Fixes #11766
Fixes #11769
Fixes #11767
Fixes #11770

Change-Id: I441382af58f60deb46dcdd70076763b2c47738d4
Reviewed-on: https://go-review.googlesource.com/12378Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>