On Fri 17-04-20 18:31:54, qiwuchen55@xxxxxxxxx wrote:
> From: chenqiwu <chenqiwu@xxxxxxxxxx>
>
> If we get a special mapping page like device mapping page or zero page
> when copy_one_pte, it's necessary add the page refcount count.
>From the changelog it is not clear what is the actual problem and how
the patch address it. Please be more verbose.
> Signed-off-by: chenqiwu <chenqiwu@xxxxxxxxxx>
> ---
> mm/memory.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index f703fe8..a57975a 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -802,8 +802,9 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
> get_page(page);
> page_dup_rmap(page, false);
> rss[mm_counter(page)]++;
> - } else if (pte_devmap(pte)) {
> + } else if (pte_devmap(pte) || is_zero_pfn(pte_pfn(pte))) {
> page = pte_page(pte);
> + get_page(page);
> }
>
> out_set_pte:
> --
> 1.9.1
>
--
Michal Hocko
SUSE Labs
