From 576b7cd2f6ff1e90b3fc0a000d2fe74f8a50a4bb Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Fri, 3 Apr 2015 12:02:37 +0200 Subject: [PATCH] netns: don't allocate an id for dead netns First, let's explain the problem. Suppose you have an ipip interface that stands in the netns foo and its link part in the netns bar (so the netns bar has an nsid into the netns foo). Now, you remove the netns bar: - the bar nsid into the netns foo is removed - the netns exit method of ipip is called, thus our ipip iface is removed: => a netlink message is built in the netns foo to advertise this deletion => this netlink message requests an nsid for bar, thus a new nsid is allocated for bar and never removed. This patch adds a check in peernet2id() so that an id cannot be allocated for a netns which is currently destroyed. Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller --- net/core/net_namespace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index cb5290b..70d3450 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -198,8 +198,10 @@ static int __peernet2id(struct net *net, struct net *peer, bool alloc) */ int peernet2id(struct net *net, struct net *peer) { - int id = __peernet2id(net, peer, true); + bool alloc = atomic_read(&peer->count) == 0 ? false : true; + int id; + id = __peernet2id(net, peer, alloc); return id >= 0 ? id : NETNSA_NSID_NOT_ASSIGNED; } EXPORT_SYMBOL(peernet2id); -- 2.7.4