linux-kernel - Re: [PATCH] input: tsc2005: fix locking issue

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Message-ID: <20110322061958.GA7990@core.coreip.homeip.net>
Date:	Mon, 21 Mar 2011 23:19:58 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Aaro Koskinen <aaro.koskinen@...ia.com>
Cc:	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] input: tsc2005: fix locking issue

On Mon, Mar 21, 2011 at 06:24:10PM +0200, Aaro Koskinen wrote:
> Commit 0b950d3 (Input: tsc2005 - add open/close) introduced a
> locking issue with the ESD watchdog: __tsc2005_disable() is calling
> cancel_delayed_work_sync() with mutex held, and the work also needs the
> same mutex.
> 
> Fix the problem by using cancel_delayed_work() on disable. If
> the ESD work was running it will check if the device is closed
> or suspended, and in that case it will do nothing and skip
> re-arming. cancel_delayed_work_sync() is still needed when the module
> is removed.

Hmm, indeed. However, instead of moving cancel_delayed_work_sync() to
remove maybe we should use mutex_trylock() in tsc2005_esd_work()?
If trylock fails that means that device is in the middle of open/close
transition. We should just reschedule the work and get out of there.
 
Thanks.

-- 
Dmitry
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