Re: [PATCH] mm/page_alloc: do bulk array bounds check after checking populated elements

Dave Jones
2021-06-28T15:38:44Z

On Mon, Jun 28, 2021 at 12:53:23PM +0100, Mel Gorman wrote:

> > This made it into 5.13 final, and completely breaks NFSD for me (Serving tcp v3 mounts).
> > Existing mounts on clients hang, as do new mounts from new clients.
> > Rebooting the server back to rc7 everything recovers. Bisect lands on
> > this commit.
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index ef2265f86b91..04220581579c 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5058,7 +5058,7 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
>
> /* Already populated array? */
> if (unlikely(page_array && nr_pages - nr_populated == 0))
> - return 0;
> + return nr_populated;

Yep, this works.

Dave