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Date: Thu, 04 Apr 2002 12:02:46 -0800
From: george anzinger <george@mvista.com>
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To: Dave Hansen <haveblue@us.ibm.com>
CC: Robert Love <rml@tech9.net>, Linus Torvalds <torvalds@transmeta.com>,
        "Adam J. Richter" <adam@yggdrasil.com>, linux-kernel@vger.kernel.org
Subject: Re: Patch: linux-2.5.8-pre1/kernel/exit.c change caused BUG() atboot 
 time
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Dave Hansen wrote:
> 
> Robert Love wrote:
> >       tsk->exit_code = code;
> >       exit_notify();
> > +     preempt_enable_no_resched();
>        * PREEMPT HERE *
> >       schedule();
> >       BUG();
> 
> Isn't there still a race here?  A preempt CAN happen after you reenable,
> right?  Admittedly, its a small window, but it _is_ a window.

Right, eliminate this line.  Since the task is going away it doesn't
matter.  Actually it doesn't matter even if schedule() returns (i.e. for
other than ZOMBIE) as long as preempt is enabled after the schedule()
call, somewhere.  It is designed to work this way for a reason, this
being one of them.

-g
> 
> --
> Dave Hansen
> haveblue@us.ibm.com
> 
> -
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-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Real time sched:  http://sourceforge.net/projects/rtsched/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
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