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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 18073C433ED for ; Mon, 17 May 2021 15:16:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EFF1B610FA for ; Mon, 17 May 2021 15:16:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243041AbhEQPRc (ORCPT ); Mon, 17 May 2021 11:17:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:47774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242440AbhEQPG6 (ORCPT ); Mon, 17 May 2021 11:06:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 06F2861C1A; Mon, 17 May 2021 14:29:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621261763; bh=gIik3LMwVlaSZYEiZ1NwSDYhkCjkG9S+J7u9h0qpwK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OliPp8eXNpLEwb2ICn12PLwMYJcOuAw8QoD46XY1UyZaQ48UEpad3JjMEt3YW+gTr Jd2ym7aUFcugSJmLldqGNDjVBXw/Us19rZpcMXFbkYj6pzrQHdEi3tl9CyDLvLyJ7q EfQE4HaI8mLujvZhi77c9Twf6G+kR4hAB4kCal/k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Torin Cooper-Bennun , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 5.4 087/141] can: m_can: m_can_tx_work_queue(): fix tx_skb race condition Date: Mon, 17 May 2021 16:02:19 +0200 Message-Id: <20210517140245.715713873@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517140242.729269392@linuxfoundation.org> References: <20210517140242.729269392@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Kleine-Budde [ Upstream commit e04b2cfe61072c7966e1a5fb73dd1feb30c206ed ] The m_can_start_xmit() function checks if the cdev->tx_skb is NULL and returns with NETDEV_TX_BUSY in case tx_sbk is not NULL. There is a race condition in the m_can_tx_work_queue(), where first the skb is send to the driver and then the case tx_sbk is set to NULL. A TX complete IRQ might come in between and wake the queue, which results in tx_skb not being cleared yet. Fixes: f524f829b75a ("can: m_can: Create a m_can platform framework") Tested-by: Torin Cooper-Bennun Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/m_can/m_can.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index b2224113987c..de275ccb4fd0 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1418,6 +1418,8 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) int i; int putidx; + cdev->tx_skb = NULL; + /* Generate ID field for TX buffer Element */ /* Common to all supported M_CAN versions */ if (cf->can_id & CAN_EFF_FLAG) { @@ -1534,7 +1536,6 @@ static void m_can_tx_work_queue(struct work_struct *ws) tx_work); m_can_tx_handler(cdev); - cdev->tx_skb = NULL; } static netdev_tx_t m_can_start_xmit(struct sk_buff *skb, -- 2.30.2