Messages in this thread | | | Date | Thu, 10 Jan 2013 14:22:45 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH] hardlockup: detect hard lockups without NMIs using secondary cpus |
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On Thu, Jan 10, 2013 at 09:02:15AM -0500, Don Zickus wrote: > On Wed, Jan 09, 2013 at 05:57:39PM -0800, Colin Cross wrote: > > Emulate NMIs on systems where they are not available by using timer > > interrupts on other cpus. Each cpu will use its softlockup hrtimer > > to check that the next cpu is processing hrtimer interrupts by > > verifying that a counter is increasing. > > > > This patch is useful on systems where the hardlockup detector is not > > available due to a lack of NMIs, for example most ARM SoCs. > > I have seen other cpus, like Sparc I think, create a 'virtual NMI' by > reserving an IRQ line as 'special' (can not be masked). Not sure if that > is something worth looking at here (or even possible).
No it isn't, because that assumes that things like spin_lock_irqsave() won't mask that interrupt. We don't have the facility to do that.
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