Re: [PATCH] gpu: host1x: fix runtime PM reference leak on remove

[Mikko Perttunen <mperttunen@nvidia.com>]

On Sunday, September 13, 2026 9:02 PM Guangshuo Li wrote:
> host1x_probe() calls pm_runtime_resume_and_get() and intentionally keeps
> the runtime PM usage reference for the lifetime of the driver because
> host1x is not yet ready for dynamic runtime PM.
> 
> The probe error path drops this reference with
> pm_runtime_put_sync_suspend(), but the remove path only calls
> pm_runtime_force_suspend().
> 
> pm_runtime_force_suspend() disables runtime PM and invokes the runtime
> suspend callback when necessary, but it does not decrement the runtime
> PM usage counter. As a result, the reference acquired by
> pm_runtime_resume_and_get() remains held after the driver is unbound.
> Repeated bind and unbind cycles can therefore leave the runtime PM
> usage counter increasingly unbalanced.
> 
> Drop the usage reference with pm_runtime_put_sync_suspend() before
> forcing the device into suspend during removal.
> 
> This issue was found by manual code inspection.
> 
> Fixes: 6b6776e2ab8a ("gpu: host1x: Add initial runtime PM and OPP support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>  drivers/gpu/host1x/dev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
> index d2c64728f804..bb6a1647e4db 100644
> --- a/drivers/gpu/host1x/dev.c
> +++ b/drivers/gpu/host1x/dev.c
> @@ -729,6 +729,7 @@ static void host1x_remove(struct platform_device *pdev)
>  	host1x_unregister(host);
>  	host1x_debug_deinit(host);
>  
> +	pm_runtime_put_sync_suspend(&pdev->dev);
>  	pm_runtime_force_suspend(&pdev->dev);

After the pm_runtime_put_sync_suspend, the device should always be 
suspended, so I think we should also replace the call to 
pm_runtime_force_suspend with a pm_runtime_disable.

Thank you!
Mikko

>  
>  	host1x_intr_deinit(host);
> -- 
> 2.43.0
> 
>