From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793169517; b=Hv9MpT68Oend/gqANqFewWdZUz0k8PAJ3kY4TirHGb9H8H1VxN4LSUKK7D9SiUM0q7wd 1AD44JjR75VdvOkArQwXDbO6j4uK7xKar9lnoeBnlqw8MiTp0RrYA2u1+zsfNoBx2lfcE sBPAz7nbxZIPPDHDm25meBOjSt5b4nObSC3czkDshnhm8CpFC5wCBzVMCKkTQOO7yJZko vH8u15vQbyBHrGAKCHyWt6gUVRaW+dJWfEizioiMOBNKDBGS0XT2fV25G5E5FTWuYU6Ka 2jh29nbp3PW7Iz+B1kr5U4vaYsV1wBbtXvz9BxP//1qKF4wkKDewS4gpSZ9/PASQJEw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793169517; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=FWLD5GjCqBr5xu1FmAfFVF8P5w+Tb9cNjY/RjAdSzVk=; b=ueQsE6T7faIaT6RAuNq3AQpWSD0EkmOxOd8c8wgXpwOFLB6jrS5/lcHZB3rIB6D2qNjT o0Cye3IrxK8xIn6GYy0UYEh/CMkNgSIysYot/ZdRF3SPd0PG6TcejENwpFSSonE+t67cV 960GkIhU/lBEuvfySdC8zIU4RRZ/5ZKVEkRwdhm9/3/ESlNvCb7Qoz7qUPOjAHU6NjSgj FFGt6rmGWhyWo5JHSWyvLj5CTdgbWFgT52ndXWw5igf3T80XU5Sv0kqepHc4fCNxBHZPN k7fvvKj0TNyxVXT3n7OQtctqv9iqebidlSv+Qz6c7tMAcKgaWn8lgE62eKu8YLTx1Jw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FvW+lXlt; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60881606A31A for ; Wed, 28 Oct 2026 06:38:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FvW+lXlt Received: by smtp.kernel.org (Postfix) with ESMTPSA id B752C1F01825; Wed, 28 Oct 2026 06:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793169517; bh=FWLD5GjCqBr5xu1FmAfFVF8P5w+Tb9cNjY/RjAdSzVk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=FvW+lXltw0D7BnDtcI0yE+Q00ffQWQQuc41BsiTQH1aPsZhFioKFiVz+ZuDL9IP13 CJWx3gThLjfOeuPJIUCzV2Y9QbE6oFP8ErcCwsLvH26bwsHlOmKYfCv7DldYycrQMP wb9/wHKfVzRrQrVaiz3FmcyNSpZvRRnIazAUaeYAUeD31G2OyB062DAdKMHh/4RJLL 5RKLbCU32ci1BvQ1Vyh6uHOx2OHd/biE4WnAJY2V/LjbDxyP9qRfvJYrFbDKTP3C3W plEdE62ByUJ7N4/Z1hqwO/x18WiIqLRZxSsL1oE+fZ5hzKmrxxTx5QEldIxjpt4e/i DKIb2VncEYoMw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC net-next] ppp: remove BSD-Compress support Reply-To: sashiko-reviews@lists.linux.dev To: "Qingfang Deng" , linux-s390@vger.kernel.org Cc: "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261028063452.25812-1-qingfang.deng@linux.dev> References: <20261028063452.25812-1-qingfang.deng@linux.dev> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 28 Oct 2026 06:38:36 +0000 X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > The BSD-Compress decoder assumes that accm is 32 bits, but declares it > as unsigned long. On 64-bit systems, consumed code bits survive the > left shift and corrupt the next code. An x86-64 PPP-over-PTY loopback > test reproduces a fatal bad-code error on the first compressed packet. >=20 > pppd normally requests Deflate in preference to BSD-Compress when both > methods can be negotiated. If BSD-Compress is selected and encounters > this fatal error, pppd disables compression and logs: >=20 > Lost compression sync: disabling compression >=20 > The link remains up and traffic can continue uncompressed. >=20 > The core compression routine has remained unchanged since Linux 2.1.67 > (1997), and the decompression routine since its introduction in Linux > [ ... ] >=20 > OpenAI Codex assisted with the commit message, cleanup, and PTY testing. >=20 > Link: https://lore.kernel.org/netdev/20240812084312.14127-1-r.smirnov@omp= .ru/ > Signed-off-by: Qingfang Deng Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261028063452.2581= 2-1-qingfang.deng@linux.dev?part=3D1