Re: [PATCH] s390/vfio-ap: lock mdev object when handling mdev remove request

Anthony Krowiak
2025-03-11T10:34:26Z

PING!

On 2/21/25 10:32 AM, Anthony Krowiak wrote:
> The vfio_ap_mdev_request function in drivers/s390/crypto/vfio_ap_ops.c
> accesses fields of an ap_matrix_mdev object without ensuring that the
> object is accessed by only one thread at a time. This patch adds the lock
> necessary to secure access to the ap_matrix_mdev object.
>
> Fixes: 2e3d8d71e285 ("s390/vfio-ap: wire in the vfio_device_ops request callback")
> Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
> Cc: <stable@vger.kernel.org>
> ---
> drivers/s390/crypto/vfio_ap_ops.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index a52c2690933f..a2784d3357d9 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -2045,6 +2045,7 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
> struct ap_matrix_mdev *matrix_mdev;
>
> matrix_mdev = container_of(vdev, struct ap_matrix_mdev, vdev);
> + mutex_lock(&matrix_dev->mdevs_lock);
>
> if (matrix_mdev->req_trigger) {
> if (!(count % 10))
> @@ -2057,6 +2058,8 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
> dev_notice(dev,
> "No device request registered, blocked until released by user\n");
> }
> +
> + mutex_unlock(&matrix_dev->mdevs_lock);
> }
>
> static int vfio_ap_mdev_get_device_info(unsigned long arg)