Re: [RFC PATCH v1.2 03/11] mm/damon/tests/core-kunit: test damon_rand()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The `counts` array computes a histogram of the generated random numbers, but the results are never validated.
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commit 545f6f76f7e281c6063dff020687345d3e3d45e4
Author: SeongJae Park <sj@kernel.org>

mm/damon/tests/core-kunit: test damon_rand()

This commit adds a kunit test for damon_rand() to ensure the generated
output falls within the specified bounds. It follows a recent change
that optimized DAMON to use a per-context lockless PRNG.

> diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
> index 1cfb8c176b873..eec7cb325a431 100644
> --- a/mm/damon/tests/core-kunit.h
> +++ b/mm/damon/tests/core-kunit.h
> @@ -1460,6 +1460,22 @@ static void damon_test_is_last_region(struct kunit *test)
>  	damon_free_target(t);
>  }
>  
> +static void damon_test_rand(struct kunit *test)
> +{
> +	struct damon_ctx ctx;
> +	int counts[10] = {};
> +	int i;
> +
> +	prandom_seed_state(&ctx.rnd_state, get_random_u64());
> +	for (i = 0; i < 10000; i++) {
> +		unsigned long rnd = damon_rand(&ctx, 0, 10);
> +
> +		KUNIT_EXPECT_GE(test, rnd, 0);
> +		KUNIT_EXPECT_LE(test, rnd, 9);
> +		counts[rnd]++;

[Severity: Low]
Are we missing a validation check here? The counts[] array computes a histogram
of the generated random numbers, but the accumulated data is never read or
verified after the loop terminates.

> +	}
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260625142357.103500-1-sj@kernel.org?part=3