diff --git a/src/pkg/sync/once.go b/src/pkg/sync/once.go
index 04b714a3e74..1699e86a9eb 100644
--- a/src/pkg/sync/once.go
+++ b/src/pkg/sync/once.go
@@ -38,6 +38,6 @@ func (o *Once) Do(f func()) {
 	defer o.m.Unlock()
 	if o.done == 0 {
 		f()
-		atomic.CompareAndSwapUint32(&o.done, 0, 1)
+		atomic.StoreUint32(&o.done, 1)
 	}
 }