On Wed, Sep 25, 2013 at 09:03:11AM -0700, Pravin Shelar wrote:

On Tue, Sep 24, 2013 at 10:55 PM, Steffen Klassert
[off-list ref] wrote:

quoted

Currently we can not update the tunnel parameters of
the fallback tunnels because we don't find them in the
hash lists. Fix this by adding them on initialization.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/ip_tunnel.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index b8ce640..f2348f2 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c

@@ -853,8 +853,10 @@ int ip_tunnel_init_net(struct net *net, int ip_tnl_net_id,
        /* FB netdevice is special: we have one, and only one per netns.
         * Allowing to move it to another netns is clearly unsafe.
         */
-       if (!IS_ERR(itn->fb_tunnel_dev))
+       if (!IS_ERR(itn->fb_tunnel_dev)) {
                itn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
+               ip_tunnel_add(itn, netdev_priv(itn->fb_tunnel_dev));
+       }
        rtnl_unlock();

fallback tunnel s not required to be in hash table, Its is returned if
none of hashed tunnels are matched, ref ip_tunnel_lookup().
Can you post command to reproduce this issue?

Something like

ip tunnel change tunl0 mode ipip remote 0.0.0.0 local 0.0.0.0 ttl 0 tos 1

worked until v3.9 and stopped working with v3.10.