Re: Panic during boot (in_arpinput).

Robert Watson wrote:
> On Wed, 15 Nov 2006, Ian FREISLICH wrote:
> > Robert Watson wrote:
> >> On Wed, 15 Nov 2006, Ian FREISLICH wrote:
> >>> Ian FREISLICH wrote:
> >>>> I have 2 servers each with 255 vlan interfaces and carp
> >>>> interfaces in each vlan.During the boot up while it's configuring
> >>>> the interfaces, it reliably panics.  It boots fine if no network
> >>>> cables are plugged in (and in the test evironment on a quient
> >>>> lan).
> >>>>
> >>>> It's an SMP machine.  My guess (from the panic message below) is
> >>>> that an arp query arives on an interface it's in the middle of
> >>>> creating or something like that (highly unsophisticated debugging
> >>>> conjecture).
> >>>>
> >>>> In the mean time I'm going to try a UP kernel and see if that
> >>>> masks the problem.
> >>>
> >>> FWIW, a UP kernel has the same problem.
> >>
> >> What happens if you disable PREEMPTION on UP and try the same thing
> >> again?
> >
> > Same thing.
> >
> > If I don't assign the carp interfaces a vhid and pass at boot time,
> > it boots up OK, but I need the carp interfaces.  I can arrange
> > serial console access.  I have a similar system from ~"Tue Aug 29
> > 09:47:50 SAST 2006" that works, but I suspect it may suffer the same
> > problem.  I'm about to test this.
>
> This suggests that it is not the race I was worried it was, which is
> really good news :-). This makes me suspect a CARP-specific bug as
> opposed to the wider issue of under-synchronization of the address
> lists.

Which is what I'm beginning to suspect.  For a long time the CARP
driver was broken in -CURRENT.  IIRC commits to ipcarp.c (1.41,
1.42 maymbe a few more) around June/July this year by Sam and Max
fixed CARP interfaces, but they have subsequently fallen into
disrepair.  I don't have the knowledge to debug this further.
I do have a crashdump for further inspection though.

Ian

--
Ian Freislich