From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756926Ab2IJJQj (ORCPT ); Mon, 10 Sep 2012 05:16:39 -0400 Received: from ppsw-43.csi.cam.ac.uk ([131.111.8.143]:35839 "EHLO ppsw-43.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810Ab2IJJQg (ORCPT ); Mon, 10 Sep 2012 05:16:36 -0400 X-Cam-AntiVirus: no malware found X-Cam-SpamDetails: not scanned X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Message-ID: <504DAFF7.1070902@jic23.retrosnub.co.uk> Date: Mon, 10 Sep 2012 10:16:39 +0100 From: Jonathan Cameron User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120827 Thunderbird/15.0 MIME-Version: 1.0 To: "Kim, Milo" CC: Jonathan Cameron , Lars-Peter Clausen , "linux-iio@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 2/2] iio: inkern: add error case in iio_channel_get() References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/09/12 09:02, Kim, Milo wrote: > The datasheet name is defined in the IIO driver. > On the other hand, the adc_channel_label is configured in > the platform machine side. > If the datasheet name is not matched with any adc_channel_label, > the iio_channel_get() should be returned as error for preventing > using invalid IIO channel data. > > Moreover, this patch detects NULL pointer dereference problem at early time. > In general, the IIO driver just accesses to any member of the iio_chan_spec > in own xxx_read_raw() function. > If the iio_chan_spec is invalid pointer, NULL dereference problem may occur > such like 'iio_chan_spec->channel' or 'iio_chan_spec->type'. > If the iio_channel_get() gets failed in the IIO consumer, > then no read_raw() operation proceeds. I guess this is marginally cleaner, but either way it is up to the calling driver to check whether the call succeeded. > > Signed-off-by: Milo(Woogyom) Kim > --- > drivers/iio/inkern.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c > index 1faa240..a5caf6b 100644 > --- a/drivers/iio/inkern.c > +++ b/drivers/iio/inkern.c > @@ -136,11 +136,15 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name) > > channel->indio_dev = c->indio_dev; > > - if (c->map->adc_channel_label) > + if (c->map->adc_channel_label) { > channel->channel = > iio_chan_spec_from_name(channel->indio_dev, > c->map->adc_channel_label); > > + if (channel->channel == NULL) > + return ERR_PTR(-ENODEV); > + } > + > return channel; > } > EXPORT_SYMBOL_GPL(iio_channel_get); >