From: Pavel Machek <pavel@ucw.cz>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Berg <johannes@sipsolutions.net>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
LKML <linux-kernel@vger.kernel.org>,
pm list <linux-pm@lists.linux-foundation.org>
Subject: Re: [PATCH] Hibernation: Fix lockdep report (v2)
Date: Wed, 14 Nov 2007 22:42:00 +0000 [thread overview]
Message-ID: <20071114224200.GB7367@ucw.cz> (raw)
In-Reply-To: <200711142225.58033.rjw@sisk.pl>
On Wed 2007-11-14 22:25:57, Rafael J. Wysocki wrote:
> [Andrew, please consider this as 2.6.24 material, thanks.]
> ---
> From: Johannes Berg <johannes@sipsolutions.net>
>
> Lockdep reports a circular locking dependency in the hibernate code
> because
> - during system boot hibernate code (from an initcall) locks pm_mutex
> and then a sysfs buffer mutex via name_to_dev_t
> - during regular operation hibernate code locks pm_mutex under a
> sysfs buffer mutex because it's called from sysfs methods.
>
> The deadlock can never happen because during initcall invocation nothing
> can write to sysfs yet. This removes the lockdep report by marking the
> initcall locking as being in a different class.
>
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Pavel Machek <pavel@ucw.cz>
ACK...
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2007-11-14 21:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-14 21:25 Rafael J. Wysocki
2007-11-14 22:42 ` Pavel Machek [this message]
2007-11-14 21:54 ` Peter Zijlstra
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