bonding: in bond_mc_swap() bond's mc addr list is walked without lock

Use netif_addr_lock_bh() to acquire the appropriate lock before walking.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -846,8 +846,10 @@ static void bond_mc_swap(struct bonding *bond, struct slave *new_active,
 		if (bond->dev->flags & IFF_ALLMULTI)
 			dev_set_allmulti(old_active->dev, -1);
 
+		netif_addr_lock_bh(bond->dev);
 		netdev_for_each_mc_addr(ha, bond->dev)
 			dev_mc_del(old_active->dev, ha->addr);
+		netif_addr_unlock_bh(bond->dev);
 	}
 
 	if (new_active) {
@@ -858,8 +860,10 @@ static void bond_mc_swap(struct bonding *bond, struct slave *new_active,
 		if (bond->dev->flags & IFF_ALLMULTI)
 			dev_set_allmulti(new_active->dev, 1);
 
+		netif_addr_lock_bh(bond->dev);
 		netdev_for_each_mc_addr(ha, bond->dev)
 			dev_mc_add(new_active->dev, ha->addr);
+		netif_addr_unlock_bh(bond->dev);
 	}
 }