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Date: Mon, 13 Feb 2017 05:39:20 -0600
From: lkml@pengaru.com
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Pavel Machek <pavel@ucw.cz>, Woody Suwalski <terraluna977@gmail.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        kernel list <linux-kernel@vger.kernel.org>, mingo@redhat.com,
        hpa@zytor.com
Subject: Re: 4.10-rc1: thinkpad x60: who ate my cpu?
Message-ID: <20170213113920.GY3712@shells.gnugeneration.com>
References: <20170115095656.GA16524@amd> <1614c21c-3626-074e-e3c3-26e9cd200454@gmail.com> <3c3d35ac-e4e4-6a6c-a78e-b0478ff39726@gmail.com> <20170212195742.GA6264@amd> <161a3edb-84f1-769d-d8e9-04102ddbbe58@gmail.com> <20170213080215.GA3730@amd> <alpine.DEB.2.20.1702130948130.3619@nanos> <20170213094236.GA2924@amd> <20170213101851.GX3712@shells.gnugeneration.com> <alpine.DEB.2.20.1702131224190.3619@nanos>
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On Mon, Feb 13, 2017 at 12:25:28PM +0100, Thomas Gleixner wrote:
> On Mon, 13 Feb 2017, lkml@pengaru.com wrote:
> 
> > On Mon, Feb 13, 2017 at 10:42:36AM +0100, Pavel Machek wrote:
> > > Hi!
> > > 
> > > On Mon 2017-02-13 09:48:41, Thomas Gleixner wrote:
> > > > On Mon, 13 Feb 2017, Pavel Machek wrote:
> > > > > cd /sys/devices/system/cpu/cpu1
> > > > > while true; do echo 0 > online; echo 1 > online; done
> > > > > 
> > > > > ...crashes x60 with 4.10-rc in few minutes. [Which is bad -- it should
> > > > > not die, but also good -- this is easier to reproduce then running 100
> > > > > suspend cycles.]
> > > > 
> > > > Can you tell where it crashes?
> > > 
> > > I did not expect a crash, so I was in X... I have a feeling that this
> > > will be reproducible on a lot of hardware, but let me try.
> > 
> > FYI: Lockup reproduced with 4.10.0-rc7 with an X61s.
> > 
> > Caught a glimpse of something about an RCU stall timeout before the system shut
> > off.  Prior to that, during the loop execution, a bunch of systemd processes
> > were experiencing watchdog timeouts, and procps `top` would start but
> > never refresh, leaving the CPU column all "nan".
> 
> Does the machine use intel_idle by chance?
> 

It's not enabled in my kernel, /proc/config.gz attached FWIW.

Regards,
Vito Caputo