diff --git a/lib/modules/Thread.pmod b/lib/modules/Thread.pmod
index 42547bae30555ad8b1858a8b1b5ae4714a7e1e8a..919c418c8ceb672776cc9f39130a492afed764ef 100644
--- a/lib/modules/Thread.pmod
+++ b/lib/modules/Thread.pmod
@@ -607,7 +607,7 @@ optional class Farm
         threads += ({ Handler() });
         free_threads += ({ threads[-1] });
       } else {
-        ft_cond->wait(mutex);
+        ft_cond->wait(lock);
       }
     }
     object(Handler) t = free_threads[0];