Re: kevent latch paths don't handle postmaster death well

On Thu, Oct 15, 2020 at 12:14 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Andres Freund <andres@anarazel.de> writes:
> > On 2020-10-15 11:10:28 +1300, Thomas Munro wrote:
> >> I don't think that's a problem -- the kernel will report the event to
> >> each interested kqueue object.  The attached fixes the problem for me.
>
> > Will it do so even if the kqueue is created after postmaster death?
>
> I did not try to test it, but there's code that purports to handle that
> in latch.c, ~ line 1150, and the behavior it's expecting mostly agrees
> with what I read in the macOS kevent man page.  One thing I'd suggest

Yep, I did handle the obvious races here.

> is that EACCES probably needs to be treated as "postmaster already dead",
> too, in case the PID is now owned by another user ID.

Good point.  I'll push that change later today.