[ 13/53] net: l2tp: unlock socket lock before returning from l2tp_ip_sendmsg

[Ben Hutchings]

3.2.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sasha Levin <levinsasha928@xxxxxxxxx>

[ Upstream commit 84768edbb2721637620b2d84501bb0d5aed603f1 ]

l2tp_ip_sendmsg could return without releasing socket lock, making it all the
way to userspace, and generating the following warning:

[  130.891594] ================================================
[  130.894569] [ BUG: lock held when returning to user space! ]
[  130.897257] 3.4.0-rc5-next-20120501-sasha #104 Tainted: G        W
[  130.900336] ------------------------------------------------
[  130.902996] trinity/8384 is leaving the kernel with locks still held!
[  130.906106] 1 lock held by trinity/8384:
[  130.907924]  #0:  (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff82b9503f>] l2tp_ip_sendmsg+0x2f/0x550

Introduced by commit 2f16270 ("l2tp: Fix locking in l2tp_ip.c").

Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/l2tp/l2tp_ip.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 55670ec..2a2a3e7 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -441,8 +441,9 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 
 		daddr = lip->l2tp_addr.s_addr;
 	} else {
+		rc = -EDESTADDRREQ;
 		if (sk->sk_state != TCP_ESTABLISHED)
-			return -EDESTADDRREQ;
+			goto out;
 
 		daddr = inet->inet_daddr;
 		connected = 1;
-- 
1.7.10.1




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