net: l2tp: unlock socket lock before returning from l2tp_ip_sendmsg

BugLink: http://bugs.launchpad.net/bugs/1002880

[ 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@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 858ca23aa6d..ea52d028632 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;