Re: [PATCH v2 0/4] driver core: generalize driver_override infrastructure

[Greg KH]

On Tue, Mar 03, 2026 at 12:53:17PM +0100, Danilo Krummrich wrote:
> Currently, there are 12 busses (including platform and PCI) that duplicate the
> driver_override logic for their individual devices.
> 
> All of them seem to be prone to the bug described in [1].
> 
> While this could be solved for every bus individually using a separate lock,
> solving this in the driver-core generically results in less (and cleaner)
> changes overall.
> 
> Thus, move driver_override to struct device, provide corresponding accessors for
> busses and handle locking with a separate lock internally.
> 
> In particular, add device_set_driver_override(), device_has_driver_override(),
> device_match_driver_override() and a helper, DEVICE_ATTR_DRIVER_OVERRIDE(), to
> declare the corresponding sysfs store() and show() callbacks.
> 
> Until all busses have migrated, keep driver_set_override() in place.
> 
> Note that we can't use the device lock for the reasons described in [2].
> 
> This patch series includes the migration of the platform bus; patches for all
> other affected busses still need to be extracted as a follow-up of the WIP
> treewide patch in [3].
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=220789
> [2] https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@xxxxxxxxxx/
> [3] https://git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=driver_override

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>