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 hidpp_allocate_input().
>
> Remove the call 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);
}
}
>
> Fixes: c39e3d5fc9dd3 ("HID: logitech-hidpp: late bind the input device on wireless connection")
> Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx>
> ---
> drivers/hid/hid-logitech-hidpp.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
> index 81de88ab2ecc..9c00a781ab57 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -3957,11 +3957,7 @@ static void hidpp_connect_event(struct hidpp_device *hidpp)
> }
>
> hidpp_populate_input(hidpp, input);
> -
> - ret = input_register_device(input);
> - if (ret)
> - input_free_device(input);
> -
The original code does look wrong there though, since the input device
is free-ed it should not be stored in hidpp->delayed_input, so this should be comes:
ret = input_register_device(input);
if (ret) {
input_free_device(input);
return;
}
Regards,
Hans
> hidpp->delayed_input = input;
> }
>
