Re: [PATCH v2] PCI: endpoint: Fix WARN() when an endpoint driver is removed

[Vidya Sagar <vidyas@nvidia.com>]

Verified on Tegra194 platform.

Tested-by: Vidya Sagar <vidyas@nvidia.com>

On 6/22/2022 8:20 AM, Yoshihiro Shimoda wrote:
> External email: Use caution opening links or attachments
> 
> 
> Add pci_epc_release() for epc->dev.release and move kfree(epc)
> to the release function. Otherwise, WARN() happened when a PCIe
> endpoint driver is removed.
> 
>   Device 'e65d0000.pcie-ep' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.
>   WARNING: CPU: 0 PID: 139 at drivers/base/core.c:2232 device_release+0x78/0x8c
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>   Changes from v1:
>   - Move kfree(epc) to the release function.
>   - Revised the commit description.
>   https://lore.kernel.org/all/20220621121147.3971001-1-yoshihiro.shimoda.uh@renesas.com/
> 
>   drivers/pci/endpoint/pci-epc-core.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 3bc9273d0a08..2542196e8c3d 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -724,7 +724,6 @@ void pci_epc_destroy(struct pci_epc *epc)
>   {
>          pci_ep_cfs_remove_epc_group(epc->group);
>          device_unregister(&epc->dev);
> -       kfree(epc);
>   }
>   EXPORT_SYMBOL_GPL(pci_epc_destroy);
> 
> @@ -746,6 +745,11 @@ void devm_pci_epc_destroy(struct device *dev, struct pci_epc *epc)
>   }
>   EXPORT_SYMBOL_GPL(devm_pci_epc_destroy);
> 
> +static void pci_epc_release(struct device *dev)
> +{
> +       kfree(to_pci_epc(dev));
> +}
> +
>   /**
>    * __pci_epc_create() - create a new endpoint controller (EPC) device
>    * @dev: device that is creating the new EPC
> @@ -779,6 +783,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
>          device_initialize(&epc->dev);
>          epc->dev.class = pci_epc_class;
>          epc->dev.parent = dev;
> +       epc->dev.release = pci_epc_release;
>          epc->ops = ops;
> 
>          ret = dev_set_name(&epc->dev, "%s", dev_name(dev));
> --
> 2.25.1
>