From nobody Thu Oct 2 01:59:14 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EDF4023909C for ; Thu, 25 Sep 2025 13:20:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758806459; cv=none; b=hpnJTskbrvoylC0XieHmX6+608Z35hbNqdaQqs6cJvwsSjVghSo/v6hAfQHWbYmr5QFi+YWoZcLSTU4b2Ce9dzA70vpN6WAe61MxPkCRtYXpAQWBm8eH6r90fGx9smaWlxzJf6Fusz6h1NdnkeMQ5XK1172QkAhVkUthKkFdOdY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758806459; c=relaxed/simple; bh=YDDEpU1bcy05koezpIh2vlp6eVzNiz9AaW8llrtCap0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mWRPSL+8IbyTx0IuSWsDm88z+ImlOAzHKtr6Ml7ArBcUysQcMi6N0z9ej8ZPlFZiAHn6ASk2OQ7SKkXYLMdbAhNorKQYHvh8Me25QKM06vmdps2JfblJgNIfs4irHrItcUuxLJSnkdBLFO49APs4f+Hevetd3SbSunSG6Mwk/Gw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W4nLUWL2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="W4nLUWL2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36CFAC4CEF0; Thu, 25 Sep 2025 13:20:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758806458; bh=YDDEpU1bcy05koezpIh2vlp6eVzNiz9AaW8llrtCap0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=W4nLUWL2A+zzUCo6d9H59e2guNgttVusX1whLsHfzD0901R3uhhgUZVNCWE9J98jk nzCbIalJ5wuUQrgeE8HSwYwgCHasKLd9rbUugh6SSO2+5AktQnwQGOGodSSDfjfBud wgWhlJBNFlKPFJhk7QreZKRCFPX54oyvRBYLPDEtG02aa2piAQlfItygjqw2fKtZh7 q17FiZ1Xq4m44sHyQCss2j6JelDA4KSnl10SjRk9xoGlkooJdLXf/nocOMGbtCKBzd n46TUrJsg3qVm8OK+rsORt5QrF/EbOo3GJPaKpAPjjJj3RrSA6oOqwUf8j/IO8x/GA m0zFjsj47Xvfg== Date: Thu, 25 Sep 2025 15:20:52 +0200 From: Alejandro Colomar To: linux-kernel@vger.kernel.org Cc: Alejandro Colomar , Marco Elver , Kees Cook , Christopher Bazley , Alexander Potapenko , Dmitry Vyukov , Jann Horn , Andrew Morton , Linus Torvalds , Rasmus Villemoes , Michal Hocko , Al Viro Subject: [PATCH v1 3/3] 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: 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 c2871180edcc..621a60a86b39 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 ENDOF(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 ENDOF(expect[1]); if (!r->access[1].fn) cur +=3D scnprintf(cur, end - cur, "race at unknown origin, with "); =20 --=20 2.51.0