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Date: Mon, 05 May 2008 18:23:49 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-core] Houston, we have a circular problem
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: Xenomai-core@domain.hid

Gilles Chanteperdrix wrote:
> On Mon, May 5, 2008 at 6:08 PM, Philippe Gerum <rpm@xenomai.org> wrote:
>>  do_schedule_event() is the culprit when it reads the pending signals on the
>>  shared queue (XNDEBUG check for rearming the timers),
> 
> A stupid suggestion: if we know that the spinlock is always locked
> when calling do_schedule_event, maybe we can simply avoid the lock
> there ?

Would be the best solution - but I don't think so. After reading a bit
more into the lockdep output, I think the issue is that _some_other_
task my hold the siglock and then acquire our rq_lock, but not
necessarily along a similar code path we took to acquire the siglock now.

Jan

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