[PATCH] net: l2tp_eth: fix kernel panic on rmmod l2tp_eth

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

We must prevent module unloading if some devices are still attached to
l2tp_eth driver.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
Cc: James Chapman <jchapman@katalix.com>
---
 net/l2tp/l2tp_eth.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 443591d..185f12f 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -162,6 +162,7 @@ static void l2tp_eth_delete(struct l2tp_session *session)
 		if (dev) {
 			unregister_netdev(dev);
 			spriv->dev = NULL;
+			module_put(THIS_MODULE);
 		}
 	}
 }
@@ -249,6 +250,7 @@ static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 p
 	if (rc < 0)
 		goto out_del_dev;
 
+	__module_get(THIS_MODULE);
 	/* Must be done after register_netdev() */
 	strlcpy(session->ifname, dev->name, IFNAMSIZ);