From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 21 Jan 2002 21:11:57 +0000
Subject: Re: [Linux-ia64] Help with Ingo scheduler on IA64
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To: linux-ia64@vger.kernel.org

On Mon, 21 Jan 2002, Erich Focht wrote:

> what's the problem with the following code?
>
> switch_tasks:
> 	prev->need_resched = 0;
>
> 	if (likely(prev != next)) {
> 		rq->nr_switches++;
> 		rq->curr = next;
> 		spin_unlock_irq(&rq->lock);          // <-
> 		context_switch(prev, next, 0);

the runqueue must not be unlocked before the current task is completely
inactive - otherwise another CPU could grab (or even free) this task.

	Ingo