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 467FC23C4F3; Wed, 9 Sep 2026 03:40:46 +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=1788925247; cv=none; b=aRY8GyiwGevSnemj6hYNszMRsFXC6yhh0UWRrOKlz5EaeAYmW8VwU/Y6j671wPjJUZKMWoKtEsrC4152B2VbTrA6M4AcNEAKxBXfhX5WHRhe7ayT33TOUhpBdZdmOQHYHaCNRzxjFxEK6JF1Pucpeij3prSSCK85XBHfUlTBg6g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788925247; c=relaxed/simple; bh=EM2Pdu31aicwyv/mzGzY54WiLWLXFL96aDnk44KZBl0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gMhyfS4hS4KRnjFZ2rEfuZt4mvJknoYQ0R3GnqpoLaKYTEDJrao9Cj+HXZ/lnj9mCmOLhmMhQBWvfgE96NEkLICH/z9fYaYfj7tfXo5aCmF3tubFuICJejcFY/s2TrVsLl7r35OV4WPTNnwOmOvlvxaIhKCjHISr24MMe8Ppor4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Nuo58iJZ; 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="Nuo58iJZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BABA51F00A3A; Wed, 9 Sep 2026 03:40:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788925245; bh=v1IsxGtC9mUTyunF/BWsPeYhvJkyYW5HoTFhqrUsPQo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Nuo58iJZhA1ZL+AuM39v2/g6zzl8nHSudH9djsnlyV7lK3F6sDZazBxnwmOkCy1eH F6vP9kp1UG+Xa16gY4LMPe2Vv+FlUrJojYTYLEWzgNahU8jmj/uxUuMA+TbA5oQqEc tChNR5/xoGplu0NnuZ1/+sQjlntKrkIFiiF5pPLu+5hbq1SVugCN7TZDBkrGeTrPTN J8iBnrEE0YtkBTAP2+myTZ+jkLj993vMTOWS7Vgxst3TiKApm0TxpozQqGgKOET72L plK7inFK+R9bKFs6HQwX0dZPYe6zNPx0gk8uMvursyHdOg1NDjv7W4tai1C8xFLqmF 2NClCfAAxNrzA== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SJ Park , Andrew Morton Subject: [PATCH 5.15.y] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Tue, 8 Sep 2026 20:40:38 -0700 Message-ID: <20260909034038.133054-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026090809-perky-underfeed-c314@gregkh> References: <2026090809-perky-underfeed-c314@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/core-test.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h index c19da2e3d4936..3350293761c4c 100644 --- a/mm/damon/core-test.h +++ b/mm/damon/core-test.h @@ -251,11 +251,14 @@ 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) != 5) + 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