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Date: Sat, 7 Jul 2007 09:56:30 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alan Stern <stern@rowland.harvard.edu>, Paul Mackerras <paulus@samba.org>,
       Johannes Berg <johannes@sipsolutions.net>,
       "Rafael J. Wysocki" <rjw@sisk.pl>,
       Linux-pm mailing list <linux-pm@lists.linux-foundation.org>,
       Kernel development list <linux-kernel@vger.kernel.org>,
       Matthew Garrett <mjg59@srcf.ucam.org>
Subject: Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway
Message-ID: <20070707075630.GC2638@elf.ucw.cz>
References: <Pine.LNX.4.44L0.0707051014180.3728-100000@iolanthe.rowland.org> <1183676393.3388.89.camel@localhost.localdomain>
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Hi!

> > How will that help?  Block the kernel thread in the freezer or block it 
> > in the driver -- either way it is blocked.  So how do your deadlocks 
> > get resolved?
> 
> Because nobody is waiting on that kernel thread anyway without a freezer
> so there is no deadlock anymore.

In the deadlock we are seeing, _someone_ is waiting on userspace
thread, that leads to deadlock with freezer. We don't know who,
because we have not seen the sysrq-t dumps.

The "unknown who" will deadlock on fused frozen by driver, too. We
really need to fix the "unknown who" here.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html