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 76FA5468C2C; Wed, 9 Sep 2026 13:50:20 +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=1788961822; cv=none; b=gdofN2PH2DHYZn7RssROr3nc3vYz8uy2ZOOe8hBUn6ub6GSd18TBIXxkohzzhf7utW862lBmYEXM6dD5i+iNGIrGzhI7CaTSVCjzK7I4uZwWJ4OFIzBn5rREqj80hREdmHGJCgxaljsJrPtrtcP57HrTcLJBqZ7WSGA6AkwpXeM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788961822; c=relaxed/simple; bh=48bU9hnoA6DplFsZLEuW8IFWx0sex0nRtjbkw8LD1GE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R1TM6uR7JpS/+WbtXq72uCVbQQBJreaw1Dsj6+j+/HBvHTrLjmHyGQI/P0bZTg00Qmw2LTCFcxIuzGY5+DTnhG1h5yiZf7s2yi89bB9C7jEAXdIkTKERYyiJ/+QdP2QGgdQap3KGRhm6UDt7Ekt0dkpHINv7TN5sIduH+Xvwl/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fAOPr7ld; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fAOPr7ld" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D116F1F00A3A; Wed, 9 Sep 2026 13:50:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788961820; bh=DZBpsvQt5GMoYiSE16jeHw3PtAee6p1rSNRYYtie9cY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fAOPr7ld7f9IEphC0qF3OPVkalUSrvJcbr5OKeVmcAveG4I+GY003jL4wU6cK3ddC BgwSg0xfshtxTOfRrXK5WoXlpA9SyyOQlF2Z48kDM2Wayes0Ez/Ynp74JYJufwYPSo RGgLS51RqINMfo1XfS0tS4rsYOqcIN+MgWtgQlmI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, SJ Park , Brendan Higgins , Andrew Morton Subject: [PATCH 7.2 076/556] mm/damon/vaddr-kunit: check region count in three_regions test Date: Wed, 9 Sep 2026 15:35:56 +0200 Message-ID: <20260909134233.170787593@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134230.441546314@linuxfoundation.org> References: <20260909134230.441546314@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: SJ Park commit 5fea07e460874c8c7cf00f728efbe22abc62c8d8 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- mm/damon/tests/vaddr-kunit.h | 5 +++++ 1 file changed, 5 insertions(+) --- a/mm/damon/tests/vaddr-kunit.h +++ b/mm/damon/tests/vaddr-kunit.h @@ -158,12 +158,17 @@ static void damon_do_test_apply_three_re kunit_skip(test, "second damon_set_regions() fail"); } + 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, NULL); }