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From: Rusty Russell <rusty@rustcorp.com.au>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: hang in call_usermodehelper_exec()
Date: Mon, 22 Feb 2010 10:53:32 +1030	[thread overview]
Message-ID: <201002221053.32560.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20100217202234.GD5256@x200>

On Thu, 18 Feb 2010 06:52:34 am Alexey Dobriyan wrote:
> I was stress-testing netns stuff in presence of removing modules.
> 
> Kernel is 2.6.33-rc8-next-20100217+:
> 
> At some point setkey(8) and modprobe hanged:
> 
> 3541 pts/1    D      0:00 /usr/sbin/setkey -f /root/ipcomp-tunnel.setkey
> 3737 pts/2    D      0:00 modprobe -r des_generic sha1_generic md5 hmac xfrm_user crypto_null af_packet xfrm4_mode_beet ipcomp xfrm_ipcomp  xfrm4_tunnel deflate zlib_deflate zlib_inflate esp4 xfrm4_mode_tran

Hmm, looks like sys_delete_module() is stuck trying to re-grab the
module_mutex.  But who's holding it?  We'd need a full task dump to see.

We do a stop_machine with the module mutex held, but not much else.  This
doesn't seem like that.  Do you have tracepoints, or dynamic debug enabled?

Puzzled,
Rusty.
-- 
Away travelling 25Feb-26Mar (6 .de + 1 .pl + 17 .lt + 2 .sg)

  reply	other threads:[~2010-02-22  0:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-17 20:22 hang in call_usermodehelper_exec() Alexey Dobriyan
2010-02-22  0:23 ` Rusty Russell [this message]
2010-02-22  6:19 ` Américo Wang
2010-02-22 12:04   ` Neil Horman
2010-02-23  6:49     ` Américo Wang

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