Got 2 cases about cl_page_state_set0()) LBUG.
- (cl_page_state_set0()) allowed_transitions[old][state]
And the cl_page cp_state is 2 (CPS_PAGEOUT) cp_owner has value. The page is meant to transit from CACHED to OWNED, but it already has been in PAGEOUT state.
- (cl_page.c:346:cl_page_state_set0()) equi(state == CPS_OWNED, page->cp_owner != NULL)
And the cl_page cp_state is 1 (CPS_OWNED) cp_onwer has value. The page is meant to transit from OWNED to PAGEOUT, but cl_page_io_start() should has cleared its cp_owner.