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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA62BC433DB for ; Thu, 11 Feb 2021 07:25:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A495164E70 for ; Thu, 11 Feb 2021 07:25:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229559AbhBKHZJ (ORCPT ); Thu, 11 Feb 2021 02:25:09 -0500 Received: from smtprelay0232.hostedemail.com ([216.40.44.232]:58398 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229533AbhBKHZI (ORCPT ); Thu, 11 Feb 2021 02:25:08 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id B098A180A68C3; Thu, 11 Feb 2021 07:24:26 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: cart80_3f0d51b27616 X-Filterd-Recvd-Size: 2439 Received: from [192.168.1.159] (unknown [47.151.137.21]) (Authenticated sender: joe@perches.com) by omf11.hostedemail.com (Postfix) with ESMTPA; Thu, 11 Feb 2021 07:24:24 +0000 (UTC) Message-ID: <7b4105ca8671a2962910deb5418a934bf07d1458.camel@perches.com> Subject: Re: [PATCH v4 2/2] pinctrl: pinmux: Add pinmux-select debugfs file From: Joe Perches To: Dan Carpenter , Drew Fustini Cc: Linus Walleij , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Lindgren , Andy Shevchenko , Alexandre Belloni , Geert Uytterhoeven , Pantelis Antoniou , Jason Kridner , Robert Nelson Date: Wed, 10 Feb 2021 23:24:23 -0800 In-Reply-To: <20210211071153.GJ20820@kadam> References: <20210210222851.232374-1-drew@beagleboard.org> <20210210222851.232374-3-drew@beagleboard.org> <20210211071153.GJ20820@kadam> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Thu, 2021-02-11 at 10:11 +0300, Dan Carpenter wrote: > On Wed, Feb 10, 2021 at 02:28:54PM -0800, Drew Fustini wrote: > > + ret = strncpy_from_user(buf, user_buf, PINMUX_MAX_NAME * 2); > > + if (ret < 0) { > > + dev_err(pctldev->dev, "failed to copy buffer from userspace"); > > + goto free_gname; > > + } > > + buf[len-1] = '\0'; > > + > > + ret = sscanf(buf, "%s %s", fname, gname); > > + if (ret != 2) { > > + dev_err(pctldev->dev, "expected format: "); > > + goto free_gname; > > We need a "ret = -EINVAL;" before the goto. sscanf doesn't return error > codes. Normally we would write it like so: > > if (sscanf(buf, "%s %s", fname, gname) != 2) { > dev_err(pctldev->dev, "expected format: "); > ret = -EINVAL; > goto free_gname; > } > > I'm going to write a Smatch check for this today. It's a pretty frequently used style: $ git grep -P '\w+\s*=\s+sscanf\b' | wc -l 327 A grep with -A5 seems to show most use some additional error assignment when checking the return value. $ git grep -P -A5 '\w+\s*=\s+sscanf\b' | grep -P '(?:return|=)\s*\-E' | wc -l 174