Date: Thu, 7 Mar 2013 00:18:49 +0400
From: Artem Savkov <artem.savkov@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Mandeep Singh Baines <msb@chromium.org>, linux-kernel@vger.kernel.org,
        linux-acpi@vger.kernel.org, ibm-acpi@hmh.eng.br,
        ibm-acpi-devel@lists.sourceforge.net,
        platform-driver-x86@vger.kernel.org, Aaron Lu <aaron.lu@intel.com>,
        Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
        Tejun Heo <tj@kernel.org>, Maciej Rutecki <maciej.rutecki@gmail.com>
Subject: Re: [PATCH] thinkpad-acpi: fix potential suspend blocking issue
Message-ID: <20130306201849.GA4897@thinkpad.lan>
References: <201303042055.38040.maciej.rutecki@gmail.com>
 <1362504883-9180-1-git-send-email-msb@chromium.org>
 <20130305141817.4e27e83aa66598115e52eb9e@linux-foundation.org>
 <20130306155039.GB7697@redhat.com>
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On Wed, Mar 06, 2013 at 04:50:39PM +0100, Oleg Nesterov wrote:
> On 03/05, Andrew Morton wrote:
> >
> > Basically the same as
> > http://ozlabs.org/~akpm/mmots/broken-out/drivers-platform-x86-thinkpad_acpic-move-hotkey_thread_mutex-lock-after-set_freezable.patch.
> >  I think Artem's patch is a little better.  There doesn't appear to be
> > any locking protocol for tpacpi_lifecycle.
> 
> Which seems to have the same problem, hotkey_kthread() still calls
> kthread_freezable_should_stop() under hotkey_thread_mutex.
> 
> IOW, we have two try_to_freeze's here, the patch moves only one of
> them outside of the hotkey_thread_mutex.

It's hard for me to judge but this lock does indeed look like it has
been used to block until the thread exits. I'm trying out the "remove
hotkey_thread_mutex completely" approach and everything looks fine so
far.

-- 
Regards,
Artem
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