On Fri, 18 Jun 2021 13:12:55 -0400
"Jason J. Herne" <jjherne@xxxxxxxxxxxxx> wrote:
> vfio_ap_matrix_dev_release is shadowing the global matrix_dev with a NULL
> pointer. Driver data for the matrix device is never set and so
> dev_get_drvdata() always returns NULL. When release is called we end up
> not freeing matrix_dev. The fix is to remove the shadow variable and get
> the correct pointer from the device using container_of. We'll also NULL
> the global to prevent any future use.
>
> Signed-off-by: Jason J. Herne <jjherne@xxxxxxxxxxxxx>
> ---
> drivers/s390/crypto/vfio_ap_drv.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
> index 7dc72cb718b0..40e66cb363d1 100644
> --- a/drivers/s390/crypto/vfio_ap_drv.c
> +++ b/drivers/s390/crypto/vfio_ap_drv.c
> @@ -82,9 +82,8 @@ static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
>
> static void vfio_ap_matrix_dev_release(struct device *dev)
> {
> - struct ap_matrix_dev *matrix_dev = dev_get_drvdata(dev);
> -
> - kfree(matrix_dev);
> + kfree(container_of(dev, struct ap_matrix_dev, device));
> + matrix_dev = NULL;
Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
I'm not sure nulling the global here buys us anything (especially after
the kfree()). But it does not hurt either, so I'm fine with it. Style
wise I think vfio_ap_matrix_dev_destroy() is a better place for the
nulling IMHO, as it is dealing with module global state.
Regards,
Halil
> }
>
> static int matrix_bus_match(struct device *dev, struct device_driver *drv)
