linux-kernel - Re: random insta-reboots on AMD Phenom II

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Date:   Sat, 30 Sep 2017 10:20:48 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     Markus Trippelsdorf <markus@...ppelsdorf.de>
Cc:     Borislav Petkov <bp@...en8.de>,
        Adam Borowski <kilobyte@...band.pl>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>, x86-ml <x86@...nel.org>
Subject: Re: random insta-reboots on AMD Phenom II

On Sat, Sep 30, 2017 at 8:47 AM, Markus Trippelsdorf
<markus@...ppelsdorf.de> wrote:
> On 2017.09.30 at 13:53 +0200, Borislav Petkov wrote:
>> On Sat, Sep 30, 2017 at 01:29:03PM +0200, Adam Borowski wrote:
>> > On Sat, Sep 30, 2017 at 01:11:37PM +0200, Borislav Petkov wrote:
>> > > On Sat, Sep 30, 2017 at 04:05:16AM +0200, Adam Borowski wrote:
>> > > > Any hints how to debug this?
>> > >
>> > > Do
>> > > rdmsr -a 0xc0010015
>> > > as root and paste it here.
>> >
>> > 1000010
>> > 1000010
>> > 1000010
>> > 1000010
>> > 1000010
>> > 1000010
>> >
>> > on both 4.13.4 and 4.14-rc2+.
>>
>> Boot into -rc2+ and do as root:
>>
>> # wrmsr -a 0xc0010015 0x1000018
>>
>> If the issue gets fixed then Mr. Luto better revert the new lazy TLB
>> flushing fun'n'games for 4.14 before it is too late and that kernel
>> releases b0rked.
>
> The issue does get fixed by setting TlbCacheDis to 1. I have been
> running it for the last few weeks without any problems.
> Performance is not affected at all. So it might by easier to just set
> the bit for older AMD processors as a boot quirk.
> Changing the TLB code so late might not be a good idea...

Looking at the AMD K10 revision guide
(http://support.amd.com/TechDocs/41322_10h_Rev_Gd.pdf), errata #298
that this fixes should only apply to revisions DR-BA and DR-B2, which
include the original Phenom, but not Phenom II.  The Phenom II X6 is
revision PH-E0, which does not have this errata.

--
Brian Gerst