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From: Tejun Heo <tj@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>, Ingo Molnar <mingo@redhat.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Yong Zhang <yong.zhang0@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: linux-next oops in __lock_acquire for process_one_work
Date: Tue, 8 May 2012 09:58:19 -0700	[thread overview]
Message-ID: <20120508165819.GB10687@google.com> (raw)
In-Reply-To: <1336482202.16236.29.camel@twins>

On Tue, May 08, 2012 at 03:03:22PM +0200, Peter Zijlstra wrote:
> I think there's a problem if indeed we do silly things like small copies
> like Hugh saw (why would gcc ever generate small copies for objects that
> are naturally aligned and naturally sized?).
> 
> Something like the below should fix that problem, but it doesn't explain
> the observed issue..

Hmmm.... Hugh, can you please verify whether this patch makes the
problem go away somehow?

> @@ -1810,7 +1810,7 @@ __acquires(&gcwq->lock)
>  	 * lock freed" warnings as well as problems when looking into
>  	 * work->lockdep_map, make a copy and use that here.
>  	 */
> -	struct lockdep_map lockdep_map = work->lockdep_map;
> +	struct lockdep_map lockdep_map = lockdep_copy_map(&work->lockdep_map);

If this is the correct fix for whatever reason, maybe we want the copy
interface to be a bit more conventional?  lockdep_copy_map(to, from)?

Thanks.

-- 
tejun

  reply	other threads:[~2012-05-08 16:58 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-07 17:19 linux-next oops in __lock_acquire for process_one_work Hugh Dickins
2012-05-07 17:57 ` Tejun Heo
2012-05-08 13:03   ` Peter Zijlstra
2012-05-08 16:58     ` Tejun Heo [this message]
2012-05-08 17:02       ` Peter Zijlstra
2012-05-08 18:11       ` Hugh Dickins
2012-05-08 22:31         ` Peter Zijlstra
2012-05-08 22:58           ` Hugh Dickins
2012-05-09  9:25             ` Ingo Molnar
2012-05-09 20:09               ` Hugh Dickins
2012-05-10 17:52                 ` Hugh Dickins
2012-05-14 21:27                   ` Tejun Heo
2012-05-15 11:11                     ` Peter Zijlstra
2012-05-15 15:10                       ` [PATCH] lockdep: fix oops in processing workqueue Tejun Heo
2012-05-15 15:29                         ` Dave Jones
2012-05-15 15:31                           ` Tejun Heo
2012-05-15 20:36                             ` Hugh Dickins
2012-05-08 18:05     ` linux-next oops in __lock_acquire for process_one_work Hugh Dickins

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