r = -ENOIOCTLCMD;
        break;
      }
      err = sock-&gt;ops-&gt;gettstamp(sock, argp,
               cmd == SIOCGSTAMP_OLD,
               !IS_ENABLED(CONFIG_64BIT));
+    break;
    case SIOCGSTAMP_NEW:
    case SIOCGSTAMPNS_NEW:
      ...
      break;
</code></pre>
<p>To address this error-prone situation,
GCC introduces a compilation warning 
on an implicit use of case fall through 
(i.e., <code>-Wimplicit-fallthrough</code>):
to avoid the warning of the fall through case,
developers should <em>exp