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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 D0199C35677 for ; Thu, 27 Feb 2020 13:59:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A74E021D7E for ; Thu, 27 Feb 2020 13:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811966; bh=bjDSwfu4eejKeiVNGo3zOWZARMf3vjVe0uMdiILHoqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vfKuHUmfP1YVnQcIjYQE9OoLDBD0CKyWmxf73AsCMk+ez4KmxZg1yAPkzX2hoXhb0 UbOqaYquoPYuoV51dmfq1Y+TaenMU+CQjOQAZL0uD5uXb/wlg0rpKdaFDcEQ0rYKyP P1xN/hZ8vl/a+GyvDgtUTyXNP2Bty8nxHi1lJFPg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732588AbgB0N7Z (ORCPT ); Thu, 27 Feb 2020 08:59:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:60658 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732590AbgB0N7R (ORCPT ); Thu, 27 Feb 2020 08:59:17 -0500 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 9220B24691; Thu, 27 Feb 2020 13:59:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811956; bh=bjDSwfu4eejKeiVNGo3zOWZARMf3vjVe0uMdiILHoqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hCt8S50L6VUvG3418Gf4okByHB0uBEPlKu+CyRpA1WfUF0DQZ9TllHIHkI9BSGB+a PZh7qlm8PMpQxC/bzIGFxQ2HduRXPkiBBmmGnrjinZHML1j5DK2Uk4LmHwAQtHkqjy JWcltqtfnHObyGVMaHX/tMB5eaGtpzuGXeSDodGE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Firo Yang , "David S. Miller" Subject: [PATCH 4.14 167/237] enic: prevent waking up stopped tx queues over watchdog reset Date: Thu, 27 Feb 2020 14:36:21 +0100 Message-Id: <20200227132308.752414569@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@linuxfoundation.org> User-Agent: quilt/0.66 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 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: Greg Kroah-Hartman --- drivers/net/ethernet/cisco/enic/enic_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/ethernet/cisco/enic/enic_main.c +++ b/drivers/net/ethernet/cisco/enic/enic_main.c @@ -1972,10 +1972,10 @@ static int enic_stop(struct net_device * napi_disable(&enic->napi[i]); 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);