Hi Manivannan On Mon, 10 Feb 2025 at 23:14, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > On Sat, Feb 08, 2025 at 07:31:08PM +0530, Anand Moon wrote: > > 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. > > What resources? > The Microchip PCIe host driver [1] handles PCI, SEC, DEBUG, and LOCAL hardware events through a dedicated framework [2]. This framework allows the core driver [3] to monitor and wait for these specific events. [1]: https://github.com/torvalds/linux/blob/master/drivers/pci/controller/plda/pcie-microchip-host.c#L90-L292 [2]: https://github.com/torvalds/linux/blob/master/drivers/pci/controller/plda/pcie-microchip-host.c#L374-L499 [3]: https://github.com/torvalds/linux/blob/master/drivers/pci/controller/plda/pcie-plda-host.c#L448-L466 StarFive PCIe driver currently lacks the necessary `request_event_irq` implementation to integrate with this event-handling mechanism, which prevents the core driver from properly responding to these events on StarFive platforms. static const struct plda_event mc_event = { . request_event_irq = mc_request_event_irq, .intx_event = EVENT_LOCAL_PM_MSI_INT_INTX, .msi_event = EVENT_LOCAL_PM_MSI_INT_MSI, }; This patch implements dummy `request_event_irq` for the StarFive PCIe driver, Since the core [3] driver is monitoring for these events > > This patch introduces an event IRQ handler and the necessary > > infrastructure to manage these IRQs, preventing the memory leak. > > > > These handles appear pointless to me. What purpose are they serving? > Yes, you are correct, the core event monitoring framework [3] triggered a kernel memory leak. This patch adds a dummy IRQ callback as a placeholder for proper event handling, which can be implemented in a future patch. > - Mani > Thanks -Anand > > Fixes: 647690479660 ("PCI: microchip: Add request_event_irq() callback function") > > Cc: Minda Chen <minda.chen@xxxxxxxxxxxxxxxx> > > Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx> > > --- > > 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 > > > > -- > மணிவண்ணன் சதாசிவம்
