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

[Chen, Xiaogang]

On 1/1/2025 11:36 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()
> to avoid possible invalid memory access on error recover path.
>
> Signed-off-by: Jiang Liu <gerry at linux.alibaba.com>
> ---
>   drivers/gpu/drm/scheduler/sched_main.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 5adab4b3386c..ce2afdfc0158 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -1331,6 +1331,8 @@ int drm_sched_init(struct drm_gpu_scheduler *sched,
>   	if (sched->own_submit_wq)
>   		destroy_workqueue(sched->submit_wq);
>   	drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
> +	// amdgpu_fence_driver_sw_fini() checks sched->ops for status.
> +	sched->ops = NULL;

Instead change drm/scheduler how about change amdgpu driver? At 
amdgpu_device_init_schedulers if drm_sched_init fail for a ring 
scheduler set

ring->sched->op = NULL;

It is not drm issue. If drm's scheduler init fail its operation has no 
meaning, we can set it to null at amdgpu driver.

Regards

Xiaogang

>   	return -ENOMEM;
>   }
>   EXPORT_SYMBOL(drm_sched_init);
> @@ -1375,6 +1377,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
>   	sched->ready = false;
>   	kfree(sched->sched_rq);
>   	sched->sched_rq = NULL;
> +	sched->ops = NULL;
>   }
>   EXPORT_SYMBOL(drm_sched_fini);
>