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 08BB7492E34; Wed, 9 Sep 2026 03:45:16 +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=1788925518; cv=none; b=eZL66w3ImErzMenHrRDxODTujzwNq/DBragzaztXuqo1sHI510U1C9AhfGJMzHEhQwjZU6nxASJKcrX1ncuDpAlrOxb/QDf0vAcr9bdNzeSj9k932TOfYzJI67NDxexpqod4swy2l2PtqCEIKAf4PppO3zBEavKf+TdYJ3MHGUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788925518; c=relaxed/simple; bh=OgBdTMiOSO4mWM0NMai55l/3o3ESJIjHRlBT0NFiQeE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rnZfyCaOP8jX024B0F/56wgnensAElO8p0Azjqb7Okf+YLykuQ7nLvjNFch3EkenaB+ABa/4DKzzzZI1mf8J/3/QszPBiVEh0fAFJwx0FshJQUDoGy8jV2lG/mhX2ilwvmm26bI3z01k0exmAKB6DBrkUfL2bg8T4nnQF6pa/Ik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oNv+1JOP; 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="oNv+1JOP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 752111F00A3A; Wed, 9 Sep 2026 03:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788925516; bh=sgl4dOjid3ViaesF0HbPp1/4EKDbGxPZqbY+ws8lPS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oNv+1JOPCzl6RLHCgd3x9J0sdTPuirk2eoXGZ2p0A+n1wJr3MFV64go1Prw3+U+Jg o5FQkP0BB04agobr7dAkpshMvT0QIYlpnu+H0vjL4F2MEQqgJg512X0bd9ZB98l5xZ eNBW5PMPbg6OXJHiZtzjOMLfREft8Q6gTav37UWGTKJeOv3m+gSt7eWhWph9xQxuSf YEmUHSAY6nItBJfJYkfQQnQmI7ZJ9Q3ean4c+j43F3LPpyuAajKqDSeeUb8W9pT+JV V2hN0/06wiOblpIc6LujWF0mWJW9bz4sORgImR/Pj1fr6yv+Koa9wpa+6z8DbgwF5X iZj/swqzGTW2w== From: SJ Park To: stable@vger.kernel.org Cc: damon@lists.linux.dev, SJ Park , Brendan Higgins , Andrew Morton Subject: [PATCH 6.12.y] mm/damon/vaddr-kunit: check region count in three_regions test Date: Tue, 8 Sep 2026 20:45:09 -0700 Message-ID: <20260909034509.142303-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026090819-haiku-machinist-83fa@gregkh> References: <2026090819-haiku-machinist-83fa@gregkh> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit damon_do_test_apply_three_regions() iterates regions after damon_set_regions() call assuming the function would succeed at setting the number of regions the same to the expected one. It might have failed. In this case, __nth_region_of() in the iteration could return NULL and NULL dereference can happen in the test. The consequent user impact (NULL dereference) is quite bad. The realistic user impact would be limited, though. It would affect only test run setups. Fix it by testing if the number of regions was also changed as expected and exit early for the failure. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260718001442.87129-4-sj@kernel.org Link: https://lore.kernel.org/20260713144757.39740-1-sj@kernel.org [1] Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SJ Park Cc: Brendan Higgins Cc: # 5.15.x Signed-off-by: Andrew Morton (cherry picked from commit 5fea07e460874c8c7cf00f728efbe22abc62c8d8) Signed-off-by: SJ Park --- mm/damon/tests/vaddr-kunit.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/damon/tests/vaddr-kunit.h b/mm/damon/tests/vaddr-kunit.h index ed2845d9f9a95..9eead9882dcce 100644 --- a/mm/damon/tests/vaddr-kunit.h +++ b/mm/damon/tests/vaddr-kunit.h @@ -149,12 +149,17 @@ static void damon_do_test_apply_three_regions(struct kunit *test, damon_set_regions(t, three_regions, 3); + KUNIT_EXPECT_EQ(test, damon_nr_regions(t), nr_expected / 2); + if (damon_nr_regions(t) != nr_expected / 2) + goto out; + for (i = 0; i < nr_expected / 2; i++) { r = __nth_region_of(t, i); KUNIT_EXPECT_EQ(test, r->ar.start, expected[i * 2]); KUNIT_EXPECT_EQ(test, r->ar.end, expected[i * 2 + 1]); } +out: damon_destroy_target(t); } -- 2.47.3