--- mtr-0.72/net.c

+++ mtr-0.72/net.c

@@ -355,7 +355,7 @@ void net_process_ping(int seq, void * addr, struct timeval now)

   totusec = (now.tv_sec  - sequence[seq].time.tv_sec ) * 1000000 +

             (now.tv_usec - sequence[seq].time.tv_usec);

-  /* impossible? if( totusec < 0 ) totusec = 0 */;

+  if (totusec < 0) totusec = 0;

   if ( addrcmp( (void *) &(host[index].addr),

 		(void *) &unspec_addr, af ) == 0 ) {