Messages in this thread | | | Date | Wed, 10 Nov 2021 11:45:10 +0100 | From | Michal Koutný <> | Subject | Re: printk deadlock due to double lock attempt on current CPU's runqueue |
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On Wed, Nov 10, 2021 at 10:00:35AM +0100, Vincent Guittot <vincent.guittot@linaro.org> wrote: > Is it the same SCHED_WARN_ON(rq->tmp_alone_branch != > &rq->leaf_cfs_rq_list); that generates the deadlock on v5.15 too ? > > one remaining tmp_alone_branch warning has been fixed in v5.15 with > 2630cde26711 ("sched/fair: Add ancestors of unthrottled undecayed cfs_rq")
AFAIK, the warning is typically triggered on v5.13 when CPU throttling is employeed. The cfs_rq list is mis-ordered but it shouldn't be fatal. But the throttling currently (since v5.13 too) also exposes a race on task_group removal that can lead to corrupting the cfs_rq list (another thread [1], I'll leave this thread for printk (non)-locking).
HTH, Michal
[1] https://lore.kernel.org/r/20211011172236.11223-1-mkoutny@suse.com/
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