Re: [RFC PATCH v1.1 04/14] mm/damon/tests/vaddr-kunit: replace damon_add_region() with damon_set_regions()

[SeongJae Park <sj@kernel.org>]

On Thu, 21 May 2026 04:05:25 +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 the `damon_target` structure and attached regions when `damon_set_regions()` fails.
> --
> 
> commit e0458a31c6f6c7f46d6a9ef3e90d4098d89686fd
> Author: SeongJae Park <sj@kernel.org>
> 
> mm/damon/tests/vaddr-kunit: replace damon_add_region() with damon_set_regions()
> 
> This commit updates the DAMON virtual address operation set unit tests to
> use damon_set_regions() instead of damon_add_region() for region setup. This
> aligns the tests with how other DAMON API callers set up regions.
> 
> > diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h
> > index 98e734d77d517..de30db9b753e5 100644
> > --- a/mm/damon/tests/vaddr-kunit.h
> > +++ b/mm/damon/tests/vaddr-kunit.h
> > @@ -132,22 +132,32 @@ static void damon_do_test_apply_three_regions(struct kunit *test,
> >  				unsigned long *expected, int nr_expected)
> >  {
> >  	struct damon_target *t;
> 
> [ ... ]
> 
> >  	t = damon_new_target();
> >  	if (!t)
> >  		kunit_skip(test, "target alloc fail");
> > +
> > +	ranges = kmalloc_array(nr_regions / 2, sizeof(*ranges), GFP_KERNEL);
> > +	if (!ranges) {
> > +		damon_destroy_target(t, NULL);
> > +		kunit_skip(test, "ranges alloc fail");
> > +	}
> 
> [ ... ]
> 
> > +	if (damon_set_regions(t, ranges, nr_regions / 2,
> > +				DAMON_MIN_REGION_SZ)) {
> > +		kfree(ranges);
> > +		kunit_skip(test, "damon_set_regions() fail");
> 
> [Severity: Medium]
> Does this error path leak the damon_target structure and its attached regions?
> 
> Unlike the earlier kmalloc_array() error path which calls
> damon_destroy_target(t, NULL) before skipping, this failure path seems
> to omit the cleanup. Because kunit_skip() aborts test execution via a
> long jump, the target allocated via damon_new_target() wouldn't get freed.
> 
> >  	}
> > +	kfree(ranges);
> >  
> > -	damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION_SZ);
> > +	if (damon_set_regions(t, three_regions, 3, DAMON_MIN_REGION_SZ))
> > +		kunit_skip(test, "second damon_set_regions() fail");
> 
> [Severity: Medium]
> Could the same memory leak occur here? 
> 
> If the second damon_set_regions() fails, kunit_skip() is called without
> first freeing the target structure.

Good points.  I will fix these in the next revision.

> 
> -- 
> Sashiko AI review · https://sashiko.dev/#/patchset/20260521035349.87565-1-sj@kernel.org?part=4


Thanks,
SJ