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Date: Thu, 26 Jan 2012 10:39:36 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Yasunori Goto <y-goto@jp.fujitsu.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Hiroyuki KAMEZAWA <kamezawa.hiroyu@jp.fujitsu.com>,
        Motohiro Kosaki <kosaki.motohiro@jp.fujitsu.com>,
        Linux Kernel ML <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] TASK_DEAD task is able to be woken up in special condition
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* Peter Zijlstra <peterz@infradead.org> wrote:

> > It can generate delays at the exact same place, and can 
> > generate much longer delays than an SMI, if a high-prio RT 
> > task comes along.
> 
> No it can't, since do_exit() plays silly games with 
> preempt_disable().

ok, it being a critical section on both -rt and vanilla upstream 
explains it.

Thanks,

	Ingo