STT unregisters nf-hook when there are no other STT devices
left in the namespace. On some kernel versions the nf-unreg API
take RTNL lock, but it is already taken in the tunnel device
destroy code path which results in deadlock. To fix the issue
I moved the unreg call into net-exit.
Bug: #1582410
Reported-by: Joe Stringer <j...@ovn.org>
Signed-off-by: Pravin B Shelar <pshe...@nicira.com>
---
datapath/linux/compat/stt.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/datapath/linux/compat/stt.c b/datapath/linux/compat/stt.c
index 85ddbe7..5046c4c 100644
--- a/datapath/linux/compat/stt.c
+++ b/datapath/linux/compat/stt.c
@@ -1586,12 +1586,6 @@ static void stt_cleanup(struct net *net)
sn->n_tunnels--;
if (sn->n_tunnels)
goto out;
-#ifdef HAVE_NF_REGISTER_NET_HOOK
- nf_unregister_net_hook(net, &nf_hook_ops);
-#else
- nf_unregister_hook(&nf_hook_ops);
-#endif
-
out:
n_tunnels--;
if (n_tunnels)
@@ -1668,6 +1662,7 @@ static int stt_stop(struct net_device *dev)
struct net *net = stt_dev->net;
list_del_rcu(&stt_dev->up_next);
+ synchronize_net();
tcp_sock_release(stt_dev->sock);
stt_dev->sock = NULL;
stt_cleanup(net);
@@ -1869,6 +1864,14 @@ static void stt_exit_net(struct net *net)
struct net_device *dev, *aux;
LIST_HEAD(list);
+#ifdef HAVE_NF_REGISTER_NET_HOOK
+ /* Ideally this should be done from stt_stop(), But on some kernels
+ * nf-unreg operation needs RTNL-lock, which can cause deallock.
+ * So it is done from here. */
+ if (!list_empty(&nf_hook_ops.list))
+ nf_unregister_net_hook(net, &nf_hook_ops);
+#endif
+
rtnl_lock();
/* gather any stt devices that were moved into this ns */
@@ -1918,6 +1921,10 @@ out1:
void stt_cleanup_module(void)
{
+#ifndef HAVE_NF_REGISTER_NET_HOOK
+ if (!list_empty(&nf_hook_ops.list))
+ nf_unregister_hook(&nf_hook_ops);
+#endif
rtnl_link_unregister(&stt_link_ops);
unregister_pernet_subsys(&stt_net_ops);
}
--
1.8.3.1
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
