Hi Liu,
On 04/18/2013 08:10 PM, Liu, Chuansheng wrote:
>> It seems that with commit "smp: Give WARN()ing when calling
>> > smp_call_function_many()/single() in serving irq" I'm getting a bunch of
>> > these:
> This patch gives the warning even when the smp_call_function_many() is called
> in softirq context,
> because it will bring the possible deadlock cases, the example is below:
> CPUA CPUB
> spin_lock(&spinlock)
> Any irq coming, call the irq handler
> irq_exit()
> spin_lock_irq(&spinlock)
> <== Blocking here due to
> CPUB hold it
> __do_softirq()
> run_timer_softirq()
> timer_cb()
> call smp_call_function_many()
> send IPI interrupt to CPUA
> wait_csd()
>
> Then both CPUA and CPUB will be deadlocked here.
Right.
So commit f55a6faa3 ("hrtimer: Provide clock_was_set_delayed()") followed by one
of the commits that used clock_was_set_delayed() may trigger the deadlock you've
described. (cc John Stultz...)
Thanks,
Sasha
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
