Re: [PATCH v3] driver core: platform: don't oops in platform_shutdown() on unbound devices

[Guenter Roeck <linux@roeck-us.net>]

On Sun, Dec 13, 2020 at 02:55:33AM +0300, Dmitry Baryshkov wrote:
> 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.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Fixes: 9c30921fe799 ("driver core: platform: use bus_type functions")

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  drivers/base/platform.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 0358dc3ea3ad..e9477e0bbca5 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -1351,9 +1351,13 @@ static int platform_remove(struct device *_dev)
>  
>  static void platform_shutdown(struct device *_dev)
>  {
> -	struct platform_driver *drv = to_platform_driver(_dev->driver);
>  	struct platform_device *dev = to_platform_device(_dev);
> +	struct platform_driver *drv;
> +
> +	if (!_dev->driver)
> +		return;
>  
> +	drv = to_platform_driver(_dev->driver);
>  	if (drv->shutdown)
>  		drv->shutdown(dev);
>  }
> -- 
> 2.29.2
>