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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 F1FA8C43381 for ; Sun, 17 Feb 2019 13:15:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC79A2192C for ; Sun, 17 Feb 2019 13:15:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="YcBvFqVC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728921AbfBQNPC (ORCPT ); Sun, 17 Feb 2019 08:15:02 -0500 Received: from mout.web.de ([212.227.15.3]:40853 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726788AbfBQNPB (ORCPT ); Sun, 17 Feb 2019 08:15:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1550409280; bh=gIrvYy3qX5P42PmaNL0dx/MTF7EVgQsDF6prqv1CgeA=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=YcBvFqVCgIX3E0Si9QH2s/n6j+Qo0hSveD5V4miunK0tF49Fw91+sHD+iU4uCIoyH nYNd/pbh4aQTdphO2UC9h2XDRK4Rq4oULaQvq2MYG7qLhYSRIzerLs9CphggpauawM S6zymcv94rvngqh1JWXEC+bcJUsdoE/2FotjKGic= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.3] ([93.132.167.97]) by smtp.web.de (mrweb001 [213.165.67.108]) with ESMTPSA (Nemesis) id 0Lcxfc-1hLvfc2pG4-00i8P6; Sun, 17 Feb 2019 14:14:40 +0100 Subject: Re: [v6] coccinelle: semantic code search for missing put_device() To: Julia Lawall , Wen Yang Cc: Gilles Muller , Nicolas Palix , Michal Marek , Masahiro Yamada , Wen Yang , Cheng Shengyu , kernel-janitors@vger.kernel.org, LKML , Coccinelle References: <8e7ba7c0-b7fe-a1f0-d28b-0c716ecbcfdb@web.de> <1c152067-0135-79d7-1285-4bb9925054c8@web.de> <782fd1c3-80ff-a296-b3a2-351257bb13b3@web.de> <10836645-5b19-a748-56d7-c0572a76ab4d@web.de> 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-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:mcW/alvgV2U2JkeM76bMIURS9xZXu7gfN8WPtB165B/WxlpuNAS URC6c9PzBDgcV1KRgwYTCihcUBduaN2PhrbyJQmlVvs8dMaM+wNn5bpeceCz+2Sx3HEt9/f FZKdqSA8Lc7/6zQ2meoTRASVEmAdd+O30BAQ07XFleRRJkgjaewRsyL9oxrf1UV1ECS+Q03 F3wr7QCBkEQDIJoFJV7tQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:FV32otE0dCM=:/wKbpDwVSz3N8VKGtXyc09 2OEB/OER9qAIhIzwkdwl4XTWDLKe+rhV7c/yVvCVLp2cMHmIht+nx9h4hpau5mY9SiaHkx6QX 9hfrjo+VOH6BCQWAT92yyPkKwZgwmAqy9x4AstufHyPOnHLdHHXWVRQGNyWJgjGzsT1uphWYk td3tp+hgXBrYhB8DSkrYVBPfDUPPukPmQ4Y+YJ3ySRrdQHCQcfa97T65usna6b89j979NJIFC WPE3HA068cBs9zYa9l+Kr8cw+KBBL6COKBIT6ZptluyOcEEokGBULuqTwLXyeETUkST20421i AotI65cDYu1zmsOTuHKi1UtpzpaFulLJbdbnGMvkmD1+C1lnnG5E0ELEjtFZ0nR6mT8OHp93Z 90nl7pZgmWR3yVPI1WbG9palVF1NzWU+uBudoYfavxpIawl1zFd+LW2T3rM0Euk5WqPNsDYzP RUjeRO5iPighZUcuoaC4voGKDPkwmQK2QSj8MziKDLcU9l9qxVKk08wdOILr8ICMinQe86psT MtoDk+I2zli1zJEtnUaN9TOq8M1AZAb++SqoGTkbK4cQ9p9bQqn0gcwDSfBk4dAEbr/SoaIeV e7dRkhs54OuBYT6JU/Mq/KhEm3nqU8K9WnVG06Z5qIPRi3H+KrcYqzWfrNlBRmntnyoThOp4W +J0fdf7NkxT9RRGOoIZoNlO3IGJ/Uq7PdIhPPzWkpF2cwgvwATW6T3wZj0cBhrGk9hoeFHNhf GjvEfq+DkNYpuZQM1psOzKj8E+uPVR5b6s3Rdr1OhXAP80L/taP+zsFeELLu//uTX+KDlQglm Uaq19iU9zk6IFNCAM2hVAyLLP/BWJWmcKdKRX9+aVoA9GRduBsPo9gL83ZZw9LgLQSHYQb2oK X6u2Iy9baEYunuG3ehe5DSOjyqe68TkVMKIrkLfIgLBR5g/AvkPTGRns9UsNfqUeRLqJquPzh OpI+mjEczxg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> =E2=80=A6 >> +@search exists@ >> +local idexpression id; >> +expression x,e,e1; >> +position p1,p2; >> =E2=80=A6 >> +@@ >> + >> +id =3D of_find_device_by_node@p1(x) >> +... when !=3D e =3D id >> =E2=80=A6 >> >> Or: >> >> =E2=80=A6 >> + ... when !=3D id =3D e >> =E2=80=A6 >> >> >> Which SmPL specification will achieve the desired software behaviour? > > The desired behavior is to check whether the allocated value is saved in > some other variable (typically a structure field) and thus it doesn't ne= ed > to be freed just because the original local variable goes out of scope a= t > the end of the function. I find this description reasonable to some degree. (I am unsure if a programmer would like to fiddle with return value storag= e in a data structure member from a local variable.) > when !=3D e =3D id achieves this behavior. I can not agree to this view completely because of the meaning that is con= nected with these variable identifiers. Both metavariables share the kind =E2=80=9Cexpression=E2=80=9D. So I can i= magine that there is an intersection for the source code match possibility. But one was intentionally restricted to the kind =E2=80=9Clocal idexpressi= on=E2=80=9D so far. Which data element should not get reassigned here (before a corresponding null pointer check)? Regards, Markus