On Mon, Jul 08, 2024 at 10:51:27AM +0800, Miaohe Lin wrote:
> There is a potential race between __update_and_free_hugetlb_folio() and
> try_memory_failure_hugetlb():
>
> CPU1 CPU2
> __update_and_free_hugetlb_folio try_memory_failure_hugetlb
> folio_test_hugetlb
> -- It's still hugetlb folio.
> folio_clear_hugetlb_hwpoison
> spin_lock_irq(&hugetlb_lock);
> __get_huge_page_for_hwpoison
> folio_set_hugetlb_hwpoison
> spin_unlock_irq(&hugetlb_lock);
> spin_lock_irq(&hugetlb_lock);
> __folio_clear_hugetlb(folio);
> -- Hugetlb flag is cleared but too late.
> spin_unlock_irq(&hugetlb_lock);
>
> When above race occurs, raw error page info will be leaked. Even worse,
> raw error pages won't have hwpoisoned flag set and hit pcplists/buddy.
> Fix this issue by deferring folio_clear_hugetlb_hwpoison() until
> __folio_clear_hugetlb() is done. So all raw error pages will have
> hwpoisoned flag set.
>
> Fixes: 32c877191e02 ("hugetlb: do not clear hugetlb dtor until allocating vmemmap")
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
--
Oscar Salvador
SUSE Labs
