diff --git a/lib/extensions.js b/lib/extensions.js
index 80adc40..e30c292 100644
--- a/lib/extensions.js
+++ b/lib/extensions.js
@@ -98,7 +98,7 @@ function kill(process, callback) {
 }
 
 
-function killAll(signal, callback) {
+function killAll(callback) {
   let counter = 1;
   for (let n in processes) {
     ++counter;