[PATCH net] ip6_gre: release cached dst on tunnel removal

From: huaibin Wang <redacted>

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 <redacted>
Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: huaibin Wang <redacted>
Signed-off-by: Nicolas Dichtel <redacted>
---
 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 a38d3ac0f18f..69f4f689f06a 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c

@@ -361,6 +361,7 @@ 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);
 }
 

-- 
2.4.2