Re: ntpd fails on recent -current/arm64

On Sun, Apr 23, 2023 at 07:34:45AM -0500, Mike Karels wrote:
> On 23 Apr 2023, at 6:47, Peter Jeremy wrote:
> 
> > Somewhere between c283016-g607bc91d90a3 and c283077-g7f658f99f7ed,
> > some change in the kernel has made ntpd stop working on my arm64 test
> > box.  (My amd64 test box is a couple of days behind so I'm not sure if
> > it's arm-specific).
> >
> > What I've identified so far:
> > * The problem is in the kernel, not userland.
> > * The impact seems to be limited to ntpd (in particular, ntpdate works).
> > * ntpd appears to be correctly exchanging NTP packets with peers.
> > * ntpd is not responding to "ntpq -p" queries
> > * ntp_gettime and ntp_adjtime both return TIME_ERROR to ntptime
> 
> I updated an amd64 system yesterday, and it is broken too.
> 
> > I've looked through the commits and, beyond much of netinet being
> > roto-tilled, I can't see anything obvious.
> 
> The netinet changes seem likely to be the culprit.  ntpd seems to
> be receiving the requests but isn’t responding.  Trivial testing
> indicates that named is working, so UDP isn’t completely broken.
> 
> > Is anyone else seeing anything similar?  Can anyone suggest where
> > to look next?
> 
> Mark may have an idea.  Finding a simpler example would be helpful,
> but I’m not sure what we’re looking for.

I can reproduce the problem.  A small example would still be useful, so
that we can turn it into a regression test case.