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

[Liam R. Howlett]

* David Hildenbrand <david@xxxxxxxxxx> [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@xxxxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/linux-mm/IA1PR07MB983017D2FBA174D2FF78CEB6ABCE9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> > Cc: David Hildenbrand <david@xxxxxxxxxx>
> > Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> 
> Fixes: ?

Fixes: (soon to be invalid git id :) ("mm/mmap: remove __vma_adjust()")

> 
> > Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> > ---
> >   mm/mmap.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index 00d90bbc250e..614ea2d93b0a 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -978,7 +978,7 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
> >   			vma = next;			/* case 3 */
> >   			vma_start = addr;
> >   			vma_end = next->vm_end;
> > -			vma_pgoff = next->vm_pgoff;
> > +			vma_pgoff = mid->vm_pgoff;
> >   			err = 0;
> >   			if (mid != next) {		/* case 8 */
> >   				remove = mid;
> 
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> 
> Thanks!
> 
> -- 
> Thanks,
> 
> David / dhildenb
>