On Thu, Oct 12, 2023 at 05:00:03PM +0800, Hao Jia wrote: > Igor Raits and Bagas Sanjaya report a RQCF_ACT_SKIP leak warning. > Link: https://lore.kernel.org/all/a5dd536d-041a-2ce9-f4b7-64d8d85c86dc@xxxxxxxxx > > This warning may be triggered in the following situations: > > CPU0 CPU1 > > __schedule() > *rq->clock_update_flags <<= 1;* unregister_fair_sched_group() > pick_next_task_fair+0x4a/0x410 destroy_cfs_bandwidth() > newidle_balance+0x115/0x3e0 for_each_possible_cpu(i) *i=0* > rq_unpin_lock(this_rq, rf) __cfsb_csd_unthrottle() > raw_spin_rq_unlock(this_rq) > rq_lock(*CPU0_rq*, &rf) > rq_clock_start_loop_update() > rq->clock_update_flags & RQCF_ACT_SKIP <-- > raw_spin_rq_lock(this_rq) > > The purpose of RQCF_ACT_SKIP is to skip the update rq clock, > but the update is very early in __schedule(), but we clear > RQCF_*_SKIP very late, causing it to span that gap above > and triggering this warning. > > In __schedule() we can clear the RQCF_*_SKIP flag immediately > after update_rq_clock() to avoid this RQCF_ACT_SKIP leak warning. > And set rq->clock_update_flags to RQCF_UPDATED to avoid > rq->clock_update_flags < RQCF_ACT_SKIP warning that may be triggered later. > Thanks!
