Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: "Dying CPU not properly vacated" splat | Date | Tue, 02 Aug 2022 10:30:02 +0100 |
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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...
> Thanx, Paul
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