Messages in this thread | | | Date | Wed, 13 Apr 2022 14:52:55 +0200 | Subject | Re: PCI: Race condition in pci_create_sysfs_dev_files (can't boot) | From | Koen Vandeputte <> |
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On 06.04.22 16:08, Koen Vandeputte wrote: > > On 01.04.22 15:50, Koen Vandeputte wrote: >> >> On 15.02.22 07:35, Krzysztof Hałasa wrote: >>> Hi Bjorn, >>> >>> Bjorn Helgaas <helgaas@kernel.org> writes: >>> >>>> Koen collected some interesting logs at >>>> https://lore.kernel.org/all/cd4812f0-1de3-0582-936c-ba30906595af@citymesh.com/ >>>> >>>> They're from v5.10, which was before all of Krzysztof W's nice work >>>> converting to static attributes, but Koen's log shows the error >>>> happening in the pci_sysfs_init() initcall, which is *after* >>>> imx6_pcie_probe(): >>>> >>>> imx6_pcie_probe # probably device initcall (level 6) >>>> ... >>>> pci_create_sysfs_dev_files >>>> >>>> pci_sysfs_init # late initcall (level 7) >>>> pci_create_sysfs_dev_files >>>> "sysfs: cannot create duplicate filename" >>> Well, imx6_pcie_probe() is called indirectly by >>> platform_driver_register(). I guess it doesn't know about the initcall >>> ordering, after it's registered. >>> >>> It looks like the problem is the imx6_pcie_probe() (via >>> dw_pcie_host_init() -> pci_host_probe()) is interfering with >>> pci_sysfs_init(). This may eventually cause some invalid memory access >>> as well. >>> >>> BTW I thought for a moment that maybe 5.14 is free from this. I was >>> wrong. The problem doesn't manifest itself on my custom i.MX6 device >>> (using Tinyrex CPU module from Voipac/Fedevel, perhaps because I don't >>> use any PCI devices there). It does on Ventana SBC from Gateworks, >>> though. BTW the above (and below) is v5.16. >>> >>> It goes like this: >>> [0.096212] do_initcall_level: 6 >>> [0.105625] imx6_pcie_init >>> [0.106106] imx6_pcie_probe <<<<<<<<<<<<<<<<<<<<< >>> [0.106412] imx6q-pcie 1ffc000.pcie: host bridge /soc/pcie@1ffc000 >>> ranges: >>> >>> [0.322613] imx6q-pcie 1ffc000.pcie: Link up >>> [0.322776] imx6q-pcie 1ffc000.pcie: PCI host bridge to bus 0000:00 >>> [0.322790] pci_bus 0000:00: root bus resource [bus 00-ff] >>> >>> [0.405251] do_initcall_level: 6 ENDs but imx6_pcie_probe() still active >>> [0.405262] do_initcall_level: 7 >>> >>> [0.410393] pci_sysfs_init <<<<<<<<<<<<<<<<<<<<< >>> [0.410423] pci 0000:00:00.0: pci_create_sysfs_dev_files >>> >>> [0.410532] [<8068091c>] (pci_create_sysfs_dev_files) >>> [0.410551] [<80918710>] (pci_sysfs_init) >>> [0.410568] [<8010166c>] (do_one_initcall) >>> >>> [0.410717] pci_sysfs_init END <<<<<<<<<<<<<<<<<<<<< >>> >>> [0.533843] [<803f1c74>] (pci_bus_add_devices) >>> [0.533862] [<803f574c>] (pci_host_probe) >>> [0.533879] [<80414310>] (dw_pcie_host_init) >>> [0.533895] [<80681ac8>] (imx6_pcie_probe) >>> [0.533915] [<8045e9e4>] (platform_probe) >>> (Repeats multiple times, I guess for each PCI device) >>> >>> [0.543893] imx6_pcie_probe END <<<<<<<<<<<<<<<<<<<<< >>> >>> [0.692244] do_initcall_level: 7 END >> >> >> Hi all, >> >> Any update on this topic? >> I just tested kernel 5.15 on imx6 (gateworks Ventana 5200) and as >> soon as I connect a pcie device on one of the ports, >> >> following happens: >> >> https://pastebin.com/raw/mgfSvTRB >> >> Any idea if this is related? >> >> >> Thanks, >> >> Koen >> > Hi all, > > I tested a bit more today and simply let the board reboot all day long. > After roughly 20 reboots, it suddenly booted once stable without any > errors/warnings. > > Looks like a race condition .. > > Any idea? > > Thanks, > > Koen > As an additional addendum:
This issue is seen on a Gateworks Ventana gw5200 which has a PLX bridge. I also have a GW5100 which is identical but without the PLX bridge, and it works fine every time.
So when a PCI device is sitting behind a bridge, the issue is triggered.
Hope this helps to easily reproduce.
Koen
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