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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 1AC51C433DB for ; Mon, 11 Jan 2021 13:08:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD0532255F for ; Mon, 11 Jan 2021 13:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729229AbhAKNIp (ORCPT ); Mon, 11 Jan 2021 08:08:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:54802 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730609AbhAKNHh (ORCPT ); Mon, 11 Jan 2021 08:07:37 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8561D22A83; Mon, 11 Jan 2021 13:07:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610370442; bh=O7NPp8LGbvyK3KDXfDwq6jIyotjkSZXFFsA7qGeYSG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ECwJ9Imp2zaqtItFej4mU7LA/1awfZG86rWVZKcsqbaBoQ1t4ha444hfBesIRf0Yt UJl4YxGQoSNPRZaa3oic5VyqjW0C81jJKjPNpv3pTNQ91HGOEq4kWNNFJ7JFDbT9fk CNaxN7owkhYvjSP1lQksq1ANtlVeUSQCmSyeJF6k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Antoine Tenart , Alexander Duyck , Jakub Kicinski Subject: [PATCH 4.19 23/77] net-sysfs: take the rtnl lock when storing xps_cpus Date: Mon, 11 Jan 2021 14:01:32 +0100 Message-Id: <20210111130037.534472302@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210111130036.414620026@linuxfoundation.org> References: <20210111130036.414620026@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Antoine Tenart [ Upstream commit 1ad58225dba3f2f598d2c6daed4323f24547168f ] Two race conditions can be triggered when storing xps cpus, resulting in various oops and invalid memory accesses: 1. Calling netdev_set_num_tc while netif_set_xps_queue: - netif_set_xps_queue uses dev->tc_num as one of the parameters to compute the size of new_dev_maps when allocating it. dev->tc_num is also used to access the map, and the compiler may generate code to retrieve this field multiple times in the function. - netdev_set_num_tc sets dev->tc_num. If new_dev_maps is allocated using dev->tc_num and then dev->tc_num is set to a higher value through netdev_set_num_tc, later accesses to new_dev_maps in netif_set_xps_queue could lead to accessing memory outside of new_dev_maps; triggering an oops. 2. Calling netif_set_xps_queue while netdev_set_num_tc is running: 2.1. netdev_set_num_tc starts by resetting the xps queues, dev->tc_num isn't updated yet. 2.2. netif_set_xps_queue is called, setting up the map with the *old* dev->num_tc. 2.3. netdev_set_num_tc updates dev->tc_num. 2.4. Later accesses to the map lead to out of bound accesses and oops. A similar issue can be found with netdev_reset_tc. One way of triggering this is to set an iface up (for which the driver uses netdev_set_num_tc in the open path, such as bnx2x) and writing to xps_cpus in a concurrent thread. With the right timing an oops is triggered. Both issues have the same fix: netif_set_xps_queue, netdev_set_num_tc and netdev_reset_tc should be mutually exclusive. We do that by taking the rtnl lock in xps_cpus_store. Fixes: 184c449f91fe ("net: Add support for XPS with QoS via traffic classes") Signed-off-by: Antoine Tenart Reviewed-by: Alexander Duyck Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/core/net-sysfs.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1323,7 +1323,13 @@ static ssize_t xps_cpus_store(struct net return err; } + if (!rtnl_trylock()) { + free_cpumask_var(mask); + return restart_syscall(); + } + err = netif_set_xps_queue(dev, mask, index); + rtnl_unlock(); free_cpumask_var(mask);