From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <4370D2B8.8070608@domain.hid>
Date: Tue, 08 Nov 2005 17:30:48 +0100
From: Jan Kiszka <kiszka@domain.hid>
MIME-Version: 1.0
Subject: Re: [Xenomai-core] [BUG] scheduling order of dying shadow threads
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To: Philippe Gerum <rpm@xenomai.org>
Cc: xenomai-core <xenomai@xenomai.org>

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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 i=
s
>> a simplified demonstration of the effect, consisting of a RTDM driver
>> and both a kernel and user space application to trigger it.
>>
>=20
> 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.
>=20

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


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