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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB2ABC433EF for ; Mon, 31 Jan 2022 16:16:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380252AbiAaQQh (ORCPT ); Mon, 31 Jan 2022 11:16:37 -0500 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:50581 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380193AbiAaQQO (ORCPT ); Mon, 31 Jan 2022 11:16:14 -0500 Received: (Authenticated sender: miquel.raynal@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 77408C0002; Mon, 31 Jan 2022 16:16:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1643645773; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gQZNpFwpLCJ2QyIMMCx53V4RScNFk6vSypQeECK4z4c=; b=NTnrvH4RJ0iYZUySnPLyEFtsw7hdyFpmXXaxYfRvf4A3oB2RQmWvP82HDlpnVT6zZDejcc yTFsBLtBz5DqIPbN+H06NMTb6Y7+uHUENEsCZvHZp492AHbg2rjLCFPLZpSRsZ8MvZjRRQ UZWGhs0QiHgHUn/8X4Y5ZwOoutcg4cRAlmQSrt3fWAyenVzewJ/5SlKAzeQAMRdrArCt4D D10feyLYD0zSL7OQriWl1VeVrZbKxPfQ0UEZpkr4RuJm8YyJHG0UHj6wER3s0Gz/kvab9L 6RkRBbWqf07yn9B8QKjxLSYAR4KdniVXfMWbZsVj8pKFbayiVy1cebVNGquauw== Date: Mon, 31 Jan 2022 17:16:06 +0100 From: Miquel Raynal To: Xin Xiong Cc: Tudor Ambarus , Richard Weinberger , Vignesh Raghavendra , Nicolas Ferre , Alexandre Belloni , Ludovic Desroches , Boris Brezillon , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn, Xiyu Yang , Xin Tan Subject: Re: [PATCH] mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init Message-ID: <20220131171606.2733d1a3@xps13> In-Reply-To: <20220127084104.3683-1-xiongx18@fudan.edu.cn> References: <20220127084104.3683-1-xiongx18@fudan.edu.cn> Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Xin, xiongx18@fudan.edu.cn wrote on Thu, 27 Jan 2022 16:41:05 +0800: > The reference counting issue happens in several error handling paths > on a refcounted object "nc->dmac". In these paths, the function simply > returns the error code, forgetting to balance the reference count of > "nc->dmac", increased earlier by dma_request_channel(), which may > cause refcount leaks. >=20 > Fix it by decrementing the refcount of specific object in those error > paths. >=20 > Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver") > Co-developed-by: Xiyu Yang > Signed-off-by: Xiyu Yang > Co-developed-by: Xin Tan > Signed-off-by: Xin Tan > Signed-off-by: Xin Xiong > --- > drivers/mtd/nand/raw/atmel/nand-controller.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) >=20 > diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/n= and/raw/atmel/nand-controller.c > index f3276ee9e4fe..7003877632fb 100644 > --- a/drivers/mtd/nand/raw/atmel/nand-controller.c > +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c > @@ -2060,13 +2060,15 @@ static int atmel_nand_controller_init(struct atme= l_nand_controller *nc, > nc->mck =3D of_clk_get(dev->parent->of_node, 0); > if (IS_ERR(nc->mck)) { > dev_err(dev, "Failed to retrieve MCK clk\n"); > - return PTR_ERR(nc->mck); > + ret =3D PTR_ERR(nc->mck); > + goto out_release_dma; > } > =20 > np =3D of_parse_phandle(dev->parent->of_node, "atmel,smc", 0); > if (!np) { > dev_err(dev, "Missing or invalid atmel,smc property\n"); > - return -EINVAL; > + ret =3D -EINVAL; > + goto out_release_dma; > } > =20 > nc->smc =3D syscon_node_to_regmap(np); > @@ -2074,10 +2076,20 @@ static int atmel_nand_controller_init(struct atme= l_nand_controller *nc, > if (IS_ERR(nc->smc)) { > ret =3D PTR_ERR(nc->smc); > dev_err(dev, "Could not get SMC regmap (err =3D %d)\n", ret); > - return ret; > + goto out_release_dma; > } > =20 > return 0; > + > +out_release_dma: > + if (nc->caps->has_dma && !atmel_nand_avoid_dma) { > + if (!IS_ERR_OR_NULL(nc->dmac)) { if (!nc->dmac) { > + dma_release_channel(nc->dmac); > + nc->dmac =3D NULL; This is then unnecessary and the whole block and the two first checks can then be ignored as dmac will not be set otherwise (and will stay NULL). > + } > + } > + > + return ret; > } > =20 > static int Thanks, Miqu=C3=A8l