netdev - [PATCH net] vxlan: add necessary locking on device removal

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Message-ID: <20130713101818.0d4fa8e0@nehalam.linuxnetplumber.net>
Date:	Sat, 13 Jul 2013 10:18:18 -0700
From:	Stephen Hemminger <stephen@...workplumber.org>
To:	Pravin Shelar <pshelar@...ira.com>
Cc:	netdev@...r.kernel.org
Subject: [PATCH net] 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@...workplumber.org>

--- a/drivers/net/vxlan.c	2013-07-08 16:31:50.080744429 -0700
+++ b/drivers/net/vxlan.c	2013-07-10 20:15:47.337653899 -0700
@@ -1767,9 +1767,15 @@ static int vxlan_newlink(struct net *net
 
 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);
 }
--
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