Re: PR/57504 CVS commit: src/sys/kern

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Fri, 18 Oct 2024 13:42:07 +0000
    From:        Taylor R Campbell <riastradh%NetBSD.org@localhost>
    Message-ID:  <20241018134212.9624084D09%mail.netbsd.org@localhost>

  | Some real applications might not keep track of the highest fd they set
  | in the fd_set, and just keep track of the highest fd they have ever
  | allocated seen, or just pass FD_SETSIZE.

They might, but most I have seen (which still use select, and not
poll) seem to use max_fd+1 -- probably just copying code from place
to place as is normal.

  | Surely we should have an automatic test in atf for this so can verify
  | it has been fixed in pullup too?

Yes, I was looking at doing one of those - waiting for that to happen
was partly what held up the commit for so long, I've had the code for
quite a while, & been running it for ages now.   I eventually decided
that I simply wasn't getting that written any time soon, and decided to
commit anyway.

  | I think a fix for this bug is also worth pulling up to 9 -- basic
  | central functionality like select should be reliable, not spuriously
  | hang in weird circumstances.

Perhaps - it isn't as if we have lots of bug reports about things like
that happening though do we?   It is also possible that -9 might be, or
approaching, EOL before I get around do doing any pullups - I think this
needs a long gestation in HEAD, just because this code is likely to be
exercised very rarely - if there is something not quite right it might
take a long time to reveal itself.

kre