Re: [PATCH v6 2/5] Drivers: hv: Add logical device ID registry for vPCI devices

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] pci-hyperv: logical device ID leaked on remove after failed resume
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commit 60c40edaf8c7fd1e4ba684f1b2ec029a89674f03
Author: Yu Zhang <zhangyu1@linux.microsoft.com>
Drivers: hv: Add logical device ID registry for vPCI devices

This commit adds a registry in hv_common.c that maps a PCI domain number to
its logical device ID prefix. The vPCI bus driver registers the prefix when a
bus is probed and unregisters it when the bus is removed.

> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index 89816a2bd7cd3..db70be47af6e1 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c

[ ... ]

> @@ -3978,6 +3985,8 @@ static void hv_pci_remove(struct hv_device *hdev)
>  
>  	hbus = hv_get_drvdata(hdev);
>  	if (hbus->state == hv_pcibus_installed) {
> +		int dom = hbus->bridge->domain_nr;
> +
>  		tasklet_disable(&hdev->channel->callback_event);
>  		hbus->state = hv_pcibus_removing;
>  		tasklet_enable(&hdev->channel->callback_event);
> @@ -3995,6 +4004,8 @@ static void hv_pci_remove(struct hv_device *hdev)
>  		hv_pci_remove_slots(hbus);
>  		pci_remove_root_bus(hbus->bridge->bus);
>  		pci_unlock_rescan_remove();
> +
> +		hv_pci_unregister_dev_id(dom);
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[Severity: Medium]
Does this code leak the logical device ID if hv_pci_resume() fails?

If the device suspends and hv_pci_resume() fails, it leaves hbus->state
as hv_pcibus_init (or if hv_pci_suspend() fails, it leaves it as
hv_pcibus_removing). Later, when the device is unbound and hv_pci_remove()
is called, it skips this if (hbus->state == hv_pcibus_installed) block,
omitting the required hv_pci_unregister_dev_id() call.

This will cause a memory leak of struct hv_pci_busdata and its hash table
entry. Because the domain remains registered, any subsequent probe (e.g.,
driver re-bind) will fail with -EEXIST in hv_pci_register_dev_id(),
permanently disabling the device until reboot.

Although the underlying hbus->state mishandling is pre-existing, the leaked
registry and the resulting -EEXIST probe failure are introduced in this patch.

>  	}
>  
>  	hv_pci_bus_exit(hdev, false);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260930141409.437904-1-zhangyu1@linux.microsoft.com?part=2