Re: [PATCH] driver core: Make sure device detached from driver before deleting it

[Rafael J. Wysocki]

On Wednesday, October 18, 2017 7:49:26 AM CEST Jeffy Chen wrote:
> There are cases we call device_del() without detaching it from the
> driver(e.g. spi core del children devices).

But device_del() itself detaches the device from its driver.

> Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> ---
> 
>  drivers/base/core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 12ebd055724c..717efc3020af 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1951,6 +1951,8 @@ void device_del(struct device *dev)
>  	struct kobject *glue_dir = NULL;
>  	struct class_interface *class_intf;
>  
> +	device_release_driver(dev);
> +
>  	/* Notify clients of device removal.  This call must come
>  	 * before dpm_sysfs_remove().
>  	 */
> 

But device_del() calls bus_remove_device() which in turn calls
device_release_driver(), so this looks like an ordering issue to me.

What *exactly* is not working?  Or rather, what symptoms do you see?

Thanks,
Rafael