[PATCH 4.4 12/34] packet: call fanout_release, while UNREGISTERING a netdev

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anoob Soman <anoob.soman@xxxxxxxxxx>


[ Upstream commit 6664498280cf17a59c3e7cf1a931444c02633ed1 ]

If a socket has FANOUT sockopt set, a new proto_hook is registered
as part of fanout_add(). When processing a NETDEV_UNREGISTER event in
af_packet, __fanout_unlink is called for all sockets, but prot_hook which was
registered as part of fanout_add is not removed. Call fanout_release, on a
NETDEV_UNREGISTER, which removes prot_hook and removes fanout from the
fanout_list.

This fixes BUG_ON(!list_empty(&dev->ptype_specific)) in netdev_run_todo()

Signed-off-by: Anoob Soman <anoob.soman@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/packet/af_packet.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3855,6 +3855,7 @@ static int packet_notifier(struct notifi
 				}
 				if (msg == NETDEV_UNREGISTER) {
 					packet_cached_dev_reset(po);
+					fanout_release(sk);
 					po->ifindex = -1;
 					if (po->prot_hook.dev)
 						dev_put(po->prot_hook.dev);