Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex and tz->lock

From	Jiri Kosina <jikos@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex and tz->lock
Date	2017-08-03 13:40 +0200
Message-ID	<uamDU-7Ls-23@gated-at.bofh.it> (permalink)
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On Thu, 3 Aug 2017, Coelho, Luciano wrote:

> Okay, so as I understand it the problem has been there for a long time,
> but the splat is only coming up now because of Thomas' patch that adds
> the lockdep map[1], right?

Yeah, sorry, forgot to mention that pre-49dfe2a67797 kernels wouldn't 
produce this, as there would not be aware of the fact that 
cpus_read_lock() is actually semantically a lock.

> I see the workqueue allocation you mentioned.  I'll try to move this 
> allocation out of the mutex and see how it goes.

I have been briefly looking into this as well -- it'll basically have to 
be moved out of the trans_pcie->mutex context, but

(a) I'm not sure whether that's actually safe
(b) iwl_pcie_rx_reuse_rbd() (which is where corresponding work is being 
    queued) is not a proper context either (it's atomic context)

Thanks,

-- 
Jiri Kosina
SUSE Labs

Thread

Re: x86/thermal: AB-BA dependency between mvm->mutex and tz->lock Jiri Kosina <jikos@kernel.org> - 2017-08-03 11:20 +0200
  Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex  and tz->lock "Coelho, Luciano" <luciano.coelho@intel.com> - 2017-08-03 11:50 +0200
    Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex and tz->lock Kalle Valo <kvalo@codeaurora.org> - 2017-08-03 12:10 +0200
      Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex  and tz->lock Jiri Kosina <jikos@kernel.org> - 2017-08-03 13:40 +0200
        Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex  and tz->lock Jiri Kosina <jikos@kernel.org> - 2017-08-03 15:10 +0200
      Re: [linuxwifi] x86/thermal: AB-BA dependency between mvm->mutex  and tz->lock "Coelho, Luciano" <luciano.coelho@intel.com> - 2017-08-03 13:40 +0200

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