vxlan: add necessary locking on device removal

The socket management is now done in workqueue (outside of RTNL)
and protected by vn->sock_lock. There were two possible bugs, first
the vxlan device was removed from the VNI hash table per socket without
holding lock. And there was a race when device is created and the workqueue
could run after deletion.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 0ba1e7edbb1b..a5ba8dd7e6be 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1767,9 +1767,15 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
 
 static void vxlan_dellink(struct net_device *dev, struct list_head *head)
 {
+        struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id);
         struct vxlan_dev *vxlan = netdev_priv(dev);
 
+        flush_workqueue(vxlan_wq);
+
+        spin_lock(&vn->sock_lock);
         hlist_del_rcu(&vxlan->hlist);
+        spin_unlock(&vn->sock_lock);
+
         list_del(&vxlan->next);
         unregister_netdevice_queue(dev, head);
 }