[+cc Arnd, Rob]
On Thu, Aug 25, 2022 at 08:27:52PM +0800, Yang Yingliang wrote:
> If device_register() fails in pci_register_host_bridge(), the refcount
> of bus device is leaked, so device name that set by dev_set_name() can
> not be freed. Fix this by calling put_device() when device_register()
> fails, so the device name will be freed in kobject_cleanup().
>
> Fixes: 37d6a0a6f470 ("PCI: Add pci_register_host_bridge() interface")
> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> ---
> drivers/pci/probe.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index e500eb9d6468..292d9da146ce 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -948,8 +948,17 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
> name = dev_name(&bus->dev);
>
> err = device_register(&bus->dev);
> - if (err)
> - goto unregister;
> + if (err) {
> + /*
> + * release_pcibus_dev() will decrease the refcount of bridge
> + * device and free the memory of bus.
> + * The memory of bus device name will be freed when the refcount
> + * get to zero.
> + */
> + put_device(&bus->dev);
> + device_unregister(&bridge->dev);
> + return err;
> + }
Calling put_device(X) after device_register(X) returns failure doesn't
need explanation because that's the standard pattern. I think that
was just missing before.
In this error case, we previously did called put_device() for the
*bridge* instead of the bus. That was likely a typo and seems like
the important thing here.
> pcibios_add_bus(bus);
>
> @@ -1025,10 +1034,6 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
>
> return 0;
>
> -unregister:
> - put_device(&bridge->dev);
> - device_unregister(&bridge->dev);
> -
> free:
> kfree(bus);
> return err;
> --
> 2.25.1
>
