svn commit: r361967 - head/sys/kern

[Mateusz Guzik]

pho@ reported triggering one of the asserts:
https://people.freebsd.org/~pho/stress/log/mjguzik028.txt

I did not have the time to properly investigate this yet and this does
not reproduce for me.

That said, I may either revert the assert (or degrade to a warning) or
add some commentary if I don't sort this out this week.

On 6/17/20, Kyle Evans <kevans at freebsd.org> wrote:
> On Tue, Jun 9, 2020 at 10:17 AM Mateusz Guzik <mjg at freebsd.org> wrote:
>>
>> Author: mjg
>> Date: Tue Jun  9 15:17:23 2020
>> New Revision: 361967
>> URL: https://svnweb.freebsd.org/changeset/base/361967
>>
>> Log:
>>   Assert on pg_jobc state.
>>
>>   Stolen from NetBSD.
>>
>> Modified:
>>   head/sys/kern/kern_proc.c
>>
>> Modified: head/sys/kern/kern_proc.c
>> ==============================================================================
>> --- head/sys/kern/kern_proc.c   Tue Jun  9 14:20:16 2020        (r361966)
>> +++ head/sys/kern/kern_proc.c   Tue Jun  9 15:17:23 2020        (r361967)
>> @@ -751,9 +751,11 @@ pgadjustjobc(struct pgrp *pgrp, int entering)
>>  {
>>
>>         PGRP_LOCK(pgrp);
>> -       if (entering)
>> +       if (entering) {
>> +               MPASS(pgrp->pg_jobc >= 0);
>>                 pgrp->pg_jobc++;
>> -       else {
>> +       } else {
>> +               MPASS(pgrp->pg_jobc > 0);
>>                 --pgrp->pg_jobc;
>>                 if (pgrp->pg_jobc == 0)
>>                         orphanpg(pgrp);
>
> We seem to be doing something wrong here, but I'm still working on
> reproducing it on a machine that actually has usable swap configured
> to get a dump. I've hit one of these asserts just from hitting the
> power button to shutoff from within xfce (hitting the latter branch
> with pgrp->pg_jobc == 0 IIRC) and another laptop panicked sometime
> overnight -- I wasn't able to catch the second one at all, because
> it's hooked up to a switch that loses its mind once that laptop
> panicks and it had to be rebooted before I could attend to it to
> revive network for the other machines on the switch.
>
> Thanks,
>
> Kyle Evans
>


-- 
Mateusz Guzik <mjguzik gmail.com>