From 36d6dfffc0b860a9ade17c96b3af5cd49108c498 Mon Sep 17 00:00:00 2001
From: huaibin Wang <huaibin.wang@6wind.com>
Date: Tue, 25 Aug 2015 16:20:34 +0200
Subject: [PATCH] ip6_gre: release cached dst on tunnel removal

commit d4257295ba1b389c693b79de857a96e4b7cd8ac0 upstream.

When a tunnel is deleted, the cached dst entry should be released.

This problem may prevent the removal of a netns (seen with a x-netns IPv6
gre tunnel):
  unregister_netdevice: waiting for lo to become free. Usage count = 3

CC: Dmitry Kozlov <xeb@mail.ru>
Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: huaibin Wang <huaibin.wang@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 net/ipv6/ip6_gre.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 07506e7a8917..f5ea5aaf75f9 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -358,6 +358,7 @@ static void ip6gre_tunnel_uninit(struct net_device *dev)
 	struct ip6gre_net *ign = net_generic(t->net, ip6gre_net_id);
 
 	ip6gre_tunnel_unlink(ign, t);
+	ip6_tnl_dst_reset(t);
 	dev_put(dev);
 }