usb: hso: check for return value in hso_serial_common_create()

in case of an error tty_register_device_attr() returns ERR_PTR(),
add IS_ERR() check

Reported-and-tested-by: syzbot+67b2bd0e34f952d0321e@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=67b2bd0e34f952d0321e
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 5f123a8..d2fdb54 100644 (file)
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2261,12 +2261,14 @@ static int hso_serial_common_create(struct hso_serial *serial, int num_urbs,
 
        minor = get_free_serial_index();
        if (minor < 0)
-               goto exit;
+               goto exit2;
 
        /* register our minor number */
        serial->parent->dev = tty_port_register_device_attr(&serial->port,
                        tty_drv, minor, &serial->parent->interface->dev,
                        serial->parent, hso_serial_dev_groups);
+       if (IS_ERR(serial->parent->dev))
+               goto exit2;
 
        /* fill in specific data for later use */
        serial->minor = minor;
@@ -2311,6 +2313,7 @@ static int hso_serial_common_create(struct hso_serial *serial, int num_urbs,
        return 0;
 exit:
        hso_serial_tty_unregister(serial);
+exit2:
        hso_serial_common_free(serial);
        return -1;
 }