Re: Missing patch from stable [6/7]

[James Chapman <jchapman@katalix.com>]

Willy Tarreau wrote:
> Hi,
> 
> this patch from mainline seems suitable for -stable, but was not proposed
> for inclusion. I think we should include it for next review unless the
> author disagrees.

OK by me.

> 
> Thanks,
> Willy
> --
> 
>>From 199f7d24ae59894243687a234a909f44a8724506 Mon Sep 17 00:00:00 2001
> From: James Chapman <jchapman@katalix.com>
> Date: Wed, 4 Jun 2008 15:07:32 -0700
> Subject: lt2p: Fix possible WARN_ON from socket code when UDP socket is closed
> 
> If an L2TP daemon closes a tunnel socket while packets are queued in
> the tunnel's reorder queue, a kernel warning is logged because the
> socket is closed while skbs are still referencing it. The fix is to
> purge the queue in the socket's release handler.
> 
> WARNING: at include/net/sock.h:351 udp_lib_unhash+0x41/0x68()
> Pid: 12998, comm: openl2tpd Not tainted 2.6.25 #8
>  [<c0423c58>] warn_on_slowpath+0x41/0x51
>  [<c05d33a7>] udp_lib_unhash+0x41/0x68
>  [<c059424d>] sk_common_release+0x23/0x90
>  [<c05d16be>] udp_lib_close+0x8/0xa
>  [<c05d8684>] inet_release+0x42/0x48
>  [<c0592599>] sock_release+0x14/0x60
>  [<c059299f>] sock_close+0x29/0x30
>  [<c046ef52>] __fput+0xad/0x15b
>  [<c046f1d9>] fput+0x17/0x19
>  [<c046c8c4>] filp_close+0x50/0x5a
>  [<c046da06>] sys_close+0x69/0x9f
>  [<c04048ce>] syscall_call+0x7/0xb
> 
> Signed-off-by: James Chapman <jchapman@katalix.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  drivers/net/pppol2tp.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
> index 8db342f..04c7e5b 100644
> --- a/drivers/net/pppol2tp.c
> +++ b/drivers/net/pppol2tp.c
> @@ -1279,6 +1279,7 @@ out:
>  static int pppol2tp_release(struct socket *sock)
>  {
>  	struct sock *sk = sock->sk;
> +	struct pppol2tp_session *session;
>  	int error;
>  
>  	if (!sk)
> @@ -1296,9 +1297,18 @@ static int pppol2tp_release(struct socket *sock)
>  	sock_orphan(sk);
>  	sock->sk = NULL;
>  
> +	session = pppol2tp_sock_to_session(sk);
> +
>  	/* Purge any queued data */
>  	skb_queue_purge(&sk->sk_receive_queue);
>  	skb_queue_purge(&sk->sk_write_queue);
> +	if (session != NULL) {
> +		struct sk_buff *skb;
> +		while ((skb = skb_dequeue(&session->reorder_q))) {
> +			kfree_skb(skb);
> +			sock_put(sk);
> +		}
> +	}
>  
>  	release_sock(sk);
>  


-- 
James Chapman
Katalix Systems Ltd
http://www.katalix.com
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