Re: [PATCH] PCI/portdrv: remove redundant pm_runtime_dont_use_autosuspend() calls

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] PCI/portdrv: autosuspend state leak in pcie_portdrv_remove()
  and shutdown()
--

commit 62458954dcb1cf459473df3e377ccf5bc59b1591
Author: Joshua Crofts <crofts@kernel.org>

PCI/portdrv: remove redundant pm_runtime_dont_use_autosuspend() calls

This commit removes the pm_runtime_dont_use_autosuspend() calls from
pcie_portdrv_remove() and pcie_portdrv_shutdown(), relying on the driver
core to undo pm_runtime_use_autosuspend().

> diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
> index 32fc623dd4108..3ce960b4ea25e 100644
> --- a/drivers/pci/pcie/portdrv.c
> +++ b/drivers/pci/pcie/portdrv.c
> @@ -728,7 +728,6 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
>  	if (pci_bridge_d3_possible(dev)) {
>  		pm_runtime_forbid(&dev->dev);
>  		pm_runtime_get_noresume(&dev->dev);
> -		pm_runtime_dont_use_autosuspend(&dev->dev);
>  	}
>  
>  	pcie_port_device_remove(dev);
> @@ -741,7 +740,6 @@ static void pcie_portdrv_shutdown(struct pci_dev *dev)
>  	if (pci_bridge_d3_possible(dev)) {
>  		pm_runtime_forbid(&dev->dev);
>  		pm_runtime_get_noresume(&dev->dev);
> -		pm_runtime_dont_use_autosuspend(&dev->dev);
>  	}

[Severity: Medium]
Does removing pm_runtime_dont_use_autosuspend() here leave
dev->dev.power.use_autosuspend enabled after driver unbind and system
shutdown?

pci_bus_add_device() enables runtime PM for the PCI device, and it remains
enabled across driver unbind.  Because pm_runtime_reinit() returns early
when runtime PM is enabled, device_unbind_cleanup() never calls
pm_runtime_dont_use_autosuspend():

drivers/base/power/runtime.c:pm_runtime_reinit() {
	if (pm_runtime_enabled(dev))
		return;

	if (dev->power.runtime_status == RPM_ACTIVE)
		pm_runtime_set_suspended(dev);

	if (dev->power.use_autosuspend)
		pm_runtime_dont_use_autosuspend(dev);
}

As a result, unbinding the driver leaves use_autosuspend set and leaks the
dev->dev.power.usage_count reference acquired by update_autosuspend() if a
negative autosuspend_delay_ms was written via sysfs.  In addition,
device_shutdown() invokes pcie_portdrv_shutdown() directly without calling
pm_runtime_reinit().

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261113-pci-remove-dont-use-autosuspend-v1-1-413cb01fa0f6@kernel.org?part=1