Hello Dmitry,

On Sun, Dec 13, 2020 at 12:38:32AM +0300, Dmitry Baryshkov wrote:
> Platform code stopped checking if the device is bound to the actual
> platform driver, thus calling non-existing drv->shutdown(). Verify that
> _dev->driver is not NULL before calling shutdown callback.

I'd write:

	On shutdown the driver core calls the bus' shutdown callback also for
	unbound devices. A driver's shutdown callback however is only called for
	devices bound to this driver. Commit 9c30921fe799 ("driver core:
	platform: use bus_type functions") changed the platform bus from driver
	callbacks to bus callbacks, so the shutdown function must be prepared to
	be called without a driver. Add the corresponding check in the
	shutdown function.

With that adding the backtrace isn't necessary (and the patch is fine).

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |