Re: [PATCH v2 1/3] driver core: platform: remove software node on release()

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Apr 23, 2026 at 02:12:02PM +0200, Bartosz Golaszewski wrote:
> If we pass a software node to a newly created device using struct
> platform_device_info, it will not be removed when the device is
> released. This may happen when a module creating the device is removed
> or on failure in platform_device_add().
> 
> When we try to reuse that software node in a subsequent call to
> platform_device_register_full(), it will fails with -EBUSY. Add the
> missing call to device_remove_software_node() in release path.
> 
> Make sure that we still function correctly if a software node is used as
> the primary firmware node.
> 
> Fixes: 0fc434bc2c45 ("driver core: platform: allow attaching software nodes when creating devices")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> ---
>  drivers/base/platform.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 75b4698d0e582e67adafa78c312d75c72fd654cf..43ea7dcd338dd3ddae57e6d0677e5cb2673f6ed5 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -599,6 +599,7 @@ static void platform_device_release(struct device *dev)
>  	struct platform_object *pa = container_of(dev, struct platform_object,
>  						  pdev.dev);
>  
> +	device_remove_software_node(dev);
>  	of_node_put(pa->pdev.dev.of_node);
>  	kfree(pa->pdev.dev.platform_data);
>  	kfree(pa->pdev.mfd_cell);
> @@ -885,6 +886,16 @@ struct platform_device *platform_device_register_full(const struct platform_devi
>  			goto err;
>  	}
>  
> +	/*
> +	 * If the primary firmware node is a software node and there's no
> +	 * secondary firmware node, the primary will be affected by the call
> +	 * to device_remove_software_node() in platform_device_release() and
> +	 * its reference count will be dropped by one. Take another reference
> +	 * here to make it have no effect.
> +	 */
> +	if (is_software_node(pdevinfo->fwnode) && !pdevinfo->swnode)
> +		fwnode_handle_get(pdevinfo->fwnode);

It is possible to pass already registered node in pdevinfo->swnode
(because device_add_software_node() can handle this just fine). In this
case we also need to take an extra reference (or figure out whether we
need to drop the reference when removing the device).

Thanks.

-- 
Dmitry