Re: [PATCH 0/5] avoid divide-by-zero due to max_nr_accesses overflow

From: SeongJae Park
Date: Fri Oct 20 2023 - 14:02:47 EST


On Fri, 20 Oct 2023 10:30:36 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, 20 Oct 2023 17:19:01 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote:
>
> > On Thu, 19 Oct 2023 19:49:19 +0000 SeongJae Park <sj@xxxxxxxxxx> wrote:
> >
> > > The maximum nr_accesses of given DAMON context can be calculated by
> > > dividing the aggregation interval by the sampling interval. Some logics
> > > in DAMON uses the maximum nr_accesses as a divisor. Hence, the value
> > > shouldn't be zero. Such case is avoided since DAMON avoids setting the
> > > agregation interval as samller than the sampling interval. However,
> > > since nr_accesses is unsigned int while the intervals are unsigned long,
> > > the maximum nr_accesses could be zero while casting.
> >
> > Actually, the issue was reported by Jakub, and I didn't add 'Reported-by:' tags
> > for him. I sure Andrew could add that on his own, but I want to minimize
> > Andrew's load, so will send v2 of this patchset. Andrew, please let me know if
> > that doesn't help but only increasing your load.
>
> Editing the changelogs is far quicker than updating a patch series ;)
>
> btw, it's now conventional to add a link to the reporter's report. The
> new "Closes:" tag, immediately after the Reported-by:. But it's not a
> big deal.

Surely it is. And in this case, the report was made privately, so no available
link. I should have mentioned this early, sorry. Anyway, thank you for your
help, Andrew :)


Thanks,
SJ