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Message-ID: <4bc7ba4f.cb3cdc0a.3ebe.0678@mx.google.com>
Date: Thu, 15 Apr 2010 18:15:59 -0700 (PDT)
From: Ben Gamari <bgamari.foss@gmail.com>
Subject: Re: Lockup inside of stop_machine() during modprobe aes (was Re:
	Another AR5008 hang)
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>, linux-kernel@vger.kernel.org,
       linux-wireless@vger.kernel.org, ath9k@venema.h4ckr.net,
       Herbert Xu <herbert@gondor.hengli.com.au>
In-Reply-To: <20100415172205.c1e57636.akpm@linux-foundation.org>
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	<20100415172205.c1e57636.akpm@linux-foundation.org>
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On Thu, 15 Apr 2010 17:22:05 -0400, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Tue, 06 Apr 2010 11:08:22 -0700 (PDT) Ben Gamari <bgamari.foss@gmail.com> wrote:
> > ...
> > In particular, it seems that the kernel is deadlocking inside of
> > stop_machine() while flushing workqueues.
> > ...
> 
> My guess would be that ieee80211 is calling crypto->request_module()
> under rtnl_lock, and the fact that rtnl_lock is held is causing
> modprobe->stop_machine to not complete.
> 
> > P.S. I am now quite certain that I was mistaken in saying that 2.6.33 was
> > affected. This seems to just be a 2.6.34 issue.
> 
> OK, thanks, I'll ask Rafael and Maciej to track this as a post-2.6.33
> regression, probably wireless.

Thanks!

- Ben

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