Re: [PATCH v3] PCI: mediatek-gen3: Fix refcount leak in mtk_pcie_init_irq_domains

From: Bjorn Helgaas <helgaas@kernel.org>
To: Miaoqian Lin <linmq006@gmail.com>
Cc: miles.chen@mediatek.com, "Ryder Lee" <ryder.lee@mediatek.com>,
	"Jianjun Wang" <jianjun.wang@mediatek.com>,
	"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Marc Zyngier" <maz@kernel.org>,
	linux-pci@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3] PCI: mediatek-gen3: Fix refcount leak in mtk_pcie_init_irq_domains
Date: Wed, 8 Jun 2022 16:20:58 -0500	[thread overview]
Message-ID: <20220608212058.GA424368@bhelgaas> (raw)
In-Reply-To: <20220601041259.56185-1-linmq006@gmail.com>

On Wed, Jun 01, 2022 at 08:12:58AM +0400, Miaoqian Lin wrote:
> of_get_child_by_name() returns a node pointer with refcount
> incremented, we should use of_node_put() on it when not need anymore.
> Add missing of_node_put() to avoid refcount leak.
> 
> Fixes: 814cceebba9b ("PCI: mediatek-gen3: Add INTx support")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>

Can we get an ack from Ryder or Jianjun, as well, since they're listed
as maintainers?

> ---
> changes in v2:
> - move of_node_put(intc_node) right after irq_domain_add_linear to cover
> normal path and error paths.
> ---
> changes in v3:
> - call of_node_put() in error paths with goto, and call of_node_put() before
>   return 0 in normal path. Since this function has a goto part to handle
>   resources, so put them together, as suggested by Miles Chen <miles.chen@mediatek.com>
> 
> v1 link: https://lore.kernel.org/all/20220526110246.53502-1-linmq006@gmail.com/
> v2 link: https://lore.kernel.org/all/20220530064807.34534-1-linmq006@gmail.com/
> ---
>  drivers/pci/controller/pcie-mediatek-gen3.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
> index 3e8d70bfabc6..bceed28446ed 100644
> --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> @@ -600,7 +600,8 @@ static int mtk_pcie_init_irq_domains(struct mtk_gen3_pcie *pcie)
>  						  &intx_domain_ops, pcie);
>  	if (!pcie->intx_domain) {
>  		dev_err(dev, "failed to create INTx IRQ domain\n");
> -		return -ENODEV;
> +		ret = -ENODEV;
> +		goto out_put_node;
>  	}
>  
>  	/* Setup MSI */
> @@ -623,13 +624,15 @@ static int mtk_pcie_init_irq_domains(struct mtk_gen3_pcie *pcie)
>  		goto err_msi_domain;
>  	}
>  
> +	of_node_put(intc_node);
>  	return 0;
>  
>  err_msi_domain:
>  	irq_domain_remove(pcie->msi_bottom_domain);
>  err_msi_bottom_domain:
>  	irq_domain_remove(pcie->intx_domain);
> -
> +out_put_node:
> +	of_node_put(intc_node);
>  	return ret;
>  }
>  
> -- 
> 2.25.1
> 
> 
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