diff --git a/lib/rake/task.rb b/lib/rake/task.rb
index 4fc1fee51..afa1b6153 100644
--- a/lib/rake/task.rb
+++ b/lib/rake/task.rb
@@ -196,7 +196,7 @@ def invoke_prerequisites_concurrently(args, invocation_chain) # :nodoc:
           application[r, @scope].invoke_with_call_chain(args, invocation_chain)
         end
       end
-      futures.each { |f| f.call }
+      futures.each { |f| f.value }
     end
 
     # Format the trace flags for display.