diff --git a/src/cfgparse.c b/src/cfgparse.c
index a6a8764..3bbb802 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -3690,7 +3690,7 @@
 					idle_conn_task->process = srv_cleanup_idle_connections;
 					idle_conn_task->context = NULL;
 					for (i = 0; i < global.nbthread; i++) {
-						idle_conn_cleanup[i] = task_new(1 << i);
+						idle_conn_cleanup[i] = task_new(1UL << i);
 						if (!idle_conn_cleanup[i])
 							goto err;
 						idle_conn_cleanup[i]->process = srv_cleanup_toremove_connections;