Re: [BUG] x86 : i486 reporting to be vulnerable to Meltdown/Spectre_V1/Spectre_V2

From: tedheadster
Date: Tue Feb 06 2018 - 14:25:05 EST


On Tue, Feb 6, 2018 at 2:17 PM, David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:
> On Tue, 2018-02-06 at 11:13 -0800, Guenter Roeck wrote:
>> On Tue, Feb 06, 2018 at 07:10:27PM +0000, David Woodhouse wrote:
>> >
>> >
>> >
>> > On Tue, 2018-02-06 at 11:02 -0800, Greg Kroah-Hartman wrote:
>> > >
>> > > .
>> > > >
>> > > >
>> > > > David
>> > > > I believe I got the patch(es) you mention in in the stable 4.15.1 kernel:
>> > > >
>> > > > Pull x86/pti updates from Thomas Gleixner: "Another set of melted
>> > > > spectrum related changes"
>> > > > (commit 6304672b7f0a5c010002e63a075160856dc4f88d).
>> > > >
>> > > > Unfortunately, the symptoms I reported remain on at least the i486 and i686.
>> > > Can you try 4.15.2-rc1? Or how about Linus's kernel tree now? There
>> > > was a lot of spectrum patches merged just this week that were not in
>> > > 4.15.1.
>> > No, for the 486 it *should* have worked. The interesting commit
>> > is fec9434a12 ("x86/pti: Do not enable PTI on CPUs which are not
>> > vulnerable to Meltdown") which is indeed pulled in with the merge
>> > commit that Matthew mentions.
>> >
>> I disagree.
>>
>> $ git describe
>> v4.15.1-61-g7ab5513e4cbc
>> $ git log --oneline v4.15.1.. | grep Melt
>> 3472b3689bab x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
>
> Ah right, for 4.15.1 perhaps yes. I was looking at Matthew's 'commit
> 6304672b7f0a5c010002e63a075160856dc4f88d' which isn't in 4.15.1 at all;
> that's the commit in Linus' tree where he pulled in the fix. So *that*
> one should have had it.

I think Guenter is correct and I mixed up my linux versus linux-stable
git repository directories. I am recompiling now Linus' tree and will
report back my results.

Apologies for the incorrect information.

- Matthew