1 files changed, 6 insertions, 1 deletions
diff --git a/src/vm.c b/src/vm.c
index 9aa21eed4..e8dcf1b80 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -718,7 +718,12 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
       mrb->stack += a;
 
       if (MRB_PROC_CFUNC_P(m)) {
-	ci->nregs = n + 1;
+        if (n == CALL_MAXARGS) {
+          ci->nregs = 3;
+        }
+        else {
+          ci->nregs = n + 2;
+        }
         mrb->stack[0] = m->body.func(mrb, recv);
         mrb->arena_idx = ai;
         if (mrb->exc) goto L_RAISE;