diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index cfdce9cd252e..261e4df94d9d 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -996,6 +996,7 @@ static void __wait_for_test(struct __test_metadata *t)
 	poll_child.fd = childfd;
 	poll_child.events = POLLIN;
 	ret = poll(&poll_child, 1, t->timeout * 1000);
+	close(childfd);
 	if (ret == -1) {
 		t->exit_code = KSFT_FAIL;
 		fprintf(TH_LOG_STREAM,