From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A25CC72 for ; Thu, 26 Aug 2021 10:19:44 +0000 (UTC) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-47-2J3p7E5dPWKSVpGnjjTmaQ-1; Thu, 26 Aug 2021 11:19:41 +0100 X-MC-Unique: 2J3p7E5dPWKSVpGnjjTmaQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Thu, 26 Aug 2021 11:19:40 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.023; Thu, 26 Aug 2021 11:19:40 +0100 From: David Laight To: 'Pavel Skripkin' CC: "Larry.Finger@lwfinger.net" , "phil@philpotter.co.uk" , "gregkh@linuxfoundation.org" , "straube.linux@gmail.com" , "fmdefrancesco@gmail.com" , "linux-staging@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v3 3/6] staging: r8188eu: add error handling of rtw_read8 Thread-Topic: [PATCH v3 3/6] staging: r8188eu: add error handling of rtw_read8 Thread-Index: AQHXmLmGl/+E/B1vJUGWAidfG7snbKuFdLBA///xloCAAC/eAA== Date: Thu, 26 Aug 2021 10:19:40 +0000 Message-ID: References: <20210826112745.5e1421ed@gmail.com> In-Reply-To: <20210826112745.5e1421ed@gmail.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com 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: Pavel Skripkin > Sent: 26 August 2021 09:28 >=20 > On Thu, 26 Aug 2021 08:21:34 +0000 > David Laight wrote: >=20 > > From: Pavel Skripkin > > > Sent: 24 August 2021 08:27 > > > > > > _rtw_read8 function can fail in case of usb transfer failure. But > > > previous function prototype wasn't designed to return an error to > > > caller. It can cause a lot uninit value bugs all across the driver > > > code, since rtw_read8() returns local stack variable to caller. > > > > > > Fix it by changing the prototype of this function. Now it returns an > > > int: 0 on success, negative error value on failure and callers > > > should pass the pointer to storage location for register value. > > > > ... > > > +=09=09len +=3D snprintf(page + len, count - len, > > > "rtw_read8(0x%x)=3D0x%x\n", > > > +=09=09=09=09proc_get_read_addr, (u8) tmp); > > > > That is broken. > > >=20 > Don't get it, sorry. Previous code did exactly the same thing, but > didn't check if read() was successful. Look up the return value of snprintf(). =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)