Re: [PATCH] thinkpad-acpi: fix potential suspend blocking issue

From: Artem Savkov
Date: Wed Mar 06 2013 - 15:18:59 EST


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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