linux-kernel - Re: [PATCH] dio: remove bogus refcounting BUG

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Date:	Thu, 05 Jul 2007 10:16:59 -0700
From:	Badari Pulavarty <pbadari@...ibm.com>
To:	Zach Brown <zach.brown@...cle.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dio: remove bogus refcounting BUG_ON

On Thu, 2007-07-05 at 10:11 -0700, Zach Brown wrote:
> > the BUG_ON(). But unfortunately, our perf. team is able reproduce the
> > problem.
> 
> What are they doing to reproduce it?  How much setup does it take?

Huge OLTP run :(

> 
> > Debug indicated that, the ret2 == 1 :(
> 
> That could be consistent with the theory that we're racing with the  
> dio struct being freed and reused before it's tested in the BUG_ON()  
> condition.  Suparna's suggestion to sample dio->is_async before  
> releasing the refcount and using that in the BUG_ON condition is a  
> good one.

I will ask them to try that.

Thanks,
Badari

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