ip6_gre: release cached dst on tunnel removal

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>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index a38d3ac0f18f6e631e3a17904bf617f7a0dfe28a..69f4f689f06afb0bc1cdb4ab7d34ca3a8471a715 100644 (file)
--- 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);
 }