svn commit: r361967 - head/sys/kern

[John Baldwin]

On 6/17/20 9:39 AM, Kyle Evans wrote:
> On Wed, Jun 17, 2020 at 10:21 AM Mateusz Guzik <mjguzik at gmail.com> wrote:
>>
>> 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.
>>
> 
> Ah, this is good to know that he's reproduced it. There's only so many
> places that we touch these. I can't quite envision how, but the only
> scenario this would seem to be possible in is doenterpgrp() ->
> fixjobc(p, p->p_grp, 0) -> adjusts some child with a different process
> group without actually changing it, orphans the group, then we manage
> to finalize killjobc() on a freshly-orphaned process, which hasn't had
> its p_pgrp nullified.
> 
> I haven't yet traced it through completely enough to determine if
> there's any way that can even happen.

I reproduced it three times yesterday in a head VM by exiting GDB while
it was attached to a live process (which kills the process), something like:

gdb /bin/ls
start
^D

Should be enough to reproduce.

-- 
John Baldwin