drm/ttm: fix LRU handling in ttm_buffer_object_transfer

[ Upstream commit d6e820fcd4cf08b11d291a1dd7bbd0636914647c ]

We need to set the NO_EVICT flag on the ghost object or otherwise we are
adding it to the LRU.

When it is added to the LRU we can run into a race between destroying
and evicting it again.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -492,8 +492,10 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 	if (!fbo)
 		return -ENOMEM;
 
-	ttm_bo_get(bo);
 	fbo->base = *bo;
+	fbo->base.mem.placement |= TTM_PL_FLAG_NO_EVICT;
+
+	ttm_bo_get(bo);
 	fbo->bo = bo;
 
 	/**