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Date: Wed, 4 Aug 2004 10:50:58 -0400 (EDT)
From: Zwane Mwaikambo <zwane@linuxpower.ca>
To: Nathan Lynch <nathanl@austin.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>, V Srivatsa <vatsa@in.ibm.com>,
       Joel Schopp <jschopp@austin.ibm.com>,
       Rusty Russell <rusty@rustcorp.com.au>,
       lkml <linux-kernel@vger.kernel.org>,
       Nick Piggin <nickpiggin@yahoo.com.au>, Con Kolivas <kernel@kolivas.org>
Subject: Re: CPU hotplug broken in 2.6.8-rc2 ?
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On Tue, 3 Aug 2004, Nathan Lynch wrote:

>                 __setscheduler(rq->idle, SCHED_NORMAL, 0);
>                 task_rq_unlock(rq, &flags);
>                 BUG_ON(rq->nr_running != 0);
>
> I can reproduce this on both ppc64 and i386.  Does anyone know why this
> is happening?
>
> If I remove the BUG_ON, things seem to go ok, but I doubt that's the
> right thing to do.

It could have something to do with the staircase scheduler, Con, got any
wise words?