diff --git a/patch-control.sh b/patch-control.sh
index 195b8b8d551dbc45345baf93bb03158cc6074bec..7983699a743b3323d7026392dc39797c788d394d 100644
--- a/patch-control.sh
+++ b/patch-control.sh
@@ -29,9 +29,12 @@ function on_exit() {
     rm_lock
   fi
 
+  local pid
+
   for pid in ${PROCS[*]}; do
     kill -9 ${pid}
   done
+  unset pid
 }
 
 function createList() {