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=-7.1 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_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 079F1C74A4B for ; Thu, 11 Jul 2019 09:04:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C400720872 for ; Thu, 11 Jul 2019 09:04:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="aiM75+U/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728180AbfGKJEx (ORCPT ); Thu, 11 Jul 2019 05:04:53 -0400 Received: from mout.web.de ([212.227.15.14]:46039 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725963AbfGKJEw (ORCPT ); Thu, 11 Jul 2019 05:04:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1562835861; bh=0tLRWbT8bBxRaR5RfH0jviIDBAhhwCwmVOO3QefF65g=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=aiM75+U/I6OU4nxzNdtQyavDvKVLyANEjks/WZJV8BmPd+9QaBL/F3jwhAU86RA3x eka3SIk5iF9J4Uq90onC6Mq66mCpjUu3DrSoOAuMuTjZ9qswFQe0K5ohSG27VPPZM+ s6bTsk+eVMlgLiQsf6t3bsDRvVqBOWDcoZTL0GH0= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([93.132.182.165]) by smtp.web.de (mrweb004 [213.165.67.108]) with ESMTPSA (Nemesis) id 0LegAQ-1iGeQV0dXa-00qTZk; Thu, 11 Jul 2019 11:04:21 +0200 Subject: Re: Coccinelle: Checking of_node_put() calls with SmPL To: Wen Yang , linux-pm@vger.kernel.org, kernel-janitors@vger.kernel.org Cc: Julia Lawall , "Rafael J. Wysocki" , Daniel Lezcano , Benjamin Herrenschmidt , Cheng Shengyu , Kumar Gala , Michael Ellerman , Paul Mackerras , Scott Wood , Xue Zhihong , Yi Wang , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <201907111435459627761@zte.com.cn> From: Markus Elfring Openpgp: preference=signencrypt Autocrypt: addr=Markus.Elfring@web.de; prefer-encrypt=mutual; keydata= mQINBFg2+xABEADBJW2hoUoFXVFWTeKbqqif8VjszdMkriilx90WB5c0ddWQX14h6w5bT/A8 +v43YoGpDNyhgA0w9CEhuwfZrE91GocMtjLO67TAc2i2nxMc/FJRDI0OemO4VJ9RwID6ltwt mpVJgXGKkNJ1ey+QOXouzlErVvE2fRh+KXXN1Q7fSmTJlAW9XJYHS3BDHb0uRpymRSX3O+E2 lA87C7R8qAigPDZi6Z7UmwIA83ZMKXQ5stA0lhPyYgQcM7fh7V4ZYhnR0I5/qkUoxKpqaYLp YHBczVP+Zx/zHOM0KQphOMbU7X3c1pmMruoe6ti9uZzqZSLsF+NKXFEPBS665tQr66HJvZvY GMDlntZFAZ6xQvCC1r3MGoxEC1tuEa24vPCC9RZ9wk2sY5Csbva0WwYv3WKRZZBv8eIhGMxs rcpeGShRFyZ/0BYO53wZAPV1pEhGLLxd8eLN/nEWjJE0ejakPC1H/mt5F+yQBJAzz9JzbToU 5jKLu0SugNI18MspJut8AiA1M44CIWrNHXvWsQ+nnBKHDHHYZu7MoXlOmB32ndsfPthR3GSv jN7YD4Ad724H8fhRijmC1+RpuSce7w2JLj5cYj4MlccmNb8YUxsE8brY2WkXQYS8Ivse39MX BE66MQN0r5DQ6oqgoJ4gHIVBUv/ZwgcmUNS5gQkNCFA0dWXznQARAQABtCZNYXJrdXMgRWxm cmluZyA8TWFya3VzLkVsZnJpbmdAd2ViLmRlPokCVAQTAQgAPhYhBHDP0hzibeXjwQ/ITuU9 Figxg9azBQJYNvsQAhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEOU9Figx g9azcyMP/iVihZkZ4VyH3/wlV3nRiXvSreqg+pGPI3c8J6DjP9zvz7QHN35zWM++1yNek7Ar