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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 DA389C282C4 for ; Thu, 7 Feb 2019 12:54:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B57CC21902 for ; Thu, 7 Feb 2019 12:54:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727231AbfBGMx7 convert rfc822-to-8bit (ORCPT ); Thu, 7 Feb 2019 07:53:59 -0500 Received: from relay12.mail.gandi.net ([217.70.178.232]:35019 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726769AbfBGMx6 (ORCPT ); Thu, 7 Feb 2019 07:53:58 -0500 Received: from xps13 (aaubervilliers-681-1-80-177.w90-88.abo.wanadoo.fr [90.88.22.177]) (Authenticated sender: miquel.raynal@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id D404020000E; Thu, 7 Feb 2019 12:53:55 +0000 (UTC) Date: Thu, 7 Feb 2019 13:53:55 +0100 From: Miquel Raynal To: Wen Yang Cc: "bbrezillon@kernel.org" , "tudor.ambarus@microchip.com" , "richard@nod.at" , "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "marek.vasut@gmail.com" , "nicolas.ferre@microchip.com" , "alexandre.belloni@bootlin.com" , "ludovic.desroches@microchip.com" , "linux-mtd@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v4 3/3] mtd: rawnand: mtk: fix possible object reference leak Message-ID: <20190207135355.19fa523f@xps13> In-Reply-To: References: <1549540786-12196-1-git-send-email-yellowriver2010@hotmail.com> Organization: Bootlin X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Wen, Wen Yang wrote on Thu, 7 Feb 2019 12:02:52 +0000: > of_find_device_by_node() takes a reference to the struct device > when it finds a match via get_device, there is no need to call > get_device() twice. > We also should make sure to drop the reference to the device > taken by of_find_device_by_node() on driver unbind. > > Fixes: 1d6b1e464950 ("mtd: mediatek: driver for MTK Smart Device") > Signed-off-by: Wen Yang > --- > v4->v3: Add people in Cc and remove all lines. > v3->v2: Avoid two times of calling grtform_get_drvdata() > v2->v1: Since there is the only one user, let's remove the err_put_device label. > > drivers/mtd/nand/raw/mtk_ecc.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/mtd/nand/raw/mtk_ecc.c b/drivers/mtd/nand/raw/mtk_ecc.c > index 6432bd7..db804fe 100644 > --- a/drivers/mtd/nand/raw/mtk_ecc.c > +++ b/drivers/mtd/nand/raw/mtk_ecc.c > @@ -267,11 +267,14 @@ static struct mtk_ecc *mtk_ecc_get(struct device_node *np) > struct mtk_ecc *ecc; > > pdev = of_find_device_by_node(np); > - if (!pdev || !platform_get_drvdata(pdev)) > + if (!pdev) > return ERR_PTR(-EPROBE_DEFER); > - Please keep this blank line. > - get_device(&pdev->dev); > ecc = platform_get_drvdata(pdev); > + if (!ecc) { > + put_device(&pdev->dev); > + return ERR_PTR(-EPROBE_DEFER); > + } > + > clk_prepare_enable(ecc->clk); > mtk_ecc_hw_init(ecc); > Thanks, Miquèl