diff --git a/src/symbol.c b/src/symbol.c
index c247de7d..e6ae8299 100644
--- a/src/symbol.c
+++ b/src/symbol.c
@@ -1,4 +1,5 @@
 #include <string.h>
+#include <stdlib.h>
 
 #include "picrin.h"
 
@@ -12,7 +13,7 @@ pic_intern_cstr(pic_state *pic, const char *name)
 
   /* clone name string */
   len = strlen(name);
-  sym->name = (char *)pic_alloc(pic, len + 1);
+  sym->name = (char *)malloc(len + 1);
   strncpy(sym->name, name, len + 1);
 
   return pic_obj_value(sym);
diff --git a/src/vm.c b/src/vm.c
index 1603106b..439d9cd8 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -161,7 +161,7 @@ pic_codegen(pic_state *pic, pic_value obj, struct pic_env *env)
   struct pic_irep *irep;
   struct pic_code *code;
 
-  proc = pic_alloc(pic, sizeof(struct pic_proc));
+  proc = (struct pic_proc *)malloc(sizeof(struct pic_proc));
 
   proc->u.irep = irep = (struct pic_irep *)malloc(sizeof(struct pic_irep));
   irep->code = code = (struct pic_code *)malloc(sizeof(struct pic_code) * 1024);