On Fri, Jun 07, 2013 at 01:10:08AM +0800, Jiang Liu wrote:
> On pci_create_root_bus() error recovery path, device_unregister(&bridge->dev)
> should have freed memory used by bridge, so we shouldn't call kfree(bridge)
> again, it's a double free.
>
> On the other hand, we should not use kfree() to free memory used by
> device object once we have invoked device_register() because it's
> reference-counted.
>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> Hi Bjorn,
> This is the patch to fix the kfree() issue, it may be a material
> for stable trees.
> Thanks!
> Gerry
> ---
> drivers/pci/probe.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 8882b5d..2f81a0a 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1729,12 +1729,16 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> bridge->dev.release = pci_release_bus_bridge_dev;
> dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
> error = pcibios_root_bridge_prepare(bridge);
> - if (error)
> - goto bridge_dev_reg_err;
> + if (error) {
> + kfree(bridge);
> + goto err_out;
> + }
>
> error = device_register(&bridge->dev);
> - if (error)
> - goto bridge_dev_reg_err;
> + if (error) {
> + kfree(bridge);
Per device_register() comment, this should be a put_device().
I added this patch with that change to my pci/jiang-bus-lock-v3 branch.
I know a subsequent patch removes this anyway. I might be a little
obsessive.
> + goto err_out;
> + }
> b->bridge = get_device(&bridge->dev);
> device_enable_async_suspend(b->bridge);
> pci_set_bus_of_node(b);
> @@ -1790,8 +1794,6 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> class_dev_reg_err:
> put_device(&bridge->dev);
> device_unregister(&bridge->dev);
> -bridge_dev_reg_err:
> - kfree(bridge);
> err_out:
> kfree(b);
> return NULL;
> --
> 1.8.1.2
>
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