linux-kernel - Re: Current mainline git (24e700e291d52bd2) hangs when building e.g. perf

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Date:   Sat, 9 Sep 2017 13:07:49 +0200
From:   Markus Trippelsdorf <markus@...ppelsdorf.de>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Andy Lutomirski <luto@...nel.org>, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: Current mainline git (24e700e291d52bd2) hangs when building e.g.
 perf

On 2017.09.09 at 12:18 +0200, Borislav Petkov wrote:
> On Sat, Sep 09, 2017 at 08:39:08AM +0200, Markus Trippelsdorf wrote:
> > Unfortunately the machine hangs in the BIOS after the first warm-reset.
> > Probably when it encounters an MCE it doesn't expect. I have to
> > warm-reset a second time to get to the boot-loader. So it is impossible
> > for me to see any possible MCE.
> 
> Ok, let's try to disable the syncflood before the test. As root:
> 
> # V=$(setpci -s 18.3 0x44.l)
> # echo $V

4a70005c

> # V=$(printf "0x%x" $((0x$V & ~(1 << 21))))
> # setpci -s 18.3 0x44.l=$V
> # echo $V

0x4a50005c

> I've added the echo $V so that you can paste them as a reply so that I
> can see their values.
> 
> And then run the triggering sequence again, better not on an X terminal
> but in the text console to see any MCEs when it freezes. I remember you
> saying that you don't have serial connected to it so catching the MCE
> would need more staring :)

It doesn't work. Compiling in a text console just freezes the machine
before any MCE gets printed.

-- 
Markus