From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 154A7C388F3 for ; Sat, 28 Sep 2019 06:57:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EAAC120830 for ; Sat, 28 Sep 2019 06:57:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726019AbfI1G5I (ORCPT ); Sat, 28 Sep 2019 02:57:08 -0400 Received: from 178.115.242.59.static.drei.at ([178.115.242.59]:33763 "EHLO mail.osadl.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725283AbfI1G5I (ORCPT ); Sat, 28 Sep 2019 02:57:08 -0400 X-Greylist: delayed 583 seconds by postgrey-1.27 at vger.kernel.org; Sat, 28 Sep 2019 02:57:07 EDT Received: by mail.osadl.at (Postfix, from userid 1001) id 98F565C0864; Sat, 28 Sep 2019 08:47:20 +0200 (CEST) Date: Sat, 28 Sep 2019 08:47:20 +0200 From: Nicholas Mc Guire To: Yizhuo Cc: csong@cs.ucr.edu, zhiyunq@cs.ucr.edu, Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Kevin Hilman , Martin Blumenstingl , Neil Armstrong , Thomas Gleixner , Nicholas Mc Guire , linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iio: adc: meson-saradc: Variables could be uninitalized if regmap_read() fails Message-ID: <20190928064720.GA24515@osadl.at> References: <20190928004642.28932-1-yzhai003@ucr.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190928004642.28932-1-yzhai003@ucr.edu> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 27, 2019 at 05:46:41PM -0700, Yizhuo wrote: > Several functions in this file are trying to use regmap_read() to > initialize the specific variable, however, if regmap_read() fails, > the variable could be uninitialized but used directly, which is > potentially unsafe. The return value of regmap_read() should be > checked and handled. > > Signed-off-by: Yizhuo Just a few minor style issues - contentwise it look correct to me. Reviewed-by: Nicholas Mc Guire > --- > drivers/iio/adc/meson_saradc.c | 28 +++++++++++++++++++++++----- > 1 file changed, 23 insertions(+), 5 deletions(-) > > diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c > index 7b28d045d271..c032a64108b4 100644 > --- a/drivers/iio/adc/meson_saradc.c > +++ b/drivers/iio/adc/meson_saradc.c > @@ -323,6 +323,7 @@ static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev) > { > struct meson_sar_adc_priv *priv = iio_priv(indio_dev); > int regval, timeout = 10000; > + int ret; > > /* > * NOTE: we need a small delay before reading the status, otherwise > @@ -331,7 +332,9 @@ static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev) > */ > do { > udelay(1); > - regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); > + ret = regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); > + if (ret) > + return ret; > } while (FIELD_GET(MESON_SAR_ADC_REG0_BUSY_MASK, regval) && timeout--); > > if (timeout < 0) > @@ -358,7 +361,11 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev, any reason not to declear ret in the declaration block ? so just for consistency with coding style within meson_saradc.c this might be: int regval, fifo_chan, fifo_val, count; + int ret; > return -EINVAL; > } > > - regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); > + int ret = regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); + ret = regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, ®val); > + > + if (ret) > + return ret; > + > fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval); > if (fifo_chan != chan->address) { > dev_err(&indio_dev->dev, > @@ -491,6 +498,7 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev) > { > struct meson_sar_adc_priv *priv = iio_priv(indio_dev); > int val, timeout = 10000; > + int ret; > > mutex_lock(&indio_dev->mlock); > > @@ -506,7 +514,10 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev) > */ > do { > udelay(1); > - regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val); > + ret = regmap_read(priv->regmap, > + MESON_SAR_ADC_DELAY, &val); checkpatch does not fuss here but the continuation should be alligned witht the ( here > + if (ret) > + return ret; > } while (val & MESON_SAR_ADC_DELAY_BL30_BUSY && timeout--); > > if (timeout < 0) { > @@ -784,7 +795,10 @@ static int meson_sar_adc_init(struct iio_dev *indio_dev) > * BL30 to make sure BL30 gets the values it expects when > * reading the temperature sensor. > */ > - regmap_read(priv->regmap, MESON_SAR_ADC_REG3, ®val); > + ret = regmap_read(priv->regmap, MESON_SAR_ADC_REG3, ®val); > + if (ret) > + return ret; > + > if (regval & MESON_SAR_ADC_REG3_BL30_INITIALIZED) > return 0; > } > @@ -1014,7 +1028,11 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data) > unsigned int cnt, threshold; > u32 regval; same as above + int ret; > > - regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); > + int ret = regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); + ret = regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val); > + > + if (ret) > + return ret; > + > cnt = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_COUNT_MASK, regval); > threshold = FIELD_GET(MESON_SAR_ADC_REG0_FIFO_CNT_IRQ_MASK, regval); > > -- > 2.17.1 >