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Date: Wed, 1 Mar 2017 18:07:11 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Meelis Roos <mroos@linux.ee>
cc: Linux Kernel list <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: PPro arch_cpu_idle: NMI watchdog: Watchdog detected hard LOCKUP
 on cpu 1
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On Wed, 1 Mar 2017, Meelis Roos wrote:

> This is on my trusty IBM PC365, dual Pentium Pro. 4.10 worked fine, 
> 4.10.0-09686-g9e314890292c and 4.10.0-10770-g2d6be4abf514 exhibit a 
> problem. Ocassionally NMI watchdog kicks in and discovers one of the 
> CPUs in LOCKUP. The system keeps running fine. The first lockup was 
> different, all the others were from arch_cpu_idle. Sometime ecey couple 
> of seconds (after some activity), sometimes nothing for a long time 
> (idle, no SSH logins).

The only watchdog related patch which hit after 4.10 is:

 8dcde9def5a1 kernel/watchdog.c: do not hardcode CPU 0 as the initial thread

Can you try to revert that for a start? I'm not seeing why it should be the
culprit from a quick glance, but ...

Thanks,

	tglx