From patchwork Thu Jun 1 22:40:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Keller, Jacob E" X-Patchwork-Id: 770013 X-Patchwork-Delegate: jeffrey.t.kirsher@intel.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3wf2Pm6ljmz9sN8 for ; Fri, 2 Jun 2017 08:41:16 +1000 (AEST) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 71A3330C69; Thu, 1 Jun 2017 22:41:15 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ccgWYv7ktbAp; Thu, 1 Jun 2017 22:41:11 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by silver.osuosl.org (Postfix) with ESMTP id 73D5230C8F; Thu, 1 Jun 2017 22:41:02 +0000 (UTC) X-Original-To: intel-wired-lan@lists.osuosl.org Delivered-To: intel-wired-lan@lists.osuosl.org Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by ash.osuosl.org (Postfix) with ESMTP id 25B781C3EBE for ; Thu, 1 Jun 2017 22:40:58 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 230F088B42 for ; Thu, 1 Jun 2017 22:40:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mJE6iLf3yopo for ; Thu, 1 Jun 2017 22:40:56 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 94B4688B39 for ; Thu, 1 Jun 2017 22:40:56 +0000 (UTC) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Jun 2017 15:40:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.39,281,1493708400"; d="scan'208"; a="1155582866" Received: from jekeller-desk.amr.corp.intel.com ([10.166.35.158]) by fmsmga001.fm.intel.com with ESMTP; 01 Jun 2017 15:40:55 -0700 From: Jacob Keller To: Intel Wired LAN Date: Thu, 1 Jun 2017 15:40:44 -0700 Message-Id: <20170601224051.6106-9-jacob.e.keller@intel.com> X-Mailer: git-send-email 2.13.0.311.g0339965c70d6 In-Reply-To: <20170601224051.6106-1-jacob.e.keller@intel.com> References: <20170601224051.6106-1-jacob.e.keller@intel.com> Subject: [Intel-wired-lan] [PATCH 08/15] fm10k: avoid divide by zero in rare cases when device is resetting X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" It is possible that under rare circumstances the device is undergoing a reset, such as when a PFLR occurs, and the device may be transmitting simultaneously. In this case, we might attempt to divide by zero when finding the proper r_idx. Instead, lets read the num_tx_queues once, and make sure it's non-zero. Signed-off-by: Jacob Keller --- drivers/net/ethernet/intel/fm10k/fm10k_netdev.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c index 24f2f6f86f5a..f0d824558fbf 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c @@ -643,9 +643,13 @@ int fm10k_close(struct net_device *netdev) static netdev_tx_t fm10k_xmit_frame(struct sk_buff *skb, struct net_device *dev) { struct fm10k_intfc *interface = netdev_priv(dev); + int num_tx_queues = READ_ONCE(interface->num_tx_queues); unsigned int r_idx = skb->queue_mapping; int err; + if (!num_tx_queues) + return NETDEV_TX_BUSY; + if ((skb->protocol == htons(ETH_P_8021Q)) && !skb_vlan_tag_present(skb)) { /* FM10K only supports hardware tagging, any tags in frame @@ -698,8 +702,8 @@ static netdev_tx_t fm10k_xmit_frame(struct sk_buff *skb, struct net_device *dev) __skb_put(skb, pad_len); } - if (r_idx >= interface->num_tx_queues) - r_idx %= interface->num_tx_queues; + if (r_idx >= num_tx_queues) + r_idx %= num_tx_queues; err = fm10k_xmit_frame_ring(skb, interface->tx_ring[r_idx]);