USB: serial: fix potential NULL-dereference at probe

Make sure we have at least one port before attempting to register a
console.

Currently, at least one driver binds to a "dummy" interface and requests
zero ports for it. Should such an interface also lack endpoints, we get
a NULL-deref during probe.

Fixes: e5b1e2062e05 ("USB: serial: make minor allocation dynamic")
Cc: stable <stable@vger.kernel.org>	# 3.11
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index d213cf44a7e45ef8ae692bf4a9e63d31088cae8b..4a037b4a79cf3168cb45d60d1b6488ac21681570 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1078,7 +1078,8 @@ static int usb_serial_probe(struct usb_interface *interface,
 
        serial->disconnected = 0;
 
-       usb_serial_console_init(serial->port[0]->minor);
+       if (num_ports > 0)
+               usb_serial_console_init(serial->port[0]->minor);
 exit:
        module_put(type->driver.owner);
        return 0;