From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB2EF331ED1; Wed, 9 Sep 2026 03:38:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788925120; cv=none; b=tD0di6eZeHh7nd3dSDV/Go3KGecEyJOxmyPGlntxbzTpOdoSXbYJwke7ZDqM8pq6CsAft18SXO/+sPNV5XQu3HhhBlpl1QwQdI0zpDamTvygHvrT1h9kTLRkIKdHlAZf5yYGPPrCiR9vG7vQjuY9tDh6EibCkOy48QIuh2cKf4Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788925120; c=relaxed/simple; bh=D/ddij/Vg4ff5Z1uOC5tTlo461t///okHimcNaQTFxM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NtSnrz45BJ8eohSKg5PvV/mH2etS7KrDVLLfg2Sr1Eu/aBxj6huMZbsKPrj1qVXB34/P2pqD/T7y3LCFO0BlGgrahxLssDMzLEjnoFdDUyBrbTBpyUZwo6cwhk4FRS70rZz1msFRrdsOk3d7nbYH/NfWec4knaU+sxmby7YugnA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J4VakY6U; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="J4VakY6U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 790141F00A3A; Wed, 9 Sep 2026 03:38:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788925119; bh=DTLoBPmPhawDk2X7sNrppY4vwdPisie0jrSHUyT41Ms=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=J4VakY6Uu3Xb4BJv+bitgA42HSc00lj16jtDJaTS1ebpRNdyJRh6t7zklz8OD3Y3q 67P3+TkJtPgutU4fbrlmcSvFRWMlNtYdl7odgvDgq6Mlx2ytmmUrz3mZXfDyIB6nsR 9FKHXqGfkuPC6Rk1xwAgW1of0jTtBf+Shzc+bX8GWJi7ZzjBwlCbLwBqfrQ+ZrH7Rx lV+NXdLKj8jm0oLL58bxB6RrH/gQis89SpZ2jOixYzBF+hZe0snpa5hXc0sDCW/ZoR DRo+xhjMQ1hbWiGubAfrT3ME7B9EBQ8vg42IY3Dab/ijyJFc1I0a95JF92whNybSvg lqXKq01gBptqw== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SJ Park , Andrew Morton Subject: [PATCH 6.18.y] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Tue, 8 Sep 2026 20:38:32 -0700 Message-ID: <20260909033832.132107-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026090808-phoniness-repaying-46f0@gregkh> References: <2026090808-phoniness-repaying-46f0@gregkh> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit KUNIT_EXPECT_EQ() does not abort the execution of test code when the expectation is not met. But damon_test_merge_regions_of() code after its initial KUNIT_EXPECT_EQ() call assumes the expectation is met. It does a per-region test with a hard-coded number of regions that is correct only if the expectation was met. As a result, __nth_region_of() could return NULL, and the test code can dereference NULL pointers. Fix the issue by catching the expectation failure and skip the per-region tests. The user impact on realistic setups should be negligible, as it is a unit test. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260715031002.108504-3-sj@kernel.org Link: https://lore.kernel.org/20260710144937.26981-1-sj@kernel.org [1] Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SJ Park Cc: # 5.15.x Signed-off-by: Andrew Morton (cherry picked from commit b640708929aa956235866bf7717d89018c661083) Signed-off-by: SJ Park --- mm/damon/tests/core-kunit.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h index 6687778752728..c1f0be6746abd 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -264,11 +264,14 @@ static void damon_test_merge_regions_of(struct kunit *test) damon_merge_regions_of(t, 9, 9999); /* 0-112, 114-130, 130-156, 156-170 */ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 5u); + if (damon_nr_regions(t) != 6) + goto out; for (i = 0; i < 5; i++) { r = __nth_region_of(t, i); KUNIT_EXPECT_EQ(test, r->ar.start, saddrs[i]); KUNIT_EXPECT_EQ(test, r->ar.end, eaddrs[i]); } +out: damon_free_target(t); } -- 2.47.3