X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fnet%2Fmacvlan.c;h=e8dc2f44fec960d9d3b58127699e5a4ed9eee838;hb=444ad82bc3eaa554be40d22dc248e58aeefd54d9;hp=2e4bcd5654c4c0b62db0e795f87c96d73c176207;hpb=f4921aff5b174349bc36551f142a5dbac782ea3f;p=linux-2.6

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 2e4bcd5654..e8dc2f44fe 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -384,6 +384,13 @@ static int macvlan_newlink(struct net_device *dev,
 	if (lowerdev == NULL)
 		return -ENODEV;
 
+	/* Don't allow macvlans on top of other macvlans - its not really
+	 * wrong, but lockdep can't handle it and its not useful for anything
+	 * you couldn't do directly on top of the real device.
+	 */
+	if (lowerdev->rtnl_link_ops == dev->rtnl_link_ops)
+		return -ENODEV;
+
 	if (!tb[IFLA_MTU])
 		dev->mtu = lowerdev->mtu;
 	else if (dev->mtu > lowerdev->mtu)