Hi Hugh,
On Sat, 16 Apr 2016 16:33:07 -0700 (PDT) Hugh Dickins <hughd@xxxxxxxxxx> wrote:
>
> Please add this fix after my 27/31, your
> huge-tmpfs-recovery-tweak-shmem_getpage_gfp-to-fill-team.patch
> for later merging into it. Great catch by Mika Penttila, a bug which
> prevented some unusual cases from being recovered into huge pages as
> intended: an initially sparse head would be set PageTeam only after
> this check. But the check is guarding against a racing disband, which
> cannot happen before the head is published as PageTeam, plus we have
> an additional reference on the head which keeps it safe throughout:
> so very easily fixed.
>
> Reported-by: Mika Penttila <mika.penttila@xxxxxxxxxxxx>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> ---
> mm/shmem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2938,7 +2938,7 @@ repeat:
> page = *pagep;
> lock_page(page);
> head = page - (index & (HPAGE_PMD_NR-1));
> - if (!PageTeam(head)) {
> + if (!PageTeam(head) && page != head) {
> error = -ENOENT;
> goto decused;
> }
Added to linux-next today.
--
Cheers,
Stephen Rothwell
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