Re: [PATCH] PCI/pwrctrl: Power off child devices on power-on failure

[Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>]

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> pci_pwrctrl_power_on_device() recursively powers on the child nodes
> of a device before powering on the device itself. If powering on a
> child fails (e.g. returning -EPROBE_DEFER), the function returned
> immediately, leaving the sibling children that were already powered
> on in the same loop iteration enabled.
> 
> Since probe deferral is a standard boot path, this leads to unbounded
> regulator and clock enable increments across retries. The error path
> in pci_pwrctrl_power_on_devices() only powers off the top-level
> children processed before the failing one and explicitly stops at it,
> so it can never clean up the siblings leaked deeper in the failed
> subtree.
> 
> Power off the sibling children that were successfully powered on
> before a child fails, and power off all children if the device's own
> power_on() fails after its children were already enabled. Switch to a
> manual child iterator so the failing node can be tracked and its
> reference released in the error path.
> 
> Fixes: b35cf3b6aa1e ("PCI/pwrctrl: Add APIs to power on/off pwrctrl devices")
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Hi all,

do you have any update about this fix? Thanks in advance.

Regards,
Lorenzo

> ---
>  drivers/pci/pwrctrl/core.c | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
> index 10d817aefb09..d29cd506972d 100644
> --- a/drivers/pci/pwrctrl/core.c
> +++ b/drivers/pci/pwrctrl/core.c
> @@ -252,14 +252,16 @@ static int __pci_pwrctrl_power_on_device(struct device *dev)
>  static int pci_pwrctrl_power_on_device(struct device_node *np)
>  {
>  	struct platform_device *pdev;
> +	struct device_node *child;
>  	int ret = 0;
>  
> -	for_each_available_child_of_node_scoped(np, child) {
> +	for_each_available_child_of_node(np, child) {
>  		ret = pci_pwrctrl_power_on_device(child);
>  		if (ret)
> -			return ret;
> +			goto err_power_off;
>  	}
>  
> +	child = NULL;
>  	if (!pci_pwrctrl_is_required(np))
>  		return 0;
>  
> @@ -279,6 +281,19 @@ static int pci_pwrctrl_power_on_device(struct device_node *np)
>  
>  	platform_device_put(pdev);
>  
> +	if (ret)
> +		goto err_power_off;
> +
> +	return 0;
> +
> +err_power_off:
> +	for_each_available_child_of_node_scoped(np, tmp) {
> +		if (tmp == child)
> +			break;
> +		pci_pwrctrl_power_off_device(tmp);
> +	}
> +	of_node_put(child);
> +
>  	return ret;
>  }
>  
> 
> ---
> base-commit: 028f86457e822ab9de5b0d6d23efddc1b8b54ae1
> change-id: 20260908-pwrtctl-power-on-rallback-5c6364b080ce
> 
> Best regards,
> -- 
> Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
> 

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