<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/wireless, branch v4.4.73</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>nl80211: fix dumpit error path RTNL deadlocks</title>
<updated>2017-03-30T07:35:18+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2017-03-15T13:26:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=74c8dd066cc06da0a7ee1a4da0ba565e3536a53a'/>
<id>74c8dd066cc06da0a7ee1a4da0ba565e3536a53a</id>
<content type='text'>
commit ea90e0dc8cecba6359b481e24d9c37160f6f524f upstream.

Sowmini pointed out Dmitry's RTNL deadlock report to me, and it turns out
to be perfectly accurate - there are various error paths that miss unlock
of the RTNL.

To fix those, change the locking a bit to not be conditional in all those
nl80211_prepare_*_dump() functions, but make those require the RTNL to
start with, and fix the buggy error paths. This also let me use sparse
(by appropriately overriding the rtnl_lock/rtnl_unlock functions) to
validate the changes.

Reported-by: Sowmini Varadhan &lt;sowmini.varadhan@oracle.com&gt;
Reported-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ea90e0dc8cecba6359b481e24d9c37160f6f524f upstream.

Sowmini pointed out Dmitry's RTNL deadlock report to me, and it turns out
to be perfectly accurate - there are various error paths that miss unlock
of the RTNL.

To fix those, change the locking a bit to not be conditional in all those
nl80211_prepare_*_dump() functions, but make those require the RTNL to
start with, and fix the buggy error paths. This also let me use sparse
(by appropriately overriding the rtnl_lock/rtnl_unlock functions) to
validate the changes.

Reported-by: Sowmini Varadhan &lt;sowmini.varadhan@oracle.com&gt;
Reported-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>nl80211: fix sched scan netlink socket owner destruction</title>
<updated>2017-01-19T19:17:20+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2017-01-05T09:57:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4a1ecf37a59f8e59e1eef75dfe885462ceda5ec4'/>
<id>4a1ecf37a59f8e59e1eef75dfe885462ceda5ec4</id>
<content type='text'>
commit 753aacfd2e95df6a0caf23c03dc309020765bea9 upstream.

A single netlink socket might own multiple interfaces *and* a
scheduled scan request (which might belong to another interface),
so when it goes away both may need to be destroyed.

Remove the schedule_scan_stop indirection to fix this - it's only
needed for interface destruction because of the way this works
right now, with a single work taking care of all interfaces.

Fixes: 93a1e86ce10e4 ("nl80211: Stop scheduled scan if netlink client disappears")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 753aacfd2e95df6a0caf23c03dc309020765bea9 upstream.

A single netlink socket might own multiple interfaces *and* a
scheduled scan request (which might belong to another interface),
so when it goes away both may need to be destroyed.

Remove the schedule_scan_stop indirection to fix this - it's only
needed for interface destruction because of the way this works
right now, with a single work taking care of all interfaces.

Fixes: 93a1e86ce10e4 ("nl80211: Stop scheduled scan if netlink client disappears")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>cfg80211/mac80211: fix BSS leaks when abandoning assoc attempts</title>
<updated>2017-01-09T07:07:42+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-12-08T16:22:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b63929e8e130a97303dfacc28f558262f0605708'/>
<id>b63929e8e130a97303dfacc28f558262f0605708</id>
<content type='text'>
commit e6f462df9acd2a3295e5d34eb29e2823220cf129 upstream.

When mac80211 abandons an association attempt, it may free
all the data structures, but inform cfg80211 and userspace
about it only by sending the deauth frame it received, in
which case cfg80211 has no link to the BSS struct that was
used and will not cfg80211_unhold_bss() it.

Fix this by providing a way to inform cfg80211 of this with
the BSS entry passed, so that it can clean up properly, and
use this ability in the appropriate places in mac80211.

This isn't ideal: some code is more or less duplicated and
tracing is missing. However, it's a fairly small change and
it's thus easier to backport - cleanups can come later.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e6f462df9acd2a3295e5d34eb29e2823220cf129 upstream.

When mac80211 abandons an association attempt, it may free
all the data structures, but inform cfg80211 and userspace
about it only by sending the deauth frame it received, in
which case cfg80211 has no link to the BSS struct that was
used and will not cfg80211_unhold_bss() it.

Fix this by providing a way to inform cfg80211 of this with
the BSS entry passed, so that it can clean up properly, and
use this ability in the appropriate places in mac80211.

This isn't ideal: some code is more or less duplicated and
tracing is missing. However, it's a fairly small change and
it's thus easier to backport - cleanups can come later.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>cfg80211: limit scan results cache size</title>
<updated>2016-12-02T08:09:01+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-11-15T11:05:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8316338a201b3cd57605fc6c4ea0d9ce8a0d35c0'/>
<id>8316338a201b3cd57605fc6c4ea0d9ce8a0d35c0</id>
<content type='text'>
commit 9853a55ef1bb66d7411136046060bbfb69c714fa upstream.

