From patchwork Tue Mar 22 21:01:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 600949 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3qV4rF6kcyz9sCy; Wed, 23 Mar 2016 08:01:49 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1aiTQs-0005PG-50; Tue, 22 Mar 2016 21:01:42 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1aiTQn-0005Or-5i for kernel-team@lists.ubuntu.com; Tue, 22 Mar 2016 21:01:37 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1aiTQl-0007WR-DL; Tue, 22 Mar 2016 21:01:35 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1aiTQi-0005Zd-I2; Tue, 22 Mar 2016 14:01:32 -0700 From: Kamal Mostafa To: Johannes Berg Subject: [3.13.y-ckt stable] Patch "wext: fix message delay/ordering" has been added to the 3.13.y-ckt tree Date: Tue, 22 Mar 2016 14:01:31 -0700 Message-Id: <1458680491-21390-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 X-Extended-Stable: 3.13 Cc: Beniamino Galvani , Kamal Mostafa , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled wext: fix message delay/ordering to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt37. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 40b14fa78ed5dcbbf3659b2bc5764fa218e1459d Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 27 Jan 2016 12:37:52 +0100 Subject: wext: fix message delay/ordering commit 8bf862739a7786ae72409220914df960a0aa80d8 upstream. Beniamino reported that he was getting an RTM_NEWLINK message for a given interface, after the RTM_DELLINK for it. It turns out that the message is a wireless extensions message, which was sent because the interface had been connected and disconnection while it was deleted caused a wext message. For its netlink messages, wext uses RTM_NEWLINK, but the message is without all the regular rtnetlink attributes, so "ip monitor link" prints just rudimentary information: 5: wlan1: mtu 1500 qdisc mq state DOWN group default link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff Deleted 5: wlan1: mtu 1500 qdisc noop state DOWN group default link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff 5: wlan1: link/ether (from my hwsim reproduction) This can cause userspace to get confused since it doesn't expect an RTM_NEWLINK message after RTM_DELLINK. The reason for this is that wext schedules a worker to send out the messages, and the scheduling delay can cause the messages to get out to userspace in different order. To fix this, have wext register a netdevice notifier and flush out any pending messages when netdevice state changes. This fixes any ordering whenever the original message wasn't sent by a notifier itself. Reported-by: Beniamino Galvani Signed-off-by: Johannes Berg Signed-off-by: Kamal Mostafa --- net/wireless/wext-core.c | 51 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 40 insertions(+), 11 deletions(-) -- 2.7.0 diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c index c8717c1..87dd619 100644 --- a/net/wireless/wext-core.c +++ b/net/wireless/wext-core.c @@ -342,6 +342,39 @@ static const int compat_event_type_size[] = { /* IW event code */ +static void wireless_nlevent_flush(void) +{ + struct sk_buff *skb; + struct net *net; + + ASSERT_RTNL(); + + for_each_net(net) { + while ((skb = skb_dequeue(&net->wext_nlevents))) + rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, + GFP_KERNEL); + } +} + +static int wext_netdev_notifier_call(struct notifier_block *nb, + unsigned long state, void *ptr) +{ + /* + * When a netdev changes state in any way, flush all pending messages + * to avoid them going out in a strange order, e.g. RTM_NEWLINK after + * RTM_DELLINK, or with IFF_UP after without IFF_UP during dev_close() + * or similar - all of which could otherwise happen due to delays from + * schedule_work(). + */ + wireless_nlevent_flush(); + + return NOTIFY_OK; +} + +static struct notifier_block wext_netdev_notifier = { + .notifier_call = wext_netdev_notifier_call, +}; + static int __net_init wext_pernet_init(struct net *net) { skb_queue_head_init(&net->wext_nlevents); @@ -360,7 +393,12 @@ static struct pernet_operations wext_pernet_ops = { static int __init wireless_nlevent_init(void) { - return register_pernet_subsys(&wext_pernet_ops); + int err = register_pernet_subsys(&wext_pernet_ops); + + if (err) + return err; + + return register_netdevice_notifier(&wext_netdev_notifier); } subsys_initcall(wireless_nlevent_init); @@ -368,17 +406,8 @@ subsys_initcall(wireless_nlevent_init); /* Process events generated by the wireless layer or the driver. */ static void wireless_nlevent_process(struct work_struct *work) { - struct sk_buff *skb; - struct net *net; - rtnl_lock(); - - for_each_net(net) { - while ((skb = skb_dequeue(&net->wext_nlevents))) - rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, - GFP_KERNEL); - } - + wireless_nlevent_flush(); rtnl_unlock(); }