diff --git a/tests/unit/test-thread-pool.c b/tests/unit/test-thread-pool.c
index 448fbf7e5f..1483e53473 100644
--- a/tests/unit/test-thread-pool.c
+++ b/tests/unit/test-thread-pool.c
@@ -70,7 +70,7 @@ static void test_submit_aio(void)
     g_assert_cmpint(data.ret, ==, 0);
 }
 
-static void co_test_cb(void *opaque)
+static void coroutine_fn co_test_cb(void *opaque)
 {
     WorkerTestData *data = opaque;