It's possible to make scanning consume almost arbitrary amounts
of memory, e.g. by sending beacon frames with random BSSIDs at
high rates while somebody is scanning.

Limit the number of BSS table entries we're willing to cache to
1000, limiting maximum memory usage to maybe 4-5MB, but lower
in practice - that would be the case for having both full-sized
beacon and probe response frames for each entry; this seems not
possible in practice, so a limit of 1000 entries will likely be
closer to 0.5 MB.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 9853a55ef1bb66d7411136046060bbfb69c714fa upstream.

It's possible to make scanning consume almost arbitrary amounts
of memory, e.g. by sending beacon frames with random BSSIDs at
high rates while somebody is scanning.

Limit the number of BSS table entries we're willing to cache to
1000, limiting maximum memory usage to maybe 4-5MB, but lower
in practice - that would be the case for having both full-sized
beacon and probe response frames for each entry; this seems not
possible in practice, so a limit of 1000 entries will likely be
closer to 0.5 MB.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>nl80211: validate number of probe response CSA counters</title>
<updated>2016-09-30T08:18:38+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-09-13T13:53:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f1b01a340b2b4bc18e90fe5e5a3e99d7d3cffe32'/>
<id>f1b01a340b2b4bc18e90fe5e5a3e99d7d3cffe32</id>
<content type='text'>
commit ad5987b47e96a0fb6d13fea250e936aed000093c upstream.

Due to an apparent copy/paste bug, the number of counters for the
beacon configuration were checked twice, instead of checking the
number of probe response counters. Fix this to check the number of
probe response counters before parsing those.

Fixes: 9a774c78e211 ("cfg80211: Support multiple CSA counters")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit ad5987b47e96a0fb6d13fea250e936aed000093c upstream.

Due to an apparent copy/paste bug, the number of counters for the
beacon configuration were checked twice, instead of checking the
number of probe response counters. Fix this to check the number of
probe response counters before parsing those.

Fixes: 9a774c78e211 ("cfg80211: Support multiple CSA counters")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel"</title>
<updated>2016-09-24T08:07:41+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-08-08T06:45:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7f71eec92e1ed8eba4c71c8bc205cfb54f2a13cf'/>
<id>7f71eec92e1ed8eba4c71c8bc205cfb54f2a13cf</id>
<content type='text'>
commit 4d0bd46a4d55383f7b925e6cf7865a77e0f0e020 upstream.

This reverts commit 3d5fdff46c4b2b9534fa2f9fc78e90a48e0ff724.

Ben Hutchings pointed out that the commit isn't safe since it assumes
that the structure used by the driver is iw_point, when in fact there's
no way to know about that.

Fortunately, the only driver in the tree that ever runs this code path
is the wilc1000 staging driver, so it doesn't really matter.

Clearly I should have investigated this better before applying, sorry.

Reported-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Fixes: 3d5fdff46c4b ("wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4d0bd46a4d55383f7b925e6cf7865a77e0f0e020 upstream.

This reverts commit 3d5fdff46c4b2b9534fa2f9fc78e90a48e0ff724.

Ben Hutchings pointed out that the commit isn't safe since it assumes
that the structure used by the driver is iw_point, when in fact there's
no way to know about that.

Fortunately, the only driver in the tree that ever runs this code path
is the wilc1000 staging driver, so it doesn't really matter.

Clearly I should have investigated this better before applying, sorry.

Reported-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Fixes: 3d5fdff46c4b ("wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel")
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel</title>
<updated>2016-06-24T17:18:20+00:00</updated>
<author>
<name>Prasun Maiti</name>
<email>prasunmaiti87@gmail.com</email>
</author>
<published>2016-06-06T14:34:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=47648b5862145187fc8273de0b5330bb9968feb3'/>
<id>47648b5862145187fc8273de0b5330bb9968feb3</id>
<content type='text'>
commit 3d5fdff46c4b2b9534fa2f9fc78e90a48e0ff724 upstream.

iwpriv app uses iw_point structure to send data to Kernel. The iw_point
structure holds a pointer. For compatibility Kernel converts the pointer
as required for WEXT IOCTLs (SIOCIWFIRST to SIOCIWLAST). Some drivers
may use iw_handler_def.private_args to populate iwpriv commands instead
of iw_handler_def.private. For those case, the IOCTLs from
SIOCIWFIRSTPRIV to SIOCIWLASTPRIV will follow the path ndo_do_ioctl().
Accordingly when the filled up iw_point structure comes from 32 bit
iwpriv to 64 bit Kernel, Kernel will not convert the pointer and sends
it to driver. So, the driver may get the invalid data.

