[PATCH 4.3 50/55] fou: clean up socket with kfree_rcu

[Greg Kroah-Hartman]

4.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 3036facbb7be3a169e35be3b271162b0fa564a2d ]

fou->udp_offloads is managed by RCU. As it is actually included inside
the fou sockets, we cannot let the memory go out of scope before a grace
period. We either can synchronize_rcu or switch over to kfree_rcu to
manage the sockets. kfree_rcu seems appropriate as it is used by vxlan
and geneve.

Fixes: 23461551c00628c ("fou: Support for foo-over-udp RX path")
Cc: Tom Herbert <tom@xxxxxxxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv4/fou.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -24,6 +24,7 @@ struct fou {
 	u16 type;
 	struct udp_offload udp_offloads;
 	struct list_head list;
+	struct rcu_head rcu;
 };
 
 #define FOU_F_REMCSUM_NOPARTIAL BIT(0)
@@ -417,7 +418,7 @@ static void fou_release(struct fou *fou)
 	list_del(&fou->list);
 	udp_tunnel_sock_release(sock);
 
-	kfree(fou);
+	kfree_rcu(fou, rcu);
 }
 
 static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)