drm/amdgpu: fix tear down order in amdgpu_vm_pt_free

When freeing PD/PT with shadows it can happen that the shadow destruction races with detaching the PD/PT from the VM causing a NULL pointer dereference in the invalidation code. Fix this by detaching the the PD/PT from the VM first and then freeing the shadow instead. Signed-off-by: Christian König <[email protected]> Fixes: https://gitlab.freedesktop.org/drm/amd/-/issues/2867 Cc: <[email protected]> Reviewed-by: Alex Deucher <[email protected]> Signed-off-by: Alex Deucher <[email protected]>
pop-os · Dec 13, 2023 · ceb9a32 · ceb9a32
1 parent 2c7300d
commit ceb9a32
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -642,13 +642,14 @@ static void amdgpu_vm_pt_free(struct amdgpu_vm_bo_base *entry)
 
 	if (!entry->bo)
 		return;
+
+	entry->bo->vm_bo = NULL;
 	shadow = amdgpu_bo_shadowed(entry->bo);
 	if (shadow) {
 		ttm_bo_set_bulk_move(&shadow->tbo, NULL);
 		amdgpu_bo_unref(&shadow);
 	}
 	ttm_bo_set_bulk_move(&entry->bo->tbo, NULL);
-	entry->bo->vm_bo = NULL;
 
 	spin_lock(&entry->vm->status_lock);
 	list_del(&entry->vm_status);