6lowpan: ndisc: fix double read unlock

This patch removes a double unlock case to accessing neighbour private
data.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Aring <aar@pengutronix.de>
Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/6lowpan/ndisc.c b/net/6lowpan/ndisc.c
index ae1d4199aa4c..030504e031b6 100644
--- a/net/6lowpan/ndisc.c
+++ b/net/6lowpan/ndisc.c
@@ -135,8 +135,9 @@ static int lowpan_ndisc_opt_addr_space(const struct net_device *dev,
                         read_unlock_bh(&neigh->lock);
                         addr_space += __ndisc_opt_addr_space(IEEE802154_SHORT_ADDR_LEN, 0);
                         *ha = ha_buf;
+                } else {
+                        read_unlock_bh(&neigh->lock);
                 }
-                read_unlock_bh(&neigh->lock);
                 break;
         case NDISC_NEIGHBOUR_ADVERTISEMENT:
         case NDISC_NEIGHBOUR_SOLICITATION: