From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97BA2C433E2 for ; Fri, 11 Sep 2020 06:51:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D23C221EE for ; Fri, 11 Sep 2020 06:51:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725774AbgIKGvA convert rfc822-to-8bit (ORCPT ); Fri, 11 Sep 2020 02:51:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725747AbgIKGu6 (ORCPT ); Fri, 11 Sep 2020 02:50:58 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25597C061573 for ; Thu, 10 Sep 2020 23:50:57 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kGctS-0007Mq-QE; Fri, 11 Sep 2020 08:50:46 +0200 Received: from ore by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kGctN-0005XU-8x; Fri, 11 Sep 2020 08:50:41 +0200 Date: Fri, 11 Sep 2020 08:50:41 +0200 From: Oleksij Rempel To: Zhang Changzhong Cc: robin@protonic.nl, linux@rempel-privat.de, kernel@pengutronix.de, socketcan@hartkopp.net, mkl@pengutronix.de, davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] can: j1939: j1939_sk_bind(): return failure if netdev is down Message-ID: <20200911065041.v4cetsbokqhdmbd4@pengutronix.de> References: <1599460308-18770-1-git-send-email-zhangchangzhong@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <1599460308-18770-1-git-send-email-zhangchangzhong@huawei.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:47:40 up 300 days, 22:06, 291 users, load average: 0.00, 0.04, 0.06 User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Sep 07, 2020 at 02:31:48PM +0800, Zhang Changzhong wrote: > When a netdev down event occurs after a successful call to > j1939_sk_bind(), j1939_netdev_notify() can handle it correctly. > > But if the netdev already in down state before calling j1939_sk_bind(), > j1939_sk_release() will stay in wait_event_interruptible() blocked > forever. Because in this case, j1939_netdev_notify() won't be called and > j1939_tp_txtimer() won't call j1939_session_cancel() or other function > to clear session for ENETDOWN error, this lead to mismatch of > j1939_session_get/put() and jsk->skb_pending will never decrease to > zero. > > To reproduce it use following commands: > 1. ip link add dev vcan0 type vcan > 2. j1939acd -r 100,80-120 1122334455667788 vcan0 > 3. presses ctrl-c and thread will be blocked forever > > This patch adds check for ndev->flags in j1939_sk_bind() to avoid this > kind of situation and return with -ENETDOWN. > > Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") > Signed-off-by: Zhang Changzhong Acked-by: Oleksij Rempel Thank you! > --- > net/can/j1939/socket.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c > index 1be4c89..f239665 100644 > --- a/net/can/j1939/socket.c > +++ b/net/can/j1939/socket.c > @@ -475,6 +475,12 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) > goto out_release_sock; > } > > + if (!(ndev->flags & IFF_UP)) { > + dev_put(ndev); > + ret = -ENETDOWN; > + goto out_release_sock; > + } > + > priv = j1939_netdev_start(ndev); > dev_put(ndev); > if (IS_ERR(priv)) { > -- > 2.9.5 > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |