Re: ktrace on NFSroot failing?

John Baldwin <jhb@FreeBSD.org> wrote:
> On 3/10/22 8:14 AM, Mateusz Guzik wrote:
> > On 3/10/22, Bjoern A. Zeeb <bzeeb-lists@lists.zabbadoz.net> wrote:
> >> Hi,
> >>
> >> I am having a weird issue with ktrace on an nfsroot machine:
> >>
> >> root:/tmp # ktrace sleep 1
> >> root:/tmp # kdump
> >> -559038242  Events dropped.
> >> kdump: bogus length 0xdeadc0de
> >>
> >> Anyone seen something like this before?
> >>
> >
> > I just did a quick check and it definitely fails on nfs mounts:
> > # ktrace pwd
> > /root/mjg
> > # kdump
> > -559038242  Events dropped.
> > kdump: bogus length 0xdeadc0de
> >
> > I don't have time to look into it this week though.
>
> Possibly related: core dumps are no longer working for me on NFS
> mounts.  I get a 0 byte foo.core instead of a valid core dump.
I just tried a core dump for a kernel built from main sources as of
to-day and it worked ok.

However my userland is several months old and I can't easily upgrade
it for now.

There was a recent ZFS problem that found its way into 13.0-p8 that
I'm pretty sure is fixed now. If you had a fairly recent server exporting
ZFS, that *might* explain it?

In particular, an NFSroot uses NFSv3 and nothing has changed for
NFSv3 in a looonnggg time.

rick

--
John Baldwin