[PATCH] mm/mmap: Fix vma_merge() offset when expanding the next vma

[Andrew Morton]

On Tue, 31 Jan 2023 15:29:59 +0100 David Hildenbrand <david at redhat.com> wrote:

> On 31.01.23 15:24, Liam R. Howlett wrote:
> > * David Hildenbrand <david at redhat.com> [230131 03:35]:
> >> On 30.01.23 20:57, Liam R. Howlett wrote:
> >>> The vm_pgoff was being set incorrectly when expanding the next VMA to a
> >>> lower address.  Fix the issue by using the mid->vm_pgoff value for this
> >>> merge case (aka case 8).  Note that this does not change case 3's
> >>> vm_pgoff as next and mid are the same VMA.
> >>>
> >>> Reported-by: Sanan Hasanov <sanan.hasanov at knights.ucf.edu>
> >>> Link: https://lore.kernel.org/linux-mm/IA1PR07MB983017D2FBA174D2FF78CEB6ABCE9@IA1PR07MB9830.namprd07.prod.outlook.com/
> >>> Cc: Matthew Wilcox <willy at infradead.org>
> >>> Cc: David Hildenbrand <david at redhat.com>
> >>> Cc: Hugh Dickins <hughd at google.com>
> >>
> >> Fixes: ?
> > 
> > Fixes: (soon to be invalid git id :) ("mm/mmap: remove __vma_adjust()")
> 
> Ah, right, upstream was not affected ... :)
> 
> ... so this should be squashed into that commit instead as long as it 
> doesn't have a stable ID.

Yup, I queued this as mm-mmap-remove-__vma_adjust-fix.patch so it's
to-be-squished.

Generally, please let's tell people when a patch fixes something which
is staged in mm-unstable - to save a few brain cycles and to hopefully
improve review.  A Fixes: with no SHA works, or simply "this fixes X".