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=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 33804C11D3D for ; Thu, 27 Feb 2020 14:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B2C12468F for ; Thu, 27 Feb 2020 14:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582814545; bh=ibY1iA5KxW8FauE0CVu3Or9H6w/lThuoa5wqbXo0y2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W5/MxwH8MGKeW/B8jYKfrxCNjHX14IcL8Dkpmy+Jl6MHfKCTJwO0yyixxUzHpb+f9 oFixVRz2gUlwsZzb+AMwCZs9i6MAhHE4Wvk9oSRs3yD+Y7t2viy11MMDvNGxuJjZ7N oC5fBJW0LYoRaFdWmrwvpjTqt+DgiblA1fuVaccc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730508AbgB0NuN (ORCPT ); Thu, 27 Feb 2020 08:50:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:47720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731130AbgB0Nt7 (ORCPT ); Thu, 27 Feb 2020 08:49:59 -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 0F7F320578; Thu, 27 Feb 2020 13:49:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811398; bh=ibY1iA5KxW8FauE0CVu3Or9H6w/lThuoa5wqbXo0y2g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ng8DM80PbMgbWml6N/JUmQS8VA7wzbxGY+/ewwHQHOcbhkMvO4qakiBFpXYZpGFfQ b1lf2qz7uV7i87AT/b9vqk8T0Ifbvxtdwh/e8LZozNiZdlHyd39J2b/AHt/imhqX5f i+f+eLORvHUXTrHXezODoqzBPIMhcCh8TTgOOg+Y= 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 4.9 116/165] enic: prevent waking up stopped tx queues over watchdog reset Date: Thu, 27 Feb 2020 14:36:30 +0100 Message-Id: <20200227132248.014843769@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132230.840899170@linuxfoundation.org> References: <20200227132230.840899170@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 @@ -1806,10 +1806,10 @@ static int enic_stop(struct net_device * } 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);