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: 0c7aecd4bd ("netns: add rtnl cmd to add and get peer netns ids")
Reported-by: Andrei Vagin <avagin@gmail.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>