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, 1 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ec54785d34f9..659366734f3f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1079,6 +1079,7 @@ extern void		synchronize_net(void);
 extern int              register_netdevice_notifier(struct notifier_block *nb);
 extern int              unregister_netdevice_notifier(struct notifier_block *nb);
 extern int              init_dummy_netdev(struct net_device *dev);
+extern void             netdev_resync_ops(struct net_device *dev);
 
 extern int call_netdevice_notifiers(unsigned long val, struct net_device *dev);
 extern struct net_device        *dev_get_by_index(struct net *net, int ifindex);