diff --git a/layers/threading.h b/layers/threading.h
index 3188161..9617539 100644
--- a/layers/threading.h
+++ b/layers/threading.h
@@ -193,6 +193,11 @@
     std::vector<VkDebugReportCallbackEXT> logging_callback;
     VkLayerDispatchTable *device_dispatch_table;
     VkLayerInstanceDispatchTable *instance_dispatch_table;
+    // The following are for keeping track of the temporary callbacks that can
+    // be used in vkCreateInstance and vkDestroyInstance:
+    uint32_t num_tmp_callbacks;
+    VkDebugReportCallbackCreateInfoEXT *tmp_dbg_create_infos;
+    VkDebugReportCallbackEXT *tmp_callbacks;
     counter<VkCommandBuffer> c_VkCommandBuffer;
     counter<VkDevice> c_VkDevice;
     counter<VkInstance> c_VkInstance;
@@ -223,7 +228,8 @@
     counter<uint64_t> c_uint64_t;
 #endif // DISTINCT_NONDISPATCHABLE_HANDLES
     layer_data()
-        : report_data(nullptr), c_VkCommandBuffer("VkCommandBuffer", VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_BUFFER_EXT),
+        : report_data(nullptr), num_tmp_callbacks(0), tmp_dbg_create_infos(nullptr), tmp_callbacks(nullptr),
+          c_VkCommandBuffer("VkCommandBuffer", VK_DEBUG_REPORT_OBJECT_TYPE_COMMAND_BUFFER_EXT),
           c_VkDevice("VkDevice", VK_DEBUG_REPORT_OBJECT_TYPE_DEVICE_EXT),
           c_VkInstance("VkInstance", VK_DEBUG_REPORT_OBJECT_TYPE_INSTANCE_EXT),
           c_VkQueue("VkQueue", VK_DEBUG_REPORT_OBJECT_TYPE_QUEUE_EXT),