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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 17918C282DB for ; Sun, 3 Feb 2019 13:59:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2A5A20815 for ; Sun, 3 Feb 2019 13:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728621AbfBCN6x (ORCPT ); Sun, 3 Feb 2019 08:58:53 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53716 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728333AbfBCNt7 (ORCPT ); Sun, 3 Feb 2019 08:49:59 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqI9k-0003wN-UT; Sun, 03 Feb 2019 13:49:57 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9e-000791-Pu; Sun, 03 Feb 2019 14:49:50 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Marc Kleine-Budde" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 178/305] can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Marc Kleine-Budde commit 7da11ba5c5066dadc2e96835a6233d56d7b7764a upstream. Prior to echoing a successfully transmitted CAN frame (by calling can_get_echo_skb()), CAN drivers have to put the CAN frame (by calling can_put_echo_skb() in the transmit function). These put and get function take an index as parameter, which is used to identify the CAN frame. A driver calling can_get_echo_skb() with a index not pointing to a skb is a BUG, so add an appropriate error message. Signed-off-by: Marc Kleine-Budde Signed-off-by: Ben Hutchings --- drivers/net/can/dev.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) --- a/drivers/net/can/dev.c +++ b/drivers/net/can/dev.c @@ -425,6 +425,8 @@ EXPORT_SYMBOL_GPL(can_put_echo_skb); struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr) { struct can_priv *priv = netdev_priv(dev); + struct sk_buff *skb = priv->echo_skb[idx]; + struct canfd_frame *cf; if (idx >= priv->echo_skb_max) { netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n", @@ -432,21 +434,20 @@ struct sk_buff *__can_get_echo_skb(struc return NULL; } - if (priv->echo_skb[idx]) { - /* Using "struct canfd_frame::len" for the frame - * length is supported on both CAN and CANFD frames. - */ - struct sk_buff *skb = priv->echo_skb[idx]; - struct canfd_frame *cf = (struct canfd_frame *)skb->data; - u8 len = cf->len; - - *len_ptr = len; - priv->echo_skb[idx] = NULL; - - return skb; + if (!skb) { + netdev_err(dev, "%s: BUG! Trying to echo non existing skb: can_priv::echo_skb[%u]\n", + __func__, idx); + return NULL; } - return NULL; + /* Using "struct canfd_frame::len" for the frame + * length is supported on both CAN and CANFD frames. + */ + cf = (struct canfd_frame *)skb->data; + *len_ptr = cf->len; + priv->echo_skb[idx] = NULL; + + return skb; } /*