From nobody Fri Oct 24 20:32:38 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A3D5C00140 for ; Mon, 15 Aug 2022 22:39:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350521AbiHOWjr (ORCPT ); Mon, 15 Aug 2022 18:39:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349650AbiHOWdY (ORCPT ); Mon, 15 Aug 2022 18:33:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53CB712D2B9; Mon, 15 Aug 2022 12:49:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BDA356068D; Mon, 15 Aug 2022 19:49:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6C03C433D6; Mon, 15 Aug 2022 19:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660592952; bh=RFhJ7oKbxaQZgjiYqpkKAEp72wMbCyf95ly99JkvQ/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nhb8g3A1+SA3nQiDgGLROhsQgLIxqe5Q5/I14C3bFAoi43FyKpMq7Sv5mKgzGo7cn ejc4V+TrkyqVY+iP8wDkQ67ff0RC6dLVAZI7gOK4YjSsGAoztCPriIW8XotfFPndpX oEi+TqwwT3jlA8kImZgzRMg2fyzqJ1ECqysCKqeU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Starke , Sasha Levin Subject: [PATCH 5.18 0871/1095] tty: n_gsm: fix wrong T1 retry count handling Date: Mon, 15 Aug 2022 20:04:30 +0200 Message-Id: <20220815180505.409612638@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Daniel Starke [ Upstream commit f30e10caa80aa1f35508bc17fc302dbbde9a833c ] n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDeta= ils.aspx?specificationId=3D1516 The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.7.3 states that the valid range for the maximum number of retransmissions (N2) is from 0 to 255 (both including). gsm_dlci_t1() handles this number incorrectly by performing N2 - 1 retransmission attempts. Setting N2 to zero results in more than 255 retransmission attempts. Fix gsm_dlci_t1() to comply with 3GPP 27.010. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220707113223.3685-1-daniel.starke@siemens= .com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/n_gsm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 17927163790e..825c4b550ee0 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1805,8 +1805,8 @@ static void gsm_dlci_t1(struct timer_list *t) =20 switch (dlci->state) { case DLCI_OPENING: - dlci->retries--; if (dlci->retries) { + dlci->retries--; gsm_command(dlci->gsm, dlci->addr, SABM|PF); mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); } else if (!dlci->addr && gsm->control =3D=3D (DM | PF)) { @@ -1821,8 +1821,8 @@ static void gsm_dlci_t1(struct timer_list *t) =20 break; case DLCI_CLOSING: - dlci->retries--; if (dlci->retries) { + dlci->retries--; gsm_command(dlci->gsm, dlci->addr, DISC|PF); mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100); } else --=20 2.35.1