USB: mos7840: fix tiocmget error handling

commit a91ccd26e75235d86248d018fe3779732bcafd8d upstream.

Make sure to return errors from tiocmget rather than rely on
uninitialised stack data.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 5d2501e..4c06746 100644 (file)
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1689,7 +1689,11 @@ static int mos7840_tiocmget(struct tty_struct *tty)
                return -ENODEV;
 
        status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
+       if (status != 1)
+               return -EIO;
        status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
+       if (status != 1)
+               return -EIO;
        result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
            | ((mcr & MCR_RTS) ? TIOCM_RTS : 0)
            | ((mcr & MCR_LOOPBACK) ? TIOCM_LOOP : 0)