[PATCH v2] perf/dwc_pcie: Fix PCI device reference leak in probe

pci_get_domain_bus_and_slot() returns a referenced PCI device. When the
subsequent RAS DES capability lookup fails, dwc_pcie_pmu_probe() returns
-ENODEV without releasing that reference. Repeated failed probes can
therefore keep the PCI device allocated after removal.

Declare the looked-up device with __free(pci_dev_put), so the temporary
reference is released on every return path. Keeping the reference scoped
to the whole probe also covers all later uses of the device during
initialization.

This issue was found by a static analysis checker and confirmed by manual
source review.

Fixes: 7f35b429802a ("perf/dwc_pcie: fix duplicate pci_dev devices")
Suggested-by: Markus Elfring <[email protected]>
Signed-off-by: Ruoyu Wang <[email protected]>
---
Changes in v2:
- Manage the lookup reference with __free(pci_dev_put).
- Keep the reference scoped through the complete probe.

Link: https://lore.kernel.org/r/[email protected]/
---
 drivers/perf/dwc_pcie_pmu.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c
index 5385401fa9cf6..0e69bd71c3e61 100644
--- a/drivers/perf/dwc_pcie_pmu.c
+++ b/drivers/perf/dwc_pcie_pmu.c
@@ -694,16 +694,16 @@ static struct notifier_block dwc_pcie_pmu_nb = {
 
 static int dwc_pcie_pmu_probe(struct platform_device *plat_dev)
 {
-	struct pci_dev *pdev;
+	u32 sbdf = plat_dev->id;
+	struct pci_dev *pdev __free(pci_dev_put) =
+		pci_get_domain_bus_and_slot(sbdf >> 16,
+					    PCI_BUS_NUM(sbdf & 0xffff),
+					    sbdf & 0xff);
 	struct dwc_pcie_pmu *pcie_pmu;
 	char *name;
-	u32 sbdf;
 	u16 vsec;
 	int ret;
 
-	sbdf = plat_dev->id;
-	pdev = pci_get_domain_bus_and_slot(sbdf >> 16, PCI_BUS_NUM(sbdf & 0xffff),
-					   sbdf & 0xff);
 	if (!pdev) {
 		pr_err("No pdev found for the sbdf 0x%x\n", sbdf);
 		return -ENODEV;
@@ -713,7 +713,6 @@ static int dwc_pcie_pmu_probe(struct platform_device *plat_dev)
 	if (!vsec)
 		return -ENODEV;
 
-	pci_dev_put(pdev);
 	name = devm_kasprintf(&plat_dev->dev, GFP_KERNEL, "dwc_rootport_%x", sbdf);
 	if (!name)
 		return -ENOMEM;
-- 
2.51.0