Re: [PATCH v9 1/9] HID: hid-sensor-hub: don't use stale platform-data on remove

Jiri Kosina
2024-11-07T13:01:08Z

On Thu, 7 Nov 2024, Heiko Stuebner wrote:

> The hid-sensor-hub creates the individual device structs and transfers them
> to the created mfd platform-devices via the platform_data in the mfd_cell.
>
> Before e651a1da442a ("HID: hid-sensor-hub: Allow parallel synchronous reads")
> the sensor-hub was managing access centrally, with one "completion" in the
> hub's data structure, which needed to be finished on removal at the latest.
>
> The mentioned commit then moved this central management to each hid sensor
> device, resulting on a completion in each struct hid_sensor_hub_device.
> The remove procedure was adapted to go through all sensor devices and
> finish any pending "completion".
>
> What this didn't take into account was, platform_device_add_data() that is
> used by mfd_add{_hotplug}_devices() does a kmemdup on the submitted
> platform-data. So the data the platform-device gets is a copy of the
> original data, meaning that the device worked on a different completion
> than what sensor_hub_remove() currently wants to access.
>
> To fix that, use device_for_each_child() to go through each child-device
> similar to how mfd_remove_devices() unregisters the devices later and
> with that get the live platform_data to finalize the correct completion.
>
> Fixes: e651a1da442a ("HID: hid-sensor-hub: Allow parallel synchronous reads")
> Cc: stable@vger.kernel.org
> Acked-by: Benjamin Tissoires <bentiss@kernel.org>
> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

Acked-by: Jiri Kosina <jkosina@suse.com>

Are you planning to merge this together with the rest of the set, or do
you want me to expedite it? I'll be happy to apply it separately as a
proper fix.

Thanks,

--
Jiri Kosina
SUSE Labs