On Sat, 14 Nov 2015 10:53:18 +0800
<yanjiang....@windriver.com> wrote:
> From: Yanjiang Jin <yanjiang....@windriver.com>
>
> This can only happen in RT kernel due to run_timer_softirq() calls
> irq_work_tick() when CONFIG_PREEMPT_RT_FULL is enabled as below:
>
> static void run_timer_softirq(struct softirq_action *h)
> {
> ........
> if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
> irq_work_tick();
> endif
> ........
> }
>
> Use raw_spin_{un,}lock_irq{save,restore} in push_irq_work_func() to
> prevent following potentially deadlock scenario:
Ug. No, the real fix is that the irq work is to be run from hard
interrupt context. Moving the scheduling of high priority real-time
tasks to ksoftirqd defeats the purpose. The question is, why is that
irq work being run from thread context when it has the
IRQ_WORK_HARD_IRQ flag set?
-- Steve
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