Re: scratch/sigchld-fd 8f0ce42 1/2: Fix deadlock when receiving SIGCHLD during 'pselect'.

[Philipp Stephani]

Am Di., 19. Jan. 2021 um 21:46 Uhr schrieb Andreas Schwab
<schwab@linux-m68k.org>:
>
> On Jan 19 2021, Eli Zaretskii wrote:
>
> > I'd be happier if we had some direct evidence to these effects.  I'd
> > also be surprised to hear that pselect doesn't return with EINTR when
> > SIGCHLD comes in.  It is more likely that SIGCHLD is delivered before
> > we call pselect, but if that is the case, we should be able to
> > reliably detect that, I think.
>
> If you want reliable detection of SIGCHLD, you need to block the signal
> around pselect and let pselect unblock it, atomically.

Right. It looks like we're not doing that because we want to support
systems that don't have pselect (and it's gnulib emulation can't be
race-free).