[PATCH] drm/radeon: check return value of radeon_ring_lock()

[Alex Deucher]

Applied.  Thanks!

On Tue, Aug 8, 2023 at 2:08 PM Nikita Zhandarovich
<n.zhandarovich at fintech.ru> wrote:
>
> In the unlikely event of radeon_ring_lock() failing, its errno return
> value should be processed. This patch checks said return value and
> prints a debug message in case of an error.
>
> Found by Linux Verification Center (linuxtesting.org) with static
> analysis tool SVACE.
>
> Fixes: 48c0c902e2e6 ("drm/radeon/kms: add support for CP setup on SI")
> Signed-off-by: Nikita Zhandarovich <n.zhandarovich at fintech.ru>
> ---
>  drivers/gpu/drm/radeon/si.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> index 8d5e4b25609d..df1b2ebc37c2 100644
> --- a/drivers/gpu/drm/radeon/si.c
> +++ b/drivers/gpu/drm/radeon/si.c
> @@ -3611,6 +3611,10 @@ static int si_cp_start(struct radeon_device *rdev)
>         for (i = RADEON_RING_TYPE_GFX_INDEX; i <= CAYMAN_RING_TYPE_CP2_INDEX; ++i) {
>                 ring = &rdev->ring[i];
>                 r = radeon_ring_lock(rdev, ring, 2);
> +               if (r) {
> +                       DRM_ERROR("radeon: cp failed to lock ring (%d).\n", r);
> +                       return r;
> +               }
>
>                 /* clear the compute context state */
>                 radeon_ring_write(ring, PACKET3_COMPUTE(PACKET3_CLEAR_STATE, 0));
> --
> 2.25.1
>