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 1D28EC433E2 for ; Thu, 27 Aug 2020 21:44:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F33A620B80 for ; Thu, 27 Aug 2020 21:44:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727814AbgH0VoH (ORCPT ); Thu, 27 Aug 2020 17:44:07 -0400 Received: from smtprelay0012.hostedemail.com ([216.40.44.12]:40380 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726147AbgH0VoH (ORCPT ); Thu, 27 Aug 2020 17:44:07 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay07.hostedemail.com (Postfix) with ESMTP id B0C1F181D337B; Thu, 27 Aug 2020 21:44:05 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: paper52_5f066c127070 X-Filterd-Recvd-Size: 4701 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf09.hostedemail.com (Postfix) with ESMTPA; Thu, 27 Aug 2020 21:44:02 +0000 (UTC) Message-ID: Subject: Re: [Cocci] [PATCH] usb: atm: don't use snprintf() for sysfs attrs From: Joe Perches To: Julia Lawall , Denis Efremov Cc: "Gustavo A. R. Silva" , Kees Cook , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Rasmus Villemoes , linux-kernel@vger.kernel.org, cocci , accessrunner-general@lists.sourceforge.net, Alex Dewar Date: Thu, 27 Aug 2020 14:44:01 -0700 In-Reply-To: References: <20200824222322.22962-1-alex.dewar90@gmail.com> <48f2dc90-7852-eaf1-55d7-2c85cf954688@rasmusvillemoes.dk> <20200827071537.GA168593@kroah.com> <20200827131819.7rcl2f5js3hkoqj2@lenovo-laptop> <20200827144846.yauuttjaqtxaldxg@lenovo-laptop> <5d1dfb9b031130d4d20763ec621233a19d6a88a2.camel@perches.com> <5853c58e-7d26-2cf9-6cbf-698ecd93cbf9@linux.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2020-08-27 at 23:36 +0200, Julia Lawall wrote: > On Fri, 28 Aug 2020, Denis Efremov wrote: [] > Regarding current device_attr_show.cocci implementation, it detects the functions > > by declaration: > > ssize_t any_name(struct device *dev, struct device_attribute *attr, char *buf) > > > > and I limited the check to: > > "return snprintf" > > pattern because there are already too many warnings. > > > > Actually, it looks more correct to check for: > > ssize_t show(struct device *dev, struct device_attribute *attr, char *buf) > > { > > <... > > * snprintf@p(...); > > ...> > > } > > > > This pattern should also highlight the snprintf calls there we save returned > > value in a var, e.g.: > > > > ret += snprintf(...); > > ... > > ret += snprintf(...); > > ... > > ret += snprintf(...); > > > > return ret; > > > > > Something like > > > > > > identifier f; > > > fresh identifier = "sysfs" ## f; > > > > > > may be useful. Let me know if further help is needed. > > > > Initially, I wrote the rule to search for DEVICE_ATTR(..., ..., func_name, ...) > > This is what I would have expected. > > > functions. However, it looks like matching function prototype is enough. At least, > > I failed to find false positives. I rejected the initial DEVICE_ATTR() searching > > because I thought that it's impossible to handle DEVICE_ATTR_RO()/DEVICE_ATTR_RW() > > macroses with coccinelle as they "generate" function names internally with > > "##". "fresh identifier" should really help here, but now I doubt it's required in > > device_attr_show.cocci, function prototype is enough. > > It's true that it is probably unique enough. I tried: @@ identifier f_show =~ "^.*_show$"; identifier dev, attr, buf; const char *chr; @@ ssize_t f_show(struct device *dev, struct device_attribute *attr, char *buf) { <... ( - sprintf + sysfs_sprintf (...); | - snprintf(buf, PAGE_SIZE, + sysfs_sprintf(buf, ...); | - scnprintf(buf, PAGE_SIZE, + sysfs_sprintf(buf, ...); | strcpy(buf, chr); sysfs_strcpy(buf, chr); ) ...> } which finds direct statements without an assign but that doesn't find arch/arm/common/dmabounce.c:static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr, char *buf) arch/arm/common/dmabounce.c-{ arch/arm/common/dmabounce.c- struct dmabounce_device_info *device_info = dev->archdata.dmabounce; arch/arm/common/dmabounce.c- return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n", arch/arm/common/dmabounce.c- device_info->small.allocs, arch/arm/common/dmabounce.c- device_info->large.allocs, arch/arm/common/dmabounce.c- device_info->total_allocs - device_info->small.allocs - arch/arm/common/dmabounce.c- device_info->large.allocs, arch/arm/common/dmabounce.c- device_info->total_allocs, arch/arm/common/dmabounce.c- device_info->map_op_count, arch/arm/common/dmabounce.c- device_info->bounce_count); arch/arm/common/dmabounce.c-}