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>
---
net/core/net_namespace.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index f61c0e0..7001da9 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -219,6 +219,8 @@ int peernet2id_alloc(struct net *net, struct net *peer)
bool alloc;
int id;
+ if (atomic_read(&net->count) == 0)
+ return NETNSA_NSID_NOT_ASSIGNED;
spin_lock_irqsave(&net->nsid_lock, flags);
alloc = atomic_read(&peer->count) == 0 ? false : true;
id = __peernet2id_alloc(net, peer, &alloc);
--
2.1.0
