vlan: Fix vlan-in-vlan crashes.

As analyzed by Patrick McHardy, vlan needs to reset it's
netdev_ops pointer in it's ->init() function but this
leaves the compat method pointers stale.

Add a netdev_resync_ops() and call it from the vlan code.

Any other driver which changes ->netdev_ops after register_netdevice()
will need to call this new function after doing so too.

With help from Patrick McHardy.

Tested-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 4a19acd3a32b..1b34135cf990 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -553,7 +553,7 @@ static int vlan_dev_neigh_setup(struct net_device *dev, struct neigh_parms *pa)
         int err = 0;
 
         if (netif_device_present(real_dev) && ops->ndo_neigh_setup)
-                err = ops->ndo_neigh_setup(dev, pa);
+                err = ops->ndo_neigh_setup(real_dev, pa);
 
         return err;
 }
@@ -639,6 +639,7 @@ static int vlan_dev_init(struct net_device *dev)
                 dev->hard_header_len = real_dev->hard_header_len + VLAN_HLEN;
                 dev->netdev_ops         = &vlan_netdev_ops;
         }
+        netdev_resync_ops(dev);
 
         if (is_vlan_dev(real_dev))
                 subclass = 1;