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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 C90EBC43441 for ; Mon, 19 Nov 2018 16:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F884208E3 for ; Mon, 19 Nov 2018 16:53:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="NOsiIWYM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F884208E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390756AbeKTDR3 (ORCPT ); Mon, 19 Nov 2018 22:17:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:55852 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390361AbeKTDR2 (ORCPT ); Mon, 19 Nov 2018 22:17:28 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 185C420851; Mon, 19 Nov 2018 16:53:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542646394; bh=bHx78wzgh7wIcVS7Jg7BwBktOg6PfW1LMic+gbUbqjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NOsiIWYMngW0dcSpE8evlo26FKLkVDSZoVm2d+ZFbxGH6NHtua0qSvTd038Py5Kwj A5BWi3u1EL7/WtjVit51rrygsU+cQmFzlV20HEp56IBG7Ey+ijSsyjKDyV+EanbfTv 0PFHgSodePI3d+ouUoSy2RL19t01PA1VpkL349Rw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincenzo Maffione , Aaron Brown , Jeff Kirsher , Sasha Levin Subject: [PATCH 4.9 24/83] e1000: fix race condition between e1000_down() and e1000_watchdog Date: Mon, 19 Nov 2018 17:28:50 +0100 Message-Id: <20181119162617.196038785@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162612.046511542@linuxfoundation.org> References: <20181119162612.046511542@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 44c445c3d1b4eacff23141fa7977c3b2ec3a45c9 ] This patch fixes a race condition that can result into the interface being up and carrier on, but with transmits disabled in the hardware. The bug may show up by repeatedly IFF_DOWN+IFF_UP the interface, which allows e1000_watchdog() interleave with e1000_down(). CPU x CPU y -------------------------------------------------------------------- e1000_down(): netif_carrier_off() e1000_watchdog(): if (carrier == off) { netif_carrier_on(); enable_hw_transmit(); } disable_hw_transmit(); e1000_watchdog(): /* carrier on, do nothing */ Signed-off-by: Vincenzo Maffione Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/e1000/e1000_main.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index dd112aa5cebb..39a09e18c1b7 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -521,8 +521,6 @@ void e1000_down(struct e1000_adapter *adapter) struct net_device *netdev = adapter->netdev; u32 rctl, tctl; - netif_carrier_off(netdev); - /* disable receives in the hardware */ rctl = er32(RCTL); ew32(RCTL, rctl & ~E1000_RCTL_EN); @@ -538,6 +536,15 @@ void e1000_down(struct e1000_adapter *adapter) E1000_WRITE_FLUSH(); msleep(10); + /* Set the carrier off after transmits have been disabled in the + * hardware, to avoid race conditions with e1000_watchdog() (which + * may be running concurrently to us, checking for the carrier + * bit to decide whether it should enable transmits again). Such + * a race condition would result into transmission being disabled + * in the hardware until the next IFF_DOWN+IFF_UP cycle. + */ + netif_carrier_off(netdev); + napi_disable(&adapter->napi); e1000_irq_disable(adapter); -- 2.17.1