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t=1550238878; bh=Zar8ETeEtVYnCttXOkDHA/cVuAPneIv8NtIX782czF4=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=RXm/IlIv/6tD6N8nxbYWdCbN222zd0hBn/XYJ7CAHDZ80dARYeyrh1Tomy4xUx/tq kxmbJzYfVvaRNSaJiiHphHKLAMPVNzs8bRA88Y9jRqeJG/NbIwWctaLHFhGOJPX7Hq WRdufwU7aW4fkxYRsUvZkuXFKGD7055JJHDJkPyQ= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.3] ([78.48.88.109]) by smtp.web.de (mrweb102 [213.165.67.124]) with ESMTPSA (Nemesis) id 0Le4Po-1hQSWo2BNE-00ppla; Fri, 15 Feb 2019 14:54:38 +0100 Subject: Re: [v5] Coccinelle: semantic code search for missing put_device() To: Julia Lawall Cc: Wen Yang , Gilles Muller , Nicolas Palix , Michal Marek , Yi Wang , Masahiro Yamada , Wen Yang , Cheng Shengyu , cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <1550217319-40418-1-git-send-email-wen.yang99@zte.com.cn> <94e4b3e6-87a4-aea2-dfef-44d308f0fb4f@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-GB Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:pp419OONgYW5ZyGGsXPnsduV1YDSuV4negovqe73DWmyC2DY6L/ W+S+1vN3m9e9Ok910dyCSoxeCQW25PdsGXAT7kV0Y4UgrjbVNSk8eCYzTQGSB6ygwcrAQFQ UnGU8ojJ3wjJZkWSc00gdXh19aHzi6owS1SOzwS0RctdYwYBFvyg4j9ONmaDEWnXb4uI6km 5YBvbQhPhgYb5jkRBlBEA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:iDDJER0E+QU=:Vgf1HICRKr8hUg7xpnhyd1 GXvQjvfs4PF3kmHqiqSXAuYoqnsDTPFsJnt9a/m4elar28czkBbm5lKzDvhs8s+fuNSrywtnw eWi/N7JUnbup5ty7OgG+xleWMatmcQLY1ufL8DHkHiKbB36HdQGUNeiYYxLaa8WDY/fMNgmWj DXxr8+wYxUhSTSLNOcQSnUBV/hDjmAy3cKEJrUiAyCdb8l3WpBNRbwON4Ws5slkbBgUBwbGq4 6KAX+lTCuiIrNxfnhHvtmjaFezec/7DsMo6qu+v2UgqE3iJZDNZNKJRD8gGOjQTFKExO3OB2x 0Z+5HTKytrf9joY1o+jFTIhGUGPznvJyFkzJvx2ak2wNMw+GmMlJkGPBK92owDZVBeCXDh0zr sSzwCNN4360Vd5yf3rnhmW7yEsqwNdbtOLt2c39zh6WUlBWVXu+dbtjkgsN9uH0cFdxhUw4ba dTw6Kjsjt87njVHYHRmIY66AFOpLy/6uVHDMO2FAp22o/AiWvnOHlD/PjUfn8XYfvq1Bw8h6e yB0yLZFreXw4+7D5h16jHms530v19LtjjB5dWWHNh4OgB0iOgG3CH9bBzky70Hq1fBF7U7W1b /uOnpjT36d71VpRlpfps58XNGN7WFZ5acqBAJwD0AarRvSToI9HTZznfDotVagf/D4r7CWD3/ ppgUvFdwVHtXQykyAhUotMjPNiXlOZLFUCdtzBRtfSDsSGwZRi5oKXqzCzMQRnwpEH/8ZN7BL NMiwyXgt2s0VkYSx6h7QoJhzxeky5NG8mled6FXGheKZcmiwdavudYUFkwtApnXfDjA9QaeDZ aQx47WHyWZpxkCs2yYtKgQvaar62ZXak9dP5zsWLJjC2Jm0idht/7w8fRGHHFEqp5ytrbPPzv GA8mto7YMdpSGFR4kn7zu0AIP+VjNOcL4W/DIaAhJGUYIhoyuYyNQp9SggwhB1Eq0dK5lVKtr JfacNQivRwg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Does the first SmPL when specification include the case that a call >> of the function =E2=80=9Cput_device=E2=80=9D can occur within a branch = of an if statement? > > It does include that, Thanks for this acknowledgement. So it seems that you find my interpretation of this bit of SmPL code appro= priate. > but there is another execution path where the put device is not present. It is tried to find such cases. > But given the test in the if in the when code, > on that execution path id is NULL, an so there is no need to put it. I would like to point out that the function =E2=80=9Cput_device=E2=80=9D b= elongs also to the category of functions which tolerate the passing of null pointers. https://elixir.bootlin.com/linux/v5.0-rc6/source/drivers/base/core.c#L2053 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dr= ivers/base/core.c?id=3Dcb5b020a8d38f77209d0472a0fea755299a8ec78#n2053 Have we got still different software development opinions about the need for an extra pointer check in the =E2=80=9Csecond=E2=80=9D SmPL when speci= fication? Regards, Markus