diff --git a/src/crypto/internal/sysrand/rand_linux_test.go b/src/crypto/internal/sysrand/rand_linux_test.go
index 417523c29d..ab43904f91 100644
--- a/src/crypto/internal/sysrand/rand_linux_test.go
+++ b/src/crypto/internal/sysrand/rand_linux_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build cgo
+
 package sysrand_test
 
 import (