The code was potentially dereferencig a NULL sync object pointer.
At the same time a sync object reference was potentially leaked.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
        if (evict) {
                ret = ttm_bo_wait(bo, false, false, false);
                spin_unlock(&bo->lock);
-               driver->sync_obj_unref(&bo->sync_obj);
-
+               if (tmp_obj)
+                       driver->sync_obj_unref(&tmp_obj);
                if (ret)
                        return ret;
 
 
                set_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags);
                spin_unlock(&bo->lock);
+               if (tmp_obj)
+                       driver->sync_obj_unref(&tmp_obj);
 
                ret = ttm_buffer_object_transfer(bo, &ghost_obj);
                if (ret)