Hi Sunil, Thanks for your reply! (really appricate it). This WARNING truly occurred. Through the added debug info, I found that the device was registered to proc via pci_proc_init and acpi_pci_root_add paths respectively, which ultimately triggered the warning message. Let me try to reproduce it on qemu first. I'll keep you updated. Thanks again. Regards, Shuan On Thu, Jul 3, 2025 at 2:36 PM Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> wrote: > > On Wed, Jul 02, 2025 at 11:51:11PM +0800, Shuan He wrote: > > Hi All. > > I encountered a WARNING printed out during the kernel starting process > > on my developing environment. > > (with RISC-V arch, 6.12 kernel, and Debian 13 OS). > > > > WARN Trace: > > [ 0.518993] proc_dir_entry '000c:00/00.0' already registered > > [ 0.519187] WARNING: CPU: 2 PID: 179 at fs/proc/generic.c:375 proc_register+0xf6/0x180 > > [ 0.519214] [<ffffffff804055a6>] proc_register+0xf6/0x180 > > [ 0.519217] [<ffffffff80405a9e>] proc_create_data+0x3e/0x60 > > [ 0.519220] [<ffffffff80616e44>] pci_proc_attach_device+0x74/0x130 > > [ 0.509991] [<ffffffff805f1af2>] pci_bus_add_device+0x42/0x100 > > [ 0.509997] [<ffffffff805f1c76>] pci_bus_add_devices+0xc6/0x110 > > [ 0.519230] [<ffffffff8066763c>] acpi_pci_root_add+0x54c/0x810 > > [ 0.519233] [<ffffffff8065d206>] acpi_bus_attach+0x196/0x2f0 > > [ 0.519234] [<ffffffff8065d390>] acpi_scan_clear_dep_fn+0x30/0x70 > > [ 0.519236] [<ffffffff800468fa>] process_one_work+0x19a/0x390 > > [ 0.519239] [<ffffffff80047a6e>] worker_thread+0x2be/0x420 > > [ 0.519241] [<ffffffff80050dc4>] kthread+0xc4/0xf0 > > [ 0.519243] [<ffffffff80ad6ad2>] ret_from_fork+0xe/0x1c > > > This should not happen. I suspect some issue in ACPI namespace/_PRT. Can > you reproduce this on qemu virt machine? > > Regards > Sunil >