[PATCH v3] PCI: imx6: fix resource leaks in probe error paths

imx_pcie_probe() leaks both pwrctrl devices and power domains on
failure:

- imx_pcie_attach_pd() attaches the "pcie" and "pcie_phy" power domains
  and creates device links to them, but the device links are only kept
  in a local variable and nothing detaches the domains on probe failure
  or deferral, so all of them leak.

- A failure of devm_pm_runtime_set_active_enabled() returns directly
  without destroying the pwrctrl devices.

- A partial failure inside imx_pcie_attach_pd() leaks the power domains
  and device links that were already attached.

Save the device links, add imx_pcie_detach_pd() to release the power
domains and device links in reverse order of acquisition, call it from
the probe error paths, and make imx_pcie_attach_pd() release everything
it has attached so far on failure.

Reported-by: [email protected]
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: hanzhijian <[email protected]>
---
 drivers/pci/controller/dwc/pci-imx6.c | 42 ++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 39790e66b..467006d83 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -182,6 +182,9 @@ struct imx_pcie {
 	struct device		*pd_pcie;
 	/* power domain for pcie phy */
 	struct device		*pd_pcie_phy;
+	/* device links for the power domains */
+	struct device_link	*pd_link;
+	struct device_link	*pd_phy_link;
 	struct phy		*phy;
 	const struct imx_pcie_drvdata *drvdata;
 
@@ -639,6 +642,26 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
 }
 #endif
 
+static void imx_pcie_detach_pd(struct imx_pcie *imx_pcie)
+{
+	if (imx_pcie->pd_phy_link) {
+		device_link_del(imx_pcie->pd_phy_link);
+		imx_pcie->pd_phy_link = NULL;
+	}
+	if (!IS_ERR_OR_NULL(imx_pcie->pd_pcie_phy)) {
+		dev_pm_domain_detach(imx_pcie->pd_pcie_phy, true);
+		imx_pcie->pd_pcie_phy = NULL;
+	}
+	if (imx_pcie->pd_link) {
+		device_link_del(imx_pcie->pd_link);
+		imx_pcie->pd_link = NULL;
+	}
+	if (!IS_ERR_OR_NULL(imx_pcie->pd_pcie)) {
+		dev_pm_domain_detach(imx_pcie->pd_pcie, true);
+		imx_pcie->pd_pcie = NULL;
+	}
+}
+
 static int imx_pcie_attach_pd(struct device *dev)
 {
 	struct imx_pcie *imx_pcie = dev_get_drvdata(dev);
@@ -660,12 +683,18 @@ static int imx_pcie_attach_pd(struct device *dev)
 			DL_FLAG_RPM_ACTIVE);
 	if (!link) {
 		dev_err(dev, "Failed to add device_link to pcie pd\n");
+		imx_pcie_detach_pd(imx_pcie);
 		return -EINVAL;
 	}
+	imx_pcie->pd_link = link;
 
 	imx_pcie->pd_pcie_phy = dev_pm_domain_attach_by_name(dev, "pcie_phy");
-	if (IS_ERR(imx_pcie->pd_pcie_phy))
-		return PTR_ERR(imx_pcie->pd_pcie_phy);
+	if (IS_ERR(imx_pcie->pd_pcie_phy)) {
+		int ret = PTR_ERR(imx_pcie->pd_pcie_phy);
+
+		imx_pcie_detach_pd(imx_pcie);
+		return ret;
+	}
 
 	link = device_link_add(dev, imx_pcie->pd_pcie_phy,
 			DL_FLAG_STATELESS |
@@ -673,8 +702,10 @@ static int imx_pcie_attach_pd(struct device *dev)
 			DL_FLAG_RPM_ACTIVE);
 	if (!link) {
 		dev_err(dev, "Failed to add device_link to pcie_phy pd\n");
+		imx_pcie_detach_pd(imx_pcie);
 		return -EINVAL;
 	}
+	imx_pcie->pd_phy_link = link;
 
 	return 0;
 }
@@ -1956,8 +1987,10 @@ static int imx_pcie_probe(struct platform_device *pdev)
 		return ret;
 
 	ret = pci_pwrctrl_create_devices(dev);
-	if (ret)
+	if (ret) {
+		imx_pcie_detach_pd(imx_pcie);
 		return dev_err_probe(dev, ret, "failed to create pwrctrl devices\n");
+	}
 
 	pci->use_parent_dt_ranges = true;
 	if (imx_pcie->drvdata->mode == DW_PCIE_EP_TYPE) {
@@ -1975,7 +2008,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
 			pm_runtime_no_callbacks(dev);
 			ret = devm_pm_runtime_set_active_enabled(dev);
 			if (ret < 0)
-				return ret;
+				goto err_pwrctrl_destroy;
 		}
 
 		if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_SKIP_L23_READY))
@@ -2001,6 +2034,7 @@ static int imx_pcie_probe(struct platform_device *pdev)
 err_pwrctrl_destroy:
 	if (ret != -EPROBE_DEFER)
 		pci_pwrctrl_destroy_devices(dev);
+	imx_pcie_detach_pd(imx_pcie);
 	return ret;
 }
 
-- 
2.43.0