Re: [v2 PATCH] arm64: mm: make linear mapping permission update more robust for patial range

[Yang Shi]

On 11/18/25 3:07 PM, Nathan Chancellor wrote:
> On Tue, Nov 18, 2025 at 09:35:08AM -0800, Yang Shi wrote:
> > Thanks for reporting this problem. It looks like I forgot to use untagged
> > address when calculating idx.
> >
> > Can you please try the below patch?
> >
> > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
> > index 08ac96b9f846..0f6417e3f9f1 100644
> > --- a/arch/arm64/mm/pageattr.c
> > +++ b/arch/arm64/mm/pageattr.c
> > @@ -183,7 +183,7 @@ static int change_memory_common(unsigned long addr, int
> > numpages,
> >           */
> >          if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
> >                              pgprot_val(clear_mask) == PTE_RDONLY)) {
> > -               unsigned long idx = (start - (unsigned long)area->addr) >>
> > PAGE_SHIFT;
> > +               unsigned long idx = (start - (unsigned
> > long)kasan_reset_tag(area->addr)) >> PAGE_SHIFT;
> >                  for (; numpages; idx++, numpages--) {
> > __change_memory_common((u64)page_address(area->pages[idx]),
> >                                                 PAGE_SIZE, set_mask,
> > clear_mask);
> Yes, that appears to resolve the issue for me, thanks for the quick fix!
>
> If a formal tag helps:
>
> Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>

Thank you. I will prepare a formal patch soon.

Yang

> Cheers,
> Nathan