USB: serial: mos7720: fix parport use-after-free on probe errors

Do not submit the interrupt URB until after the parport has been
successfully registered to avoid another use-after-free in the
completion handler when accessing the freed parport private data in case
of a racing completion.

Fixes: b69578df7e98 ("USB: usbserial: mos7720: add support for parallel
port on moschip 7715")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 9170ae8..e494821 100644 (file)
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1952,22 +1952,20 @@ static int mos7720_startup(struct usb_serial *serial)
        usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        (__u8)0x03, 0x00, 0x01, 0x00, NULL, 0x00, 5000);
 
-       /* start the interrupt urb */
-       ret_val = usb_submit_urb(serial->port[0]->interrupt_in_urb, GFP_KERNEL);
-       if (ret_val)
-               dev_err(&dev->dev,
-                       "%s - Error %d submitting control urb\n",
-                       __func__, ret_val);
-
 #ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
        if (product == MOSCHIP_DEVICE_ID_7715) {
                ret_val = mos7715_parport_init(serial);
-               if (ret_val < 0) {
-                       usb_kill_urb(serial->port[0]->interrupt_in_urb);
+               if (ret_val < 0)
                        return ret_val;
-               }
        }
 #endif
+       /* start the interrupt urb */
+       ret_val = usb_submit_urb(serial->port[0]->interrupt_in_urb, GFP_KERNEL);
+       if (ret_val) {
+               dev_err(&dev->dev, "failed to submit interrupt urb: %d\n",
+                       ret_val);
+       }
+
        /* LSR For Port 1 */
        read_mos_reg(serial, 0, MOS7720_LSR, &data);
        dev_dbg(&dev->dev, "LSR:%x\n", data);