[PATCH v2 5/6] amdgpu: fix invalid memory access in amdgpu_fence_driver_sw_fini()

[Chen, Xiaogang]

On 1/4/2025 8:45 PM, Jiang Liu wrote:
> Function detects initialization status by checking sched->ops, so set
> sched->ops to non-NULL just before return in function drm_sched_init()

This commit message is not what the change did: you set sched->ops to 
NULL just after return from drm_sched_init.

Other than that this change looks good to me.

Regards

Xiaogang


> to avoid possible invalid memory access on error recover path.
>
> Signed-off-by: Jiang Liu<gerry at linux.alibaba.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c  | 4 +++-
>   2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 5ff53a3b9851..475ab635c699 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -2857,6 +2857,7 @@ static int amdgpu_device_init_schedulers(struct amdgpu_device *adev)
>   		if (r) {
>   			DRM_ERROR("Failed to create scheduler on ring %s.\n",
>   				  ring->name);
> +			ring->sched.ops = NULL;
>   			return r;
>   		}
>   		r = amdgpu_uvd_entity_init(adev, ring);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> index 2f24a6aa13bf..b5e87b515139 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> @@ -656,8 +656,10 @@ void amdgpu_fence_driver_sw_fini(struct amdgpu_device *adev)
>   		 * The natural check would be sched.ready, which is
>   		 * set as drm_sched_init() finishes...
>   		 */
> -		if (ring->sched.ops)
> +		if (ring->sched.ops) {
>   			drm_sched_fini(&ring->sched);
> +			ring->sched.ops = NULL;
> +		}
>   
>   		for (j = 0; j <= ring->fence_drv.num_fences_mask; ++j)
>   			dma_fence_put(ring->fence_drv.fences[j]);
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