Re: BUG, 3.4.1, l2tp, kernel panic on rmmod l2tp_eth

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

On Thu, 2012-06-07 at 11:31 +0300, Denys Fedoryshchenko wrote:
> Hi
> 
> Sorry for weird looking message, but this is how i got it over 
> netconsole
> 
> If i have any tunnel+session configured and up and will do rmmod 
> l2tp_eth,
> i will get panic, after my userspace program will fetch interfaces 
> information (over netlink).
> 
> Probably it should not rmmod if there is tunnels configured?

Sure, can you try the following patch ?

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);