From nobody Tue Dec 30 09:18:52 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 66991C072A2 for ; Fri, 17 Nov 2023 12:50:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345987AbjKQMuN (ORCPT ); Fri, 17 Nov 2023 07:50:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230383AbjKQMuL (ORCPT ); Fri, 17 Nov 2023 07:50:11 -0500 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [IPv6:2a0a:edc0:2:b01:1d::104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99F57D55 for ; Fri, 17 Nov 2023 04:50:08 -0800 (PST) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1r3yIL-0005eC-Co; Fri, 17 Nov 2023 13:50:01 +0100 Received: from [2a0a:edc0:0:1101:1d::ac] (helo=dude04.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1r3yIK-009gMy-L2; Fri, 17 Nov 2023 13:50:00 +0100 Received: from ore by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1r3yIK-00423C-1v; Fri, 17 Nov 2023 13:50:00 +0100 From: Oleksij Rempel To: Robin van der Gracht , Oliver Hartkopp , Marc Kleine-Budde Cc: Oleksij Rempel , syzbot+daa36413a5cedf799ae4@syzkaller.appspotmail.com, stable@vger.kernel.org, kernel@pengutronix.de, linux-can@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1] net: can: j1939: enhanced error handling for tightly received RTS messages in xtp_rx_rts_session_new Date: Fri, 17 Nov 2023 13:49:59 +0100 Message-Id: <20231117124959.961171-1-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This patch enhances error handling in scenarios with RTS (Request to Send) messages arriving closely. It replaces the less informative WARN_ON_O= NCE backtraces with a new error handling method. This provides clearer error messages and allows for the early termination of problematic sessions. Previously, sessions were only released at the end of j1939_xtp_rx_rts(). Potentially this could be reproduced with something like: testj1939 -r vcan0:0x80 & while true; do # send first RTS cansend vcan0 18EC8090#1014000303002301; # send second RTS cansend vcan0 18EC8090#1014000303002301; # send abort cansend vcan0 18EC8090#ff00000000002301; done Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Reported-by: syzbot+daa36413a5cedf799ae4@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel --- net/can/j1939/transport.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index fe3df23a2595..c6569f98d251 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -1593,8 +1593,8 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j1= 939_priv *priv, struct j1939_sk_buff_cb skcb =3D *j1939_skb_to_cb(skb); struct j1939_session *session; const u8 *dat; + int len, ret; pgn_t pgn; - int len; =20 netdev_dbg(priv->ndev, "%s\n", __func__); =20 @@ -1653,7 +1653,22 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j= 1939_priv *priv, session->tskey =3D priv->rx_tskey++; j1939_sk_errqueue(session, J1939_ERRQUEUE_RX_RTS); =20 - WARN_ON_ONCE(j1939_session_activate(session)); + ret =3D j1939_session_activate(session); + if (ret) { + /* Entering this scope indicates an issue with the J1939 bus. + * Possible scenarios include: + * - A time lapse occurred, and a new session was initiated + * due to another packet being sent correctly. This could + * have been caused by too long interrupt, debugger, or being + * out-scheduled by another task. + * - The bus is receiving numerous erroneous packets, either + * from a malfunctioning device or during a test scenario. + */ + netdev_alert(priv->ndev, "%s: 0x%p: concurrent session with same addr (%= 02x %02x) is already active.\n", + __func__, session, skcb.addr.sa, skcb.addr.da); + j1939_session_put(session); + return NULL; + } =20 return session; } --=20 2.39.2