From: Cong Wang <xiyou.wangc...@gmail.com>
Date: Wed, 16 Nov 2016 10:27:02 -0800
> Andrei reports we still allocate netns ID from idr after we destroy
> it in cleanup_net().
>
> cleanup_net():
> ...
> idr_destroy(&net->netns_ids);
> ...
> list_for_each_entry_reverse(ops, &pernet_list, list)
> ops_exit_list(ops, &net_exit_list);
> -> rollback_registered_many()
> -> rtmsg_ifinfo_build_skb()
> -> rtnl_fill_ifinfo()
> -> peernet2id_alloc()
>
> After that point we should not even access net->netns_ids, we
> should check the death of the current netns as early as we can in
> peernet2id_alloc().
>
> For net-next we can consider to avoid sending rtmsg totally,
> it is a good optimization for netns teardown path.
>
> Fixes: 0c7aecd4bde4 ("netns: add rtnl cmd to add and get peer netns ids")
> Reported-by: Andrei Vagin <ava...@gmail.com>
> Cc: Nicolas Dichtel <nicolas.dich...@6wind.com>
> Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
Applied and queued up for -stable, thanks.
