On Fri, Feb 2, 2024 at 10:53 AM Srinivasan Shanmugam
<srinivasan.shanmugam@xxxxxxx> wrote:
>
> The issue arises when the array 'adev->vcn.vcn_config' is accessed
> before checking if the index 'adev->vcn.num_vcn_inst' is within the
> bounds of the array.
>
> The fix involves moving the bounds check before the array access. This
> ensures that 'adev->vcn.num_vcn_inst' is within the bounds of the array
> before it is used as an index.
>
> Fixes the below:
> drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1289 amdgpu_discovery_reg_base_init() error: testing array offset 'adev->vcn.num_vcn_inst' after use.
>
> Fixes: aaf1090a6cb6 ("drm/amdgpu: Add instance mask for VCN and JPEG")
This tag is not correct. I think it's actually:
Fixes: a0ccc717c4ab ("drm/amdgpu/discovery: validate VCN and SDMA instances")
With that fixed, the patch is:
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
> Cc: Christian König <christian.koenig@xxxxxxx>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
> ---
> v3:
> - Added fixes tag.
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> index ef800590c1ab..93c84a1c1d3e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> @@ -1282,11 +1282,10 @@ static int amdgpu_discovery_reg_base_init(struct amdgpu_device *adev)
> * 0b10 : encode is disabled
> * 0b01 : decode is disabled
> */
> - adev->vcn.vcn_config[adev->vcn.num_vcn_inst] =
> - ip->revision & 0xc0;
> - ip->revision &= ~0xc0;
> if (adev->vcn.num_vcn_inst <
> AMDGPU_MAX_VCN_INSTANCES) {
> + adev->vcn.vcn_config[adev->vcn.num_vcn_inst] =
> + ip->revision & 0xc0;
> adev->vcn.num_vcn_inst++;
> adev->vcn.inst_mask |=
> (1U << ip->instance_number);
> @@ -1297,6 +1296,7 @@ static int amdgpu_discovery_reg_base_init(struct amdgpu_device *adev)
> adev->vcn.num_vcn_inst + 1,
> AMDGPU_MAX_VCN_INSTANCES);
> }
> + ip->revision &= ~0xc0;
> }
> if (le16_to_cpu(ip->hw_id) == SDMA0_HWID ||
> le16_to_cpu(ip->hw_id) == SDMA1_HWID ||
> --
> 2.34.1
>
