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=-20.2 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, USER_AGENT_GIT autolearn=ham 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 6A1E8C433FE for ; Mon, 20 Sep 2021 18:55:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57D3560F6B for ; Mon, 20 Sep 2021 18:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355008AbhITS4f (ORCPT ); Mon, 20 Sep 2021 14:56:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:37126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1385800AbhITSw2 (ORCPT ); Mon, 20 Sep 2021 14:52:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6606663395; Mon, 20 Sep 2021 17:35:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632159315; bh=dTZ0jGQNK7l0rIGdBei6joEsPHyNhNMqX4OAAJcD33w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KspgJuxkbFQiszHTkuKaov8Acht3lx/pXjXC9CDGjrl+sTQE6+zcJ1XaxzIst8KGS 3y9Y+M7xWOtrQmPkjUCIRgQyflAcpxc4Rgsto4u1v8O2KrmAf126H32lwUxqQOaiwz boAh6iWlGD2HirhK90kyuMXDTHpOF8k9kTDqUmdI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yoshihiro Shimoda , "David S. Miller" , Sasha Levin Subject: [PATCH 5.14 168/168] net: renesas: sh_eth: Fix freeing wrong tx descriptor Date: Mon, 20 Sep 2021 18:45:06 +0200 Message-Id: <20210920163927.199009618@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163921.633181900@linuxfoundation.org> References: <20210920163921.633181900@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: stable@vger.kernel.org From: Yoshihiro Shimoda [ Upstream commit 0341d5e3d1ee2a36dd5a49b5bef2ce4ad1cfa6b4 ] The cur_tx counter must be incremented after TACT bit of txdesc->status was set. However, a CPU is possible to reorder instructions and/or memory accesses between cur_tx and txdesc->status. And then, if TX interrupt happened at such a timing, the sh_eth_tx_free() may free the descriptor wrongly. So, add wmb() before cur_tx++. Otherwise NETDEV WATCHDOG timeout is possible to happen. Fixes: 86a74ff21a7a ("net: sh_eth: add support for Renesas SuperH Ethernet") Signed-off-by: Yoshihiro Shimoda Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/renesas/sh_eth.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 840478692a37..dfd439eadd49 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -2533,6 +2533,7 @@ static netdev_tx_t sh_eth_start_xmit(struct sk_buff *skb, else txdesc->status |= cpu_to_le32(TD_TACT); + wmb(); /* cur_tx must be incremented after TACT bit was set */ mdp->cur_tx++; if (!(sh_eth_read(ndev, EDTRR) & mdp->cd->edtrr_trns)) -- 2.30.2