Commit 199f7d24 authored Jun 04, 2008 by James Chapman Committed by David S. Miller Jun 04, 2008

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>

parent b4496d44

drivers/net/pppol2tp.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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);

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