diff --git a/src/backtrace.c b/src/backtrace.c
index 5d581dd2d..751f6ef8b 100644
--- a/src/backtrace.c
+++ b/src/backtrace.c
@@ -22,9 +22,6 @@ count_backtrace(mrb_state *mrb, ptrdiff_t ciidx)
 {
   int n = 0;
 
-  if (ciidx >= mrb->c->ciend - mrb->c->cibase)
-    ciidx = 10; /* ciidx is broken... */
-
   for (ptrdiff_t i=ciidx; i >= 0; i--) {
     mrb_callinfo *ci;
     const mrb_irep *irep = 0;
@@ -61,9 +58,6 @@ each_backtrace(mrb_state *mrb, ptrdiff_t ciidx, each_backtrace_func func, void *
 {
   uint32_t n = 0;
 
-  if (ciidx >= mrb->c->ciend - mrb->c->cibase)
-    ciidx = 10; /* ciidx is broken... */
-
   for (ptrdiff_t i=ciidx; i >= 0; i--) {
     struct backtrace_location loc;
     mrb_callinfo *ci;
@@ -135,6 +129,9 @@ packed_backtrace(mrb_state *mrb)
   int size;
   void *ptr;
 
+  if (ciidx >= mrb->c->ciend - mrb->c->cibase)
+    ciidx = mrb->c->ciend - mrb->c->cibase; /* ciidx is broken... */
+
   len = count_backtrace(mrb, ciidx);
   size = len * sizeof(struct backtrace_location);
   backtrace = mrb_data_object_alloc(mrb, NULL, NULL, &bt_type);