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

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Date:   Sat, 9 Sep 2017 20:14:45 +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 19:36 +0200, Borislav Petkov wrote:
> On Sat, Sep 09, 2017 at 07:23:52PM +0200, Markus Trippelsdorf wrote:
> > Hmm, the output is exactly the same as before your patch.
> 
> Bah, that patch doesn't account for the fact that we're rereading the
> status field again in do_machine_check().
> 
> Ok, let's force MCi_ADDR out. Ontop:

Thanks, will try it later.

I think the issue gets fixed by:

 # wrmsr -a 0xc0010015 0x1000018

Setting bit 3 of the Hardware Configuration Register to 1.

Quote for the docs:
»TlbCacheDis: cacheable memory disable. Read-write. 0=Enables performance optimization that
assumes PML4, PDP, PDE, and PTE entries are in cacheable WB-DRAM; memory type checks may
be bypassed, and addresses outside of WB-DRAM may result in undefined behavior or NB protocol
errors. 1=Disables performance optimization and allows PML4, PDP, PDE and PTE entries to be in
any memory type. Operating systems that maintain page tables in memory types other than WB-
DRAM must set TlbCacheDis to insure proper operation.«

I've been successfully compiling for over 15 minutes now. 

-- 
Markus