From: Jiri Pirko <redacted>
Date: Thu, 30 Jul 2009 13:06:12 +0200

There is a path when an assetion in dev_unicast_sync() appears. 

igmp6_group_added -> dev_mc_add -> __dev_set_rx_mode ->
-> vlan_dev_set_rx_mode -> dev_unicast_sync

Therefore we cannot protect this list with rtnl. This patch restores the
original protecting this list with spinlock.

Signed-off-by: Jiri Pirko <redacted>

Applied, thanks.