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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 F2812C76186 for ; Wed, 24 Jul 2019 20:20:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C636421873 for ; Wed, 24 Jul 2019 20:20:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563999651; bh=GZeLJdKWfkh5/3ogdWPp6RHl5g2nVdsr3q883PV/5wE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QTv2PoVHgn2yV8thv4qsvjvmiCW7hVBvoc2EohYJXWEiVCZkH2GadLYx6DekWRxFJ nple1ZymK4mg6MDedQmz9uhHRHfjc4tS170gO9j2VtXij3y+1Dln03IJro7koEGjGn WAK9DscC7T3WZzt6c5wwRznOSGZaCX3HwRGxOyHY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391213AbfGXUUl (ORCPT ); Wed, 24 Jul 2019 16:20:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:51298 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390684AbfGXTqN (ORCPT ); Wed, 24 Jul 2019 15:46:13 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 002DC22ADB; Wed, 24 Jul 2019 19:46:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563997572; bh=GZeLJdKWfkh5/3ogdWPp6RHl5g2nVdsr3q883PV/5wE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ds9VcsQPOdymy6rXX693uhJ0OZH2lNMOR1JrqbmhYz/S5iblEZakBzRx1RFLVCraM EhrioWxJNoGNtbp0If0SoQeDXYi00+EPzQIe7BSe1IVo2qwCzGUIQeLoNKbQt6r+P3 H3mX6D+nhCVyP7mCqBxqOpa9MNu7Xu1r4E8F+FlM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Robert Hancock , "David S. Miller" , Sasha Levin Subject: [PATCH 5.1 068/371] net: axienet: Fix race condition causing TX hang Date: Wed, 24 Jul 2019 21:17:00 +0200 Message-Id: <20190724191730.025248278@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191724.382593077@linuxfoundation.org> References: <20190724191724.382593077@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 7de44285c1f69ccfbe8be1d6a16fcd956681fee6 ] 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 axienet_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. Signed-off-by: Robert Hancock Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- .../net/ethernet/xilinx/xilinx_axienet_main.c | 20 ++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 4041c75997ba..38a8ef194e05 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -614,6 +614,10 @@ static void axienet_start_xmit_done(struct net_device *ndev) ndev->stats.tx_packets += packets; ndev->stats.tx_bytes += size; + + /* Matches barrier in axienet_start_xmit */ + smp_mb(); + netif_wake_queue(ndev); } @@ -669,9 +673,19 @@ axienet_start_xmit(struct sk_buff *skb, struct net_device *ndev) cur_p = &lp->tx_bd_v[lp->tx_bd_tail]; if (axienet_check_tx_bd_space(lp, num_frag)) { - 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 axienet_start_xmit_done */ + smp_mb(); + + /* Space might have just been freed - check again */ + if (axienet_check_tx_bd_space(lp, num_frag)) + return NETDEV_TX_BUSY; + + netif_wake_queue(ndev); } if (skb->ip_summed == CHECKSUM_PARTIAL) { -- 2.20.1