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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>,
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	ath9k@venema.h4ckr.net, Herbert Xu <herbert@gondor.hengli.com.au>
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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