document and partially fix a race
document and partially fix a race

R=r
DELTA=24  (21 added, 0 deleted, 3 changed)
OCL=27527
CL=27527

dsriram/golang,nightlyone/golang,gnanderson/go,bdwalton/debian-golang,gnanderson/go,tianon/debian-golang,pombredanne/go-deleteme,wesolows/golang,h8liu/golang,firebitsbr/golang-old,ssrl/go,tv42/old-go,dsriram/golang,ssrl/go,apparentlymart/golang,h8liu/golang,wesolows/golang-old,bdwalton/debian-golang,wesolows/golang,tv42/old-go,firebitsbr/golang-old,nightlyone/golang,firebitsbr/golang-old,wesolows/golang,ssrl/go,firebitsbr/golang-old,dsriram/golang,apparentlymart/golang,nightlyone/golang,wesolows/golang,wesolows/golang-old,dsriram/golang,nightlyone/golang,gnanderson/go,tv42/old-go,wesolows/golang,tv42/old-go,gnanderson/go,bdwalton/debian-golang,tianon/debian-golang,gnanderson/go,gnanderson/go,wesolows/golang-old,bdwalton/debian-golang,wesolows/golang-old,pombredanne/go-deleteme,pombredanne/go-deleteme,firebitsbr/golang-old,dsriram/golang,firebitsbr/golang-old,dsriram/golang,pombredanne/go-deleteme,apparentlymart/golang,tianon/debian-golang,h8liu/golang,wesolows/golang-old,tianon/debian-golang,apparentlymart/golang,wesolows/golang-old,gnanderson/go,bdwalton/debian-golang,tianon/debian-golang,tianon/debian-golang,tianon/debian-golang,h8liu/golang,tv42/old-go,nightlyone/golang,tv42/old-go,ssrl/go,apparentlymart/golang,h8liu/golang,h8liu/golang,pombredanne/go-deleteme,bdwalton/debian-golang,pombredanne/go-deleteme,h8liu/golang,wesolows/golang,apparentlymart/golang,tv42/old-go,firebitsbr/golang-old,bdwalton/debian-golang,tianon/debian-golang,nightlyone/golang,pombredanne/go-deleteme,firebitsbr/golang-old,ssrl/go,dsriram/golang,nightlyone/golang,ssrl/go,ssrl/go,apparentlymart/golang,wesolows/golang-old,bdwalton/debian-golang,wesolows/golang