Re: [PATCH] device property: Fix the secondary firmware node handling in set_primary_fwnode()

From: Rafael J. Wysocki
Date: Fri Aug 21 2020 - 14:29:20 EST


On Fri, Aug 21, 2020 at 12:53 PM Heikki Krogerus
<heikki.krogerus@xxxxxxxxxxxxxxx> wrote:
>
> When the primary firmware node pointer is removed from a
> device (set to NULL) the secondary firmware node pointer,
> when it exists, is made the primary node for the device.
> However, the secondary firmware node pointer of the original
> primary firmware node is never cleared (set to NULL).
>
> To avoid situation where the secondary firmware node pointer
> is pointing to a non-existing object, clearing it properly
> when the primary node is removed from a device in
> set_primary_fwnode().
>
> Fixes: 97badf873ab6 ("device property: Make it possible to use secondary firmware nodes")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/base/core.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index ac1046a382bc0..f6f620aa94086 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -4264,9 +4264,9 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
> */
> void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> {
> - if (fwnode) {
> - struct fwnode_handle *fn = dev->fwnode;
> + struct fwnode_handle *fn = dev->fwnode;
>
> + if (fwnode) {
> if (fwnode_is_primary(fn))
> fn = fn->secondary;
>
> @@ -4276,8 +4276,12 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> }
> dev->fwnode = fwnode;
> } else {
> - dev->fwnode = fwnode_is_primary(dev->fwnode) ?
> - dev->fwnode->secondary : NULL;
> + if (fwnode_is_primary(fn)) {
> + dev->fwnode = fn->secondary;
> + fn->secondary = NULL;
> + } else {
> + dev->fwnode = NULL;
> + }
> }
> }
> EXPORT_SYMBOL_GPL(set_primary_fwnode);
> --

Applied as 5.9-rc material, thanks!