--- x/net/lapb/lapb_iface.c
+++ y/net/lapb/lapb_iface.c
@@ -457,6 +457,7 @@ static int lapb_device_event(struct noti
 {
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct lapb_cb *lapb;
+	int estab = 0;
 
 	if (!net_eq(dev_net(dev), &init_net))
 		return NOTIFY_DONE;
@@ -482,7 +483,7 @@ static int lapb_device_event(struct noti
 			} else {
 				if (lapb->state == LAPB_STATE_0) {
 					lapb->state = LAPB_STATE_1;
-					lapb_establish_data_link(lapb);
+					estab = 1;
 				}
 			}
 		}
@@ -509,7 +510,7 @@ static int lapb_device_event(struct noti
 			} else {
 				if (lapb->state == LAPB_STATE_0) {
 					lapb->state = LAPB_STATE_1;
-					lapb_establish_data_link(lapb);
+					estab = 1;
 				}
 			}
 		} else {
@@ -525,6 +526,8 @@ static int lapb_device_event(struct noti
 	}
 
 	spin_unlock_bh(&lapb->lock);
+	if (estab)
+		lapb_establish_data_link(lapb);
 	lapb_put(lapb);
 	return NOTIFY_DONE;
 }