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Date: Mon, 21 Jan 2013 12:57:26 +0100
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] [CRITICAL PATCH] ipipe: Re-read domain context after
	IRQ processing
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Xenomai <xenomai@xenomai.org>

On 01/21/2013 12:30 PM, Jan Kiszka wrote:

> On 2013-01-18 21:09, Jan Kiszka wrote:
>> On 2013-01-18 20:04, Jan Kiszka wrote:
>>> On 2013-01-18 18:04, Jan Kiszka wrote:
>>>> On 2013-01-18 17:37, Philippe Gerum wrote:
>>>>> On 01/18/2013 04:38 PM, Jan Kiszka wrote:
>>>>>> This fixes a nasty bug on SMP boxes: We may migrate to root in the
>>>>>> context of an IRQ handler, and then also to a different CPU. Therefore,
>>>>>> we must not use domain contexts read before the invocation but update
>>>>>> them afterward or use stable information like the domain reference.
>>>>>
>>>>> Ack.
>>>>>
>>>>>>
>>>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>>>> ---
>>>>>>
>>>>>> We are still facing stalled, unkillable RT processes despite this fix,
>>>>>
>>>>> Is TASK_HARDENING still lingering in task->state despite the recent 
>>>>> switch_tail fix, or is this something different?
>>>>
>>>> Patch is applied, but I didn't check this detail yet.
>>>>
>>>> I just found a potential SMP race in schedule_linux_call, patch follows.
>>>> But now I triggered XENO_BUGON(NUCLEUS, need_resched == 0); for unknown
>>>> reasons...
>>>
>>> Probably found the problem - or at least another one: XNINLOCK must be
>>> used with xnsched::lflags, not status. It is set/cleared by the RTDM
>>> spin locks outside nklock. Will patch that and retest.
>>
>> Wasn't able to run all tests yet, but it looked promising so far. Will
>> finish this on Monday.
> 
> Looks stable now according to the testers.


Ok, we are good to go for the 2.6.2 re-release then.


-- 
                                                                Gilles.