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Sun, 09 Nov 2025 20:45:25 +0100 (CET) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 90F6060007 for ; Sun, 9 Nov 2025 19:45:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) id 509C9C19423; Sun, 9 Nov 2025 19:45:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A8DCC4CEF7; Sun, 9 Nov 2025 19:45:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762717524; bh=59w6p5OIO0ukVj/H6iWXGVoWsjSUgZ8nYZ9Xx2PeP8w=; h=Date:From:Cc:Subject:References:In-Reply-To:From; b=JQbX0SYaltov8l0e0BerHUgvsTz54JcE1WPi6+4IiR+p1BvijSeI6ervSU80qRB+o FllD2PIOOkkHC1jHSIgDYpBWYqel4+midyGZUl4R+xxrygeMdm6HSkxBJgh6rf/NEs JVfor2abuR3KKFGj6Iy1HM0rPYkx5G2R1V/ojEXpRLLEyykJGBaQVFVi6eWXDR65+c 06zNA3/i+qvGWdyu/4nUFlEJk+/jlCC33rWbmEYSTZLTCpcsXFBJbwZfNqdUFNoX5j ycmH0B9510YwmOK0QK0jb10tG6mFU0ZlmeJ6qjczeBMPAjtOGBEx1SpNHhYbpYDzip gzn+IOntLahvw== Date: Sun, 9 Nov 2025 20:45:19 +0100 From: Alejandro Colomar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , Rasmus Villemoes , Marco Elver , Michal Hocko , Linus Torvalds , Al Viro , Alexander Potapenko , Dmitry Vyukov , Jann Horn , Andrew Morton , "Maciej W. Rozycki" Subject: [PATCH v4 3/4] kernel: Fix off-by-one benign bugs Message-ID: X-Mailer: git-send-email 2.51.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_IN X-Migadu-Country: SG X-Migadu-Spam-Score: -1.11 X-Spam-Score: -1.11 X-Migadu-Queue-Id: 702BAD7A60 X-Migadu-Scanner: mx10.migadu.com X-TUID: yG/nyHhor1Yn Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" We were wasting a byte due to an off-by-one bug. s[c]nprintf() doesn't write more than $2 bytes including the null byte, so trying to pass 'size-1' there is wasting one byte. This is essentially the same as the previous commit, in a different file. Cc: Marco Elver Cc: Kees Cook Cc: Christopher Bazley Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: Jann Horn Cc: Andrew Morton Cc: Linus Torvalds Cc: Rasmus Villemoes Cc: Marco Elver Cc: Michal Hocko Cc: Al Viro Signed-off-by: Alejandro Colomar --- kernel/kcsan/kcsan_test.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c index 219d22857c98..8ef8167be745 100644 --- a/kernel/kcsan/kcsan_test.c +++ b/kernel/kcsan/kcsan_test.c @@ -176,7 +176,7 @@ static bool __report_matches(const struct expect_report= *r) =20 /* Title */ cur =3D expect[0]; - end =3D &expect[0][sizeof(expect[0]) - 1]; + end =3D ARRAY_END(expect[0]); cur +=3D scnprintf(cur, end - cur, "BUG: KCSAN: %s in ", is_assert ? "assert: race" : "data-race"); if (r->access[1].fn) { @@ -200,7 +200,7 @@ static bool __report_matches(const struct expect_report= *r) =20 /* Access 1 */ cur =3D expect[1]; - end =3D &expect[1][sizeof(expect[1]) - 1]; + end =3D ARRAY_END(expect[1]); if (!r->access[1].fn) cur +=3D scnprintf(cur, end - cur, "race at unknown origin, with "); =20 --=20 2.51.0