[BRIDGE] br_if: Fix oops in port_carrier_check

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -108,6 +108,7 @@ static void port_carrier_check(struct work_struct *work)
 		spin_unlock_bh(&br->lock);
 	}
 done:
+	dev_put(dev);
 	rtnl_unlock();
 }
 
@@ -161,7 +162,8 @@ static void del_nbp(struct net_bridge_port *p)
 
 	dev_set_promiscuity(dev, -1);
 
-	cancel_delayed_work(&p->carrier_check);
+	if (cancel_delayed_work(&p->carrier_check))
+		dev_put(dev);
 
 	spin_lock_bh(&br->lock);
 	br_stp_disable_port(p);
@@ -444,7 +446,9 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 	spin_lock_bh(&br->lock);
 	br_stp_recalculate_bridge_id(br);
 	br_features_recompute(br);
-	schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE);
+	if (schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE))
+		dev_hold(dev);
+
 	spin_unlock_bh(&br->lock);
 
 	dev_set_mtu(br->dev, br_min_mtu(br));

net/bridge/br_notify.c

@@ -56,7 +56,9 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 
 	case NETDEV_CHANGE:
 		if (br->dev->flags & IFF_UP)
-			schedule_delayed_work(&p->carrier_check, BR_PORT_DEBOUNCE);
+			if (schedule_delayed_work(&p->carrier_check,
+						BR_PORT_DEBOUNCE))
+				dev_hold(dev);
 		break;
 
 	case NETDEV_FEAT_CHANGE: