[patch 1/1][NETNS] resend: fix net released by rcu callback

[Eric W. Biederman]

Daniel Lezcano <dlezcano at fr.ibm.com> writes:

> When a network namespace reference is held by a network subsystem,
> and when this reference is decremented in a rcu update callback, we
> must ensure that there is no more outstanding rcu update before 
> trying to free the network namespace.
>
> In the normal case, the rcu_barrier is called when the network namespace
> is exiting in the cleanup_net function.
>
> But when a network namespace creation fails, and the subsystems are
> undone (like the cleanup), the rcu_barrier is missing.
>
> This patch adds the missing rcu_barrier.

Looks sane.  Did you have any specific failures related to this or was
this something that was just caught in review?

Eric