linux-kernel - Re: [PATCH] PCI: mediatek-gen3: Fix refcount leak in mtk_pcie_init_irq

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Date:   Fri, 27 May 2022 16:45:25 +0800
From:   Miles Chen <miles.chen@...iatek.com>
To:     <linmq006@...il.com>
CC:     <bhelgaas@...gle.com>, <jianjun.wang@...iatek.com>, <kw@...ux.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <linux-pci@...r.kernel.org>,
        <lorenzo.pieralisi@....com>, <matthias.bgg@...il.com>,
        <maz@...nel.org>, <robh@...nel.org>, <ryder.lee@...iatek.com>
Subject: Re: [PATCH] PCI: mediatek-gen3: Fix refcount leak in mtk_pcie_init_irq_domains

Hi Miaoqian,

>Signed-off-by: Miaoqian Lin <linmq006@...il.com>
>---
> drivers/pci/controller/pcie-mediatek-gen3.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
>index 3e8d70bfabc6..da8e9db0abdf 100644
>--- a/drivers/pci/controller/pcie-mediatek-gen3.c
>+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
>@@ -600,6 +600,7 @@ 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");
>+		of_node_put(intc_node);
> 		return -ENODEV;
> 	}

Thanks for doing this.

I checked mtk_pcie_init_irq_domains() and there are multiple exit paths like
err_msi_domain and err_msi_bottom_domain and the normal path which also
need of_node_put(intc_node).

Maybe we can move the of_node_put(intc_node) to #54 below and cover
all possible paths?


cheers,
Miles

e.g.,

static int mtk_pcie_init_irq_domains(struct mtk_gen3_pcie *pcie)
{
	struct device *dev = pcie->dev;
	struct device_node *intc_node, *node = dev->of_node;
	int ret;

	raw_spin_lock_init(&pcie->irq_lock);

	/* Setup INTx */
	intc_node = of_get_child_by_name(node, "interrupt-controller");
	if (!intc_node) {
		dev_err(dev, "missing interrupt-controller node\n");
		return -ENODEV;
	}

	pcie->intx_domain = irq_domain_add_linear(intc_node, PCI_NUM_INTX,
						  &intx_domain_ops, pcie);
	of_node_put(intc_node);
	if (!pcie->intx_domain) {
		dev_err(dev, "failed to create INTx IRQ domain\n");
		return -ENODEV;
	}

	/* Setup MSI */
	mutex_init(&pcie->lock);

	pcie->msi_bottom_domain = irq_domain_add_linear(node, PCIE_MSI_IRQS_NUM,
				  &mtk_msi_bottom_domain_ops, pcie);
	if (!pcie->msi_bottom_domain) {
		dev_err(dev, "failed to create MSI bottom domain\n");
		ret = -ENODEV;
		goto err_msi_bottom_domain;
	}

	pcie->msi_domain = pci_msi_create_irq_domain(dev->fwnode,
						     &mtk_msi_domain_info,
						     pcie->msi_bottom_domain);
	if (!pcie->msi_domain) {
		dev_err(dev, "failed to create MSI domain\n");
		ret = -ENODEV;
		goto err_msi_domain;
	}

	return 0;

err_msi_domain:
	irq_domain_remove(pcie->msi_bottom_domain);
err_msi_bottom_domain:
	irq_domain_remove(pcie->intx_domain);

	return ret;
}
> 
>-- 
>2.25.1