On Mon, May 30, 2022 at 10:44:50PM -0400, Zi Yan wrote:
> From: Zi Yan <[email protected]>
>
> When compound_nr(page) was used, page was not guaranteed to be the head
> of the compound page and it could cause an infinite loop. Fix it by calling
> it on the head page.
>
> Fixes: b2c9e2fbba32 ("mm: make alloc_contig_range work at pageblock granularity")
> Reported-by: Anshuman Khandual <[email protected]>
> Link: https://lore.kernel.org/linux-mm/[email protected]/
> Signed-off-by: Zi Yan <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
> ---
> mm/page_isolation.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 6021f8444b5a..d200d41ad0d3 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -385,9 +385,9 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
> * above do the rest. If migration is not possible, just fail.
> */
> if (PageCompound(page)) {
> - unsigned long nr_pages = compound_nr(page);
> struct page *head = compound_head(page);
> unsigned long head_pfn = page_to_pfn(head);
> + unsigned long nr_pages = compound_nr(head);
>
> if (head_pfn + nr_pages <= boundary_pfn) {
> pfn = head_pfn + nr_pages;
> --
> 2.35.1
>
--
Oscar Salvador
SUSE Labs