diff --git a/block/throttle.c b/block/throttle.c
index 6e8d52fa2451..ddd450593ade 100644
--- a/block/throttle.c
+++ b/block/throttle.c
@@ -162,7 +162,7 @@ static int coroutine_fn throttle_co_pwritev_compressed(BlockDriverState *bs,
                                BDRV_REQ_WRITE_COMPRESSED);
 }
 
-static int throttle_co_flush(BlockDriverState *bs)
+static int coroutine_fn throttle_co_flush(BlockDriverState *bs)
 {
     return bdrv_co_flush(bs->file->bs);
 }