Panic: 12.2 fails to use VIMAGE jails

[Kristof Provost]

On 7 Dec 2020, at 13:54, Peter wrote:
> After clean upgrade (from source) from 11.4 to 12.2-p1 my jails do
> no longer work correctly.
>
> Old-fashioned jails seem to work, but most are VIMAGE+NETGRAPH style,
> and do not work properly.
> All did work flawlessly for nearly a year with Rel.11.
>
> If I start 2-3 jails, and then stop them again, there is always a
> panic.
> Also reproducible with GENERIC kernel.
>
> Can this be fixed, or do I need to revert to 11.4?
>
> The backtrace looks like this:
>
> #4 0xffffffff810bbadf at trap_pfault+0x4f
> #5 0xffffffff810bb23f at trap+0x4cf
> #6 0xffffffff810933f8 at calltrap+0x8
> #7 0xffffffff80cdd555 at _if_delgroup_locked+0x465
> #8 0xffffffff80cdbfbe at if_detach_internal+0x24e
> #9 0xffffffff80ce305c at if_vmove+0x3c
> #10 0xffffffff80ce3010 at vnet_if_return+0x50
> #11 0xffffffff80d0e696 at vnet_destroy+0x136
> #12 0xffffffff80ba781d at prison_deref+0x27d
> #13 0xffffffff80c3e38a at taskqueue_run_locked+0x14a
> #14 0xffffffff80c3f799 at taskqueue_thread_loop+0xb9
> #15 0xffffffff80b9fd52 at fork_exit+0x82
> #16 0xffffffff8109442e at fork_trampoline+0xe
>
> This is my typical jail config, designed and tested with Rel.11:
>
That smells a lot like the epair/vnet issues in bugs 238870, 234985, 
244703, 250870.
I pushed a fix for that in CURRENT in r368237. It’s scheduled to go 
into stable/12 sometime next week, but it’d be good to know that it 
fixes your problem too before I merge it.
In other words: can you test a recent CURRENT? It’s likely fixed 
there, and if it’s not I may be able to fix it quickly.

Best regards,
Kristof