Messages in this thread | | | Date | Sat, 14 Nov 2015 12:40:42 +0800 | From | yjin <> | Subject | Re: [RT PATCH] sched: rt: fix two possible deadlocks in push_irq_work_func |
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On 2015年11月14日 12:25, Steven Rostedt wrote: > On Sat, 14 Nov 2015 10:53:18 +0800 > <yanjiang.jin@windriver.com> wrote: > >> From: Yanjiang Jin <yanjiang.jin@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. But if so, we shouldn't call irq_work_tick() in run_timer_softirq(), right?
Thanks! Yanjiang > 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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