Re: [Xenomai-core] [BUG] scheduling order of dying shadow threads

[Jan Kiszka <kiszka@domain.hid>]

[-- Attachment #1: Type: text/plain, Size: 1222 bytes --]

Philippe Gerum wrote:
> Jan Kiszka wrote:
>> Hi Philippe,
>>
>> I think this one is for you: ;)
>>
>> Sebastian got almost mad with his CAN driver while tracing a strange
>> scheduling behaviour during shadow thread deletion for several days(!) -
>> and I was right on the way to follow him yesterday evening. Attached is
>> a simplified demonstration of the effect, consisting of a RTDM driver
>> and both a kernel and user space application to trigger it.
>>
> 
> I've spotted the issue in nucleus/shadow.c. Basically, the root thread
> priority boost was leaking to a non-shadow thread due to a missing
> priority reset in the lostage APC handler, whilst a shadow was in the
> process of relaxing. Really funky bug, thanks! :o> Fixed in the repo
> hopefully for good. The scheduling sequence is now correct with your
> demo app on my box.
> 

Yep, looks good here as well. Great and quick work! Just don't expect
that someone can follow your explanations easily. :)

I think this issue has some similarity with the one I once stumbled over
regarding non-RT signalling to Linux. I'm not going to repeat my general
concerns regarding the priority boosting of the root thread now... ;)

Jan


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 250 bytes --]