runtime/race: race detector not detecting data race when mutex is used

[sarathsp06]

What version of Go are you using (go version)?

go version go1.6.4 linux/amd64

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/sarath/go"
GORACE=""
GOROOT="/home/sarath/goroot"
GOTOOLDIR="/home/sarath/goroot/pkg/tool/linux_amd64"
GO15VENDOREXPERIMENT="1"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

What did you do?

I tried making a go program that has two routines runnig that writes to and read from a variable . The writes and read were protected by locks ,but since locks does not guarantee order of execution data race could happen . The race detector is not detecting that

Here is play link : https://play.golang.org/p/MGpRIkE2-L

What did you expect to see?

Data race error stack

What did you see instead?

No data race detected though it occured

[dgryski]

/cc @dvyukov

[ALTree]

There's no race on l (i.e. two or more threads accessing l concurrently, at least one on write); the fact that the order of execution of the goroutines is not guaranteed is not a data race.

[dvyukov]

This is not a data race, this is a high-level logical race. The race detector detects only data races.
Most logical races are intentional and it is not possible to distinguish between intentional and harmful unintentional races.
WAI