From patchwork Thu Dec 17 16:25:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 345349 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=-17.0 required=3.0 tests=BAYES_00, 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 DC7F9C4361B for ; Thu, 17 Dec 2020 16:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7697239E4 for ; Thu, 17 Dec 2020 16:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728652AbgLQQ0R (ORCPT ); Thu, 17 Dec 2020 11:26:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:33944 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725930AbgLQQ0Q (ORCPT ); Thu, 17 Dec 2020 11:26:16 -0500 From: Antoine Tenart Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: davem@davemloft.net, kuba@kernel.org Cc: Antoine Tenart , netdev@vger.kernel.org, pabeni@redhat.com Subject: [PATCH net 4/4] net-sysfs: take the rtnl lock when accessing xps_rxqs_map and num_tc Date: Thu, 17 Dec 2020 17:25:21 +0100 Message-Id: <20201217162521.1134496-5-atenart@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201217162521.1134496-1-atenart@kernel.org> References: <20201217162521.1134496-1-atenart@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Accesses to dev->xps_rxqs_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: 8af2c06ff4b1 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue") Signed-off-by: Antoine Tenart --- net/core/net-sysfs.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 62ca2f2c0ee6..daf502c13d6d 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1429,22 +1429,29 @@ static struct netdev_queue_attribute xps_cpus_attribute __ro_after_init static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) { + int j, len, ret, num_tc = 1, tc = 0; struct net_device *dev = queue->dev; struct xps_dev_maps *dev_maps; unsigned long *mask, index; - int j, len, num_tc = 1, tc = 0; index = get_netdev_queue_index(queue); + if (!rtnl_trylock()) + return restart_syscall(); + if (dev->num_tc) { num_tc = dev->num_tc; tc = netdev_txq_to_tc(dev, index); - if (tc < 0) - return -EINVAL; + if (tc < 0) { + ret = -EINVAL; + goto err_rtnl_unlock; + } } mask = bitmap_zalloc(dev->num_rx_queues, GFP_KERNEL); - if (!mask) - return -ENOMEM; + if (!mask) { + ret = -ENOMEM; + goto err_rtnl_unlock; + } rcu_read_lock(); dev_maps = rcu_dereference(dev->xps_rxqs_map); @@ -1470,10 +1477,16 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) out_no_maps: rcu_read_unlock(); + rtnl_unlock(); + len = bitmap_print_to_pagebuf(false, buf, mask, dev->num_rx_queues); bitmap_free(mask); return len < PAGE_SIZE ? len : -EINVAL; + +err_rtnl_unlock: + rtnl_unlock(); + return ret; } static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,