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 487C9C7618E for ; Sun, 23 Apr 2023 02:35:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230092AbjDWCfC (ORCPT ); Sat, 22 Apr 2023 22:35:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229771AbjDWCfA (ORCPT ); Sat, 22 Apr 2023 22:35:00 -0400 Received: from hust.edu.cn (unknown [202.114.0.240]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24B1A1BF0; Sat, 22 Apr 2023 19:34:58 -0700 (PDT) Received: from [IPV6:2001:250:4000:5113:78e9:d35:fdff:4057] ([172.16.0.254]) (user=dzm91@hust.edu.cn mech=PLAIN bits=0) by mx1.hust.edu.cn with ESMTP id 33N2XTsv018716-33N2XTsw018716 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Sun, 23 Apr 2023 10:33:29 +0800 Message-ID: Date: Sun, 23 Apr 2023 10:33:29 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH] Input: xpad - fix GPF in xpad_probe To: Dan Carpenter , Dan Carpenter Cc: Vicki Pfau , kernel-janitors@vger.kernel.org, Dmitry Torokhov , Pavel Rojtberg , Nate Yocom , Mattijs Korpershoek , John Butler , Matthias Benkmann , Christopher Crockett , Santosh De Massari , hust-os-kernel-patches@googlegroups.com, syzbot+a3f758b8d8cb7e49afec@syzkaller.appspotmail.com, "Pierre-Loup A. Griffais" , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230414125603.686123-1-dzm91@hust.edu.cn> <011c00e7-c351-4331-8be4-1c184d5773e1@kili.mountain> <3ccc85bd-0541-4ffb-a207-dfc533a2c0aa@kili.mountain> From: Dongliang Mu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-FEAS-AUTH-USER: dzm91@hust.edu.cn Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/4/23 03:48, Dan Carpenter wrote: > The warnings from this are quite promising. > > When you're writing a check, you start with a simple idea and then try > it and then filter out the common false positives. > > The first 10 warnings are from loops like: > > p = NULL; > > for (i = 0; i < limit; i++) { > if (i == 0) > p = non_null(); > else > *p = something(); > } > > Smatch doesn't handle loops correctly. (I know how to fix this but I've > never gotten around to it because it would make Smatch slow)... > > So instead of that maybe I would do a hack to silence this type of > warning. Not sure what... > > drivers/usb/gadget/udc/amd5536udc_pci.c:61 udc_pci_remove() warn: pointer dereferenced without being set '&udc->gadget' > This one is interesting. Seems like a real bug. > > drivers/mtd/ubi/block.c:391 ubiblock_create() warn: pointer dereferenced without being set 'dev->gd' > > This one too. So maybe we could make this a separate warning where > NULL dereferences happen on error paths. Or maybe when they happen in > printks. > > So there are ways to take this first draft and massage it and get > fewer false positives, by filtering false positives or taking things > which work and creating new checks instead. Hi Dan, thanks for your efforts. After finishing the current task list, we can first ask senior students to check this result quickly and then assign highly-to-be True Positive to students. BTW, do you have any plans to improve the code readability, directory orgranization, documentation etc. of Smatch? It's hard even for senior students to start with. > Anyway, results attached. > > regards, > dan carpenter >