Fixes #11144

Change-Id: I1da0b72ef00a84c9b5751be0e72ad07d664bc98b
Reviewed-on: https://go-review.googlesource.com/10883Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>