From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D3AD1719 for ; Thu, 7 Dec 2023 11:46:13 -0800 (PST) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-216-Lg-bH7P_MLmKxgoy-bEtjA-1; Thu, 07 Dec 2023 19:46:10 +0000 X-MC-Unique: Lg-bH7P_MLmKxgoy-bEtjA-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Thu, 7 Dec 2023 19:45:55 +0000 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Thu, 7 Dec 2023 19:45:55 +0000 From: David Laight To: 'Hugo Villeneuve' , kernel test robot CC: "gregkh@linuxfoundation.org" , "jirislaby@kernel.org" , "hvilleneuve@dimonoff.com" , "oe-kbuild-all@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-serial@vger.kernel.org" , "stable@vger.kernel.org" , Andy Shevchenko Subject: RE: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name() Thread-Topic: [PATCH 1/7] serial: sc16is7xx: fix snprintf format specifier in sc16is7xx_regmap_name() Thread-Index: AQHaKTY2EJh7ggNIk0GV0BoNbt/4DLCeM6bg Date: Thu, 7 Dec 2023 19:45:55 +0000 Message-ID: <16093ec23ca34085824987456eac8f2a@AcuMS.aculab.com> References: <20231130191050.3165862-2-hugo@hugovil.com> <202312061443.Cknef7Uq-lkp@intel.com> <20231207125243.c056d5cd0f875ea6dfdfa194@hugovil.com> In-Reply-To: <20231207125243.c056d5cd0f875ea6dfdfa194@hugovil.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable From: Hugo Villeneuve > Sent: 07 December 2023 17:53 ... > > kernel test robot noticed the following build warnings: > > > > [auto build test WARNING on d804987153e7bedf503f8e4ba649afe52cfd7f6d] > > > > url: https://github.com/intel-lab-lkp/linux/commits/Hugo-Villeneuve/= serial-sc16is7xx-fix- > snprintf-format-specifier-in-sc16is7xx_regmap_name/20231201-031413 > > base: d804987153e7bedf503f8e4ba649afe52cfd7f6d > > patch link: https://lore.kernel.org/r/20231130191050.3165862-2-hugo%= 40hugovil.com > > patch subject: [PATCH 1/7] serial: sc16is7xx: fix snprintf format speci= fier in > sc16is7xx_regmap_name() > > config: x86_64-buildonly-randconfig-001-20231201 (https://download.01.o= rg/0day- > ci/archive/20231206/202312061443.Cknef7Uq-lkp@intel.com/config) > > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 > > reproduce (this is a W=3D1 build): (https://download.01.org/0day- > ci/archive/20231206/202312061443.Cknef7Uq-lkp@intel.com/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new ve= rsion of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot > > | Closes: https://lore.kernel.org/oe-kbuild-all/202312061443.Cknef7Uq-l= kp@intel.com/ > > > > All warnings (new ones prefixed by >>): > > > > drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_i2c_probe': > > >> drivers/tty/serial/sc16is7xx.c:1703:41: warning: '%u' directive outp= ut may be truncated writing > between 1 and 10 bytes into a region of size 2 [-Wformat-truncation=3D] > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id); > > | ^~ > > In function 'sc16is7xx_regmap_name', > > inlined from 'sc16is7xx_i2c_probe' at drivers/tty/serial/sc16is7= xx.c:1805:17: > > drivers/tty/serial/sc16is7xx.c:1703:36: note: directive argument in = the range [0, 4294967294] > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id); > > | ^~~~~~~~ > > drivers/tty/serial/sc16is7xx.c:1703:9: note: 'snprintf' output betwe= en 6 and 15 bytes into a > destination of size 6 > > 1703 | snprintf(buf, sizeof(buf), "port%u", port_id); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >=20 > Hi, > the only solution I could find is to add this line just before snprintf: >=20 > BUG_ON(port_id > MAX310X_MAX_PORTS); >=20 > it allows us to have the smallest buffer size possible. Or "port%c", '0' + port_id); Or maybe: =09size_t buflen =3D sizeof (buf); =09OPTIMIZER_HIDE_VAR(buflen); =09snprintf(buf, buflen, fmt, args); See https://godbolt.org/z/Wjz3xG5c4 Maybe there should be snprintf_may_truncate() (etc) in one of the headers. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)