Re: [PATCH v2 0/4] fix unexpected type conversions and potential overflows

From: Michal Hocko

Date: Thu Mar 26 2026 - 04:18:24 EST


On Thu 26-03-26 16:51:44, Harry Yoo (Oracle) wrote:
> On Thu, Mar 26, 2026 at 08:14:36AM +0100, Michal Hocko wrote:
> > On Wed 25-03-26 22:13:21, Qi Zheng wrote:
> > > From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> > >
> > > Hi all,
> > >
> > > As Harry Yoo pointed out [1], in scenarios where massive state updates occur
> > > (e.g., during the reparenting of LRU folios), the values passed to memcg stat
> > > update functions can accumulate and exceed the upper limit of a 32-bit integer.
> >
> > Is this a real problem without reparenting? In other words is this a
> > follow up for that work or something that we need on its own?
>
> This is not a problem (as discussed in [1]) without reparenting.
> [1] https://lore.kernel.org/linux-mm/138d9363-ab0c-4f5c-bedc-b326f5aaee91@xxxxxxxxx

Please make it explicit in the changelogs and/or make them part of the
series.

Thanks!
--
Michal Hocko
SUSE Labs