bridge: Fix null pointer dereference.

If the netdev_open() fails then iface->netdev will be NULL and
iface_refresh_stats() will cause a null pointer dereference in
netdev_get_stats().

Fixes a problem introduced by commit 1101a0b47 "bridge: Populate interface
status/statistics as soon as a port is added."

Reported-by: Aaron Rosen <arosen@clemson.edu>

diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 9354403..446f4fc 100644 (file)
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -869,7 +869,7 @@ bridge_add_ofproto_ports(struct bridge *br)
             }
 
             /* Populate stats columns in new Interface rows. */
-            if (!iface->cfg->mtu) {
+            if (iface->netdev && !iface->cfg->mtu) {
                 iface_refresh_stats(iface);
                 iface_refresh_status(iface);
             }