[PATCH 4.9 02/32] usbnet: ipheth: fix potential null pointer dereference in ipheth_carrier_set

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Gustavo A. R. Silva <garsilva@embeddedor.com>

commit 61c59355e0154a938b28710dfa6c1d8be2ddcefa upstream.

_dev_ is being dereferenced before it is null checked, hence there
is a potential null pointer dereference.

Fix this by moving the pointer dereference after _dev_ has been null
checked.

Addresses-Coverity-ID: 1462020
Fixes: bb1b40c7cb86 ("usbnet: ipheth: prevent TX queue timeouts when device not ready")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/usb/ipheth.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/usb/ipheth.c
+++ b/drivers/net/usb/ipheth.c
@@ -290,12 +290,15 @@ static void ipheth_sndbulk_callback(stru
 
 static int ipheth_carrier_set(struct ipheth_device *dev)
 {
-	struct usb_device *udev = dev->udev;
+	struct usb_device *udev;
 	int retval;
+
 	if (!dev)
 		return 0;
 	if (!dev->confirmed_pairing)
 		return 0;
+
+	udev = dev->udev;
 	retval = usb_control_msg(udev,
 			usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
 			IPHETH_CMD_CARRIER_CHECK, /* request */