Re: somewhat reproducable vimage panic

From: John-Mark Gurney <jmg_at_funkthat.com>
Date: Thu, 23 Jul 2020 16:49:25 -0700
Kristof Provost wrote this message on Thu, Jul 23, 2020 at 11:02 +0200:
> On 23 Jul 2020, at 11:00, Bjoern A. Zeeb wrote:
> > On 23 Jul 2020, at 8:09, Kristof Provost wrote:
> >
> >> On 23 Jul 2020, at 9:19, Kristof Provost wrote:
> >>> On 23 Jul 2020, at 0:15, John-Mark Gurney wrote:
> >>>> So, it's pretty easy to trigger, just attach a couple USB ethernet
> >>>> adapters, in my case, they were ure, but likely any two spare 
> >>>> ethernet
> >>>> interfaces will work, and wire them back to back..
> >>>>
> >>> I???ve been able to trigger it using epair as well:
> >>>
> >>> `sudo sh testinterfaces.txt epair0a epair0b`
> >>>
> >>> I did have to comment out the waitcarrier() check.
> >>>
> >> I???ve done a little bit of digging, and I think I???m starting to 
> >> see how this breaks.
> >>
> >> This always affects the jailed vlan interfaces. They???re getting 
> >> deleted, but the ifp doesn???t go away just yet because it???s still 
> >> in use by the multicast code.
> >> The multicast code does its cleanup in task queues,
> >
> > Wow, did I miss that back then? Did I review a change and not notice? 
> > Sorry if that was the case.
> >
> > Vnet teardown is blocking and forceful.
> > Doing deferred cleanup work isn???t a good idea at all.
> > I think that is the real problem here.
> >
> > I???d rather have us fix this than putting more bandaids into the 
> > code.
> >
> Yeah, agreed. I think hselasky has a better fix: 
> https://reviews.freebsd.org/D24914
> 
> I just saw his e-mail in a different thread.

I'm testing out this patch now, and let people know how it goes.. It'll
be nice to not have to worry about these panics..

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."
Received on Thu Jul 23 2020 - 21:49:35 UTC

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