OVXwuKBo18ASlYzZPTFJZwQQdkZSV+atwIzG3US50ZZ4p7VyUuDuQQVVqFlaf6qZOkwHSnk+ CeGxlDz1POSHY17VbJG2CzPuqMfgBtqIU1dODFLpFq4oIAwEOG6fxRa59qbsTLXxyw+PzRaR LIjVOit28raM83Efk07JKow8URb4u1n7k9RGAcnsM5/WMLRbDYjWTx0lJ2WO9zYwPgRykhn2 sOyJVXk9xVESGTwEPbTtfHM+4x0n0gC6GzfTMvwvZ9G6xoM0S4/+lgbaaa9t5tT/PrsvJiob kfqDrPbmSwr2G5mHnSM9M7B+w8odjmQFOwAjfcxoVIHxC4Cl/GAAKsX3KNKTspCHR0Yag78w i8duH/eEd4tB8twcqCi3aCgWoIrhjNS0myusmuA89kAWFFW5z26qNCOefovCx8drdMXQfMYv g5lRk821ZCNBosfRUvcMXoY6lTwHLIDrEfkJQtjxfdTlWQdwr0mM5ye7vd83AManSQwutgpI q+wE8CNY2VN9xAlE7OhcmWXlnAw3MJLW863SXdGlnkA3N+U4BoKQSIToGuXARQ14IMNvfeKX NphLPpUUnUNdfxAHu/S3tPTc/E/oePbHo794dnEm57LuuQINBFg2+xABEADZg/T+4o5qj4cw nd0G5pFy7ACxk28mSrLuva9tyzqPgRZ2bdPiwNXJUvBg1es2u81urekeUvGvnERB/TKekp25 4wU3I2lEhIXj5NVdLc6eU5czZQs4YEZbu1U5iqhhZmKhlLrhLlZv2whLOXRlLwi4jAzXIZAu 76mT813jbczl2dwxFxcT8XRzk9+dwzNTdOg75683uinMgskiiul+dzd6sumdOhRZR7YBT+xC wzfykOgBKnzfFscMwKR0iuHNB+VdEnZw80XGZi4N1ku81DHxmo2HG3icg7CwO1ih2jx8ik0r riIyMhJrTXgR1hF6kQnX7p2mXe6K0s8tQFK0ZZmYpZuGYYsV05OvU8yqrRVL/GYvy4Xgplm3 DuMuC7/A9/BfmxZVEPAS1gW6QQ8vSO4zf60zREKoSNYeiv+tURM2KOEj8tCMZN3k3sNASfoG fMvTvOjT0yzMbJsI1jwLwy5uA2JVdSLoWzBD8awZ2X/eCU9YDZeGuWmxzIHvkuMj8FfX8cK/ 2m437UA877eqmcgiEy/3B7XeHUipOL83gjfq4ETzVmxVswkVvZvR6j2blQVr+MhCZPq83Ota xNB7QptPxJuNRZ49gtT6uQkyGI+2daXqkj/Mot5tKxNKtM1Vbr/3b+AEMA7qLz7QjhgGJcie qp4b0gELjY1Oe9dBAXMiDwARAQABiQI8BBgBCAAmFiEEcM/SHOJt5ePBD8hO5T0WKDGD1rMF Alg2+xACGwwFCQlmAYAACgkQ5T0WKDGD1rOYSw/+P6fYSZjTJDAl9XNfXRjRRyJSfaw6N1pA Ahuu0MIa3djFRuFCrAHUaaFZf5V2iW5xhGnrhDwE1Ksf7tlstSne/G0a+Ef7vhUyeTn6U/0m +/BrsCsBUXhqeNuraGUtaleatQijXfuemUwgB+mE3B0SobE601XLo6MYIhPh8MG32MKO5kOY hB5jzyor7WoN3ETVNQoGgMzPVWIRElwpcXr+yGoTLAOpG7nkAUBBj9n9TPpSdt/npfok9ZfL /Q+ranrxb2Cy4tvOPxeVfR58XveX85ICrW9VHPVq9sJf/a24bMm6+qEg1V/G7u/AM3fM8U2m tdrTqOrfxklZ7beppGKzC1/WLrcr072vrdiN0icyOHQlfWmaPv0pUnW3AwtiMYngT96BevfA qlwaymjPTvH+cTXScnbydfOQW8220JQwykUe+sHRZfAF5TS2YCkQvsyf7vIpSqo/ttDk4+xc Z/wsLiWTgKlih2QYULvW61XU+mWsK8+ZlYUrRMpkauN4CJ5yTpvp+Orcz5KixHQmc5tbkLWf x0n1QFc1xxJhbzN+r9djSGGN/5IBDfUqSANC8cWzHpWaHmSuU3JSAMB/N+yQjIad2ztTckZY pwT6oxng29LzZspTYUEzMz3wK2jQHw+U66qBFk8whA7B2uAU1QdGyPgahLYSOa4XAEGb6wbI FEE= Message-ID: <90e538ac-a1d8-8c21-34a8-830dd9a07a7b@web.de> Date: Thu, 11 Jul 2019 11:04:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <201907111435459627761@zte.com.cn> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:9RNU8qY6xcsR+ujnesLnOasysSPpyrZB+HpnaqUCNo04Re6ran2 ir2NEuvVxBQdimmcXV7fgs+Ffh+wvC3eRjsWOZmujoGT/L3dhH58rJ9R/G0zu79fTRoMEFw m1PVrkVpvChyobpWT0PosOG/xjvoQgtEQFXPOWtjfHW7VgGuleI+4DEpMtCAtthKaMciJ8C ntu6uxD1Ul2w1/Jg1ZbRw== X-UI-Out-Filterresults: