Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754190Ab1CVPmL (ORCPT ); Tue, 22 Mar 2011 11:42:11 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:35107 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733Ab1CVPmJ (ORCPT ); Tue, 22 Mar 2011 11:42:09 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=v+iNb3p2DqiYlqP05Fxl6teB/DP/J8/5FE1xSeUP6MtVd6Ty8AtFqKl2vL2OukHfMQ B2DBApYDKirS5SobT8OVQpRI+yhTD6T+j+nUnPDGbmeZeP1YLW6mUFTgi9G3TJ2VRGCH 116SR8u3hyzNZD72/XQwo0Cma4RN/9d66c9JM= Date: Tue, 22 Mar 2011 08:42:02 -0700 From: Dmitry Torokhov To: Aaro Koskinen Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] input: tsc2005: fix locking issue Message-ID: <20110322154202.GA24772@core.coreip.homeip.net> References: <1300724650-6641-1-git-send-email-aaro.koskinen@nokia.com> <20110322061958.GA7990@core.coreip.homeip.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 38 On Tue, Mar 22, 2011 at 04:59:02PM +0200, Aaro Koskinen wrote: > Hi, > > On Mon, 21 Mar 2011, Dmitry Torokhov wrote: > >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. > > But I guess the reschedule should not happen if we are in the middle of > close/disable? And without the mutex we cannot know that. It should be OK to reschedule even as we enabling/disabling because cancel_delayed_work_sync() handles re-arming works so even if ESD work is being executed at the time we closing the device it will be killed off completely. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/