On Mon, 2024-09-16 at 12:00 +0530, Venkat Rao Bagalkote wrote:
> Greetings!!!
Greetings,
> I am seeing below kernel crash from 6.11.0-rc4-next-20240820.
>
>
> Tried to do git bisect, but it didnt point to right patch. Attached is
> the bisect log.
>
> Any help in fixing this is much appriciated.
I met this, as well as other ways the wheels can fall off that turned
out to have the same root. I gave Peter a heads up with diag offline,
but having now convinced myself that all is well, I'll go ahead and
post a patchlet.
At the very least it's worth putting out for wider testing.. and should
anyone have something prettier in mind, yeah, do that instead.
sched: Fix sched_delayed vs cfs_bandwidth
Meeting an unfinished DELAY_DEQUEUE treated entity in unthrottle_cfs_rq()
leads to a couple terminal scenarios. Finish it first, so ENQUEUE_WAKEUP
can proceed as it would have sans DELAY_DEQUEUE treatment.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Signed-off-by: Mike Galbraith <efa...@gmx.de>
---
kernel/sched/fair.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6049,10 +6049,14 @@ void unthrottle_cfs_rq(struct cfs_rq *cf
for_each_sched_entity(se) {
struct cfs_rq *qcfs_rq = cfs_rq_of(se);
- if (se->on_rq) {
- SCHED_WARN_ON(se->sched_delayed);
- break;
+ /* Handle any unfinished DELAY_DEQUEUE business first. */
+ if (unlikely(se->on_rq && se->sched_delayed)) {
+ int flags = DEQUEUE_SLEEP | DEQUEUE_SPECIAL;
+
+ dequeue_entity(qcfs_rq, se, flags | DEQUEUE_DELAYED);
}
+ if (se->on_rq)
+ break;
enqueue_entity(qcfs_rq, se, ENQUEUE_WAKEUP);
if (cfs_rq_is_idle(group_cfs_rq(se)))
