diff --git a/mrbgems/mruby-io/src/io.c b/mrbgems/mruby-io/src/io.c
index 9add9be3a..d4d268350 100644
--- a/mrbgems/mruby-io/src/io.c
+++ b/mrbgems/mruby-io/src/io.c
@@ -813,6 +813,7 @@ io_get_read_fptr(mrb_state *mrb, mrb_value self)
 static mrb_value
 io_check_readable(mrb_state *mrb, mrb_value self)
 {
+  mrb->c->ci->mid = 0;
   io_get_read_fptr(mrb, self);
   return mrb_nil_value();
 }