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 896ECC433F5 for ; Tue, 1 Mar 2022 08:50:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233605AbiCAIv3 (ORCPT ); Tue, 1 Mar 2022 03:51:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233585AbiCAIv1 (ORCPT ); Tue, 1 Mar 2022 03:51:27 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A35558931F for ; Tue, 1 Mar 2022 00:50:46 -0800 (PST) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id AA7871F43F9D; Tue, 1 Mar 2022 08:50:43 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1646124644; bh=0ZrsARjiH24wsElmcwQCEqvABOocHSYJJ1IUet5VHj0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VkssrVfGYwFWa86K5JP4dvVJi6C+6lIuwJgIlWE43OPqM0Jkp6M9+FhyeHzetVEl+ GHv/S5dgJcAckf4Rz8kTvMI3l2e5f8DT3pWg6E9FH0/dMdwYbVh3DloQHKlmplgNrl /OS4LXT69IGzmAt7ExHejLoZJgKgThPU/lkUtaI3B1X8gsNlxdIrX/2m3NQApgnQ9s O7VmwhqHFJ0gpWAB6+nSGvaOOTp/YOQwllykSHbIkN/HgNEHhmUQyObYJGUj+vP1Ua w61pUvqu9bVvZlIXtQ7a3Nw/3CJkFwNzfWJj0KB7IwvU14dF5AExlse8rU/ajiY6Zm YPGpFHL9UWlOQ== Date: Tue, 1 Mar 2022 09:50:37 +0100 From: Boris Brezillon To: Xin Xiong Cc: Tudor Ambarus , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Nicolas Ferre , Alexandre Belloni , Claudiu Beznea , 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 v2] mtd: rawnand: atmel: fix refcount issue in atmel_nand_controller_init Message-ID: <20220301095037.1763e051@collabora.com> In-Reply-To: <20220301044556.36162-1-xiongx18@fudan.edu.cn> References: <20220301044556.36162-1-xiongx18@fudan.edu.cn> Organization: Collabora X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 Mar 2022 12:45:56 +0800 Xin Xiong wrote: > 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. > > Fix it by decrementing the refcount of specific object in those error > paths. > > 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 > --- > V1 -> V2: Rewrited the error handling block > --- > drivers/mtd/nand/raw/atmel/nand-controller.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c > index f3276ee9e4fe..0efeb5d77be0 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 atmel_nand_controller *nc, > nc->mck = 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 = PTR_ERR(nc->mck); > + goto out_release_dma; > } > > np = 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 = -EINVAL; > + goto out_release_dma; > } > > nc->smc = syscon_node_to_regmap(np); > @@ -2074,10 +2076,20 @@ static int atmel_nand_controller_init(struct atmel_nand_controller *nc, > if (IS_ERR(nc->smc)) { > ret = PTR_ERR(nc->smc); > dev_err(dev, "Could not get SMC regmap (err = %d)\n", ret); > - return ret; > + goto out_release_dma; > } > > return 0; > + > +out_release_dma: > + if (nc->caps->has_dma && !atmel_nand_avoid_dma) { > + if (nc->dmac) { > + dma_release_channel(nc->dmac); > + nc->dmac = NULL; > + } > + } Nit: if (nc->dmac) dma_release_channel(nc->dmac); should work just fine. > + > + return ret; > } > > static int