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Add patches to fix suprious NEWLINK netlink messages (rhbz 1302037)

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Josh Boyer 2016-01-28 15:01:43 -05:00
parent 867ae5556f
commit 5befe5453f
3 changed files with 210 additions and 0 deletions
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83
cfg80211-wext-fix-message-ordering.patch Normal file
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@ -0,0 +1,83 @@
From ae47d3756cfb9f55edac25fccbebe0a4bf1cbf1e Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 27 Jan 2016 13:41:35 +0100
Subject: [PATCH 2/2] cfg80211/wext: fix message ordering
Since cfg80211 frequently takes actions from its netdev notifier
call, wireless extensions messages could still be ordered badly
since the wext netdev notifier, since wext is built into the
kernel, runs before the cfg80211 netdev notifier. For example,
the following can happen:
5: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default
link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff
5: wlan1: <BROADCAST,MULTICAST,UP>
link/ether
when setting the interface down causes the wext message.
To also fix this, export the wireless_nlevent_flush() function
and also call it from the cfg80211 notifier.
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
include/net/iw_handler.h | 6 ++++++
net/wireless/core.c | 2 ++
net/wireless/wext-core.c | 3 ++-
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/include/net/iw_handler.h b/include/net/iw_handler.h
index 8f81bbbc38fc..8a3ec3955f20 100644
--- a/include/net/iw_handler.h
+++ b/include/net/iw_handler.h
@@ -439,6 +439,12 @@ int dev_get_wireless_info(char *buffer, char **start, off_t offset, int length);
/* Send a single event to user space */
void wireless_send_event(struct net_device *dev, unsigned int cmd,
union iwreq_data *wrqu, const char *extra);
+#ifdef CONFIG_WEXT_CORE
+/* flush all previous wext events - if work is done from netdev notifiers */
+void wireless_nlevent_flush(void);
+#else
+static void wireless_nlevent_flush(void) {}
+#endif
/* We may need a function to send a stream of events to user space.
* More on that later... */
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 3893409dee95..335830eccb01 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -1143,6 +1143,8 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
return NOTIFY_DONE;
}
+ wireless_nlevent_flush();
+
return NOTIFY_OK;
}
diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
index 5f429637efff..abdfcb5f3e48 100644
--- a/net/wireless/wext-core.c
+++ b/net/wireless/wext-core.c
@@ -342,7 +342,7 @@ static const int compat_event_type_size[] = {
/* IW event code */
-static void wireless_nlevent_flush(void)
+void wireless_nlevent_flush(void)
{
struct sk_buff *skb;
struct net *net;
@@ -355,6 +355,7 @@ static void wireless_nlevent_flush(void)
GFP_KERNEL);
}
}
+EXPORT_SYMBOL_GPL(wireless_nlevent_flush);
static int wext_netdev_notifier_call(struct notifier_block *nb,
unsigned long state, void *ptr)
--
2.5.0

7
kernel.spec
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@ -608,6 +608,10 @@ Patch641: disable-CONFIG_EXPERT-for-ZONE_DMA.patch
#rhbz 1301099
Patch642: KEYS-only-apply-KEY_FLAG_KEEP-to-a-key-if-a-parent.patch
#rhbz 1302037
Patch644: wext-fix-message-delay-ordering.patch
Patch645: cfg80211-wext-fix-message-ordering.patch
# END OF PATCH DEFINITIONS
%endif
@ -2053,6 +2057,9 @@ fi
#
#
%changelog
* Thu Jan 28 2016 Josh Boyer <jwboyer@fedoraproject.org>
- Add patches to fix suprious NEWLINK netlink messages (rhbz 1302037)
* Thu Jan 28 2016 Justin M. Forbes <jforbes@fedoraproject.org> - 4.5.0-0.rc1.git1.1
- Linux v4.5-rc1-28-g03c21cb
- Reenable debugging options.

120
wext-fix-message-delay-ordering.patch Normal file
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@ -0,0 +1,120 @@
From 699a8adb3553e2a7fb5930e1f962e2ef6d6f4104 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 27 Jan 2016 13:41:34 +0100
Subject: [PATCH 1/2] wext: fix message delay/ordering
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: <BROADCAST,MULTICAST> 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: <BROADCAST,MULTICAST> 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: <BROADCAST,MULTICAST,UP>
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.
Cc: stable@vger.kernel.org
Reported-by: Beniamino Galvani <bgalvani@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
net/wireless/wext-core.c | 49 ++++++++++++++++++++++++++++++++++++++----------
1 file changed, 39 insertions(+), 10 deletions(-)
diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
index c8717c1d082e..5f429637efff 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);
@@ -360,6 +393,11 @@ static struct pernet_operations wext_pernet_ops = {
static int __init wireless_nlevent_init(void)
{
+ int err = register_netdevice_notifier(&wext_netdev_notifier);
+
+ if (err)
+ return err;
+
return register_pernet_subsys(&wext_pernet_ops);
}
@@ -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();
}
--
2.5.0