diff --git a/net/atm/lec.c b/net/atm/lec.c
index 6257bf12e5a00b7250c6b1ae52e50176c33e88d6..2240976d75c74e5a5cca2a5ad1889744f5ebe77f 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -124,6 +124,7 @@ static unsigned char bus_mac[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
 /* Device structures */
 static struct net_device *dev_lec[MAX_LEC_ITF];
+static DEFINE_MUTEX(lec_mutex);
 
 #if IS_ENABLED(CONFIG_BRIDGE)
 static void lec_handle_bridge(struct sk_buff *skb, struct net_device *dev)
@@ -684,6 +685,7 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg)
 	int bytes_left;
 	struct atmlec_ioc ioc_data;
 
+	lockdep_assert_held(&lec_mutex);
 	/* Lecd must be up in this case */
 	bytes_left = copy_from_user(&ioc_data, arg, sizeof(struct atmlec_ioc));
 	if (bytes_left != 0)
@@ -709,6 +711,7 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg)
 
 static int lec_mcast_attach(struct atm_vcc *vcc, int arg)
 {
+	lockdep_assert_held(&lec_mutex);
 	if (arg < 0 || arg >= MAX_LEC_ITF)
 		return -EINVAL;
 	arg = array_index_nospec(arg, MAX_LEC_ITF);
@@ -724,6 +727,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg)
 	int i;
 	struct lec_priv *priv;
 
+	lockdep_assert_held(&lec_mutex);
 	if (arg < 0)
 		arg = 0;
 	if (arg >= MAX_LEC_ITF)
@@ -741,6 +745,7 @@ static int lecd_attach(struct atm_vcc *vcc, int arg)
 		snprintf(dev_lec[i]->name, IFNAMSIZ, "lec%d", i);
 		if (register_netdev(dev_lec[i])) {
 			free_netdev(dev_lec[i]);
+			dev_lec[i] = NULL;
 			return -EINVAL;
 		}
 
@@ -1002,6 +1007,7 @@ static int lane_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		return -ENOIOCTLCMD;
 	}
 
+	mutex_lock(&lec_mutex);
 	switch (cmd) {
 	case ATMLEC_CTRL:
 		err = lecd_attach(vcc, (int)arg);
@@ -1016,6 +1022,7 @@ static int lane_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		break;
 	}
 
+	mutex_unlock(&lec_mutex);
 	return err;
 }