Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 02/28] net: check dead netns for peernet2id_alloc() | Date | Fri, 9 Dec 2016 17:17:44 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: WANG Cong <xiyou.wangcong@gmail.com>
[ Upstream commit cfc44a4d147ea605d66ccb917cc24467d15ff867 ]
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 <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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/net_namespace.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -217,6 +217,8 @@ int peernet2id_alloc(struct net *net, st 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);
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