BBB boot failure between r366365 and r366386

[Ed Maste]

On Tue, 6 Oct 2020 at 14:59, Ed Maste <emaste at freebsd.org> wrote:
>
> On Mon, 5 Oct 2020 at 15:56, Ed Maste <emaste at freebsd.org> wrote:
> >
> >   On Mon, 5 Oct 2020 at 09:53, Ed Maste <emaste at freebsd.org> wrote:
> > >
> > > Sometime after r366365 and up to r366365 BBB stopped booting in the HW
> > > test environment.
> >
> > That should of course be after r366365 and up to (and including)
> > r366386.
>
> Discussed on IRC; the second U-Boot banner comes out ~60s after the
> first, which might suggest a watchdog timeout.
>
> We seem to get stuck after
> > random: unblocking device.

kevans points out that std.armv7 includes VERBOSE_SYSINIT=0, so
verbose sysinits are available with a loader tunable. We get this far:

subsystem 2140000
   init_hwpmc(0)... done.
   init_dtrace(0)... done.
   pmc_soft_ev_register(&pmc___lock_failed)... done.
   pmc_soft_ev_register(&pmc___clock_prof)... done.
   pmc_soft_ev_register(&pmc___clock_hard)... done.
   pmc_soft_ev_register(&pmc___clock_stat)... done.
subsystem 2160000
   random_fortuna_init_alg(0)... done.
   random_harvestq_init(0)... done.
   random_harvestq_prime(0)... done.
   __stack_chk_init(0)... random: unblocking device.
done.
subsystem 2180000
   mac_init(0)... done.
subsystem 21d0000
   mac_late_init(0)... done.
subsystem 21e0000
   vnet0_init(0)... done.
subsystem 2200000
   proc0_init(0)... done.
   shutdown_conf(0)... done.
subsystem 2300000
   vm_stats_init(0)... done.
   uma_startup3(0)... done.
   vm_page_init_cache_zones(0)... done.
subsystem 2380000
   db_capture_sysinit(0)... done.
subsystem 2400000
   sched_setup(0)... done.
subsystem 2480000
   ktrace_init(0)...