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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFE11C433F5 for ; Sun, 22 May 2022 10:52:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244499AbiEVKwa (ORCPT ); Sun, 22 May 2022 06:52:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231797AbiEVKw1 (ORCPT ); Sun, 22 May 2022 06:52:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE10513DC8; Sun, 22 May 2022 03:52:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6658F60F89; Sun, 22 May 2022 10:52:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 615E1C385AA; Sun, 22 May 2022 10:52:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653216744; bh=XkjzRJOvGbnB6EuU1d328KQW9nW7oibHRbiluKzJMms=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Ekg6Lmowqi6XMY4Fr/+jw/DJ6EF7j+joDBwDNtGU3vjZezb7uBfIT+VDORZ/HYceB eGJV2FJWqmbcolnDdqhvTHxcPXrVsMvmRdY64/O7jwb5B4vTVC/4fdb+uVfS9A1MZ+ RVvcNGrTZKRaMS1tD+sPdfU1lJkf7KXwsI6VTaUFPvLLtD8BtkHga0X/xV3c1g25kj CV2HL6suuC1A1+ce6/BwV604FPvkhqx/iakaNjTcmVONZXVT5Tb7jA2MuFl88U/SEy yxPK+oY+6pD9+nqJvS/Z7N0MgIU2gj7r7wkfO4hM/MBKm6HkiTwss8d+OtO3wWFdjn cqBqxjNCTVgFA== Date: Sun, 22 May 2022 12:01:09 +0100 From: Jonathan Cameron To: Yongzhi Liu Cc: agross@kernel.org, bjorn.andersson@linaro.org, lars@metafoo.de, svarbanov@mm-sol.com, iivanov@mm-sol.com, jonathan.cameron@huawei.com, linux-arm-msm@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, fuyq@stu.pku.edu.cn Subject: Re: [PATCH v3] iio: vadc: Fix potential dereference of NULL pointer Message-ID: <20220522120109.7ead18a7@jic23-huawei> In-Reply-To: <1653104135-36259-1-git-send-email-lyz_cs@pku.edu.cn> References: <20220520181323.00002892@huawei.com> <1653104135-36259-1-git-send-email-lyz_cs@pku.edu.cn> X-Mailer: Claws Mail 4.1.0 (GTK 3.24.34; 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-kernel@vger.kernel.org On Fri, 20 May 2022 20:35:35 -0700 Yongzhi Liu wrote: > The return value of vadc_get_channel() needs to be checked to > avoid use of NULL pointer. Fix this by adding the null pointer > check on prop and dropping general error prints. > > Fixes: 0917de94c02f ("iio: vadc: Qualcomm SPMI PMIC voltage ADC driver") > Signed-off-by: Yongzhi Liu Hi, Heading in the right direction. A few comments inline. Thanks, Jonathan > --- > drivers/iio/adc/qcom-spmi-vadc.c | 38 ++++++++++++++++++++++++++++---------- > 1 file changed, 28 insertions(+), 10 deletions(-) > > diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c > index 34202ba..43a52b1 100644 > --- a/drivers/iio/adc/qcom-spmi-vadc.c > +++ b/drivers/iio/adc/qcom-spmi-vadc.c > @@ -358,22 +358,33 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc) > vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV; > > prop = vadc_get_channel(vadc, VADC_REF_1250MV); > + if (!prop) { > + dev_err(vadc->dev, "Please define 1.25V channel\n"); > + ret = -ENODEV; > + return ret; return -ENODEV; Same for the other case below. > + } > ret = vadc_do_conversion(vadc, prop, &read_1); > if (ret) > - goto err; Good to add a note to the patch description that vadc_do_conversion() already provides error prints in at least some of it's error paths. Thus it is reasonable to drop the extra reporting in this function. > + return ret; > > /* Try with buffered 625mV channel first */ > prop = vadc_get_channel(vadc, VADC_SPARE1); > - if (!prop) > + if (!prop) { > prop = vadc_get_channel(vadc, VADC_REF_625MV); > + if (!prop) { > + dev_err(vadc->dev, "Please define 0.625V channel\n"); > + ret = -ENODEV; > + return ret; > + } > + } > > ret = vadc_do_conversion(vadc, prop, &read_2); > if (ret) > - goto err; > + return ret; > > if (read_1 == read_2) { > ret = -EINVAL; > - goto err; > + return ret; > } > > vadc->graph[VADC_CALIB_ABSOLUTE].dy = read_1 - read_2; > @@ -381,25 +392,32 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc) > > /* Ratiometric calibration */ > prop = vadc_get_channel(vadc, VADC_VDD_VADC); > + if (!prop) { > + dev_err(vadc->dev, "Please define VDD channel\n"); > + ret = -ENODEV; > + return ret; > + } > ret = vadc_do_conversion(vadc, prop, &read_1); > if (ret) > - goto err; > + return ret; > > prop = vadc_get_channel(vadc, VADC_GND_REF); > + if (!prop) { > + dev_err(vadc->dev, "Please define GND channel\n"); > + ret = -ENODEV; > + return ret; > + } > ret = vadc_do_conversion(vadc, prop, &read_2); > if (ret) > - goto err; > + return ret; > > if (read_1 == read_2) { > ret = -EINVAL; > - goto err; > + return ret; > } > > vadc->graph[VADC_CALIB_RATIOMETRIC].dy = read_1 - read_2; > vadc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_2; > -err: > - if (ret) > - dev_err(vadc->dev, "measure reference points failed\n"); > > return ret; > }