Re: [PATCH] usb: dwc3: am62: Fix runtime PM usage count leak on probe error path

[Thinh Nguyen]

On Wed, Sep 02, 2026, Radhey Shyam Pandey wrote:
> dwc3_ti_probe() takes a runtime PM reference with pm_runtime_get_noresume()
> before creating the dwc3 core child device, and releases it with
> pm_runtime_put_autosuspend() once probe has succeeded. The err_pm_disable
> error path only disables runtime PM, so the reference taken a few lines
> earlier is never dropped.
> 
> The usage counter lives in struct device and is not reset when the driver
> is unbound, so the leaked reference outlives the failed probe. If the
> device is probed again, through a manual rebind or a module reload, the
> counter starts at one instead of zero and the pm_runtime_put_autosuspend()
> on the success path can no longer bring it back down. The wrapper then
> stays runtime resumed for good and autosuspend never kicks in.
> 
> Drop the reference before disabling runtime PM, matching the ordering
> already used in dwc3_ti_remove().
> 
> Fixes: e8784c0aec03 ("drivers: usb: dwc3: Add AM62 USB wrapper driver")
> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
> ---
>  drivers/usb/dwc3/dwc3-am62.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
> index 632634d6e81e..d03b3950ce04 100644
> --- a/drivers/usb/dwc3/dwc3-am62.c
> +++ b/drivers/usb/dwc3/dwc3-am62.c
> @@ -299,6 +299,7 @@ static int dwc3_ti_probe(struct platform_device *pdev)
>  
>  err_pm_disable:
>  	clk_disable_unprepare(am62->usb2_refclk);
> +	pm_runtime_put_noidle(dev);
>  	pm_runtime_disable(dev);
>  	pm_runtime_set_suspended(dev);
>  	return ret;
> 
> ---
> base-commit: 8b72f6626dc39b9e7e82b2721d4f7c3b86286012
> change-id: 20260902-dwc3-am62-rpm-fix-514ccf0696a3
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>

BR,
Thinh