Re: [RFC PATCH v2 2/8] mm/damon/core: commit hugepage_size type damon filter

[SJ Park <sj@kernel.org>]

On Mon, 14 Sep 2026 14:52:16 +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 `damon_filter` on the error path in `damon_commit_filters()`.
> --
> 
> commit 5bd56b851690ccc1ea59e5d967224bde8e275c2a
> Author: SJ Park <sj@kernel.org>
> 
> mm/damon/core: commit hugepage_size type damon filter
> 
> Extend data attribute probe filters commit logic for the new hugepage_size
> filter type. This updates the size range fields of the commit destination
> filter struct and validates the given range.
> 
> > 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 error path leak the newly allocated new_filter?
> 
> It looks like damon_commit_filters() returns early here without adding
> new_filter to the destination list or freeing it. Since this is reachable
> via the sysfs interface when a user configures a filter with a minimum
> larger than the maximum, can this cause a memory leak on invalid input?

Good finding.  I will fix in the next revision.

> 
> > +			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=2


Thanks,
SJ