linux-kernel - Re: Bricked x86 CPU with software?

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Message-ID: <5A4E9D49.11571.23941BD@tim.ml.ipcopper.com>
Date:   Thu, 04 Jan 2018 13:31:53 -0800
From:   "Tim Mouraveiko" <tim.ml@...opper.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
CC:     Pavel Machek <pavel@....cz>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Bricked x86 CPU with software?

> On Thu, Jan 4, 2018 at 11:00 PM, Tim Mouraveiko <tim.ml@...opper.com> wrote:
> > Pavel,
> >
> > As I mentioned before, I repeatedly and fully power-cycled the motherboard and reset BIOS
> > and etc. It made no difference. I can see that the processor was not drawing any power. The
> > software code behaved in a similar fashion on other processors, until I fixed it so that it would
> > not kill any more processors.
> >
> > In case you are curious there was no overheating, no 100% utilization, no tampering with
> > hardware (GPIO pins or anything of that sort), no overclocking and etc. No hardware issues
> > or changes at all.
> 
> Please, do not top post.
> 
> Just to be sure, have you checked same CPU on different motherboard?
> It might be that voltage regulators on it just died.

I did not check the same CPU on a different motherboard, but I did test the code on both the 
same type of CPU and a different type of CPU.

> 
> 
> >> > In all my years of extensive experience writing drivers and kernels, I never came across a situation
> >> > where you could brick an x86 CPU. Not until recently, when I was working on debugging a piece of
> >> > code and I bricked an Intel CPU. I am not talking about an experimental motherboard or anything
> >> > exotic or an electrical issue where the CPU got fried, but before the software code execution the CPU
> >> > was fine and then it dead. There were signs that something was not right, that the code was causing
> >> > unusual behavior, which is what I was debugging.
> >> >
> >> > Has anyone else ever experienced a bricked CPU after executing software code? I just wanted to get
> >> > input from the community to see if anyone had had any experience like that, since it seems rather
> >> > unusual to me.
> >>
> >> Never seen that before. Can you try to brick another one? :-).
> >>
> >> You may want to remove AC power and battery, wait for half an hour,
> >> then attempt to boot it...
> >>
> >>                                                                       Pavel
> >> --
> >> (english) http://www.livejournal.com/~pavelmachek
> >> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> >>
> >
> >
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko