Index: kernel/generic/src/ipc/ipc.c
===================================================================
--- kernel/generic/src/ipc/ipc.c	(revision 201abde2f6d30f23f1aab2b46d1a55da556278f1)
+++ kernel/generic/src/ipc/ipc.c	(revision b8f11baa46965e8fdd2b64a92dc659e89c8b5243)
@@ -164,5 +164,5 @@
 	list_append(&call->link, &callerbox->answers);
 	spinlock_unlock(&callerbox->lock);
-	waitq_wakeup(&callerbox->wq, 0);
+	waitq_wakeup(&callerbox->wq, WAKEUP_FIRST);
 }
 
@@ -206,5 +206,5 @@
 	list_append(&call->link, &box->calls);
 	spinlock_unlock(&box->lock);
-	waitq_wakeup(&box->wq, 0);
+	waitq_wakeup(&box->wq, WAKEUP_FIRST);
 }