code review 10782044: syscall: apply go:norace to forkAndExecInChild() functions

syscall: apply go:norace to forkAndExecInChild() functions
Race instrumentation can allocate, switch stacks, preempt, etc.
All that is not allowed in between fork and exec.
Fixes issue 4840.

[dvyukov, 2013-06-29 11:57:02]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[dvyukov, 2013-06-29 12:00:30]

This depends on https://codereview.appspot.com/10783043/ which adds go:norace
annotation.

[rsc, 2013-07-01 21:53:05]

I am really unsure about this precedent. I don't want to see the library become
littered with annotations suppressing race warnings.

syscall.forkAndExecInChild is truly special. Perhaps instead of a general
annotation we can just tell the compiler to look for it.

[rsc, 2013-07-11 17:50:12]

I'd like, for now, to just look for syscall.forkAndExecInChild in
src/cmd/gc/race.c and not annotate it. Let's wait until there is more need
before defining new semantic comments.

[dvyukov, 2013-07-16 09:44:18]

On 2013/07/11 17:50:12, rsc wrote:
> I'd like, for now, to just look for syscall.forkAndExecInChild in
> src/cmd/gc/race.c and not annotate it. Let's wait until there is more need
> before defining new semantic comments.

Agree.
Sent https://codereview.appspot.com/11324044 instead.

[dvyukov, 2013-07-16 09:45:13]

*** Abandoned ***