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 B8D5FEB64DA for ; Wed, 12 Jul 2023 07:58:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230360AbjGLH6L convert rfc822-to-8bit (ORCPT ); Wed, 12 Jul 2023 03:58:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230233AbjGLH6J (ORCPT ); Wed, 12 Jul 2023 03:58:09 -0400 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 73BCC10E3 for ; Wed, 12 Jul 2023 00:58:07 -0700 (PDT) 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-136-LBapHPsiOIqyNB-rdI5Dgg-1; Wed, 12 Jul 2023 08:58:04 +0100 X-MC-Unique: LBapHPsiOIqyNB-rdI5Dgg-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Wed, 12 Jul 2023 08:58:03 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Wed, 12 Jul 2023 08:58:03 +0100 From: David Laight To: "'sunran001@208suo.com'" , "jejb@linux.ibm.com" , "martin.petersen@oracle.com" CC: "hare@kernel.org" , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] csi: myrs: Convert snprintf to scnprintf Thread-Topic: [PATCH] csi: myrs: Convert snprintf to scnprintf Thread-Index: AQHZsKXLD4JVpB9Y5EKt/m8ncbihma+1ypnQ Date: Wed, 12 Jul 2023 07:58:03 +0000 Message-ID: <6dbbfdf90a1c42d4927ee8fda439ee11@AcuMS.aculab.com> References: <20230707073016.11786-1-xujianghui@cdjrlc.com> <20fbbc099e132bb4d3c367da18051c7c@208suo.com> In-Reply-To: <20fbbc099e132bb4d3c367da18051c7c@208suo.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] 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: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: sunran001@208suo.com > Sent: 07 July 2023 08:37 > > Coccinelle reports: WARNING: use scnprintf or sprintf > > Adding to that, there has also been some slow migration from snprintf to > scnprintf. This article explains the rationale for this change: > https: //lwn.net/Articles/69419/ > > Signed-off-by: RAN SUN > --- > drivers/scsi/myrs.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c > index a1eec65a9713..852aceb81f28 100644 > --- a/drivers/scsi/myrs.c > +++ b/drivers/scsi/myrs.c > @@ -1408,7 +1408,8 @@ static ssize_t cache_size_show(struct device *dev, > struct Scsi_Host *shost = class_to_shost(dev); > struct myrs_hba *cs = shost_priv(shost); > > - return snprintf(buf, 8, "%d MB\n", cs->ctlr_info->cache_size_mb); > + return scnprintf(buf, 8, "%d MB\n", cs->ctlr_info->cache_size_mb); > + You've added a 'random' blank line. The '8' ought to be ringing alarm bells as well. If you actually look at the code I think this should be sysfs_emit(). In any case it looks like someone changed a load of sprintf() to snprintf() with the expected max size of the output rather than using a bound for the output buffer. IIRC at least one of the length is just plain wrong and leads to valid output being truncated. Using (say) 256 for all the snprint() would have been more sensible. David > } > static DEVICE_ATTR_RO(cache_size); - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)