From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752214AbeCMPYA (ORCPT ); Tue, 13 Mar 2018 11:24:00 -0400 Received: from gateway31.websitewelcome.com ([192.185.144.95]:30086 "EHLO gateway31.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751970AbeCMPXp (ORCPT ); Tue, 13 Mar 2018 11:23:45 -0400 Date: Tue, 13 Mar 2018 10:23:43 -0500 From: "Gustavo A. R. Silva" To: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] iio: potentiometer: ds1803: remove VLA usage Message-ID: <20180313152343.GA31789@embeddedgus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.175.117.58 X-Source-L: No X-Exim-ID: 1evlmC-001kPA-8b X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedgus) [189.175.117.58]:56212 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 6 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation to enabling -Wvla, remove VLA. In this particular case use macro ARRAY_SIZE so the length of array _result_ can be computed at preprocessing time. The use of stack Variable Length Arrays needs to be avoided, as they can be a vector for stack exhaustion, which can be both a runtime bug or a security flaw. Also, in general, as code evolves it is easy to lose track of how big a VLA can get. Thus, we can end up having runtime failures that are hard to debug. Also, fixed as part of the directive to remove all VLAs from the kernel: https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Gustavo A. R. Silva --- drivers/iio/potentiometer/ds1803.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iio/potentiometer/ds1803.c b/drivers/iio/potentiometer/ds1803.c index 9b0ff4a..6bf12c9 100644 --- a/drivers/iio/potentiometer/ds1803.c +++ b/drivers/iio/potentiometer/ds1803.c @@ -64,7 +64,7 @@ static int ds1803_read_raw(struct iio_dev *indio_dev, struct ds1803_data *data = iio_priv(indio_dev); int pot = chan->channel; int ret; - u8 result[indio_dev->num_channels]; + u8 result[ARRAY_SIZE(ds1803_channels)]; switch (mask) { case IIO_CHAN_INFO_RAW: -- 2.7.4