threads/101323: fork(2) in threaded programs broken.

[Daniel Eischen]

On Thu, 3 Aug 2006, Poul-Henning Kamp wrote:

> In message <Pine.GSO.4.64.0608031558540.13543 at sea.ntplx.net>, Daniel Eischen wr
> ites:
>
>
>> There's no easy way to hold all library locks.  They are
>> littered in libc and libpthread and the application doesn't
>> have access to them.  You would have to teach libc to
>> record these locks and export a function to lib<thread>
>> to lock and unlock these them.
>
> I would be perfectly happy if libpthread would just at the very
> least release the locks it specifically grabs for the fork.
>
> There's a big difference between giving it a sensible shot and
> downright sabotaging it the way we do currently.

Actually, I would prefer to emit an error message of the
form:

   "fork() from a threaded process is not defined by POSIX"

and purposefully segfault ;-)

> Anyway, apart from the view from the theoretical high ground and
> the fact that POSIX doesn't actually say anything helpful here, are
> there any objections to the fix I proposed ?

For that one specific change, no objection.  I have an
objection to enabling the NOTYET in thr_kern.c without
having an overall solution for libc as well.

-- 
DE