Re: [PATCH v2] driver core: Fix bus_type.match() error handling

[Guenter Roeck]

On Mon, Aug 15, 2022 at 02:19:18PM -0700, Isaac J. Manjarres wrote:
> Both __device_attach_driver() and __driver_attach() check the return
> code of the bus_type.match() function to see if the device needs to be
> added to the deferred probe list. After adding the device to the list,
> the logic attempts to bind the device to the driver anyway, as if the
> device had matched with the driver, which is not correct.
> 
> If __device_attach_driver() detects that the device in question is not
> ready to match with a driver on the bus, then it doesn't make sense for
> the device to attempt to bind with the current driver or continue
> attempting to match with any of the other drivers on the bus. So, update
> the logic in __device_attach_driver() to reflect this.
> 
> If __driver_attach() detects that a driver tried to match with a device
> and that results in any error, then the driver should not attempt to bind
> with the device. However, the driver can still attempt to match and bind
> with other devices on the bus, as drivers can be bound to multiple
> devices. So, update the logic in __driver_attach() to reflect this.
> 
> Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxx
> Fixes: 656b8035b0ee ("ARM: 8524/1: driver cohandle -EPROBE_DEFER from bus_type.match()")
> Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx>
> ---
>  drivers/base/dd.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> v1 -> v2:
> - Fixed the logic in __driver_attach() to allow a driver to continue
>   attempting to match and bind with devices in case of any error, not
>   just probe deferral.
> 
> Guenter,
> 
> Can you please give test this patch to make sure it still works for you?
> 

Not as well as v1. I still see the clk crash with versatileab, and imx25-pdk
emulations now stall during boot when trying to boot from usb.

Guenter