Re: [PATCH -next] mm/vmscan: fix an undefined behavior for zone id

From: Michal Hocko
Date: Mon Nov 11 2019 - 05:12:52 EST


On Fri 08-11-19 16:26:52, Qian Cai wrote:
>
>
> > On Nov 8, 2019, at 3:44 PM, Qian Cai <cai@xxxxxx> wrote:
> >
> > - for (zid = 0; zid <= zone_idx; zid++) {
> > + for (zid = 0; zid < zone_idx; zid++) {
> > struct zone *zone =
>
> Oops, I think here needs to be,
>
> for (zid = 0; zid <= zone_idx && zid < MAX_NR_ZONES; zid++) {
>
> to deal with this MAX_NR_ZONES special case.

Yep this looks correct.

Thanks!

--
Michal Hocko
SUSE Labs