ip_gre: fix fallback tunnel setup

Before making the fallback tunnel visible to lookups, we should make
sure it is completely setup, once ipgre_tunnel_init() had been called
and tstats per_cpu pointer allocated.

move rcu_assign_pointer(ign->tunnels_wc[0], tunnel); from
ipgre_fb_tunnel_init() to ipgre_init_net()

Based on a patch from Pavel Emelyanov

Reported-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 01087e035b7d..70ff77f02eee 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1325,7 +1325,6 @@ static void ipgre_fb_tunnel_init(struct net_device *dev)
 {
         struct ip_tunnel *tunnel = netdev_priv(dev);
         struct iphdr *iph = &tunnel->parms.iph;
-        struct ipgre_net *ign = net_generic(dev_net(dev), ipgre_net_id);
 
         tunnel->dev = dev;
         strcpy(tunnel->parms.name, dev->name);
@@ -1336,7 +1335,6 @@ static void ipgre_fb_tunnel_init(struct net_device *dev)
         tunnel->hlen            = sizeof(struct iphdr) + 4;
 
         dev_hold(dev);
-        rcu_assign_pointer(ign->tunnels_wc[0], tunnel);
 }
 
 
@@ -1383,10 +1381,12 @@ static int __net_init ipgre_init_net(struct net *net)
         if ((err = register_netdev(ign->fb_tunnel_dev)))
                 goto err_reg_dev;
 
+        rcu_assign_pointer(ign->tunnels_wc[0],
+                           netdev_priv(ign->fb_tunnel_dev));
         return 0;
 
 err_reg_dev:
-        free_netdev(ign->fb_tunnel_dev);
+        ipgre_dev_free(ign->fb_tunnel_dev);
 err_alloc_dev:
         return err;
 }