Hi Manivannan On Fri, 14 Feb 2025 at 11:39, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > On Tue, Feb 11, 2025 at 01:09:04AM +0530, Anand Moon wrote: > > 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. > > > > Microchip driver also has its own 'event_ops' and 'event_irq_chip', so defining > 'request_event_irq()' callback makes sense to me. > > > [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 still doesn't make sense to me. Under what condition you observed the > kmemleak? Since it points to devm_request_irq(), I can understand that the > memory allocated for the IRQ is not freed. But when does it happen? > The PCIe host driver is responsible for monitoring the PLDA PCIe EVENT irq. However, I have been unable to locate the register map necessary to implement the required code updates, alarm@archriscv:/media/nvme0/mainline/linux-riscv-6.y-devel$ cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 10: 101145 76126 79040 80218 RISC-V INTC 5 Edge riscv-timer 12: 3 0 0 0 SiFive PLIC 111 Edge 17030000.power-controller 13: 20 0 0 0 SiFive PLIC 30 Edge 1600c000.rng 14: 0 0 0 0 SiFive PLIC 1 Edge ccache_ecc 15: 0 0 0 0 SiFive PLIC 3 Edge ccache_ecc 16: 0 0 0 0 SiFive PLIC 4 Edge ccache_ecc 17: 0 0 0 0 SiFive PLIC 2 Edge ccache_ecc 20: 0 0 0 0 SiFive PLIC 73 Edge dw_axi_dmac_platform 21: 1694 0 0 0 SiFive PLIC 32 Edge ttyS0 22: 0 0 0 0 SiFive PLIC 35 Edge 10030000.i2c 23: 0 0 0 0 SiFive PLIC 75 Edge dw-mci 24: 0 0 0 0 SiFive PLIC 37 Edge 10050000.i2c 25: 171 0 0 0 SiFive PLIC 50 Edge 12050000.i2c 26: 0 0 0 0 SiFive PLIC 51 Edge 12060000.i2c 27: 10419 0 0 0 SiFive PLIC 74 Edge dw-mci 28: 6 0 0 0 SiFive PLIC 25 Edge 13010000.spi 29: 0 0 0 0 SiFive PLIC 38 Edge pl022 31: 0 0 0 0 PLDA PCIe EVENT 16 Edge 940000000.pcie 32: 0 0 0 0 PLDA PCIe EVENT 17 Edge 940000000.pcie 33: 0 0 0 0 PLDA PCIe EVENT 18 Edge 940000000.pcie 34: 0 0 0 0 PLDA PCIe EVENT 20 Edge 940000000.pcie 35: 0 0 0 0 PLDA PCIe EVENT 21 Edge 940000000.pcie 36: 0 0 0 0 PLDA PCIe EVENT 22 Edge 940000000.pcie 39: 0 0 0 0 PLDA PCIe EVENT 26 Edge 940000000.pcie 40: 0 0 0 0 PLDA PCIe EVENT 27 Edge 940000000.pcie 41: 0 0 0 0 17020000.pinctrl 41 Edge 16020000.mmc cd 42: 0 0 0 0 PLDA PCIe EVENT 28 Edge 940000000.pcie 44: 0 0 0 0 PLDA PCIe MSI 0 Edge PCIe PME, aerdrv, PCIe bwctrl 46: 0 0 0 0 PLDA PCIe EVENT 16 Edge 9c0000000.pcie 47: 0 0 0 0 PLDA PCIe EVENT 17 Edge 9c0000000.pcie 48: 0 0 0 0 PLDA PCIe EVENT 18 Edge 9c0000000.pcie 49: 0 0 0 0 PLDA PCIe EVENT 20 Edge 9c0000000.pcie 50: 0 0 0 0 PLDA PCIe EVENT 21 Edge 9c0000000.pcie 51: 0 0 0 0 PLDA PCIe EVENT 22 Edge 9c0000000.pcie 54: 0 0 0 0 PLDA PCIe EVENT 26 Edge 9c0000000.pcie 55: 0 0 0 0 PLDA PCIe EVENT 27 Edge 9c0000000.pcie 56: 0 0 0 0 PLDA PCIe EVENT 28 Edge 9c0000000.pcie 58: 0 0 0 0 PLDA PCIe MSI 134217728 Edge PCIe PME, aerdrv, PCIe bwctrl Yep, Thanks for your review comment. The following changes fix the kernel memory leak warning at my end. $ git diff diff --git a/drivers/pci/controller/plda/pcie-plda-host.c b/drivers/pci/controller/plda/pcie-plda-host.c index 4153214ca410..d4e7c1b49607 100644 --- a/drivers/pci/controller/plda/pcie-plda-host.c +++ b/drivers/pci/controller/plda/pcie-plda-host.c @@ -461,6 +461,7 @@ int plda_init_interrupts(struct platform_device *pdev, if (ret) { dev_err(dev, "failed to request IRQ %d\n", event_irq); + irq_dispose_mapping(event_irq); return ret; } } > > > > 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. > > > > The dummy request_event_irq() callback is not supposed to be needed in the first > place. So clearly, this patch is not fixing the actual memory leak but trying to > cover it up. You are correct. > > - Mani > Thanks -Anand > -- > மணிவண்ணன் சதாசிவம்
