From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932738Ab0EYWSU (ORCPT ); Tue, 25 May 2010 18:18:20 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:53107 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759020Ab0EYWSR convert rfc822-to-8bit (ORCPT ); Tue, 25 May 2010 18:18:17 -0400 To: Mike Frysinger Cc: Dmitry Torokhov , linux-input@vger.kernel.org, linux-omap@vger.kernel.org, Michael Roth , Pavel Machek , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] touchscreen: ads7846: please don't touch free'd memory References: <1274226413-8520-1-git-send-email-khilman@deeprootsystems.com> <20100519000019.GA17475@core.coreip.homeip.net> <87mxvnlpxv.fsf@deeprootsystems.com> <20100525202135.GC4455@core.coreip.homeip.net> <8739xflkn5.fsf@deeprootsystems.com> From: Kevin Hilman Organization: Deep Root Systems, LLC Date: Tue, 25 May 2010 15:18:13 -0700 In-Reply-To: (Mike Frysinger's message of "Tue\, 25 May 2010 17\:56\:27 -0400") Message-ID: <87r5kzk4m2.fsf@deeprootsystems.com> User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mike Frysinger writes: > On Tue, May 25, 2010 at 17:46, Kevin Hilman wrote: >> After digging into the driver core and realizing that it seemed to >> have sane error handling itself, I took a closer look at >> ads7846_probe() and discovered it doesn't actually return an error >> code for certain failure cases!  That was the root cause. > > that is crappy > >> Subject: [PATCH] input: touchscreen: ads7846: return error on probe failure > > i'd refer to the specific probe issue rather than just "probe". maybe: > input: touchscreen: ads7846: return error on regulator_get() failure Thanks for the review, here's one with updated subject and ack added. Kevin >>From 8ce49a91341d8713f870d2a931969f227a82b8ad Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Tue, 25 May 2010 14:38:04 -0700 Subject: [PATCH] input: touchscreen: ads7846: return error on regulator_get() failure In probe(), if regulator_get() failed, an error code was not being returned causing the driver to be successfully bound, even though probe failed. This in turn caused the suspend, resume and remove methods to be registered and accessed via the SPI core. Since these functions all access private driver data using pointers that had been freed during the failed probe, this would lead to unpredictable behavior. This patch ensures that probe() returns an error code in this failure case so the driver is not bound. Found using lockdep and noticing the lock used in the suspend/resum path pointed to a bogus lock due to the freed memory. Signed-off-by: Kevin Hilman Acked-by: Mike Frysinger --- drivers/input/touchscreen/ads7846.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index 532279c..634f6f6 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c @@ -1163,8 +1163,8 @@ static int __devinit ads7846_probe(struct spi_device *spi) ts->reg = regulator_get(&spi->dev, "vcc"); if (IS_ERR(ts->reg)) { - dev_err(&spi->dev, "unable to get regulator: %ld\n", - PTR_ERR(ts->reg)); + err = PTR_ERR(ts->reg); + dev_err(&spi->dev, "unable to get regulator: %ld\n", err); goto err_free_gpio; } -- 1.7.0.2