diff --git a/include/mruby/dump.h b/include/mruby/dump.h
index fea0ac2b1..20400714c 100644
--- a/include/mruby/dump.h
+++ b/include/mruby/dump.h
@@ -30,6 +30,7 @@ mrb_irep *mrb_read_irep_file(mrb_state*, FILE*);
 MRB_API mrb_value mrb_load_irep_file(mrb_state*,FILE*);
 MRB_API mrb_value mrb_load_irep_file_cxt(mrb_state*, FILE*, mrbc_context*);
 #endif
+/* avoid mrb_read_irep(); use mrb_read_irep_buf() instead (may cause buffer overflow) */
 MRB_API mrb_irep *mrb_read_irep(mrb_state*, const uint8_t*);
 MRB_API mrb_irep *mrb_read_irep_buf(mrb_state*, const void*, size_t);
 
diff --git a/include/mruby/irep.h b/include/mruby/irep.h
index 8382c3b18..ff78c1857 100644
--- a/include/mruby/irep.h
+++ b/include/mruby/irep.h
@@ -99,7 +99,7 @@ MRB_API mrb_value mrb_load_irep(mrb_state*, const uint8_t*);
 
 /*
  * @param [const void*] irep code
- * @param [size_t] size of irep buffer. If -1 is given, it is considered unrestricted.
+ * @param [size_t] size of irep buffer.
  */
 MRB_API mrb_value mrb_load_irep_buf(mrb_state*, const void*, size_t);
 
@@ -108,7 +108,7 @@ MRB_API mrb_value mrb_load_irep_cxt(mrb_state*, const uint8_t*, mrbc_context*);
 
 /*
  * @param [const void*] irep code
- * @param [size_t] size of irep buffer. If -1 is given, it is considered unrestricted.
+ * @param [size_t] size of irep buffer.
  */
 MRB_API mrb_value mrb_load_irep_buf_cxt(mrb_state*, const void*, size_t, mrbc_context*);