--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1006,17 +1006,18 @@ static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
        if (!ifname_is_set)
                snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ppp->file.index);
 
+       mutex_unlock(&pn->all_ppp_mutex);
+
        ret = register_netdevice(ppp->dev);
        if (ret < 0)
                goto err_unit;
 
        atomic_inc(&ppp_unit_count);
 
-       mutex_unlock(&pn->all_ppp_mutex);
-
        return 0;
 
 err_unit:
+       mutex_lock(&pn->all_ppp_mutex);
        unit_put(&pn->units_idr, ppp->file.index);
 err:
        mutex_unlock(&pn->all_ppp_mutex);