Re: [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 <ge...@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);