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=-5.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS autolearn=ham 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 3DB14C43381 for ; Mon, 18 Feb 2019 08:20:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2C4D218AD for ; Mon, 18 Feb 2019 08:20:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="i8aXmBBn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728976AbfBRIUO (ORCPT ); Mon, 18 Feb 2019 03:20:14 -0500 Received: from mout.web.de ([212.227.15.4]:46969 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725920AbfBRIUN (ORCPT ); Mon, 18 Feb 2019 03:20:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1550477987; bh=Gzozkklv+IHrtUVNGXYvPX4o1QM+OQ228VE0F162nxc=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=i8aXmBBnKf73ERFLeGep9+fHFIyALksZYSXfy42o12NeV53tTxdM5zIvhHIio5XrC JZJ8H31M0cmk29B+jE8z/IsRg5FztL+eH2fLx83v46exDSupIGvMXh/OpBPEVGgWHt O+Go+F/2AeVtbyPuKxrH6saa+hwO4wwlbpI7Nc4s= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([78.49.162.105]) by smtp.web.de (mrweb002 [213.165.67.108]) with ESMTPSA (Nemesis) id 0LvB6w-1h3vai44OY-010KC0; Mon, 18 Feb 2019 09:19:47 +0100 Subject: Re: [v6] coccinelle: semantic code search for missing put_device() To: Julia Lawall , Wen Yang Cc: Wen Yang , Gilles Muller , Nicolas Palix , Michal Marek , Masahiro Yamada , Cheng Shengyu , kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr References: <201902181122502228026@zte.com.cn> From: Markus Elfring Openpgp: preference=signencrypt Autocrypt: addr=Markus.Elfring@web.de; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:s0Qmnm++jcdIjGkNjhKEHp/e/fkruH15Vk30MeSnGtIxaR+5ES2 I+nhhcnV81gqKecXZaUUSfA5Y+t7+Vj+f0GiwwuibFwgtDahkC010SXnbtLTWFFKh/JE25r 6BkZkzhf2+qyT4ApmHP5kw7y6BnWaPxdwrVmEzuQbEvAUxbkQSeyea+z6N+PeMo3Fq1pHXf PRNae7VG7AHnSbNbOxoiA== X-UI-Out-Filterresults: notjunk:1;V03:K0:rqHtMltt+Ks=:kbdKVSHjB9PASC/dWqG3Cp kSimnsKneM743zklCXJFnyoGdIMYaVV8f5hvCQFQQnlKF3mbhcpi+LTw0dxqYCj/UR0WHgvb+ AP5aCj/JPLwNZDFNfmTIjLMuJNJIM+GvZH3uXJJK1KITPNUVIfUb+s+n/CSU6jtX8TKyBrch9 ka7QKHcyf8hR3pe4N3YyBYEHmGbAZXWgfFm8J9+WhxeD254gnG27Vcdb5P+pt8zuYsr0SPVAE nqO2wRxjlQy9PTIYgLNDjfG++6k+N96eziaoJvCfEofLay83/Q4jzdIqUoXzZUrud2OcEblmx j0OsFyw7Zhf3IC3J09bFwmJ4Ih1QeMaG/HmctAru4XpO7k9ld4uzGUiGKSPixONMYUXQdYLxH nhGYVdVoUX3te75RGzI1RBuyTv2inAh+0KtjnFUtnuhzxl9tD3tkIKyv7eS6BTYYSfBstppW4 QLyQtY6w9LkLybjNH6BVk3/+nj0lfBUZts6yzy/qHLzQzLiZYkVMAP5Vp1BAB6Vl/c1KUuugR UsRiWh7lg0mrizvi32BSHVJJir8BWBQkp8le6gYAOxt+dQVaGbgxX0UAHa81VGM50pgYRu25S fDv06X4pzNKOxE+Lz7tIVe6NT0Rh68y8J7FHqwbB3vYJ2xmbWzanbLn3FFda28kLmCN6FMxH9 rcD537sCkcKLlH+n7g5mZItuYK0CPIX3F4ebaDjOfXNLVZKvRu2W5XPL9XvQwwPSnxCPRl1Lm M2QynyczVFcBPBUxRnd+NYHXd3FKQTeocP9jjQKtTB+djXZ+roYXJRkWJMGxO9ypmIMK5zzjE 5WpTHxh3jLBPjXMj5fn8qn+3iGNSJG8i6om++v1Te5l26kIDxc37nUzhYVh097mypKC0Ko9Xf vE53cOfd3bQeZxjfom/9pVvG1fBuLWGHZ5rpbt0cLilPo15ty2ZZSmM2PTA0976U1Ipnnc8Sc y1kzLWHy8yQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> Which data element should not get reassigned here (before a correspond= ing >>> null pointer check)? >>> >> >> Thank you for your comments. >> We did some experiments: >> +id =3D of_find_device_by_node@p1(x) >> +... when !=3D e =3D id >> ... >> Or: >> ... >> + ... when !=3D id =3D e >> >> The number of issuses found by these two methods is the same. This can be because these SmPL specifications share some source code searc= h functionality. >> When !=3D e =3D id achieves this behavior. > > They are the same because neither issue arises. You might not notice a difference from a specific source file selection so= far. > I would have a hard time saying which one is more reasonable to test, I suggest to reconsider the interpretation of this software situation once= more. > since both are extremely unlikely. I disagree to this view because two ellipses were intentionally specified in published SmPL scripts. So some software developers found these =E2=80=9Cspecial use cases=E2=80= =9D important enough. >> In addition, we feel that we should probably accept this patch first, I disagree to this imagination because I would prefer to integrate a sourc= e code variant without a bug (which was copied from a version on 2013-05-08 by Petr Strna= d). https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sc= ripts/coccinelle/free/pci_free_consistent.cocci?id=3Df7b167113753e95ae6138= 3e234f8d10142782ace#n12 I hope that nicer run time behaviour can become also relevant here. >> use it to find more memory leaks, and solve the actual problems in the = kernel code. Your are not hindered to achieve specific software improvements with evolv= ing development approaches while the clarification and the final integration of useful scripts for the semantic patch language can take a bit longer. >> As for the patch itself, we can continue to pursue perfect in the proce= ss >> of using it to solve practical problems. I am curious on how your attention will evolve further for the correspondi= ng software correctness. 1. How much will you care for the order of identifiers within the applicat= ion of SmPL assignment exclusions? 2. Would you like to take additional data type restrictions into account? Regards, Markus