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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,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 17A08C04AAF for ; Mon, 20 May 2019 19:54:00 +0000 (UTC) Received: from isis.lip6.fr (isis.lip6.fr [132.227.60.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7D04A20863 for ; Mon, 20 May 2019 19:53:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D04A20863 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lip6.fr Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=cocci-bounces@systeme.lip6.fr Received: from systeme.lip6.fr (systeme.lip6.fr [132.227.104.7]) by isis.lip6.fr (8.15.2/8.15.2) with ESMTP id x4KJrjP3019684; Mon, 20 May 2019 21:53:45 +0200 (CEST) Received: from systeme.lip6.fr (systeme.lip6.fr [127.0.0.1]) by systeme.lip6.fr (Postfix) with ESMTP id 02CD87741; Mon, 20 May 2019 21:53:45 +0200 (CEST) Received: from isis.lip6.fr (isis.lip6.fr [132.227.60.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by systeme.lip6.fr (Postfix) with ESMTPS id 3BB49768D for ; Mon, 20 May 2019 21:53:42 +0200 (CEST) Received: from mail3-relais-sop.national.inria.fr (mail3-relais-sop.national.inria.fr [192.134.164.104]) by isis.lip6.fr (8.15.2/8.15.2) with ESMTP id x4KJrfQK016525 for ; Mon, 20 May 2019 21:53:41 +0200 (CEST) X-IronPort-AV: E=Sophos;i="5.60,492,1549926000"; d="scan'208";a="306653735" Received: from abo-218-110-68.mrs.modulonet.fr (HELO hadrien) ([85.68.110.218]) by mail3-relais-sop.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 May 2019 21:53:41 +0200 Date: Mon, 20 May 2019 21:53:40 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: Sasha Levin In-Reply-To: <20190520172041.GH11972@sasha-vm> Message-ID: References: <201905171432571474636@zte.com.cn> <20190520093303.GA9320@atrey.karlin.mff.cuni.cz> <20190520172041.GH11972@sasha-vm> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 X-Greylist: Sender IP whitelisted, Sender e-mail whitelisted, not delayed by milter-greylist-4.4.3 (isis.lip6.fr [132.227.60.2]); Mon, 20 May 2019 21:53:45 +0200 (CEST) X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.4.3 (isis.lip6.fr [132.227.60.2]); Mon, 20 May 2019 21:53:41 +0200 (CEST) X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 X-Scanned-By: MIMEDefang 2.78 on 132.227.60.2 Cc: michal.lkml@markovi.net, nicolas.palix@imag.fr, linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr, Markus.Elfring@web.de, Pavel Machek , wen.yang99@zte.com.cn Subject: Re: [Cocci] Coccinelle: semantic patch for missing of_node_put X-BeenThere: cocci@systeme.lip6.fr X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: cocci-bounces@systeme.lip6.fr Errors-To: cocci-bounces@systeme.lip6.fr On Mon, 20 May 2019, Sasha Levin wrote: > On Mon, May 20, 2019 at 11:52:37AM +0200, Julia Lawall wrote: > > > > > > On Mon, 20 May 2019, Pavel Machek wrote: > > > > > Hi! > > > > > > > A semantic patch has no access to comments. The only thing I can see to > > > > do is to use python to interact with some external tools. For example, > > > > you could write some code to collect the comments in a file and the > > > lines > > > > on which they occur, and then get the comment that most closely precedes > > > > the start of the function. > > > > > > How dangerous is missing of_node_put? AFAICT it will only result into > > > very small, one-time memory leak, right? > > > > > > Could we make sure these patches are _not_ going to stable? Leaking > > > few bytes once per boot is not really a serious bug. > > > > Sasha, > > > > Probably patches that add only of_node_put should not be auto selected for > > stable. > > I can filter them out, but those are fixes, right? Why are we concerned > about them making it into -stable? One of them may have introduced a crash. If there is a bad reference count manipulation elsewhere, then fixing one could cause a later incorrect one to make a double free. On the other hand, I don't know if the one that seemed to cause a crash really caused a crash. It was detected by syzkaller, and it is also possible that git bisect ended up at the wrong place. In any case, forgetting an of_node_put will normally just waste a little memory, so probably stable kernels don't care. julia _______________________________________________ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci