From patchwork Wed Dec 23 21:23:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 11988885 X-Patchwork-Delegate: kuba@kernel.org 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=-19.0 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,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 8958CC433E6 for ; Wed, 23 Dec 2020 21:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DF132246B for ; Wed, 23 Dec 2020 21:24:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729198AbgLWVYM (ORCPT ); Wed, 23 Dec 2020 16:24:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:50998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727147AbgLWVYM (ORCPT ); Wed, 23 Dec 2020 16:24:12 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5FFAD22473; Wed, 23 Dec 2020 21:23:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608758612; bh=7cSPm7QGIHghZ6g3wS5iD5HhlF4JxgKP24qbxWRjUCo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AdeajCkP3NgAQzomHf/14ssHAJDvnS69dT9PeM6hf062YqNgb/zt9aUcycN4kuDU0 1U5KZtlu3+qmjzXMi7hPZ6ih3D5i94xLXt9ZD4AQQkoxUlVdgo/xaUEpSTYU1EhlWz HmCFGu7ZK09xFFwPyR90xJkPDI9CYhqRF+Tg5kvdNoMkHzExMNWOMn2u82eipVwxqH +VV+Pc6UtXGklQgk9tFbcYSTMJAXILf/rjeUm0PWZIFPD0R+atbOJipVK4ow59hqL8 4VvA0+gtELjytFOHMVY3paW2C7/Z/K6oBA6vTlMA0nNuKkBsvK1UXqbCOUWwWSylv5 kEVi9ArwegECg== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, alexander.duyck@gmail.com Cc: Antoine Tenart , netdev@vger.kernel.org, pabeni@redhat.com Subject: [PATCH net v3 2/4] net-sysfs: take the rtnl lock when accessing xps_cpus_map and num_tc Date: Wed, 23 Dec 2020 22:23:21 +0100 Message-Id: <20201223212323.3603139-3-atenart@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201223212323.3603139-1-atenart@kernel.org> References: <20201223212323.3603139-1-atenart@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Accesses to dev->xps_cpus_map (when using dev->num_tc) should be protected by the rtnl lock, like we do for netif_set_xps_queue. I didn't see an actual bug being triggered, but let's be safe here and take the rtnl lock while accessing the map in sysfs. Fixes: 184c449f91fe ("net: Add support for XPS with QoS via traffic classes") Signed-off-by: Antoine Tenart --- net/core/net-sysfs.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 7cc15dec1717..65886bfbf822 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1317,8 +1317,8 @@ static const struct attribute_group dql_group = { static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf) { + int cpu, len, ret, num_tc = 1, tc = 0; struct net_device *dev = queue->dev; - int cpu, len, num_tc = 1, tc = 0; struct xps_dev_maps *dev_maps; cpumask_var_t mask; unsigned long index; @@ -1328,22 +1328,31 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, index = get_netdev_queue_index(queue); + if (!rtnl_trylock()) + return restart_syscall(); + if (dev->num_tc) { /* Do not allow XPS on subordinate device directly */ num_tc = dev->num_tc; - if (num_tc < 0) - return -EINVAL; + if (num_tc < 0) { + ret = -EINVAL; + goto err_rtnl_unlock; + } /* If queue belongs to subordinate dev use its map */ dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev; tc = netdev_txq_to_tc(dev, index); - if (tc < 0) - return -EINVAL; + if (tc < 0) { + ret = -EINVAL; + goto err_rtnl_unlock; + } } - if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) - return -ENOMEM; + if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) { + ret = -ENOMEM; + goto err_rtnl_unlock; + } rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_cpus_map); @@ -1366,9 +1375,15 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, } rcu_read_unlock(); + rtnl_unlock(); + len = snprintf(buf, PAGE_SIZE, "%*pb\n", cpumask_pr_args(mask)); free_cpumask_var(mask); return len < PAGE_SIZE ? len : -EINVAL; + +err_rtnl_unlock: + rtnl_unlock(); + return ret; } static ssize_t xps_cpus_store(struct netdev_queue *queue,