diff --git a/drivers/net/usb/cdc-phonet.c b/drivers/net/usb/cdc-phonet.c
index 288ecd9..3c40312 100644
--- a/drivers/net/usb/cdc-phonet.c
+++ b/drivers/net/usb/cdc-phonet.c
@@ -99,6 +99,7 @@ static void tx_complete(struct urb *req)
 	struct net_device *dev = skb->dev;
 	struct usbpn_dev *pnd = netdev_priv(dev);
 	int status = req->status;
+	unsigned long flags;
 
 	switch (status) {
 	case 0:
@@ -115,10 +116,10 @@ static void tx_complete(struct urb *req)
 	}
 	dev->stats.tx_packets++;
 
-	spin_lock(&pnd->tx_lock);
+	spin_lock_irqsave(&pnd->tx_lock, flags);
 	pnd->tx_queue--;
 	netif_wake_queue(dev);
-	spin_unlock(&pnd->tx_lock);
+	spin_unlock_irqrestore(&pnd->tx_lock, flags);
 
 	dev_kfree_skb_any(skb);
 	usb_free_urb(req);