diff --git a/source/dnode/mgmt/mgmt_vnode/src/vmHandle.c b/source/dnode/mgmt/mgmt_vnode/src/vmHandle.c
index 35b25cb85a..2abf292e73 100644
--- a/source/dnode/mgmt/mgmt_vnode/src/vmHandle.c
+++ b/source/dnode/mgmt/mgmt_vnode/src/vmHandle.c
@@ -143,8 +143,8 @@ void vmCleanExpriedSamples(SVnodeMgmt *pMgmt) {
     }
   }
   (void)taosThreadRwlockUnlock(&pMgmt->lock);
-  taosMemoryFree(vgroup_ids);
-  taosMemoryFree(keys);
+  if (vgroup_ids) taosMemoryFree(vgroup_ids);
+  if (keys) taosMemoryFree(keys);
   return;
 }
 
diff --git a/source/libs/monitorfw/src/taos_counter.c b/source/libs/monitorfw/src/taos_counter.c
index be5e1f781f..e60e5a5f3f 100644
--- a/source/libs/monitorfw/src/taos_counter.c
+++ b/source/libs/monitorfw/src/taos_counter.c
@@ -76,15 +76,21 @@ int taos_counter_get_vgroup_ids(taos_counter_t *self, char ***keys, int32_t **vg
     return 1;
   }
   if (self->samples == NULL) return 1;
+  pthread_rwlock_rdlock(self->rwlock);
   taos_linked_list_t *key_list = self->samples->keys;
   *list_size = key_list->size;
   int r = 0;
   *vgroup_ids = (int32_t *)taos_malloc(*list_size * sizeof(int32_t));
-  if (vgroup_ids == NULL) return 1;
+  if (vgroup_ids == NULL) {
+    pthread_rwlock_unlock(self->rwlock);
+    return 1;
+  }
   *keys = (char **)taos_malloc(*list_size * sizeof(char *));
-  if (keys == NULL) return 1;
+  if (keys == NULL) {
+    pthread_rwlock_unlock(self->rwlock);
+    return 1;
+  }
   int index = 0;
-  pthread_rwlock_rdlock(self->rwlock);
   for (taos_linked_list_node_t *current_key = key_list->head; current_key != NULL; current_key = current_key->next) {
     char   *key = (char *)current_key->item;
     int32_t vgroup_id = taos_metric_formatter_get_vgroup_id(key);