USB: serial: io_edgeport: fix use after free in debug printk

The "dev_dbg(&urb->dev->dev, ..." which happens after usb_free_urb(urb)
is a use after free of the "urb" pointer.  Store the "dev" pointer at the
start of the function to avoid this issue.

Fixes: 984f68683298 ("USB: serial: io_edgeport.c: remove dbg() usage")
Cc: stable@vger.kernel.org
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index c7d6b5e3f8982b5bbf9b3bd602c21a4bc3447ccb..28c71d99e857262c7359b9050c649ef8784f6bed 100644 (file)
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -770,11 +770,12 @@ static void edge_bulk_out_data_callback(struct urb *urb)
 static void edge_bulk_out_cmd_callback(struct urb *urb)
 {
        struct edgeport_port *edge_port = urb->context;
+       struct device *dev = &urb->dev->dev;
        int status = urb->status;
 
        atomic_dec(&CmdUrbs);
-       dev_dbg(&urb->dev->dev, "%s - FREE URB %p (outstanding %d)\n",
-               __func__, urb, atomic_read(&CmdUrbs));
+       dev_dbg(dev, "%s - FREE URB %p (outstanding %d)\n", __func__, urb,
+               atomic_read(&CmdUrbs));
 
 
        /* clean up the transfer buffer */
@@ -784,8 +785,7 @@ static void edge_bulk_out_cmd_callback(struct urb *urb)
        usb_free_urb(urb);
 
        if (status) {
-               dev_dbg(&urb->dev->dev,
-                       "%s - nonzero write bulk status received: %d\n",
+               dev_dbg(dev, "%s - nonzero write bulk status received: %d\n",
                        __func__, status);
                return;
        }