The pointer conversion for the IOCTLs (SIOCIWFIRSTPRIV to
SIOCIWLASTPRIV), which follow the path ndo_do_ioctl(), is mandatory.
This patch adds pointer conversion from 32 bit to 64 bit and vice versa,
if the ioctl comes from 32 bit iwpriv to 64 bit Kernel.

Signed-off-by: Prasun Maiti &lt;prasunmaiti87@gmail.com&gt;
Signed-off-by: Ujjal Roy &lt;royujjal@gmail.com&gt;
Tested-by: Dibyajyoti Ghosh &lt;dibyajyotig@gmail.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3d5fdff46c4b2b9534fa2f9fc78e90a48e0ff724 upstream.

iwpriv app uses iw_point structure to send data to Kernel. The iw_point
structure holds a pointer. For compatibility Kernel converts the pointer
as required for WEXT IOCTLs (SIOCIWFIRST to SIOCIWLAST). Some drivers
may use iw_handler_def.private_args to populate iwpriv commands instead
of iw_handler_def.private. For those case, the IOCTLs from
SIOCIWFIRSTPRIV to SIOCIWLASTPRIV will follow the path ndo_do_ioctl().
Accordingly when the filled up iw_point structure comes from 32 bit
iwpriv to 64 bit Kernel, Kernel will not convert the pointer and sends
it to driver. So, the driver may get the invalid data.

The pointer conversion for the IOCTLs (SIOCIWFIRSTPRIV to
SIOCIWLASTPRIV), which follow the path ndo_do_ioctl(), is mandatory.
This patch adds pointer conversion from 32 bit to 64 bit and vice versa,
if the ioctl comes from 32 bit iwpriv to 64 bit Kernel.

Signed-off-by: Prasun Maiti &lt;prasunmaiti87@gmail.com&gt;
Signed-off-by: Ujjal Roy &lt;royujjal@gmail.com&gt;
Tested-by: Dibyajyoti Ghosh &lt;dibyajyotig@gmail.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>nl80211: check netlink protocol in socket release notification</title>
<updated>2016-05-04T21:48:45+00:00</updated>
<author>
<name>Dmitry Ivanov</name>
<email>dmitrijs.ivanovs@ubnt.com</email>
</author>
<published>2016-04-06T14:23:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=56b8eaa38b04f147a6b825a73a31b826b6051604'/>
<id>56b8eaa38b04f147a6b825a73a31b826b6051604</id>
<content type='text'>
commit 8f815cdde3e550e10c2736990d791f60c2ce43eb upstream.

A non-privileged user can create a netlink socket with the same port_id as
used by an existing open nl80211 netlink socket (e.g. as used by a hostapd
process) with a different protocol number.

Closing this socket will then lead to the notification going to nl80211's
socket release notification handler, and possibly cause an action such as
removing a virtual interface.

Fix this issue by checking that the netlink protocol is NETLINK_GENERIC.
Since generic netlink has no notifier chain of its own, we can't fix the
problem more generically.

Fixes: 026331c4d9b5 ("cfg80211/mac80211: allow registering for and sending action frames")
Signed-off-by: Dmitry Ivanov &lt;dima@ubnt.com&gt;
[rewrite commit message]
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8f815cdde3e550e10c2736990d791f60c2ce43eb upstream.

A non-privileged user can create a netlink socket with the same port_id as
used by an existing open nl80211 netlink socket (e.g. as used by a hostapd
process) with a different protocol number.

Closing this socket will then lead to the notification going to nl80211's
socket release notification handler, and possibly cause an action such as
removing a virtual interface.

Fix this issue by checking that the netlink protocol is NETLINK_GENERIC.
Since generic netlink has no notifier chain of its own, we can't fix the
problem more generically.

Fixes: 026331c4d9b5 ("cfg80211/mac80211: allow registering for and sending action frames")
Signed-off-by: Dmitry Ivanov &lt;dima@ubnt.com&gt;
[rewrite commit message]
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>cfg80211/wext: fix message ordering</title>
<updated>2016-03-16T15:42:59+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-01-27T12:29:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bfed1f518daa78346fb3f118367212ad352b2f07'/>
<id>bfed1f518daa78346fb3f118367212ad352b2f07</id>
<content type='text'>
commit cb150b9d23be6ee7f3a0fff29784f1c5b5ac514d upstream.

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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST,UP&gt;
    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.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cb150b9d23be6ee7f3a0fff29784f1c5b5ac514d upstream.

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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST,UP&gt;
    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.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>wext: fix message delay/ordering</title>
<updated>2016-03-16T15:42:59+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2016-01-27T11:37:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=176e879db6c9ecd702b4deac2bc419c030afd630'/>
<id>176e879db6c9ecd702b4deac2bc419c030afd630</id>
<content type='text'>
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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST,UP&gt;
    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 &lt;bgalvani@redhat.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
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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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST&gt; 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: &lt;BROADCAST,MULTICAST,UP&gt;
    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 &lt;bgalvani@redhat.com&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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