Re: PCI: Race condition in pci_create_sysfs_dev_files (can't boot)

["Pali Rohár" <pali@kernel.org>]

On Friday 30 July 2021 10:18:44 Krzysztof Hałasa wrote:
> Pali, et al,
> 
> I'm encountering a problem booting an i.MX6-based device (Gateworks
> Ventana SBC). This is apparently a known issue:
> https://lkml.org/lkml/2020/7/16/388
> 
> Do you guys know of a fix for this? Booting this machine reliably is
> lately impossible.

Hello Krzysztof Hałasa! This is known issue and Krzysztof Wilczyński is
working on it... Just it will take some time as fixing it is not so
easy.

> First, it spews a warning:
> 
> pcieport 0000:00:00.0: PME: Signaling with IRQ 310
> 
> sysfs: cannot create duplicate filename '/devices/platform/soc/1ffc000.pcie/pci0000:00/0000:00:00.0/0000:e0'
> CPU: 2 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-rc3+ #40
> Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> Workqueue: events_unbound async_run_entry_fn
> 
> unwind_backtrace from show_stack+0x10/0x14
> show_stack from dump_stack_lvl+0x40/0x4c
> dump_stack_lvl from sysfs_warn_dup+0x54/0x60
> sysfs_warn_dup from sysfs_add_file_mode_ns+0x154/0x1a8
> sysfs_add_file_mode_ns from sysfs_create_bin_file+0x60/0x8c
> sysfs_create_bin_file from pci_create_resource_files+0xf4/0x140
> pci_create_resource_files from pci_bus_add_device+0x20/0x8c
> pci_bus_add_device from pci_bus_add_devices+0x3c/0x80
> pci_bus_add_devices from pci_bus_add_devices+0x70/0x80
> pci_bus_add_devices from pci_host_probe+0x3c/0x90
> pci_host_probe from dw_pcie_host_init+0x200/0x4b4
> dw_pcie_host_init from imx6_pcie_probe+0x338/0x668
> imx6_pcie_probe from platform_probe+0x80/0xc0
> platform_probe from really_probe+0x158/0x324
> really_probe from __driver_probe_device+0x84/0xe4
> __driver_probe_device from driver_probe_device+0x34/0xd0
> driver_probe_device from __driver_attach_async_helper+0x20/0x38
> __driver_attach_async_helper from async_run_entry_fn+0x24/0xb4
> async_run_entry_fn from process_one_work+0x164/0x3b0
> process_one_work from worker_thread+0x2c/0x52c
> worker_thread from kthread+0x110/0x154
> kthread from ret_from_fork+0x14/0x24
> 
> pcieport 0000:01:00.0: enabling device (0140 -> 0143)
> 
> Then:
> Unable to handle kernel paging request at virtual address 6f736572 (ASCII = "reso")
> pgd = (ptrval)
> [6f736572] *pgd=00000000
> Internal error: Oops: 5 [#1] SMP ARM
> Modules linked in:
> CPU: 2 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-rc3+ #40
> Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> Workqueue: events_unbound async_run_entry_fn
> PC is at string_nocheck+0x20/0xa0
> LR is at string+0x54/0x64
> Process kworker/u8:0 (pid: 7, stack limit = 0x(ptrval))
> 
> string_nocheck from string+0x54/0x64
> string from vsnprintf+0x1c4/0x48c
> vsnprintf from vprintk_store+0x80/0x33c
> vprintk_store from vprintk_emit+0x6c/0x1e0
> vprintk_emit from vprintk_default+0x20/0x28
> vprintk_default from printk+0x1c/0x2c
> printk from sysfs_warn_dup+0x50/0x60
> sysfs_warn_dup from sysfs_add_file_mode_ns+0x154/0x1a8
> sysfs_add_file_mode_ns from sysfs_create_bin_file+0x60/0x8c
> sysfs_create_bin_file from pci_create_resource_files+0xf4/0x140
> pci_create_resource_files from pci_bus_add_device+0x20/0x8c
> pci_bus_add_device from pci_bus_add_devices+0x3c/0x80
> pci_bus_add_devices from pci_bus_add_devices+0x70/0x80
> pci_bus_add_devices from pci_host_probe+0x3c/0x90
> pci_host_probe from dw_pcie_host_init+0x200/0x4b4
> dw_pcie_host_init from imx6_pcie_probe+0x338/0x668
> imx6_pcie_probe from platform_probe+0x80/0xc0
> platform_probe from really_probe+0x158/0x324
> really_probe from __driver_probe_device+0x84/0xe4
> __driver_probe_device from driver_probe_device+0x34/0xd0
> driver_probe_device from __driver_attach_async_helper+0x20/0x38
> __driver_attach_async_helper from async_run_entry_fn+0x24/0xb4
> async_run_entry_fn from process_one_work+0x164/0x3b0
> process_one_work from worker_thread+0x2c/0x52c
> worker_thread from kthread+0x110/0x154
> kthread from ret_from_fork+0x14/0x24
> Code: e1dd42b2 e58d301c e3540000 0a000019 (e5d2e000)
> --
> Krzysztof "Chris" Hałasa
> 
> Sieć Badawcza Łukasiewicz
> Przemysłowy Instytut Automatyki i Pomiarów PIAP
> Al. Jerozolimskie 202, 02-486 Warszawa