Good catch.
Acked-by: Chris Li <chrisl@xxxxxxxxxx>
Chris
On Thu, May 23, 2024 at 5:55 PM Barry Song <21cnbao@xxxxxxxxx> wrote:
>
> From: Barry Song <v-songbaohua@xxxxxxxx>
>
> We are passing a huge nr to __clear_young_dirty_ptes() right
> now. While we should pass the number of pages, we are actually
> passing CONT_PTE_SIZE. This is causing lots of crashes of
> MADV_FREE, panic oops could vary everytime.
>
> Fixes: 89e86854fb0a ("mm/arm64: override clear_young_dirty_ptes() batch helper")
> Cc: Lance Yang <ioworker0@xxxxxxxxx>
> Cc: Barry Song <21cnbao@xxxxxxxxx>
> Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Jeff Xie <xiehuan09@xxxxxxxxx>
> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Cc: Peter Xu <peterx@xxxxxxxxxx>
> Cc: Yang Shi <shy828301@xxxxxxxxx>
> Cc: Yin Fengwei <fengwei.yin@xxxxxxxxx>
> Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
> ---
> arch/arm64/mm/contpte.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
> index 9f9486de0004..a3edced29ac1 100644
> --- a/arch/arm64/mm/contpte.c
> +++ b/arch/arm64/mm/contpte.c
> @@ -376,7 +376,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma,
> * clearing access/dirty for the whole block.
> */
> unsigned long start = addr;
> - unsigned long end = start + nr;
> + unsigned long end = start + nr * PAGE_SIZE;
>
> if (pte_cont(__ptep_get(ptep + nr - 1)))
> end = ALIGN(end, CONT_PTE_SIZE);
> @@ -386,7 +386,7 @@ void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma,
> ptep = contpte_align_down(ptep);
> }
>
> - __clear_young_dirty_ptes(vma, start, ptep, end - start, flags);
> + __clear_young_dirty_ptes(vma, start, ptep, (end - start) / PAGE_SIZE, flags);
> }
> EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes);
>
> --
> 2.34.1
>
>
