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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 A66F1C3F2D2 for ; Thu, 5 Mar 2020 17:22:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C4942072D for ; Thu, 5 Mar 2020 17:22:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583428941; bh=apxNGTTawxO88AhaRt5S23Z7rTLns5Lk95jgyvF3/SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wQ09PnwBBASvnfLLGHJxHfNw6CGb5xJ4Sjn7MobVeVZhgwVMvzLTMIhZF8qU0tXk6 4Ez4BS7ChkD4M9rQMT1Ri1hPxj1h5G58hbzv3cdnFANkaaqoo9auJeJMqbI1iR12ST W6SL4Cw3N6udxL4BT388DxT8eOghhALVnZSJtTPY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727785AbgCERWR (ORCPT ); Thu, 5 Mar 2020 12:22:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:39800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727405AbgCERN6 (ORCPT ); Thu, 5 Mar 2020 12:13:58 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1660E2166E; Thu, 5 Mar 2020 17:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583428437; bh=apxNGTTawxO88AhaRt5S23Z7rTLns5Lk95jgyvF3/SA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pcz/2oswnYUZTcyl/uqXNbSEokJjxU3pwudTbJXkyBd7TTTf4Lq9abNMExkNQKHpj Eqfvz/uWSm6lZDNwziJIRo92u30OyyvgJNcepQlhYSxnDFvi8tUasb2ZvTLQKn+z+e f+3Zqa3xyPbqQKqrhSf4F4gN0sMaYazzTmAPvEXg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Esben Haabendal , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.5 35/67] net: ll_temac: Fix race condition causing TX hang Date: Thu, 5 Mar 2020 12:12:36 -0500 Message-Id: <20200305171309.29118-35-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200305171309.29118-1-sashal@kernel.org> References: <20200305171309.29118-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Esben Haabendal [ Upstream commit 84823ff80f7403752b59e00bb198724100dc611c ] It is possible that the interrupt handler fires and frees up space in the TX ring in between checking for sufficient TX ring space and stopping the TX queue in temac_start_xmit. If this happens, the queue wake from the interrupt handler will occur before the queue is stopped, causing a lost wakeup and the adapter's transmit hanging. To avoid this, after stopping the queue, check again whether there is sufficient space in the TX ring. If so, wake up the queue again. This is a port of the similar fix in axienet driver, commit 7de44285c1f6 ("net: axienet: Fix race condition causing TX hang"). Fixes: 23ecc4bde21f ("net: ll_temac: fix checksum offload logic") Signed-off-by: Esben Haabendal Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/xilinx/ll_temac_main.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c index 21c1b4322ea78..fd578568b3bff 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -788,6 +788,9 @@ static void temac_start_xmit_done(struct net_device *ndev) stat = be32_to_cpu(cur_p->app0); } + /* Matches barrier in temac_start_xmit */ + smp_mb(); + netif_wake_queue(ndev); } @@ -830,9 +833,19 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (temac_check_tx_bd_space(lp, num_frag + 1)) { - if (!netif_queue_stopped(ndev)) - netif_stop_queue(ndev); - return NETDEV_TX_BUSY; + if (netif_queue_stopped(ndev)) + return NETDEV_TX_BUSY; + + netif_stop_queue(ndev); + + /* Matches barrier in temac_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (temac_check_tx_bd_space(lp, num_frag)) + return NETDEV_TX_BUSY; + + netif_wake_queue(ndev); } cur_p->app0 = 0; -- 2.20.1