From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:58696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731628AbeK3BbO (ORCPT ); Thu, 29 Nov 2018 20:31:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Kleine-Budde Subject: [PATCH 4.14 039/100] can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb Date: Thu, 29 Nov 2018 15:12:09 +0100 Message-Id: <20181129140102.139885270@linuxfoundation.org> In-Reply-To: <20181129140058.768942700@linuxfoundation.org> References: <20181129140058.768942700@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable 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. Cc: linux-stable Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- 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 @@ -479,6 +479,8 @@ 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", @@ -486,21 +488,20 @@ 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; } /*