Updates #15617

Change-Id: I2104776f8e789d987b4f2f7f08f2ebe979b747a1
Reviewed-on: https://go-review.googlesource.com/23001
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Minux Ma <minux@golang.org>