Re: Writing watchdog_thresh triggers BUG: sleeping function called from invalid context

From: Michal Hocko
Date: Tue Jun 17 2014 - 04:59:49 EST


On Mon 16-06-14 16:52:45, Don Zickus wrote:
[...]
> Michal, do you remember why we needed preempt here? I wouldn't think it
> mattered as we are not doing anything per-cpu specific.

Yes, you are right. Preempt can be enabled because we are always
accessing watchdog_ev on a specific cpu so reschedule doesn't matter.

> Cheers,
> Don
>
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 516203e..30e4822 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -527,10 +527,8 @@ static void update_timers_all_cpus(void)
> int cpu;
>
> get_online_cpus();
> - preempt_disable();
> for_each_online_cpu(cpu)
> update_timers(cpu);
> - preempt_enable();
> put_online_cpus();
> }
>

--
Michal Hocko
SUSE Labs
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