On Fri, 22 Aug 2025 at 18:39, Chenghai Huang <huangchenghai2@xxxxxxxxxx> wrote:
>
> From: Wenkai Lin <linwenkai6@xxxxxxxxxxxxx>
>
> If adding uacce cdev to the system fails, it could be due to two
> reasons: either the device's devt exists when the failure occurs,
> or the device_add operation fails. In the latter case, cdev_del
> will be executed, but in the former case, it will not, leading to a
> resource leak. Therefore, it is necessary to perform the cdev_del
> action during abnormal exit.
>
> Fixes: 015d239ac014 ("uacce: add uacce driver")
> Signed-off-by: Wenkai Lin <linwenkai6@xxxxxxxxxxxxx>
> Signed-off-by: Chenghai Huang <huangchenghai2@xxxxxxxxxx>
> ---
> drivers/misc/uacce/uacce.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
> index 42e7d2a2a90c..3604f722ed60 100644
> --- a/drivers/misc/uacce/uacce.c
> +++ b/drivers/misc/uacce/uacce.c
> @@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(uacce_alloc);
> */
> int uacce_register(struct uacce_device *uacce)
> {
> + int ret;
> +
> if (!uacce)
> return -ENODEV;
>
> @@ -529,7 +531,14 @@ int uacce_register(struct uacce_device *uacce)
> uacce->cdev->ops = &uacce_fops;
> uacce->cdev->owner = THIS_MODULE;
>
> - return cdev_device_add(uacce->cdev, &uacce->dev);
> + ret = cdev_device_add(uacce->cdev, &uacce->dev);
> + if (ret) {
> + cdev_del(uacce->cdev);
Can cdev_del be called multi-times? since cdev_device_add may call
cdev_device_add itself.
Does this introduce another issue?
Not understand the case: "either the device's devt exists when the
failure occurs,"
Looks it is cdev_device_add itself issue, or need add check
if (uacce->dev.devt)
cdev_del(uacce->cdev);
how about other drivers' behavior.
Thanks
