diff --git a/src/crypto/rand/rand_plan9.go b/src/crypto/rand/rand_plan9.go
index 5d0af0959e..8db19157a7 100644
--- a/src/crypto/rand/rand_plan9.go
+++ b/src/crypto/rand/rand_plan9.go
@@ -44,6 +44,7 @@ func (r *reader) Read(b []byte) (n int, err error) {
 			r.seedErr = err
 			return
 		}
+		defer entropy.Close()
 		_, r.seedErr = io.ReadFull(entropy, r.key[:])
 	})
 	if r.seedErr != nil {