diff --git a/smcinvoke/smcinvoke.c b/smcinvoke/smcinvoke.c
index 75b2937c7a..95798de9a9 100644
--- a/smcinvoke/smcinvoke.c
+++ b/smcinvoke/smcinvoke.c
@@ -389,6 +389,8 @@ static inline void free_mem_obj_locked(struct smcinvoke_mem_obj *mem_obj)
 				ret, dmabuf_to_free);
 	else
 		dma_buf_put(dmabuf_to_free);
+
+	mutex_lock(&g_smcinvoke_lock);
 }
 
 static void del_mem_regn_obj_locked(struct kref *kref)