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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BADDC433F5 for ; Thu, 17 Mar 2022 08:13:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbiCQIO1 (ORCPT ); Thu, 17 Mar 2022 04:14:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230507AbiCQIO0 (ORCPT ); Thu, 17 Mar 2022 04:14:26 -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 4C3E5135094 for ; Thu, 17 Mar 2022 01:13:09 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nUlFr-0004It-Oc for linux-can@vger.kernel.org; Thu, 17 Mar 2022 09:13:07 +0100 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 3F4B14CFEA for ; Thu, 17 Mar 2022 08:13:07 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 2D0BF4CFE7; Thu, 17 Mar 2022 08:13:07 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id 30025072; Thu, 17 Mar 2022 08:13:07 +0000 (UTC) From: Marc Kleine-Budde To: linux-can@vger.kernel.org Cc: Marc Kleine-Budde , Hangyu Hua Subject: [PATCH v2] can: m_can: m_can_tx_handler(): fix use after free of skb Date: Thu, 17 Mar 2022 09:13:05 +0100 Message-Id: <20220317081305.739554-1-mkl@pengutronix.de> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org can_put_echo_skb() will clone skb then free the skb. Move the can_put_echo_skb() for the m_can version 3.0.x directly before the start of the xmit in hardware, similar to the 3.1.x branch. Reported-by: Hangyu Hua Signed-off-by: Marc Kleine-Budde --- Hello, picking up Hangyu Hua's work from: | https://lore.kernel.org/all/20220317030143.14668-1-hbh25y@gmail.com/ Instead of using a temporary variable, move the can_put_echo_skb() instead. regads, Marc drivers/net/can/m_can/m_can.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index 1a4b56f6fa8c..b3b5bc1c803b 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1637,8 +1637,6 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) if (err) goto out_fail; - can_put_echo_skb(skb, dev, 0, 0); - if (cdev->can.ctrlmode & CAN_CTRLMODE_FD) { cccr = m_can_read(cdev, M_CAN_CCCR); cccr &= ~CCCR_CMR_MASK; @@ -1655,6 +1653,9 @@ static netdev_tx_t m_can_tx_handler(struct m_can_classdev *cdev) m_can_write(cdev, M_CAN_CCCR, cccr); } m_can_write(cdev, M_CAN_TXBTIE, 0x1); + + can_put_echo_skb(skb, dev, 0, 0); + m_can_write(cdev, M_CAN_TXBAR, 0x1); /* End of xmit function for version 3.0.x */ } else { -- 2.35.1