Re: [RFC PATCH v2 3/8] mm/damon/ops-common: support hugepage_size damon filter matching

[SJ Park <sj@kernel.org>]

On Mon, 14 Sep 2026 14:59:36 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Memory leak of newly allocated filter when HUGEPAGE_SIZE range is invalid.
> --
> 
> commit 5ea2818b5d3def212dc5a08d79877c1ebf66bd6e
> Author: SJ Park <sj@kernel.org>
> 
> mm/damon/ops-common: support hugepage_size damon filter matching
> 
> Update ops-common data attribute filter matching logic to support
> hugepage_size filter type.
> 
> > diff --git a/mm/damon/core.c b/mm/damon/core.c
> > index 0c98f7e267d07..ecfe99450e5f0 100644
> > --- a/mm/damon/core.c
> > +++ b/mm/damon/core.c
> [ ... ]
> > @@ -1838,6 +1848,12 @@ static int damon_commit_filters(struct damon_probe *dst,
> >  		case DAMON_FILTER_TYPE_MEMCG:
> >  			new_filter->memcg_id = src_filter->memcg_id;
> >  			break;
> > +		case DAMON_FILTER_TYPE_HUGEPAGE_SIZE:
> > +			if (src_filter->range_max < src_filter->range_min)
> > +				return -EINVAL;
> 
> [Severity: Medium]
> Does this return path leak new_filter?
> 
> When src_filter->range_max < src_filter->range_min evaluates to true
> in damon_commit_filters(), the function returns -EINVAL immediately.
> 
> Since new_filter was already allocated earlier in the loop:
> 
>         new_filter = damon_new_filter(src_filter->type,
>                         src_filter->matching, src_filter->allow);
>         if (!new_filter)
>                 return -ENOMEM;
> 
> and has not yet been added to the probe's filter list or freed before
> this return, does this drop the only reference to it?

Will fix in the next spin.

> 
> > +			new_filter->range_min = src_filter->range_min;
> > +			new_filter->range_max = src_filter->range_max;
> > +			break;
> >  		default:
> >  			break;
> >  		}
> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260914144448.93732-1-sj@kernel.org?part=3
> 


Thanks,
SJ