diff --git a/src/opr/impl/tensor_manip.cpp b/src/opr/impl/tensor_manip.cpp
index 03e453bc..9cbae01e 100644
--- a/src/opr/impl/tensor_manip.cpp
+++ b/src/opr/impl/tensor_manip.cpp
@@ -1410,8 +1410,11 @@ SymbolVar ParamPackConcat::make(const SmallVector<SymbolVar>& inp,
 void ParamPackConcat::scn_do_execute() {
     mgb_assert(m_opr.comp_node() == comp_node());
     auto&& inputs = input();
-    m_inp_ptr.resize(inputs.size() - 1);
-    auto ptr = m_inp_ptr.data();
+    if (!m_inp_ptr) {
+        void** raw_inp_ptr = (void**)comp_node().alloc_host(sizeof(void*)*inputs.size());
+        m_inp_ptr = {raw_inp_ptr, [comp_node=comp_node()](void** ptr){comp_node.free_host(ptr);}};
+    }
+    auto ptr = m_inp_ptr.get();
     for (size_t i = 0; i < inputs.size() - 1; i++) {
         ptr[i] = inputs[i]->dev_tensor().as_megdnn().raw_ptr;
     }
diff --git a/src/opr/include/megbrain/opr/tensor_manip.h b/src/opr/include/megbrain/opr/tensor_manip.h
index dd3713e3..74d4f2ed 100644
--- a/src/opr/include/megbrain/opr/tensor_manip.h
+++ b/src/opr/include/megbrain/opr/tensor_manip.h
@@ -544,7 +544,7 @@ MGB_DEFINE_OPR_CLASS(Concat, cg::SingleCNOutshapePureByInshapeOprBase) // {
  */
 MGB_DEFINE_OPR_CLASS(ParamPackConcat, cg::SingleCNOperatorNodeBase) // {
     //! input pointer buffer
-    SmallVector<void*> m_inp_ptr;
+    std::shared_ptr<void*> m_inp_ptr;
     std::vector<dt_int32> m_offsets;
     intl::UniqPtrWithCN<megdnn::ParamPackConcat> m_opr;