Re: [PATCH 1/7] s390/pci: fix double-free in zpci MSI cleanup

["Tobias Schumacher" <ts@linux.ibm.com>]

On Wed Aug 19, 2026 at 11:03 AM CEST, sashiko-bot wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
>
> Pre-existing issues:
> - [Medium] Pre-existing memory leak of `struct resource_entry` in `zbus->resources` when PCI root bus creation fails.
> --

-- snip --

> [Severity: Medium]
> This is a pre-existing issue, but while reviewing the error path discussed in
> the commit message (when pci_create_root_bus() fails), does zpci_bus_release()
> leak zbus->resources?
>
> In arch/s390/pci/pci_bus.c:zpci_bus_alloc(), a resource is added to the list:
>
>     INIT_LIST_HEAD(&zbus->resources);
>     zbus->bus_resource.start = 0;
>     zbus->bus_resource.end = ZPCI_BUS_NR;
>     zbus->bus_resource.flags = IORESOURCE_BUS;
>     pci_add_resource(&zbus->resources, &zbus->bus_resource);
>
> But in the error path where pci_create_root_bus() fails, zbus->bus is not set.
> Later in zpci_bus_release(), pci_free_resource_list() is only called if
> zbus->bus is true:
>
>     if (zbus->bus) {
>         pci_lock_rescan_remove();
>         pci_stop_root_bus(zbus->bus);
>
>         zpci_free_domain(zbus->domain_nr);
>         pci_free_resource_list(&zbus->resources);
>
>         pci_remove_root_bus(zbus->bus);
>         pci_unlock_rescan_remove();
>     }
>
> Can this leak the struct resource_entry on this initialization error path?

Yes, seems like pci_free_resource_list() should be moved outside the if
block. But this should be fixed in a separate patch outside this series
since it is unrelated to the introduction of the irq domains.

Tobias