From patchwork Mon Mar 22 20:25:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saeed Mahameed X-Patchwork-Id: 406497 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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 2E165C433E2 for ; Mon, 22 Mar 2021 20:26:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F254C6192D for ; Mon, 22 Mar 2021 20:26:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231799AbhCVU0C (ORCPT ); Mon, 22 Mar 2021 16:26:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:58416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231331AbhCVUZg (ORCPT ); Mon, 22 Mar 2021 16:25:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 25546619A4; Mon, 22 Mar 2021 20:25:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616444735; bh=IJC7vxBm4wOCHhacfNjJC1LmHxhi7h8ZLK2DxTaocnM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GvuZOezh5g0evWQR73la1QJozaFon4hcZ9k9oZfgZgaUjf75AUsDs67tC3Rv/oeNb cgmPfdJV19kxpY7in3uJX6R3FJt51BgiEakY8NLI6GO+sWXpLT0LIb9+Gjm0a1SXnX AIa8jdrnFTtLjc2pccEQWW2IFVz5MBp8FL/E1eFHrpZLwIfFLOWOV4Gi1RR3lJ0S2c hHJtnMGH6GKXZXOwJpd97E2v+K05Quld0jzRC7ddqH8TSqXsgTdGvdOS+jEvffdn2f voPdGMua5pD5DBwmCvox0/mgb7S6H1u2raBVU9Y80Vk+/gDJ4zOtdMFb1CXz0AC9+K sRC5tdT+OzouA== From: Saeed Mahameed To: "David S. Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Maxim Mikityanskiy , Jesper Dangaard Brouer , Tariq Toukan , Saeed Mahameed Subject: [net 5/6] net/mlx5e: Fix division by 0 in mlx5e_select_queue Date: Mon, 22 Mar 2021 13:25:23 -0700 Message-Id: <20210322202524.68886-6-saeed@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210322202524.68886-1-saeed@kernel.org> References: <20210322202524.68886-1-saeed@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Maxim Mikityanskiy mlx5e_select_queue compares num_tc_x_num_ch to real_num_tx_queues to determine if HTB and/or PTP offloads are active. If they are, it calculates netdev_pick_tx() % num_tc_x_num_ch to prevent it from selecting HTB and PTP queues for regular traffic. However, before the channels are first activated, num_tc_x_num_ch is zero. If ndo_select_queue gets called at this point, the HTB/PTP check will pass, and mlx5e_select_queue will attempt to take a modulo by num_tc_x_num_ch, which equals to zero. This commit fixes the bug by assigning num_tc_x_num_ch to a non-zero value before registering the netdev. Fixes: 214baf22870c ("net/mlx5e: Support HTB offload") Reported-by: Jesper Dangaard Brouer Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index c8b8249846a9..158f947a8503 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -4979,6 +4979,11 @@ void mlx5e_build_nic_params(struct mlx5e_priv *priv, struct mlx5e_xsk *xsk, u16 priv->max_nch); params->num_tc = 1; + /* Set an initial non-zero value, so that mlx5e_select_queue won't + * divide by zero if called before first activating channels. + */ + priv->num_tc_x_num_ch = params->num_channels * params->num_tc; + /* SQ */ params->log_sq_size = is_kdump_kernel() ? MLX5E_PARAMS_MINIMUM_LOG_SQ_SIZE :