On Tue, 13 May 2014 11:20:58 -0700
Cong Wang [off-list ref] wrote:

On Tue, May 13, 2014 at 8:39 AM, Stephen Hemminger
[off-list ref] wrote:

quoted

There have been a couple of bugzilla reports already about cases where a macvlan
or vlan is moved into another namespace. In these cases the parent device ifindex (iflink)
is no longer valid.


Normally it is not a big issue, until another device is created using the ifindex
of the parent

Does anyone have a suggested fix? Marking iflink as 0 won't work then the devices no
longer appear as slaves. Another possibility would be to make block creation of device
where ifindex matches existing iflink of other devices; but this would slow down device
creation.

I have a pending fix which converts ->iflink to a pointer to struct net_device,
this is a suggested fix from Ben. And so, when the lower device is not
in the same
namespace with the upper device, we should not display the iflink information.

I will send it soon.

That won't solve the problem.
 1. a pointer increase size of netns and requires refcount
 2. iflink is still exposed in kernel user API and has to be set
    otherwise the device is falsely reported.