Re: [RFC PATCH v1.3 05/18] mm/damon/core: use damon_nr_accesses_mvsum() in __damos_valid_target()

[SeongJae Park <sj@kernel.org>]

On Mon, 22 Jun 2026 14:37:24 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [High] 32-bit integer overflow in damon_nr_accesses_mvsum() leads to incorrect region access frequency scores.
> --
> 
> commit 31c0062dc1352032d1779ac0035b6e2cd5a7461a
> Author: SeongJae Park <sj@kernel.org>
> 
> mm/damon/core: use damon_nr_accesses_mvsum() in __damos_valid_target()
> 
> This commit changes __damos_valid_target() to use damon_nr_accesses_mvsum()
> instead of reading the nr_accesses_bp field directly. This provides a more
> error-tolerant moving sum access score for DAMOS scheme logic.
> 
> > diff --git a/mm/damon/core.c b/mm/damon/core.c
> > index 8a7351b4a27c2..b9d47599f5cbc 100644
> > --- a/mm/damon/core.c
> > +++ b/mm/damon/core.c
> > @@ -2128,10 +2128,11 @@ static void kdamond_tune_intervals(struct damon_ctx *c)
> >  	damon_set_attrs(c, &new_attrs);
> >  }
> >  
> > -static bool __damos_valid_target(struct damon_region *r, struct damos *s)
> > +static bool __damos_valid_target(struct damon_region *r, struct damos *s,
> > +		struct damon_ctx *c)
> >  {
> >  	unsigned long sz;
> > -	unsigned int nr_accesses = r->nr_accesses_bp / 10000;
> > +	unsigned int nr_accesses = damon_nr_accesses_mvsum(r, c);
> 
> [Severity: High]
> Does this introduction of damon_nr_accesses_mvsum() expose an integer overflow
> on 32-bit systems?

Known low priority issue.  Not a blocker for this patch.


Thanks,
SJ

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