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mm-damon-core-kunit-test-damon_valid_probe_params.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Oct 7

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The quilt patch titled
Subject: mm/damon/core-kunit: test damon_valid_probe_params()
has been removed from the -mm tree. Its filename was
mm-damon-core-kunit-test-damon_valid_probe_params.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Jason Angelov <[email protected]>
Subject: mm/damon/core-kunit: test damon_valid_probe_params()
Date: Mon, 31 Aug 2026 08:06:49 -0700

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

Link https://lore.kernel.org/[email protected] open here
Signed-off-by Jason Angelov <[email protected]>
Signed-off-by SJ Park <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Reviewed-by SJ Park <[email protected]>
Cc Brendan Higgins <[email protected]>
Cc David Gow <[email protected]>

---

 mm/damon/tests/core-kunit.h |   57 ++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
mm/damon/tests/core-kunit.h renamed from mm/damon/tests/core-kunit.h~mm-damon-core-kunit-test-damon_valid_probe_params +57 -0
@@ -1338,6 +1338,62 @@ static void damon_test_commit_ctx(struct
 	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;

@@ -1664,6 +1720,7 @@ static struct kunit_case damon_test_case
 	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),

_

Patches currently in -mm which might be from [email protected] are