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 125FF1AC45D; Wed, 9 Sep 2026 03:43:05 +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=1788925387; cv=none; b=n/oWT3INJ1TTWgXLWRjj2ec1eLcHxJ2D1dUsO5mzBQMdWC8ZPOsFhxE23F5+sE+zro4WzbngxFDKCw6cavrtDT2Pm9ZXkMsxcBNJF3yZlM4/uedBO/CLiaHf/GErRpRw2kply07x5uH9Mc/w89q6c3xS47CZ5TGn/X5xvMxOB5M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788925387; c=relaxed/simple; bh=vIN6pI5hrdWIMTi1O7LAZdqJI3QU39qxnIGpSh5VUIk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NrLvEnItpZ7sAjdCFs41FrM2zR/syPT4QCoq9284vBELlPE7v/bPjp79tuaE5q1zgkjgUawWeKso3eWS7pn+m1CyXnPIOBrk+mATXh8PNSws/Kp34X3nH3n/ktnTcwx/5FM2k3/R2cIP9TL3CqRpi4jtEcrDZLEvSMuWWp1fnok= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hfd0iem3; 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="hfd0iem3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7177C1F00A3A; Wed, 9 Sep 2026 03:43:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788925385; bh=e9FpkvDmp3PEnqr6wgedx3qxEpGcs0a2EfmabuK1U7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hfd0iem30Injxw5n6GXcMj8HPgqRMjEEEQzlRL0HCJwfRY2WBS03wZK0zM27Avef6 4khfyBcuhH7RrPmTNkCH6CoW86Bl0s1+XF8qYgrnWMlVRRPMfPSun0GFLge96ofFak 1OjNmvnso4Zps06MwLuTnLgN8ohiMxvargudzuoKOHPpqz9mE3QNimY5KQp9EM5WhX AuACYW4lUgcC3ySmxmLh1po6KB8y+lOOs6m4egeWRc9sLIPUvO8EHS/LEp8cMhoj1l ThDOEcKBdjQLQgknwVOHjOu2P0+ZIhksMCOeJr2Y0NaeFhpYFlimyzez2dP7HU9kqh fz1m0pe1O69Zw== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SJ Park , Andrew Morton Subject: [PATCH 6.1.y] mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() Date: Tue, 8 Sep 2026 20:42:57 -0700 Message-ID: <20260909034257.139428-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026090809-vice-ribbon-cf5a@gregkh> References: <2026090809-vice-ribbon-cf5a@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 d8fef225930a5..094714172e581 100644 --- a/mm/damon/core-test.h +++ b/mm/damon/core-test.h @@ -253,11 +253,14 @@ 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