drm/ttm: unbind ttm before destroying node in accel move cleanup

Nouveau makes the assumption that if a TTM is bound there will be a mm_node
around for it and the backwards ordering here resulted in a use-after-free
on some eviction paths.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 77dbf40..ae3c6f5 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -635,13 +635,13 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
                if (ret)
                        return ret;
 
-               ttm_bo_free_old_node(bo);
                if ((man->flags & TTM_MEMTYPE_FLAG_FIXED) &&
                    (bo->ttm != NULL)) {
                        ttm_tt_unbind(bo->ttm);
                        ttm_tt_destroy(bo->ttm);
                        bo->ttm = NULL;
                }
+               ttm_bo_free_old_node(bo);
        } else {
                /**
                 * This should help pipeline ordinary buffer moves.