The "r" variable is an int and "bufsize" is an unsigned int so the comparison is type promoted to unsigned. If usb_control_msg() returns a negative that is treated as a high positive value and the error handling doesn't work. Fixes: 2d5a9c72d0c4 ("USB: serial: ch341: fix control-message error handling") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/serial/ch341.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -118,7 +118,7 @@ static int ch341_control_in(struct usb_d r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, value, index, buf, bufsize, DEFAULT_TIMEOUT); - if (r < bufsize) { + if (r < (int)bufsize) { if (r >= 0) { dev_err(&dev->dev, "short control message received (%d < %u)\n",