Re: [PATCH] drivers/base: use a worker for sysfs unbind

From: Rafael J. Wysocki
Date: Thu Dec 13 2018 - 04:38:30 EST


On Mon, Dec 10, 2018 at 9:47 AM Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
>
> Drivers might want to remove some sysfs files, which needs the same
> locks and ends up angering lockdep. Relevant snippet of the stack
> trace:
>
> kernfs_remove_by_name_ns+0x3b/0x80
> bus_remove_driver+0x92/0xa0
> acpi_video_unregister+0x24/0x40
> i915_driver_unload+0x42/0x130 [i915]
> i915_pci_remove+0x19/0x30 [i915]
> pci_device_remove+0x36/0xb0
> device_release_driver_internal+0x185/0x250
> unbind_store+0xaf/0x180
> kernfs_fop_write+0x104/0x190

Is the acpi_bus_unregister_driver() in acpi_video_unregister() the
source of the lockdep unhappiness?