diff --git a/include/cubescript/cubescript.hh b/include/cubescript/cubescript.hh
index 3dd12b9b..cfb4ec6c 100644
--- a/include/cubescript/cubescript.hh
+++ b/include/cubescript/cubescript.hh
@@ -363,6 +363,14 @@ enum class CsLoopState {
     Normal = 0, Break, Continue
 };
 
+static inline void *cs_default_alloc(void *, void *p, ostd::Size, ostd::Size ns) {
+    if (!ns) {
+        delete[] static_cast<unsigned char *>(p);
+        return nullptr;
+    }
+    return new unsigned char[ns];
+}
+
 struct OSTD_EXPORT CsState {
     friend struct CsErrorException;
     friend struct GenState;
@@ -372,7 +380,7 @@ struct OSTD_EXPORT CsState {
 
     int identflags = 0;
 
-    CsState(CsAllocCb func = nullptr, void *data = nullptr);
+    CsState(CsAllocCb func = cs_default_alloc, void *data = nullptr);
     virtual ~CsState();
 
     CsHookCb set_call_hook(CsHookCb func);
@@ -563,9 +571,6 @@ private:
     GenState *p_pstate = nullptr;
     int p_inloop = 0;
 
-    CsAllocCb p_allocf;
-    void *p_aptr;
-
     char p_errbuf[512];
 
     CsHookCb p_callhook;
diff --git a/src/cs_vm.hh b/src/cs_vm.hh
index b53ca106..111b49ab 100644
--- a/src/cs_vm.hh
+++ b/src/cs_vm.hh
@@ -97,6 +97,8 @@ enum {
 struct CsSharedState {
     CsMap<ostd::ConstCharRange, CsIdent *> idents;
     CsVector<CsIdent *> identmap;
+    CsAllocCb allocf;
+    void *aptr;
 };
 
 struct CsBreakException {
diff --git a/src/cubescript.cc b/src/cubescript.cc
index 6424bcec..04104bd8 100644
--- a/src/cubescript.cc
+++ b/src/cubescript.cc
@@ -287,10 +287,20 @@ int CsCommand::get_num_args() const {
 void cs_init_lib_base(CsState &cs);
 
 CsState::CsState(CsAllocCb func, void *data):
-    p_state(nullptr),
-    p_allocf(func), p_aptr(data), p_callhook()
+    p_state(nullptr), p_callhook()
 {
-    p_state = create<CsSharedState>();
+    if (!func) {
+        func = cs_default_alloc;
+    }
+    /* allocator is not set up yet, use func directly */
+    p_state = static_cast<CsSharedState *>(
+        func(data, nullptr, 0, sizeof(CsSharedState))
+    );
+    new (p_state) CsSharedState();
+    /* set up allocator, from now we can call into alloc() */
+    p_state->allocf = func;
+    p_state->aptr = data;
+
     for (int i = 0; i < MaxArguments; ++i) {
         char buf[32];
         snprintf(buf, sizeof(buf), "arg%d", i + 1);
@@ -415,14 +425,7 @@ CsHookCb &CsState::get_call_hook() {
 }
 
 void *CsState::alloc(void *ptr, ostd::Size os, ostd::Size ns) {
-    if (p_allocf) {
-        return p_allocf(p_aptr, ptr, os, ns);
-    }
-    if (!ns) {
-        delete[] static_cast<unsigned char *>(ptr);
-        return nullptr;
-    }
-    return new unsigned char[ns];
+    return p_state->allocf(p_state->aptr, ptr, os, ns);
 }
 
 void CsState::clear_override(CsIdent &id) {