Messages in this thread | | | Date | Fri, 7 Feb 2014 12:30:06 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH RT] rt: Make cpu_chill() use hrtimer instead of msleep() |
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* Steven Rostedt | 2014-02-05 11:51:25 [-0500]:
>Ulrich Obergfell pointed out that cpu_chill() calls msleep() which is woken >up by the ksoftirqd running the TIMER softirq. But as the cpu_chill() is >called from softirq context, it may block the ksoftirqd() from running, in >which case, it may never wake up the msleep() causing the deadlock. > >I checked the vmcore, and irq/74-qla2xxx is stuck in the msleep() call, >running on CPU 8. The one ksoftirqd that is stuck, happens to be the one that >runs on CPU 8, and it is blocked on a lock held by irq/74-qla2xxx. As that >ksoftirqd is the one that will wake up irq/74-qla2xxx, and it happens to be >blocked on a lock that irq/74-qla2xxx holds, we have our deadlock.
could you please tell me which two locks are invovled here?
Sebastian
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