[PATCH v1] PCI: starfive: Fix kmemleak in StarFive PCIe driver's IRQ handling

[Anand Moon <linux.amoon@gmail.com>]

kmemleak reported following debug log

$ sudo cat /sys/kernel/debug/kmemleak
unreferenced object 0xffffffd6c47c2600 (size 128):
  comm "kworker/u16:2", pid 38, jiffies 4294942263
  hex dump (first 32 bytes):
    cc 7c 5a 8d ff ff ff ff 40 b0 47 c8 d6 ff ff ff  .|Z.....@.G.....
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace (crc 4f07ff07):
    __create_object+0x2a/0xfc
    kmemleak_alloc+0x38/0x98
    __kmalloc_cache_noprof+0x296/0x444
    request_threaded_irq+0x168/0x284
    devm_request_threaded_irq+0xa8/0x13c
    plda_init_interrupts+0x46e/0x858
    plda_pcie_host_init+0x356/0x468
    starfive_pcie_probe+0x2f6/0x398
    platform_probe+0x106/0x150
    really_probe+0x30e/0x746
    __driver_probe_device+0x11c/0x2c2
    driver_probe_device+0x5e/0x316
    __device_attach_driver+0x296/0x3a4
    bus_for_each_drv+0x1d0/0x260
    __device_attach+0x1fa/0x2d6
    device_initial_probe+0x14/0x28
unreferenced object 0xffffffd6c47c2900 (size 128):
  comm "kworker/u16:2", pid 38, jiffies 4294942281

This patch addresses a kmemleak reported during StarFive PCIe driver
initialization. The leak was observed with kmemleak reporting
unreferenced objects related to IRQ handling. The backtrace pointed
to the `request_threaded_irq` and related functions within the
`plda_init_interrupts` path, indicating that some allocated memory
related to IRQs was not being properly freed.

The issue was that while the driver requested IRQs, it wasn't
correctly handling the lifecycle of the associated resources.
This patch introduces an event IRQ handler and the necessary
infrastructure to manage these IRQs, preventing the memory leak.

Fixes: 647690479660 ("PCI: microchip: Add request_event_irq() callback function")
Cc: Minda Chen <minda.chen@starfivetech.com>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
 drivers/pci/controller/plda/pcie-starfive.c | 39 +++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/pci/controller/plda/pcie-starfive.c b/drivers/pci/controller/plda/pcie-starfive.c
index e73c1b7bc8ef..a57177a8be8a 100644
--- a/drivers/pci/controller/plda/pcie-starfive.c
+++ b/drivers/pci/controller/plda/pcie-starfive.c
@@ -381,7 +381,46 @@ static const struct plda_pcie_host_ops sf_host_ops = {
 	.host_deinit = starfive_pcie_host_deinit,
 };
 
+/* IRQ handler for PCIe events */
+static irqreturn_t starfive_event_handler(int irq, void *dev_id)
+{
+	struct plda_pcie_rp *port = dev_id;
+	struct irq_data *data;
+
+	/* Retrieve IRQ data */
+	data = irq_domain_get_irq_data(port->event_domain, irq);
+
+	if (data) {
+		dev_err_ratelimited(port->dev, "Event IRQ %ld triggered\n",
+				    data->hwirq);
+	} else {
+		dev_err_ratelimited(port->dev, "Invalid event IRQ %d\n", irq);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* Request an IRQ for a specific event */
+static int starfive_request_event_irq(struct plda_pcie_rp *plda, int event_irq,
+				      int event)
+{
+	int ret;
+
+	/* Request the IRQ and associate it with the handler */
+	ret = devm_request_irq(plda->dev, event_irq, starfive_event_handler,
+			       IRQF_SHARED, "starfivepcie", plda);
+
+	if (ret) {
+		dev_err(plda->dev, "Failed to request IRQ %d: %d\n", event_irq,
+			ret);
+		return ret;
+	}
+
+	return ret;
+}
+
 static const struct plda_event stf_pcie_event = {
+	.request_event_irq = starfive_request_event_irq,
 	.intx_event = EVENT_PM_MSI_INT_INTX,
 	.msi_event  = EVENT_PM_MSI_INT_MSI
 };

base-commit: bb066fe812d6fb3a9d01c073d9f1e2fd5a63403b
-- 
2.48.1