Re: Deadlock during PCIe hot remove and SPDK exit

[Lukas Wunner <lukas@wunner.de>]

On Wed, Nov 27, 2024 at 02:56:57PM +0800, fengnan chang wrote:
> Dear PCI maintainers:
>    I'm having a deadlock issue, somewhat similar to a previous one https://lore.kernel.org/linux-pci/CS1PR8401MB0728FC6FDAB8A35C22BD90EC95F10@CS1PR8401MB0728.NAMPRD84.PROD.OUTLOOK.COM/#t??? but my kernel (6.6.40) already included the fix f5eff55.

Could you try a contemporary kernel such as v6.12 and test if it
still exhibits the issue?


> irq/148-pciehp stack, cat /proc/513/stack
> [<0>] vfio_unregister_group_dev+0x97/0xe0 [vfio]     //wait for 
> [<0>] vfio_pci_core_unregister_device+0x19/0x80 [vfio_pci_core]
> [<0>] vfio_pci_remove+0x15/0x20 [vfio_pci]
> [<0>] pci_device_remove+0x39/0xb0
> [<0>] device_release_driver_internal+0xad/0x120
> [<0>] pci_stop_bus_device+0x5d/0x80
> [<0>] pci_stop_and_remove_bus_device+0xe/0x20
> [<0>] pciehp_unconfigure_device+0x91/0x160   //hold pci_rescan_remove_lock, release reset_lock of ctrl B 
> [<0>] pciehp_disable_slot+0x6b/0x130
> [<0>] pciehp_handle_presence_or_link_change+0x7d/0x4d0
> [<0>] pciehp_ist+0x236/0x260             //hold reset_lock of ctrl B

It says here "wait for".

Wait for what?  Why is vfio_unregister_group_dev() blocking?

Thanks,

Lukas