1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index 71add7a8d53c..be1ed38cdcfd 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -575,8 +575,11 @@ void ipoib_mcast_join_task(struct work_struct *work)
 
         priv->mcast_mtu = IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
 
-        if (!ipoib_cm_admin_enabled(dev))
+        if (!ipoib_cm_admin_enabled(dev)) {
+                rtnl_lock();
                 dev->mtu = min(priv->mcast_mtu, priv->admin_mtu);
+                rtnl_unlock();
+        }
 
         ipoib_dbg_mcast(priv, "successfully joined all multicast groups\n");