| From | Arnd Bergmann <> | Subject | Re: [patch v2 15/35] Hexagon: Add init_task and process functions | Date | Wed, 31 Aug 2011 15:45:14 +0200 |
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On Tuesday 30 August 2011, Richard Kuo wrote: > Fixed potential race-to-sleep condition in cpu_idle(). I hope. > > If called with interrupts disabled, our __vmwait() actually just returns > without servicing it. Let me know if there's any other condition that > I've missed...
The race should be gone now, but
> +void cpu_idle(void) > +{ > + while (1) { > + tick_nohz_stop_sched_tick(1); > + local_irq_disable(); > + while (!need_resched()) { > + idle_sleep(); > + /* interrupts wake us up, but aren't serviced */ > + local_irq_enable(); /* service interrupt */ > + local_irq_disable(); > + } > + tick_nohz_restart_sched_tick(); > + schedule(); > + } > +}
you now call schedule() with interrupts disabled, which isn't strictly allowed.
I think it should all be fine if you write it as
while (1) { tick_nohz_stop_sched_tick(1); local_irq_disable(); while (!need_resched()) { idle_sleep(); } local_irq_enable(); tick_nohz_restart_sched_tick(); schedule(); }
Arnd
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