netdev - Re: BUG, 3.4.1, l2tp, kernel panic on rmmod l2tp

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Date:	Thu, 07 Jun 2012 12:42:53 +0300
From:	Denys Fedoryshchenko <denys@...p.net.lb>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	<netdev@...r.kernel.org>
Subject: Re: BUG, 3.4.1, l2tp, kernel panic on rmmod
 l2tp_eth

It is not crashing anymore, after removing tunnel, i can unload module. 
Thanks.

On 2012-06-07 12:12, Eric Dumazet wrote:
> 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);
>
>
>
> --
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---
Denys Fedoryshchenko, Network Engineer, Virtual ISP S.A.L.
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