Re: [PATCH 0/8] Stop special-casing hugetlb mappings in get_unmapped_area

[Lorenzo Stoakes]

On Sat, Jun 27, 2026 at 11:55:12PM -0700, Andrew Morton wrote:
> On Sat,  6 Jun 2026 05:49:55 +0200 Oscar Salvador <osalvador@xxxxxxx> wrote:
>
> > A regression was reported on AMD 15h Family for hugetlb mappings when 'align_va_addr'
> > is set [1].
>
> It would be helpful to say right here that this regression results in a
> runtime BUG().  Helps get attention ;)
>
> > Historically, for hugetlb mappings we always ignored 'align_offset' in get_unmapped_area
> > functions, but after commit 7bd3f1e1a9ae ("mm: make hugetlb mappings go through
> > mm_get_unmapped_area_vmflags") that was no longer the case for x86.
> >
> > While we could fix that by work it around in x86 code, the truth is that the current
> > functioning of hugetlb mappings with get_unmapped_area functions is a bit clumsy, and
> > we can do better.
> > This patchset aims at two things:
> >
> > 1) Fix regression reported in [1]
> > 2) Stop special-casing hugetlb mappings in get_unmapped_area functions
>
> OK, so the offending commit was about 1.5 years ago.
>
> Do we want to fix -stable kernels?  If so, can we start out with
> something minimal for backporting?  And narrow down its Fixes:?
>
> The series was sent at an awkward time in the -rc cycle, which perhaps
> explains the lack of feedback.  I suggest a refresh/retest/resend to
> help bring people up to speed.

Yes please rebase + resend :)

>
> Sashiko has quite a lot to say - I hope some of it is useful?
> 	https://sashiko.dev/#/patchset/20260606035003.529685-1-osalvador@xxxxxxx
>

Cheers, Lorenzo