Re: [PATCHv4, REBASED 1/4] x86/mm/ident_map: Fix virtual address wrap to zero

[Kirill A. Shutemov]

On Thu, Oct 31, 2024 at 02:59:16PM +0100, Borislav Petkov wrote:
> On Thu, Oct 31, 2024 at 12:11:52PM +0200, Kirill A. Shutemov wrote:
> > Do we have magic words for that?
> 
> No clue.
> 
> > I tried to express that in the second paragraph: "no such users in the
> > upstream".
> 
> Right, so perhaps better to spell it out explicitly:
> 
> "Backporter's note:
> 
> This fixes a theoretical issue only and there's no need to backport it to
> stable."
> 
> at the end of the commit message.

Okay.

> 
> > > And which commit is it fixing?
> > > 
> > > aece27851d44 ("x86, 64bit, mm: Add generic kernel/ident mapping helper")
> > > perhaps?
> > 
> > This one is closer:
> > 
> > e4630fdd4763 ("x86/power/64: Always create temporary identity mapping correctly")
> > 
> > It adds x86_mapping_info::offset.
> 
> But aece27851d44 has the faulty check...

It cannot be triggered without 'offset'.

I'll put both.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov