If, for some reason, a netdev has no debugfs dir, we shouldn't
try to rename that dir.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
 
        sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-       sprintf(buf, "netdev:%s", dev->name);
        dir = sdata->debugfsdir;
+
+       if (!dir)
+               return 0;
+
+       sprintf(buf, "netdev:%s", dev->name);
        if (!debugfs_rename(dir->d_parent, dir, dir->d_parent, buf))
                printk(KERN_ERR "mac80211: debugfs: failed to rename debugfs "
                       "dir to %s\n", buf);