On Wed, May 31, 2017 at 11:32 PM, Eric W. Biederman
<ebied...@xmission.com> wrote:
> Cong Wang <xiyou.wangc...@gmail.com> writes:
>> Network namespace does not special-case the physical devices,
>> it treats them all equally as abstract net devices.
>
> Absolutely not true.
>
> The relevant code is in net/core/dev.c:default_device_exit
>
> If a network device does not implement rntl_link_ops it is returned to
> the initial network namespace. Anything else will loose physical
> devices.
Hmm, I never noticed that if check...
>
> Only for pure software based devices do we delete them. Perhaps your
> sub interface implements rtnl_link_ops? Either that or something is
> still holding a reference to your network namespace, which would prevent
> the network device from being returned.
>
But this simply sucks:
snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex);
err = dev_change_net_namespace(dev, &init_net, fb_name);
if (err) {
pr_emerg("%s: failed to move %s to init_net: %d\n",
__func__, dev->name, err);
BUG();
}
It is essentially hard to handle the error here, but it is quite easy to
trigger such BUG() by naming other device devX, it is no better
than just losing it.
