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Date:   Sat, 28 Oct 2017 03:25:45 +0200
From:   Christoph Anton Mitterer <calestyo@...entia.net>
To:     linux-kernel@...r.kernel.org
Subject: "Core temperature above threshold" on Fujitsu U757 with 2 core Kaby
 Lake (i7-7600U)

Hey.

Perhaps someone can help me with this.


I got a brand new notebook from the university, a Fujitsu U757[0][1],
with a 2 core Kaby Lake (i7-7600U) and 32GB RAM.
It runs Debian unstable, that is as of now kernel 4.13.4.

Even at pretty simple tasks (just some VM running) and a bit more, the
CPUs seem to overheat (>100°C).
I brought the thing back to the university's vendor and they claimed
that they couldn't reproduce this with the (Windows based) tests and it
might be a OS issue (they did replace the heat paste at my request).


The kernel logs quite regularly give:
Oct 28 03:15:19 heisenberg kernel: CPU2: Core temperature above threshold, cpu clock throttled (total events = 1207)
Oct 28 03:15:19 heisenberg kernel: CPU0: Core temperature above threshold, cpu clock throttled (total events = 1207)
Oct 28 03:15:19 heisenberg kernel: CPU1: Package temperature above threshold, cpu clock throttled (total events = 1394)
Oct 28 03:15:19 heisenberg kernel: CPU3: Package temperature above threshold, cpu clock throttled (total events = 1394)
Oct 28 03:15:19 heisenberg kernel: CPU0: Package temperature above threshold, cpu clock throttled (total events = 1394)
Oct 28 03:15:19 heisenberg kernel: CPU2: Package temperature above threshold, cpu clock throttled (total events = 1394)
Oct 28 03:15:19 heisenberg kernel: CPU0: Core temperature/speed normal
Oct 28 03:15:19 heisenberg kernel: CPU2: Core temperature/speed normal
Oct 28 03:15:19 heisenberg kernel: CPU3: Package temperature/speed normal
Oct 28 03:15:19 heisenberg kernel: CPU1: Package temperature/speed normal
Oct 28 03:15:19 heisenberg kernel: CPU2: Package temperature/speed normal
Oct 28 03:15:19 heisenberg kernel: CPU0: Package temperature/speed normal

I guess every time it goes beyond 100° C.

Once so far I had a complete lockup of the machine (it still seemed to
write data to the HDD, but I could only hard power cycle to get
it usable again.
Not sure if this is related to the temperature issue.
See the attached kernel log.

At around Oct 15 22:46:39 there seems to be first a crash of the Wifi
microcode a bit later, beginning at about Oct 16 01:27:16, there are
numerous stack traces with "BUG: soft lockup - CPU".


Could this be some kernel issue? Especially the overheating... I mean
obviously not in the sense that it's the kernels fault, but in the
sense that is should speed it down earlier or so...?


Interestingly, when I run e.g. stress or stress-ng on all 4 logical
CPUs... then sometimes I do get the overheating, sometimes not (in
which case temperature stays above 90°C.. but always below 100°C (I
assume).



Any help would be welcome, do not hesitate to ask if you need more data
(keep me CCed).

Thanks,
Chris.



[0] http://www.fujitsu.com/fts/products/computing/pc/notebooks/lifebook-u757/
[1] http://docs.ts.fujitsu.com/dl.aspx?id=addf5093-b73b-407b-ae78-90c5baf6456a
Download attachment "kern.log.xz" of type "application/x-xz" (37440 bytes)

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