HADOOP-18905. Negative timeout in ZKFailovercontroller due to overflow. (#6092). Contributed by ConfX.

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/ZKFailoverController.java

@@ -660,6 +660,7 @@ public abstract class ZKFailoverController {
   private void doGracefulFailover()
       throws ServiceFailedException, IOException, InterruptedException {
     int timeout = FailoverController.getGracefulFenceTimeout(conf) * 2;
+    Preconditions.checkArgument(timeout >= 0, "timeout should be non-negative.");
     
     // Phase 1: pre-flight checks
     checkEligibleForFailover();