Commit 053ca37c authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI: j721e: Initialize pcie->cdns_pcie before using it 

Christian reported a NULL pointer dereference in j721e_pcie_probe() caused
by 19e86382 ("PCI: j721e: Drop redundant struct device *"), which
removed struct j721e_pcie.dev since there's another copy in struct
cdns_pcie.dev reachable via j721e_pcie->cdns_pcie->dev.

The problem is that j721e_pcie->cdns_pcie was dereferenced before being
initialized:

  j721e_pcie_probe
    pcie = devm_kzalloc()             # struct j721e_pcie
    j721e_pcie_ctrl_init(pcie)
      dev = pcie->cdns_pcie->dev      <-- dereference cdns_pcie
    switch (mode) {
    case PCI_MODE_RC:
      cdns_pcie = ...                 # alloc as part of pci_host_bridge
      pcie->cdns_pcie = cdns_pcie     <-- initialize pcie->cdns_pcie

Move the cdns_pcie initialization earlier so it is done before it is used.
This also simplifies the error exits.

Fixes: 19e86382 ("PCI: j721e: Drop redundant struct device *")
Link: https://lore.kernel.org/r/20220127222951.GA144828@bhelgaas
Link: https://lore.kernel.org/r/20220124122132.435743-1-christian.gmeiner@gmail.com


Reported-by: default avatarChristian Gmeiner <christian.gmeiner@gmail.com>
Tested-by: default avatarChristian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent e783362e

drivers/pci/controller/cadence/pci-j721e.c

+42 −43
Original line number Diff line number Diff line
@@ -356,8 +356,8 @@ static int j721e_pcie_probe(struct platform_device *pdev) 
	const struct j721e_pcie_data *data;

	struct cdns_pcie *cdns_pcie;

	struct j721e_pcie *pcie;

	struct cdns_pcie_rc *rc;

	struct cdns_pcie_ep *ep;

	struct cdns_pcie_rc *rc = NULL;

	struct cdns_pcie_ep *ep = NULL;

	struct gpio_desc *gpiod;

	void __iomem *base;

	struct clk *clk;
@@ -376,6 +376,46 @@ static int j721e_pcie_probe(struct platform_device *pdev) 
	if (!pcie)

		return -ENOMEM;



	switch (mode) {

	case PCI_MODE_RC:

		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST))

			return -ENODEV;



		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));

		if (!bridge)

			return -ENOMEM;



		if (!data->byte_access_allowed)

			bridge->ops = &cdns_ti_pcie_host_ops;

		rc = pci_host_bridge_priv(bridge);

		rc->quirk_retrain_flag = data->quirk_retrain_flag;

		rc->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;



		cdns_pcie = &rc->pcie;

		cdns_pcie->dev = dev;

		cdns_pcie->ops = &j721e_pcie_ops;

		pcie->cdns_pcie = cdns_pcie;

		break;

	case PCI_MODE_EP:

		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP))

			return -ENODEV;



		ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);

		if (!ep)

			return -ENOMEM;



		ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;



		cdns_pcie = &ep->pcie;

		cdns_pcie->dev = dev;

		cdns_pcie->ops = &j721e_pcie_ops;

		pcie->cdns_pcie = cdns_pcie;

		break;

	default:

		dev_err(dev, "INVALID device type %d\n", mode);

		return 0;

	}



	pcie->mode = mode;

	pcie->linkdown_irq_regfield = data->linkdown_irq_regfield;
@@ -426,28 +466,6 @@ static int j721e_pcie_probe(struct platform_device *pdev) 


	switch (mode) {

	case PCI_MODE_RC:

		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_HOST)) {

			ret = -ENODEV;

			goto err_get_sync;

		}



		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));

		if (!bridge) {

			ret = -ENOMEM;

			goto err_get_sync;

		}



		if (!data->byte_access_allowed)

			bridge->ops = &cdns_ti_pcie_host_ops;

		rc = pci_host_bridge_priv(bridge);

		rc->quirk_retrain_flag = data->quirk_retrain_flag;

		rc->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;



		cdns_pcie = &rc->pcie;

		cdns_pcie->dev = dev;

		cdns_pcie->ops = &j721e_pcie_ops;

		pcie->cdns_pcie = cdns_pcie;



		gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);

		if (IS_ERR(gpiod)) {

			ret = PTR_ERR(gpiod);
@@ -497,23 +515,6 @@ static int j721e_pcie_probe(struct platform_device *pdev) 


		break;

	case PCI_MODE_EP:

		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_EP)) {

			ret = -ENODEV;

			goto err_get_sync;

		}



		ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);

		if (!ep) {

			ret = -ENOMEM;

			goto err_get_sync;

		}

		ep->quirk_detect_quiet_flag = data->quirk_detect_quiet_flag;



		cdns_pcie = &ep->pcie;

		cdns_pcie->dev = dev;

		cdns_pcie->ops = &j721e_pcie_ops;

		pcie->cdns_pcie = cdns_pcie;



		ret = cdns_pcie_init_phy(dev, cdns_pcie);

		if (ret) {

			dev_err(dev, "Failed to init phy\n");
@@ -525,8 +526,6 @@ static int j721e_pcie_probe(struct platform_device *pdev) 
			goto err_pcie_setup;



		break;

	default:

		dev_err(dev, "INVALID device type %d\n", mode);

	}



	return 0;