Index: java/org/apache/catalina/valves/AbstractAccessLogValve.java
===================================================================
--- java/org/apache/catalina/valves/AbstractAccessLogValve.java	(revision 1602359)
+++ java/org/apache/catalina/valves/AbstractAccessLogValve.java	(working copy)
@@ -628,6 +628,10 @@
          * (duration) from the interface.
          */
         long start = request.getCoyoteRequest().getStartTime();
+        if (start == -1) {
+            // Request processing has not started yet
+            log.warn("Unexpected timestamp", new Throwable());
+        }
         Date date = getDate(start + time);
 
         CharArrayWriter result = charArrayWriters.pop();