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

[SeongJae Park]

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.

So sent the second version[1] with the
"Reported-by: akub Acs <acsjakub@xxxxxxxxx>" line, but then I noticed the patch
is already added to mm queue[2].  Somehow the notification mails delivered bit
later than usual.

Sorry for making this noise, Andrew.  Please add
"Reported-by: akub Acs <acsjakub@xxxxxxxxx>" to already added patches, or
replace those with the v2 if possible.  Also, please let me know if there's
anything I could help.

[1] https://lore.kernel.org/damon/20231020172317.64192-1-sj@xxxxxxxxxx/
[2] https://lore.kernel.org/mm-commits/20231020171847.C6EEAC433C7@xxxxxxxxxxxxxxx/


Thanks,
SJ

> 
> 
> Thanks,
> SJ
>