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a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=SHLKyJlQ92ycclVRVclHzYt7AhLEu/8J5eYn5vce5kI=; b=ijmtIpiDqGjAg+LyC4KtjTcqPEfytqF3S8pSW81KfNo/73c6OSQ+umrfumunmcizZaVSKkein ECUjBwpEvNk409dyr1Pf309w/eDSEK5rCEr7ZQN1M/CRKF3IG/XxdjH4oafKDdxf33H+PwgWcna Vi7kFdG0/jk70YncXV8qvUI= Received: from mail.maildlp.com (unknown [172.19.163.15]) by canpmsgout07.his.huawei.com (SkyGuard) with ESMTPS id 4jDSfm0dc8zLlXn; Tue, 27 Oct 2026 19:18:40 +0800 (CST) Received: from whupemo200011.china.huawei.com (unknown [7.152.185.179]) by mail.maildlp.com (Postfix) with ESMTPS id EE4B940578; Tue, 27 Oct 2026 19:18:45 +0800 (CST) Received: from [10.174.178.46] (10.174.178.46) by whupemo200011.china.huawei.com (7.152.185.179) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.45; Tue, 27 Oct 2026 19:18:44 +0800 Subject: Re: [PATCH] mtd: ubi: nvmem: Fix device_node leak in ubi_nvmem_add() To: Vishal Satle , Richard Weinberger , Daniel Golle , Miquel Raynal , Vignesh Raghavendra CC: , , References: <20261027091507.130294-1-vishalsatleit24@gmail.com> From: Zhihao Cheng Message-ID: <67bc8e42-c4e9-bfbd-f451-1ef5b492a084@huawei.com> Date: Tue, 27 Oct 2026 19:18:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 In-Reply-To: <20261027091507.130294-1-vishalsatleit24@gmail.com> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems200001.china.huawei.com (7.221.188.67) To whupemo200011.china.huawei.com (7.152.185.179) ÔÚ 2026/10/27 17:15, Vishal Satle дµÀ: > ubi_nvmem_add() calls of_get_child_by_name() to verify that the UBI > volume device node contains an "nvmem-layout" subnode. > of_get_child_by_name() returns a pointer to the child device_node > with its reference count incremented. > > Because the returned pointer was only evaluated as a boolean condition > and not retained or put, the reference count of the "nvmem-layout" node > was leaked whenever an NVMEM-enabled UBI volume was registered. > > Assign the child node to a local variable and release it with > of_node_put() once existence has been validated. > > Fixes: 34a5d8525b6a ("mtd: ubi: add NVMEM support") > Cc: stable@vger.kernel.org > Signed-off-by: Vishal Satle > --- > drivers/mtd/ubi/nvmem.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) Reviewed-by: Zhihao Cheng > > diff --git a/drivers/mtd/ubi/nvmem.c b/drivers/mtd/ubi/nvmem.c > index 2dade9727..15737d511 100644 > --- a/drivers/mtd/ubi/nvmem.c > +++ b/drivers/mtd/ubi/nvmem.c > @@ -61,6 +61,7 @@ static int ubi_nvmem_reg_read(void *priv, unsigned int from, > static int ubi_nvmem_add(struct ubi_volume_info *vi) > { > struct device_node *np = dev_of_node(vi->dev); > + struct device_node *layout; > struct nvmem_config config = {}; > struct ubi_nvmem *unv; > int ret; > @@ -68,9 +69,12 @@ static int ubi_nvmem_add(struct ubi_volume_info *vi) > if (!np) > return 0; > > - if (!of_get_child_by_name(np, "nvmem-layout")) > + layout = of_get_child_by_name(np, "nvmem-layout"); > + if (!layout) > return 0; > > + of_node_put(layout); > + > if (WARN_ON_ONCE(vi->usable_leb_size <= 0) || > WARN_ON_ONCE(vi->size <= 0)) > return -EINVAL; >