Commit 96a86dcb authored by Jesse.Zhang's avatar Jesse.Zhang Committed by Alex Deucher
Browse files

drm/amdgpu: Fix circular locking in userq creation 



A circular locking dependency was detected between the global
`adev->userq_mutex` and per-file `userq_mgr->userq_mutex` when
creating user queues. The issue occurs because:

1. `amdgpu_userq_suspend()` and `amdgpu_userq_resume` take `adev->userq_mutex` first, then
   `userq_mgr->userq_mutex`
2. While `amdgpu_userq_create()` takes them in reverse order

This patch resolves the issue by:
1. Moving the `adev->userq_mutex` lock earlier in `amdgpu_userq_create()`
   to cover the `amdgpu_userq_ensure_ev_fence()` call
2. Releasing it after we're done with both queue creation and the
   scheduling halt check

v2: remove unused adev->userq_mutex lock (Prike)

Signed-off-by: default avatarJesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: default avatarPrike Liang <Prike.Liang@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 07c9db09

drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c

+2 −3
Original line number Diff line number Diff line
@@ -394,6 +394,7 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args) 
	 *

	 * This will also make sure we have a valid eviction fence ready to be used.

	 */

	mutex_lock(&adev->userq_mutex);

	amdgpu_userq_ensure_ev_fence(&fpriv->userq_mgr, &fpriv->evf_mgr);



	uq_funcs = adev->userq_funcs[args->in.ip_type];
@@ -456,7 +457,6 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args) 
	}



	/* don't map the queue if scheduling is halted */

	mutex_lock(&adev->userq_mutex);

	if (adev->userq_halt_for_enforce_isolation &&

	    ((queue->queue_type == AMDGPU_HW_IP_GFX) ||

	     (queue->queue_type == AMDGPU_HW_IP_COMPUTE)))
@@ -466,7 +466,6 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args) 
	if (!skip_map_queue) {

		r = amdgpu_userq_map_helper(uq_mgr, queue);

		if (r) {

			mutex_unlock(&adev->userq_mutex);

			drm_file_err(uq_mgr->file, "Failed to map Queue\n");

			idr_remove(&uq_mgr->userq_idr, qid);

			amdgpu_userq_fence_driver_free(queue);
@@ -475,13 +474,13 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args) 
			goto unlock;

		}

	}

	mutex_unlock(&adev->userq_mutex);





	args->out.queue_id = qid;



unlock:

	mutex_unlock(&uq_mgr->userq_mutex);

	mutex_unlock(&adev->userq_mutex);



	return r;

}