diff --git a/server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java b/server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java
index 30805d67e7fe3..477a1d07b3569 100644
--- a/server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java
+++ b/server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java
@@ -310,7 +310,7 @@ protected void fork(final Runnable runnable) {
         executor.execute(new AbstractRunnable() {
             @Override
             public void onFailure(Exception e) {
-                assert false : "Unexpected failure";
+                assert false : new AssertionError(e);
             }
 
             @Override