Re: [PATCH v4 18/79] media: sti/delta: fix pm_runtime_get_sync() usage count

[Jonathan Cameron]

On Wed, 28 Apr 2021 16:51:39 +0200
Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> wrote:

> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
> Replace it by the new pm_runtime_resume_and_get(), introduced by:
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter and avoid memory
> leaks.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
This looks wrong.    The caller of this calls delta_put_autosuspend()
on error which calls pm_runtime_put_autosuspend() on something where
we never incremented the count after your change.

> ---
>  drivers/media/platform/sti/delta/delta-v4l2.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/sti/delta/delta-v4l2.c b/drivers/media/platform/sti/delta/delta-v4l2.c
> index c691b3d81549..9928b7c46a41 100644
> --- a/drivers/media/platform/sti/delta/delta-v4l2.c
> +++ b/drivers/media/platform/sti/delta/delta-v4l2.c
> @@ -1277,9 +1277,9 @@ int delta_get_sync(struct delta_ctx *ctx)
>  	int ret = 0;
>  
>  	/* enable the hardware */
> -	ret = pm_runtime_get_sync(delta->dev);
> +	ret = pm_runtime_resume_and_get(delta->dev);
>  	if (ret < 0) {
> -		dev_err(delta->dev, "%s pm_runtime_get_sync failed (%d)\n",
> +		dev_err(delta->dev, "%s pm_runtime_resume_and_get failed (%d)\n",
>  			__func__, ret);
>  		return ret;
>  	}