Messages in this thread | | | Date | Wed, 6 Sep 2023 06:08:16 -0700 | From | "Paul E. McKenney" <> | Subject | Re: "Dying CPU not properly vacated" splat |
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On Tue, Aug 02, 2022 at 10:30:02AM +0100, Valentin Schneider wrote: > On 05/07/22 10:23, Paul E. McKenney wrote: > > The second of these occurred near shutdown, but the first was quite some > > time before shutdown. In case that makes a difference. > > > > I have not seen this since. > > > > Any other diagnostics I should add? > > > > Sorry, I let this get buried to the bottom of my inbox :( > > I've had another look at rcutorture.c but just like for > rcu_torture_reader(), I don't see any obvious culprit (no > kthread_set_per_cpu() usage)). > > One thing I think would help is a scheduling trace (say sched_switch, > sched_wakeup and cpuhp*, combined with ftrace_dump_on_oops + panic_on_warn > ?) - that should at least tell us if the issue is in the wakeup placement > (if the task gets placed on a dying CPU *after* CPUHP_AP_ACTIVE), or in the > balance_push() mechanism (the task was *already* on the CPU when it started > dying and never moved away). > > Neither make sense to me, but it has to be somewhere in there...
And given that it has been more than a year since I have seen this, I am considering it to be fixed, whether purposefully or accidentally.
Thanx, Paul
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