diff --git a/qemu/util/qemu-thread-win32.c b/qemu/util/qemu-thread-win32.c
index 2035ddac..3a85e6a4 100644
--- a/qemu/util/qemu-thread-win32.c
+++ b/qemu/util/qemu-thread-win32.c
@@ -97,7 +97,9 @@ void *qemu_thread_join(QemuThread *thread)
     ret = data->ret;
     assert(data->mode != QEMU_THREAD_DETACHED);
     DeleteCriticalSection(&data->cs);
+    data->uc->qemu_thread_data = NULL;
     g_free(data);
+    data = NULL;
     return ret;
 }
 
diff --git a/uc.c b/uc.c
index 19aedaee..348e47c1 100644
--- a/uc.c
+++ b/uc.c
@@ -310,7 +310,7 @@ uc_err uc_close(uc_engine *uc)
 
     // Thread relateds.
     if (uc->qemu_thread_data)
-        free(uc->qemu_thread_data);
+        g_free(uc->qemu_thread_data);
 
     // Other auxilaries.
     free(uc->l1_map);