Re: [PATCH v3] watchdog: touch_nmi_watchdog should only touch localcpu not every one

From: Ingo Molnar
Date: Wed Nov 10 2010 - 02:50:10 EST



* Don Zickus <dzickus@xxxxxxxxxx> wrote:

> I ran into a scenario where while one cpu was stuck and should have panic'd
> because of the NMI watchdog, it didn't. The reason was another cpu was spewing
> stack dumps on to the console. Upon investigation, I noticed that when writing to
> the console and also when dumping the stack, the watchdog is touched.
>
> This causes all the cpus to reset their NMI watchdog flags and the 'stuck' cpu
> just spins forever.

Hm, the flip side is that if a CPU is stuck spewing backtraces, we will now make all
the other CPUs a lot more noisy - which might only 'lock up' because this CPU is
stuck spewing oopses, right?

Andrew, what would be your preference?

Thanks,

Ingo
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