From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 List-ID: 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