Re: [RFC PATCH v2 05/18] sched: add task flag for preempt IRQ tracking

Jiri Kosina
2016-04-29T22:11:53Z

On Fri, 29 Apr 2016, Andy Lutomirski wrote:

> > NMI, MCE and interrupts aren't a problem because they have dedicated
> > stacks, which are easy to detect. If the tasks' stack is on an
> > exception stack or an irq stack, we consider it unreliable.
>
> Only on x86_64.

Well, MCEs are more or less x86-specific as well. But otherwise good
point, thanks Andy.

So, how does stack layout generally look like in case when NMI is actually
running on proper kernel stack? I thought it's guaranteed to contain
pt_regs anyway in all cases. Is that not guaranteed to be the case?

Thanks,

--
Jiri Kosina
SUSE Labs