Re: [PATCH] device property: set fwnode->secondary to NULL in fwnode_init()

[Rafael J. Wysocki]

On Wed, May 6, 2026 at 1:57 PM Bartosz Golaszewski
<bartosz.golaszewski@xxxxxxxxxxxxxxxx> wrote:
>
> If a firmware node is allocated on the stack (for instance: temporary
> software node whose life-time we control) or on the heap - but using a
> non-zeroing allocation function - and initialized using fwnode_init(),
> its secondary pointer will contain uninitalized memory which likely will
> be neither NULL nor IS_ERR() and so may end up being dereferenced (for
> example: in dev_to_swnode()). Set fwnode->secondary to NULL on
> initialization.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 01bb86b380a3 ("driver core: Add fwnode_init()")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>

Reviewed-by: Rafael J. Wysocki (Intel) <rafael@xxxxxxxxxx>

> ---
>  include/linux/fwnode.h | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
> index 80b38fbf2121..31df7608737e 100644
> --- a/include/linux/fwnode.h
> +++ b/include/linux/fwnode.h
> @@ -208,6 +208,7 @@ struct fwnode_operations {
>  static inline void fwnode_init(struct fwnode_handle *fwnode,
>                                const struct fwnode_operations *ops)
>  {
> +       fwnode->secondary = NULL;
>         fwnode->ops = ops;
>         INIT_LIST_HEAD(&fwnode->consumers);
>         INIT_LIST_HEAD(&fwnode->suppliers);
> --
> 2.47.3
>
>