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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham 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 83E41C4338F for ; Sun, 8 Aug 2021 17:29:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5320360F0F for ; Sun, 8 Aug 2021 17:29:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231933AbhHHRaR (ORCPT ); Sun, 8 Aug 2021 13:30:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:57808 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230448AbhHHRaQ (ORCPT ); Sun, 8 Aug 2021 13:30:16 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 075EE60EE9; Sun, 8 Aug 2021 17:29:53 +0000 (UTC) Date: Sun, 8 Aug 2021 18:32:43 +0100 From: Jonathan Cameron To: Yizhuo Cc: Lars-Peter Clausen , Maxime Coquelin , Alexandre Torgue , Andy Shevchenko , Mark Brown , Mugilraj Dhavachelvan , Olivier Moysan , Krzysztof Kozlowski , Arnaud Pouliquen , linux-iio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails Message-ID: <20210808183243.70619aa8@jic23-huawei> In-Reply-To: <20210724164840.7381053b@jic23-huawei> References: <20210719195313.40341-1-yzhai003@ucr.edu> <20210724164840.7381053b@jic23-huawei> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sat, 24 Jul 2021 16:48:40 +0100 Jonathan Cameron wrote: > On Mon, 19 Jul 2021 19:53:11 +0000 > Yizhuo wrote: > > > Inside function stm32_dfsdm_irq(), the variable "status", "int_en" > > could be uninitialized if the regmap_read() fails and returns an error > > code. However, they are directly used in the later context to decide > > the control flow, which is potentially unsafe. > > > > Fixes: e2e6771c64625 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support") > > > > Signed-off-by: Yizhuo > > Hi Yizhou > > I want to get some review of this from people familiar with the > hardware as there is a small possibility your reordering might have > introduced a problem. To stm32 people, can someone take a look at this? Thanks, Jonathan > > > --- > > drivers/iio/adc/stm32-dfsdm-adc.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c > > index 1cfefb3b5e56..d8b78aead942 100644 > > --- a/drivers/iio/adc/stm32-dfsdm-adc.c > > +++ b/drivers/iio/adc/stm32-dfsdm-adc.c > > @@ -1292,9 +1292,11 @@ static irqreturn_t stm32_dfsdm_irq(int irq, void *arg) > > struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); > > struct regmap *regmap = adc->dfsdm->regmap; > > unsigned int status, int_en; > > + int ret; > > > > - regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status); > > - regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en); > > Moving this later is only valid if there aren't any side effects. > The current ordering is strange enough it makes me wonder if there might be! > > Jonathan > > > + ret = regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status); > > + if (ret) > > + return IRQ_HANDLED; > > > > if (status & DFSDM_ISR_REOCF_MASK) { > > /* Read the data register clean the IRQ status */ > > @@ -1303,6 +1305,9 @@ static irqreturn_t stm32_dfsdm_irq(int irq, void *arg) > > } > > > > if (status & DFSDM_ISR_ROVRF_MASK) { > > + ret = regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en); > > + if (ret) > > + return IRQ_HANDLED; > > if (int_en & DFSDM_CR2_ROVRIE_MASK) > > dev_warn(&indio_dev->dev, "Overrun detected\n"); > > regmap_update_bits(regmap, DFSDM_ICR(adc->fl_id), >