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

[David Woodhouse <dwmw2@infradead.org>]

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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.

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