From: Jason Angelov <[email protected]> damon_valid_probe_params() makes damon_commit_ctx() reject probe configurations that could overflow a probe_hits counter, a single (weight * probe_hits) product, or the sum of those products.
Add a kunit test covering each rejection at its boundary: - samples per aggregation interval: U8_MAX is allowed, one more could overflow a probe_hits counter - single weight: the largest whose product fits in unsigned int is allowed, one larger is rejected - multiple probes: each product fits, but their sum overflows - no weight set: the validation is skipped Signed-off-by: Jason Angelov <[email protected]> Reviewed-by: SJ Park <[email protected]> Signed-off-by: SJ Park <[email protected]> --- mm/damon/tests/core-kunit.h | 57 +++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h index 68591ca99a4f7..af26b3d60957b 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -1341,6 +1341,62 @@ static void damon_test_commit_ctx(struct kunit *test) damon_destroy_ctx(dst); } +static void damon_test_valid_probe_params(struct kunit *test) +{ + struct damon_ctx *ctx; + struct damon_probe *probe, *probe2; + + ctx = damon_new_ctx(); + if (!ctx) + kunit_skip(test, "ctx alloc fail"); + probe = damon_new_probe(); + if (!probe) { + damon_destroy_ctx(ctx); + kunit_skip(test, "probe alloc fail"); + } + damon_add_probe(ctx, probe); + + /* Parameters are validated only if any probe weight is set. */ + ctx->attrs.sample_interval = 1; + ctx->attrs.aggr_interval = 1000000; + KUNIT_EXPECT_TRUE(test, damon_valid_probe_params(ctx)); + + /* Up to U8_MAX samples per aggregation interval are allowed. */ + probe->weight = 100; + ctx->attrs.aggr_interval = 255; + KUNIT_EXPECT_TRUE(test, damon_valid_probe_params(ctx)); + + /* More samples could overflow the probe_hits counters. */ + ctx->attrs.aggr_interval = 256; + KUNIT_EXPECT_FALSE(test, damon_valid_probe_params(ctx)); + + /* The largest weight whose weighted hit count fits in unsigned int. */ + ctx->attrs.aggr_interval = 255; + probe->weight = UINT_MAX / 255; + KUNIT_EXPECT_TRUE(test, damon_valid_probe_params(ctx)); + + /* Any larger weight could overflow its weighted hit count. */ + probe->weight = UINT_MAX / 255 + 1; + KUNIT_EXPECT_FALSE(test, damon_valid_probe_params(ctx)); + + /* With one sample per aggregation, even the largest weight fits. */ + ctx->attrs.aggr_interval = 1; + probe->weight = UINT_MAX; + KUNIT_EXPECT_TRUE(test, damon_valid_probe_params(ctx)); + + /* The sum of all probes' weighted hit counts could also overflow. */ + probe2 = damon_new_probe(); + if (!probe2) { + damon_destroy_ctx(ctx); + kunit_skip(test, "probe2 alloc fail"); + } + probe2->weight = 1; + damon_add_probe(ctx, probe2); + KUNIT_EXPECT_FALSE(test, damon_valid_probe_params(ctx)); + + damon_destroy_ctx(ctx); +} + static void damos_test_filter_out(struct kunit *test) { struct damon_target *t; @@ -1667,6 +1723,7 @@ static struct kunit_case damon_test_cases[] = { KUNIT_CASE(damos_test_commit_migrate_hot), KUNIT_CASE(damon_test_commit_target_regions), KUNIT_CASE(damon_test_commit_ctx), + KUNIT_CASE(damon_test_valid_probe_params), KUNIT_CASE(damos_test_filter_out), KUNIT_CASE(damon_test_feed_loop_next_input), KUNIT_CASE(damon_test_set_filters_default_reject), -- 2.47.3
