[MACVLAN]: Prevent nesting macvlan devices Don't allow to nest macvlan devices since it will cause lockdep warnings and isn't really useful for anything. Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx> --- commit 80a76fbde679793a17482a3dd842386801fca66b tree 07f67e78ac0ae505a5de81e7e770a1b7d597f120 parent 4d14fded63dcaf9d5dcf78e2a8ea3f5de2c29eb9 author Patrick McHardy <kaber@xxxxxxxxx> Thu, 10 Jan 2008 16:25:01 +0100 committer Patrick McHardy <kaber@xxxxxxxxx> Thu, 10 Jan 2008 16:25:01 +0100 drivers/net/macvlan.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 2e4bcd5..e8dc2f4 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)
