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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 110DAC2BB1D for ; Thu, 12 Mar 2020 14:49:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D81402051A for ; Thu, 12 Mar 2020 14:49:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727652AbgCLOtK (ORCPT ); Thu, 12 Mar 2020 10:49:10 -0400 Received: from mga03.intel.com ([134.134.136.65]:33482 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727072AbgCLOtK (ORCPT ); Thu, 12 Mar 2020 10:49:10 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Mar 2020 07:49:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,545,1574150400"; d="scan'208";a="389624041" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga004.jf.intel.com with ESMTP; 12 Mar 2020 07:49:06 -0700 Received: from andy by smile with local (Exim 4.93) (envelope-from ) id 1jCP92-0090qA-NX; Thu, 12 Mar 2020 16:49:08 +0200 Date: Thu, 12 Mar 2020 16:49:08 +0200 From: Andy Shevchenko To: Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-acpi@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Mika Westerberg , Jarkko Nikula , Wolfram Sang , Geert Uytterhoeven Subject: Re: [RFC PATCH] i2c: acpi: put device when verifying client fails Message-ID: <20200312144908.GX1922688@smile.fi.intel.com> References: <20200312133244.9564-1-wsa@the-dreams.de> <20200312144739.GW1922688@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200312144739.GW1922688@smile.fi.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Thu, Mar 12, 2020 at 04:47:39PM +0200, Andy Shevchenko wrote: > On Thu, Mar 12, 2020 at 02:32:44PM +0100, Wolfram Sang wrote: > > From: Wolfram Sang > > > > i2c_verify_client() can fail, so we need to put the device when that > > happens. > > NAK, this will do double put and messing up with reference counters. > Besides the fact, that device may disappear after looking up which leads us to > even more problems. > > See how i2c_acpi_find_client_by_adev() is used in callers. Perhaps proper "fix" is to add the explanation to a comment in the code to prevent false positive reports in the future? -- With Best Regards, Andy Shevchenko