panic: deadlres_td_sleep_q: possible deadlock detected on RPI3

[Mark Millard]

On 2020-Jan-30, at 08:20, bob prohaska <fbsd at www.zefox.net> wrote:

> On Sun, Jan 26, 2020 at 08:42:11AM -0800, bob prohaska wrote:
>> On Sun, Jan 26, 2020 at 11:31:47AM +0100, Ralf Wenk wrote:
>>> 
>>> I got this panic two times in a row with a r357112 kernel during
>>> make installworld at the same place. So it looks like I am able to
>>> reproduce it. 
>>> 
>>> # panic: deadlres_td_sleep_q: possible deadlock detected for
>>>  0xfffffd0000f33560, blocked for 1802833 ticks
>>> 
>>> But I think it is just a symptom of the r356776 changes.
>>> 
>>>> Attempts to reboot are also rebuffed with 
>>>> cpu_reset failed
>>>> leaving a power cycle as the only option, which is new to me.
>>>> 
>>>> Does this give any hints as to what's going on?
>>> 
>>> After doing the update from r356767 to r356776 my system began to
>>> show the "cpu_reset failed" message as well.
>>> 
>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=243464
>>> 
>> 
> My Pi3 still panics at r357204, but ntp seems to work fine.

Does kldstat show mac_ntpd as loaded?

On 4 arm systems here, 2 boot loading mac_ntpd,
2 boot without loading mac_ntpd, and ntp works
for all. But this is head -r356426 .

So checking more specifically for if mac_ntpd
was loaded is apparently needed.

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=243464
is not explicit of other kernel modules load okay
when no attempt is made for mac_ntpd. (If nothing
loads automatically, it might require manually
loading something to find out.)

(I've not done anything intended to control the
mac_ntpd load behavior on any of the 4 arm systems
and do not know why there is the variation that
there is.)

> One other oddity: During the loader countdown to boot, time
> seems to run about 5x slower than it should, each second
> on the screen taking about five seconds. The string 
> deadlres_td_sleep_q turns up in sys/kern/kern_clock.c,
> might there be a connection between the panic and the
> very slow boot countdown?

Odd.


===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)