--- x/net/ax25/af_ax25.c
+++ y/net/ax25/af_ax25.c
@@ -694,8 +694,10 @@ static int ax25_setsockopt(struct socket
 			ax25_dev_put(ax25->ax25_dev);
 		}
 
+		spin_lock_bh(&ax25_dev_lock);
 		ax25->ax25_dev = ax25_dev_ax25dev(dev);
 		if (!ax25->ax25_dev) {
+			spin_unlock_bh(&ax25_dev_lock);
 			rcu_read_unlock();
 			res = -ENODEV;
 			break;
@@ -703,6 +705,7 @@ static int ax25_setsockopt(struct socket
 		ax25_fillin_cb(ax25, ax25->ax25_dev);
 		netdev_hold(dev, &ax25->dev_tracker, GFP_ATOMIC);
 		ax25_dev_hold(ax25->ax25_dev);
+		spin_unlock_bh(&ax25_dev_lock);
 		rcu_read_unlock();
 		break;