On Fri, 2022-11-11 at 22:54 +0800, Yang Yingliang wrote:
> If device_register() fails in cxl_pci_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error
> path, otherwise it will cause a null-ptr-deref because of removing
> not added device.
>
> As comment of device_register() says, it should use put_device() to
> give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register
> fails.
>
> Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards
> for userspace access")
> Signed-off-by: Yang Yingliang <yangyingli...@huawei.com>
See reply to patch #1.
This patch puts a few things between the device_del() call and the
put_device() call, but that looks fine - we don't touch afu->dev in the
middle.
Thanks for the fix!
Acked-by: Andrew Donnellan <a...@linux.ibm.com>
> ---
> drivers/misc/cxl/pci.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 3de0aea62ade..6d495d641c95 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -1164,10 +1164,10 @@ static int pci_init_afu(struct cxl *adapter,
> int slice, struct pci_dev *dev)
> * if it returns an error!
> */
> if ((rc = cxl_register_afu(afu)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_afu_add(afu)))
> - goto err_put1;
> + goto err_del_dev;
>
> adapter->afu[afu->slice] = afu;
>
> @@ -1176,10 +1176,12 @@ static int pci_init_afu(struct cxl *adapter,
> int slice, struct pci_dev *dev)
>
> return 0;
>
> -err_put1:
> +err_del_dev:
> + device_del(&afu->dev);
> +err_put_dev:
> pci_deconfigure_afu(afu);
> cxl_debugfs_afu_remove(afu);
> - device_unregister(&afu->dev);
> + put_device(&afu->dev);
> return rc;
>
> err_free_native:
> @@ -1667,23 +1669,25 @@ static struct cxl
> *cxl_pci_init_adapter(struct pci_dev *dev)
> * even if it returns an error!
> */
> if ((rc = cxl_register_adapter(adapter)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_adapter_add(adapter)))
> - goto err_put1;
> + goto err_del_dev;
>
> /* Release the context lock as adapter is configured */
> cxl_adapter_context_unlock(adapter);
>
> return adapter;
>
> -err_put1:
> +err_del_dev:
> + device_del(&adapter->dev);
> +err_put_dev:
> /* This should mirror cxl_remove_adapter, except without the
> * sysfs parts
> */
> cxl_debugfs_adapter_remove(adapter);
> cxl_deconfigure_adapter(adapter);
> - device_unregister(&adapter->dev);
> + put_device(&adapter->dev);
> return ERR_PTR(rc);
>
> err_release:
--
Andrew Donnellan OzLabs, ADL Canberra
a...@linux.ibm.com IBM Australia Limited
