From 6d458f5b4ece8542a5c2281e40008823fec91814 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Fri, 3 Apr 2015 12:02:36 +0200 Subject: Revert "netns: don't clear nsid too early on removal" This reverts commit 4217291e592d ("netns: don't clear nsid too early on removal"). This is not the right fix, it introduces races. Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller --- net/core/net_namespace.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-) (limited to 'net/core/net_namespace.c') diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 5221f975a4cc..cb5290b8c428 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -349,7 +349,7 @@ static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */ static void cleanup_net(struct work_struct *work) { const struct pernet_operations *ops; - struct net *net, *tmp, *peer; + struct net *net, *tmp; struct list_head net_kill_list; LIST_HEAD(net_exit_list); @@ -365,6 +365,14 @@ static void cleanup_net(struct work_struct *work) list_for_each_entry(net, &net_kill_list, cleanup_list) { list_del_rcu(&net->list); list_add_tail(&net->exit_list, &net_exit_list); + for_each_net(tmp) { + int id = __peernet2id(tmp, net, false); + + if (id >= 0) + idr_remove(&tmp->netns_ids, id); + } + idr_destroy(&net->netns_ids); + } rtnl_unlock(); @@ -390,26 +398,12 @@ static void cleanup_net(struct work_struct *work) */ rcu_barrier(); - rtnl_lock(); /* Finally it is safe to free my network namespace structure */ list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { - /* Unreference net from all peers (no need to loop over - * net_exit_list because idr_destroy() will be called for each - * element of this list. - */ - for_each_net(peer) { - int id = __peernet2id(peer, net, false); - - if (id >= 0) - idr_remove(&peer->netns_ids, id); - } - idr_destroy(&net->netns_ids); - list_del_init(&net->exit_list); put_user_ns(net->user_ns); net_drop_ns(net); } - rtnl_unlock(); } static DECLARE_WORK(net_cleanup_work, cleanup_net); -- cgit v1.2.3-70-g09d2 From 576b7cd2f6ff1e90b3fc0a000d2fe74f8a50a4bb Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Fri, 3 Apr 2015 12:02:37 +0200 Subject: 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(-) (limited to 'net/core/net_namespace.c') diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index cb5290b8c428..70d3450588b2 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); -- cgit v1.2.3-70-g09d2