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 5072FC35673 for ; Sun, 23 Feb 2020 02:25:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 27A6222525 for ; Sun, 23 Feb 2020 02:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582424732; bh=4BrJ9EXZcJa6znthVl0F5PfVP+9GqPmq6sX3Q6IIDOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tH8m7ueAVwRjinzSU1mcPy+mvvLXOLQXACBNE2PVqlI/cNvGtGAxAW3aztrgrVEYo lBoyk+SyLUWqC6d1rm68/M9EctTWrrp8Mf9koxR/BPLiq1Nz/6eWrhQOv+ItbvymNn RQ4N9JFkZVXkVOJmQ+UMx7es8fb1vsRJrJVwyn+w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728747AbgBWCZ3 (ORCPT ); Sat, 22 Feb 2020 21:25:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:55668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729603AbgBWCZG (ORCPT ); Sat, 22 Feb 2020 21:25:06 -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 0CFB120707; Sun, 23 Feb 2020 02:25:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582424705; bh=4BrJ9EXZcJa6znthVl0F5PfVP+9GqPmq6sX3Q6IIDOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fd2mDTtZgU3jgSQPGK9wl1KxUmfnuFGC+Rhp+M/pMdSRbJFcSPltA5bnpjiXryk+2 LDfunowOjMeLP7fUcBA2ZHljUgqxf9bNcmCF89MYUXVHopwFO1Pi3XyLdsQq2TH/Wu hDvHAt0vKPV0dwi/kUimTXQ5qLiaO+ym7om4/ZFs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Firo Yang , "David S . Miller" , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 5/7] enic: prevent waking up stopped tx queues over watchdog reset Date: Sat, 22 Feb 2020 21:24:57 -0500 Message-Id: <20200223022459.2594-5-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200223022459.2594-1-sashal@kernel.org> References: <20200223022459.2594-1-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: Firo Yang [ Upstream commit 0f90522591fd09dd201065c53ebefdfe3c6b55cb ] Recent months, our customer reported several kernel crashes all preceding with following message: NETDEV WATCHDOG: eth2 (enic): transmit queue 0 timed out Error message of one of those crashes: BUG: unable to handle kernel paging request at ffffffffa007e090 After analyzing severl vmcores, I found that most of crashes are caused by memory corruption. And all the corrupted memory areas are overwritten by data of network packets. Moreover, I also found that the tx queues were enabled over watchdog reset. After going through the source code, I found that in enic_stop(), the tx queues stopped by netif_tx_disable() could be woken up over a small time window between netif_tx_disable() and the napi_disable() by the following code path: napi_poll-> enic_poll_msix_wq-> vnic_cq_service-> enic_wq_service-> netif_wake_subqueue(enic->netdev, q_number)-> test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &txq->state) In turn, upper netowrk stack could queue skb to ENIC NIC though enic_hard_start_xmit(). And this might introduce some race condition. Our customer comfirmed that this kind of kernel crash doesn't occur over 90 days since they applied this patch. Signed-off-by: Firo Yang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/cisco/enic/enic_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c index 3c20d0dc92568..9b97933338163 100644 --- a/drivers/net/ethernet/cisco/enic/enic_main.c +++ b/drivers/net/ethernet/cisco/enic/enic_main.c @@ -1807,10 +1807,10 @@ static int enic_stop(struct net_device *netdev) } netif_carrier_off(netdev); - netif_tx_disable(netdev); if (vnic_dev_get_intr_mode(enic->vdev) == VNIC_DEV_INTR_MODE_MSIX) for (i = 0; i < enic->wq_count; i++) napi_disable(&enic->napi[enic_cq_wq(enic, i)]); + netif_tx_disable(netdev); if (!enic_is_dynamic(enic) && !enic_is_sriov_vf(enic)) enic_dev_del_station_addr(enic); -- 2.20.1