Subject: Re: new link failing on duplicate names in different namespaces

From: [email-masked] (Eric W. Biederman)
Date: Thu, 26 Feb 2015 07:55:04 -0600

Nicolas Dichtel <[email-masked]> writes:

> Le 26/02/2015 06:56, Cong Wang a écrit :
>> On Wed, Feb 25, 2015 at 9:29 PM, Cong Wang <[email-masked]> wrote:
> [snip]
>>
>> Please give the attached patch a try.
>>
> It's hard to comment a patch which is sent in attachment
> (see
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches#n333).
>
> +				err = rtnl_group_changelink(skb, dest_net,
> It should probably be something like 'link_net ? : dest_net' instead of
> dest_net.
>
> I also don't understand why you need two label ('out' and 'err'). I think one is
> enough (link_net is initialized to NULL for this purpose).
> And why not keeping the same name as before, ie 'out'? It will minimize the
> patch.

Sigh.

We can not give the guarantee that a new network device will only live
in and have a unique name in a single network namespace until we get
rid of dev_change_net_namespace in the code.

Cong your patch does not get rid of that and so is insufficient to solve
this problem and buggy.

Eric