decnet: add RTNL lock when reading address list

Add missing locking in the case of auto binding to the
default device. The address list might change while this code is looking
at the list.

Compile tested only, I am not a decnet user.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index b5ef237c8a74..5790d660bc7d 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -828,13 +828,17 @@ static int dn_dev_get_first(struct net_device *dev, __le16 *addr)
         struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
         struct dn_ifaddr *ifa;
         int rv = -ENODEV;
+
         if (dn_db == NULL)
                 goto out;
+
+        rtnl_lock();
         ifa = dn_db->ifa_list;
         if (ifa != NULL) {
                 *addr = ifa->ifa_local;
                 rv = 0;
         }
+        rtnl_unlock();
 out:
         return rv;
 }