net: l2tp_eth: fix kernel panic on rmmod l2tp_eth

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 443591d629ca..185f12f4a5fa 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);