Hi,
On 4/22/22 18:17, José Expósito wrote:
> As described in the documentation for devm_input_allocate_device():
>
> Managed input devices do not need to be explicitly unregistered or
> freed as it will be done automatically when owner device unbinds from
> its driver (or binding fails).
>
> However this driver was explicitly freeing the input device, allocated
> using devm_input_allocate_device() through wacom_allocate_input().
>
> Remove the calls to input_free_device() to avoid a possible double free
> error.
Actually calling input_free_device() on a devm allocated input device
is fine. The input subsystem has chosen to not have a
separate devm_input_free_device(), instead input_free_device() knows
if a device is allocated through devm and then also frees the devres
tied to it:
void input_free_device(struct input_dev *dev)
{
if (dev) {
if (dev->devres_managed)
WARN_ON(devres_destroy(dev->dev.parent,
devm_input_device_release,
devm_input_device_match,
dev));
input_put_device(dev);
}
}
So there is no need for this patch.
Regards,
Hans
>
> Fixes: d2d13f18aaa51 ("Input: wacom - create a separate input device for pads")
> Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx>
> ---
> drivers/hid/wacom_sys.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
> index 066c567dbaa2..164c0f7cb796 100644
> --- a/drivers/hid/wacom_sys.c
> +++ b/drivers/hid/wacom_sys.c
> @@ -2098,7 +2098,6 @@ static int wacom_register_inputs(struct wacom *wacom)
> error = wacom_setup_pen_input_capabilities(pen_input_dev, wacom_wac);
> if (error) {
> /* no pen in use on this interface */
> - input_free_device(pen_input_dev);
> wacom_wac->pen_input = NULL;
> pen_input_dev = NULL;
> } else {
> @@ -2110,7 +2109,6 @@ static int wacom_register_inputs(struct wacom *wacom)
> error = wacom_setup_touch_input_capabilities(touch_input_dev, wacom_wac);
> if (error) {
> /* no touch in use on this interface */
> - input_free_device(touch_input_dev);
> wacom_wac->touch_input = NULL;
> touch_input_dev = NULL;
> } else {
> @@ -2122,7 +2120,6 @@ static int wacom_register_inputs(struct wacom *wacom)
> error = wacom_setup_pad_input_capabilities(pad_input_dev, wacom_wac);
> if (error) {
> /* no pad in use on this interface */
> - input_free_device(pad_input_dev);
> wacom_wac->pad_input = NULL;
> pad_input_dev = NULL;
> } else {