notjunk:1;V03:K0:5VucwHuFbjU=:0dFnGsejHk/MbQPs3dcOSO TM7ob4pb4ZpHEkTuyHHrFON3e2A4LuW5B2XyqvoDXetsPUHgye19xdYM3gX6zVyRpuHbSll2J NpmL6kym89LL7C+1iO3yAebAByOfOa+cc+hBBjnKIG8ZaVCAMoVD5IBo4PiEdtewU4M4IWAv1 iFVhMn8FM1jTYiMXH2v4/pxi8Wxi3dMALGe8dFiUPXlPDhDn//n7PCCZHiHo991XTe35h49Hq wovGUX+7ymm21FEfyzjdb2pLpbAUn8wcD+GatsDNSnGVpZPmMk6W5dW+y61LdcjIyqfWqUvHB BVB5JhTbEPBZLYYHwVjUfLhCebKYXJz+v6DqQ2vEppnK93omHFyF59eSOZ1lE1ao4X61PDEBf l/wmIMNNUF/F+irE7re+WFhB3ysgbLtYjBYTvwIJoBwjlhkYO2mxFc+vuYisT1BHOjiULt/ra Y9f5p88k35n8V9gzETGEWapbuL9d2xAN+JEFVvJ1BD0kKysF6bJCQQPq2eQ4Ar3e+O6oa2Gjv 63HfTSKxEx+8OPQkQzXWQOpBbjJ9UKfKuzPPvyJqlEzrgbKm8uk31Me5Vf/r1nbLF6W5thoFe azoW1MVjPH5/aw0Ceob1L9QO21IaQTgQkT/BkkGX7/EApHn4gKDNZ4WFShD1ynwa2r4RI4YU4 87rSP2wcWwcI+ntuROz4aWP+TEphC8B2jTRx8z88m7Pzyb9/y3ifC4hl+SbTmvPjywSC69dHR ktd24WWuMXCLXvKM8v1EQSCNdH8yptjCj66DTqiqZ4gH5pFbdANqqMLA7c/6w4xUMnx+tzBAp Cl/XvFZm5osg/YiDHmATWl+XtIBoLIFjwHe/NTWnd4CEEHa/Dgw2lSR3YkulxDBiRGB5RU7Zi rCqKfSUUPAyXXd1XYReNUD78v6dJ6lXKsj4oxHczhmTq3O/wN9m1K1VvvX6zhpYZGy91954Nl whtzN9L44tFHHW41nllIvgJ/sYfcjn46VCPBpwJn+0JzSHqysbU2uYU5nA2WeXVn1xA+sve4v 0QxuGO0rHeRTSTnzEiLGfVT/9fkYe+LSQM2mi4NWlWg23y0FkwruiPLLE88MnbFmzyPUWQ2ta eEagrkYDzYZDcLnXu0sFlEp6rnoL1Ggw229 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org > 180 break; ---> Jump ou= t of the loop without releasing it The device node reference is released behind this for loop. > 183 if (!of_device_is_available(state_node)) { > 184 of_node_put(state_node); This function call was added by the commit =E2=80=9Ccpuidle: dt: Add missi= ng 'of_node_put()'=E2=80=9D on 2017-06-12. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/= drivers/cpuidle/dt_idle_states.c?id=3Db2cdd8e1b54849477a32d820acc2e87828a3= 8f3d > 185 continue; ---> Release t= he object references within a loop I became curious on the applicability of an other coding style (for a software refactoring) at this place. How do you think about to achieve the same effect by using a goto statemen= t instead of two statements in such an if branch? > 208 of_node_put(state_node); --> Release the object re= ferences within a loop > 209 } > 210 > 211 of_node_put(state_node); --> There may be double fr= ee here. This information points a recurring challenge out for safe source code ana= lysis. How would you like to exclude the detection of false positives finally? > This code pattern is very interesting Thanks that you think also in this direction. > and the coccinelle software should also recognize this pattern. There are some open issues to consider for available analysis tools. How will corresponding details be clarified then? Regards, Markus