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Date: Fri, 20 Apr 2007 00:48:44 +1000
From: David Chinner <dgc@sgi.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jarek Poplawski <jarkao2@o2.pl>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -mm] workqueue: debug possible endless loop in cancel_rearming_delayed_work
Message-ID: <20070419144844.GH32602149@melbourne.sgi.com>
References: <20070419065404.GB1782@ff.dom.local> <20070419073222.GA438@elte.hu>
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On Thu, Apr 19, 2007 at 09:32:22AM +0200, Ingo Molnar wrote:
> 
> * Jarek Poplawski <jarkao2@o2.pl> wrote:
> 
> > +		int i = 1000;
> >  
> > -		while (!cancel_delayed_work(dwork))
> > +		while (!cancel_delayed_work(dwork)) {
> >  			flush_workqueue(wq);
> > +			BUG_ON(!i--);
> > +		}
> 
> if then make it a WARN_ON(). But ... dont we have the softlockup 
> detector for such cases? Does CONFIG_DETECT_SOFTLOCKUP=y give you enough 
> information?

No, you won't get a soft lockup - flush_workqueue() has a 
schedule() call in the middle of it.

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group