Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Sa, Nuno" <Nuno.Sa@analog.com>
To:     Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        "Tanislav, Cosmin" <Cosmin.Tanislav@analog.com>,
        Lars-Peter Clausen <lars@metafoo.de>,
        "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>
CC:     "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] iio: addac: ad74413r: fix integer promotion bug in
 ad74413_get_input_current_offset()
Thread-Topic: [PATCH] iio: addac: ad74413r: fix integer promotion bug in
 ad74413_get_input_current_offset()
Thread-Index: AQHY+0nukLxESZ4Qd0qamFCmhurvmK5EqRgg
Date:   Fri, 18 Nov 2022 13:17:29 +0000
Message-ID: <SJ0PR03MB6778D6C0682294002296E54C99099@SJ0PR03MB6778.namprd03.prod.outlook.com>
References: <20221118123209.1658420-1-linux@rasmusvillemoes.dk>
In-Reply-To: <20221118123209.1658420-1-linux@rasmusvillemoes.dk>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?k5ZJ6XcBztvihLD5eQ3UKbjLz5gM9fQMhYxI1/df66gch6AUdYSIpyDrO+?=
 =?iso-8859-1?Q?GGMgCNTbwRjDzPrK5Ivu65G04rp08GJ7vJ/BtO1imJVQBPMZ6DvlGbguRs?=
 =?iso-8859-1?Q?fI98irlsY5/Qj2JX5h151dew0qOP1tt974a5PZvdnLoMx9qL/LPzVC1QwP?=
 =?iso-8859-1?Q?SCSzKldsCD2g41qi7RLKba+ND7kQ+ZQ8QAHwd0KSshfeYBruaWn/p27HA8?=
 =?iso-8859-1?Q?9/LvBjrjMcRzlMwtuFej2rznLsjR+Q4YdFnoltsgwjQfr8D5nTB+UqIQHM?=
 =?iso-8859-1?Q?WVbNRF6u3qKnR68d12D5+9USXD/D03uPiPjyNUj+0yhXch6foKcxL3mDzL?=
 =?iso-8859-1?Q?mTI9Y9JvJ0aPwslTXznophZK9FmASAVuKBw3WTa+6stE5SbtqS8f/vj6jB?=
 =?iso-8859-1?Q?25tBa17FSzv2twGklKJffiCPouFzKOf9mPyNVJOdTvSM4pWgPydPtoD8AQ?=
 =?iso-8859-1?Q?ViZq9yfbzNSroMIm70FfJmt67nCDjBILCptucStWBNs3hl11ZLO3T8peNe?=
 =?iso-8859-1?Q?S5wNUGyA9The15fAiQh2cNDvBqFpT0trO53ft+gifYSMMEkXTXCKpVS71J?=
 =?iso-8859-1?Q?g38ytBPKp1zEtTZAdw6vYw9NXlF8d6Y1wYBodlQPf7d5s2j9tSqPPtnR/f?=
 =?iso-8859-1?Q?DJjDU5kNq+0Oh6RJTBoTm8LtKACqRppHfyb5czayauhwpzmhUBS4lwfxQf?=
 =?iso-8859-1?Q?TguUlMFHuK3aqVlAjZC5ANGKLSQg1X3RIhFvIu8Fvp2tCuYzoBJ1WaOhz8?=
 =?iso-8859-1?Q?WWChlTTUBUd67n4i+LLe9NlLKEsYEVEGC8jspryi8APY9yGsOx0DjO/EKK?=
 =?iso-8859-1?Q?37li484/wd6Xvt4z780iM5iW2If/JUW+Ps3/b7Wu4jCpo8+QGaKqj5NaFT?=
 =?iso-8859-1?Q?buD+Adh6AQcB46Gcsp2rzaN3TxFMQvhiF574s3v9+RXMmEfhSpZ86KYh78?=
 =?iso-8859-1?Q?GlWSRIO6jKbFiXe8qgaoQh+BfhAaiHALAcq4htRtSzpxri1/iP/rM7lyQT?=
 =?iso-8859-1?Q?Le4B0dbJ2EcZuYKHXVvLPWAu7oldEGNcxhzMN6dKkGswF9BXLeEGRQlkKT?=
 =?iso-8859-1?Q?yd/5YwtG5wR3fWB9rWxhKy5XSBNFeOODsWfaBGlhgM3LWTn+ZmtozOS8Fz?=
 =?iso-8859-1?Q?gGZr6sriniH/RmgZ8haH545iz54IX86aDhVgkCM70LYDcJVzk7AcazAx86?=
 =?iso-8859-1?Q?WUWMThc+dM7TmzyuRARYKI0RJS840oqXTYi9TbqnJneomepJvT4IUuaxX/?=
 =?iso-8859-1?Q?BbQSq4ByXMR1JPG/SxcnGTJSiixszLBAlso1+C5Fd6iUkpj84pYUCupK0s?=
 =?iso-8859-1?Q?n8SkeDRe2i63iK14VWU99w77xAm0lqvXAtiJRMAzGGPJfniRjc1M0XTmPE?=
 =?iso-8859-1?Q?WC20l5BvBjx1gGZl7uEUaamqLNeLBVMWXYnmHJQTdWcyxHVkPCWOLZikhI?=
 =?iso-8859-1?Q?/lkgucTjuPk7DVE33860YGq0j8ThwdIBM0xOXZVeKOtwhf+azHr8Paf8Rl?=
