diff --git a/fs/aio/aio_fsync.c b/fs/aio/aio_fsync.c
index 932656bd25..9c2075a6c1 100644
--- a/fs/aio/aio_fsync.c
+++ b/fs/aio/aio_fsync.c
@@ -191,7 +191,12 @@ int aio_fsync(int op, FAR struct aiocb *aiocbp)
   FAR struct aio_container_s *aioc;
   int ret;
 
-  DEBUGASSERT(op == O_SYNC); /* || op == O_DSYNC */
+  if (op != O_SYNC)
+    {
+      set_errno(EINVAL);
+      return ERROR;
+    }
+
   DEBUGASSERT(aiocbp);
 
   /* The result -EINPROGRESS means that the transfer has not yet completed */