Re: [PATCH] watchdog: starfive: fix runtime PM usage counter leak in pm_start

On 8/23/26 04:22, manushprajwal wrote:
> starfive_wdt_pm_start() calls pm_runtime_get_sync() and returns its
> error code directly on failure. Per Documentation/power/runtime_pm.rst,
> pm_runtime_get_sync() does not drop the usage counter on error, so the
> caller is expected to release the reference itself. The early return
> here skips that, leaking a runtime PM usage count on wdd->parent on
> every failed resume, which prevents the device from being suspended
> correctly afterwards.
> 
> Fix it by calling pm_runtime_put_noidle() before returning, mirroring
> the same balance the counterpart starfive_wdt_pm_stop() already
> maintains with pm_runtime_put_sync().
> 
> Signed-off-by: manushprajwal <[email protected]>
> ---
>   drivers/watchdog/starfive-wdt.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/starfive-wdt.c b/drivers/watchdog/starfive-wdt.c
> index af55adc4a..ecb704b2e 100644
> --- a/drivers/watchdog/starfive-wdt.c
> +++ b/drivers/watchdog/starfive-wdt.c
> @@ -373,8 +373,10 @@ static int starfive_wdt_pm_start(struct watchdog_device *wdd)
>   	struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>   	int ret = pm_runtime_get_sync(wdd->parent);
>   
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(wdd->parent);
>   		return ret;
> +	}
>   
>   	return starfive_wdt_start(wdt);
>   }

As Sashiko points out, there is still a runtime PM leak if starfive_wdt_start()
fails (plus all the other issues in the driver, but those can be fixed with
separate patches).

Thanks,
Guenter