 =?iso-8859-1?Q?sqv6a6Tz8pExlJ+KllZ2o3ofCriFpHnCHlPfsACvsT919cH0yxb+G29mER?=
 =?iso-8859-1?Q?dC8ITQo5mihO0tVuX44ZOTKFlnPdSplyHUzsMvh8J+okXss0VK63arnY/h?=
 =?iso-8859-1?Q?vE0KyGvfnLky4kHTfpItG8BWiF7iLQf9rY?=
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: analog.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SJ0PR03MB6778.namprd03.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 642d0062-10b2-48a1-9d7d-08dac9673e8d
X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Nov 2022 13:17:29.4160
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: eaa689b4-8f87-40e0-9c6f-7228de4d754a
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: i31G4WzPaQUtITSgssiLgE2+QlvJcOFPomhQWvUTeSoa1YRsq/DoYpOvxUX+8kB2HU+AfDi+WsxyTL3zDRlVPg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR03MB5201
X-Proofpoint-ORIG-GUID: oP2IAAr14q5242JTnScMJrdmp7XWp3g2
X-Proofpoint-GUID: oP2IAAr14q5242JTnScMJrdmp7XWp3g2
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.219,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1
 definitions=2022-11-18_02,2022-11-18_01,2022-06-22_01
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=846
 priorityscore=1501 adultscore=0 suspectscore=0 phishscore=0 mlxscore=0
 malwarescore=0 spamscore=0 impostorscore=0 bulkscore=0 lowpriorityscore=0
 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2210170000 definitions=main-2211180080
X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,RCVD_IN_DNSWL_LOW,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Sent: Friday, November 18, 2022 1:32 PM
> To: Tanislav, Cosmin <Cosmin.Tanislav@analog.com>; Lars-Peter Clausen
> <lars@metafoo.de>; Hennerich, Michael <Michael.Hennerich@analog.com>;
> Jonathan Cameron <jic23@kernel.org>
> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>; linux-
> iio@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [PATCH] iio: addac: ad74413r: fix integer promotion bug in
> ad74413_get_input_current_offset()
>=20
> [External]
>=20
> The constant AD74413R_ADC_RESULT_MAX is defined via GENMASK, so its
> type is "unsigned long".
>=20
> Hence in the expression voltage_offset * AD74413R_ADC_RESULT_MAX,
> voltage_offset is first promoted to unsigned long, and since it may be
> negative, that results in a garbage value. For example, when range is
> AD74413R_ADC_RANGE_5V_BI_DIR, voltage_offset is -2500 and
> voltage_range is 5000, so the RHS of this assignment is, depending on
> sizeof(long), either 826225UL or 3689348814709142UL, which after
> truncation to int then results in either 826225 or 1972216214 being
> the output from in_currentX_offset.
>=20
> Casting to int avoids that promotion and results in the correct -32767
> output.
>=20
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> ---

After adding proper Fixes: tag,

Reviewed-by: Nuno S=E1 <nuno.sa@analog.com>