dbus errors, frequent roaming and unstable connectivity

Bug #1879087 reported by Thomas M Steenholdt on 2020-05-16
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
wpa (Ubuntu)
High
Unassigned
Focal
High
Unassigned

Bug Description

* Impact
extra roaming events are been generated

* Test case
check the output of `journalctl -lu wpa_supplicant`, it should have warnings
dbus: wpa_dbus_property_changed: no property RoamComplete in object /fi/w1/wpa_supplicant1/Interfaces/3

the roaming events should not be too frequent

* Regression potential
check that wifi connection keep working correctly

--------------

When using this version of wpa_supplicant with my company WPA2-Enterprise wireless setup, I'm experiencing far too frequent roaming events (even when not moving around) accompanied by hiccups in connectivity. I also see these messages in the wpa_supplicant log:

dbus: wpa_dbus_property_changed: no property RoamComplete in object /fi/w1/wpa_supplicant1/Interfaces/3
dbus: wpa_dbus_property_changed: no property RoamTime in object /fi/w1/wpa_supplicant1/Interfaces/3
dbus: wpa_dbus_property_changed: no property SessionLength in object /fi/w1/wpa_supplicant1/Interfaces/3

Having done a little research, at least the dbus errors seem to be fixed by this commit upstream:

https://w1.fi/cgit/hostap/commit/wpa_supplicant/dbus/dbus_new.c?id=23d87687c2428f3b94865580b0d33e05c03e6756

So I built a version of wpa_supplicant including this particular patch and installed on my machine. Apart from solving the dbus errors completely, it seems to have had a positive impact on the frequent roaming and unstable connectivity as well (I've run for a day with no burst of roaming events at all, where they used to happen every few minutes most of the time.)

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: wpasupplicant 2:2.9-1ubuntu4
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: GNOME
Date: Sat May 16 16:47:27 2020
InstallationDate: Installed on 2020-05-12 (4 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: wpa
UpgradeStatus: No upgrade log present (probably fresh install)

Thomas M Steenholdt (tmus) wrote :
Sebastien Bacher (seb128) wrote :

Thank you for your bug report and indicating this patch, sounds like an useful fix to cherry pick indeed

Changed in wpa (Ubuntu):
importance: Undecided → High
status: New → Fix Committed
Sebastien Bacher (seb128) wrote :

I've uploaded the fix and a stable update, improving the description for a better testcase would be useful though if you have an idea how to trigger the issue and test the fix

description: updated
Thomas M Steenholdt (tmus) wrote :

Thank you for taking care of this so swiftly.

I don't believe I have much to add to the test-case. From testing locally I can see that the warnings disappear from the log and the connection _seems_ more stable. I underscore _seems_ because I have not been able to figure out which other parts of the system are actually using these particular dbus messages, if any. If nobody is actually using these, the perceived improvement could be placebo.

I will keep testing though, because I've generally been struggling with a stable wifi connection on 20.04.

Thanks again.

Steve Langasek (vorlon) wrote :

> the roaming events should not be too frequent

That's not an objective test case. Please provide a clear test case that anyone should be able to follow to determine whether this bug has been fixed.

description: updated
Changed in wpa (Ubuntu Focal):
status: New → Incomplete
Mathew Hodson (mhodson) on 2020-05-23
Changed in wpa (Ubuntu Focal):
importance: Undecided → High
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package wpa - 2:2.9-1ubuntu7

---------------
wpa (2:2.9-1ubuntu7) groovy; urgency=medium

  * debian/patches/git_roaming_interface.patch:
    - backport upstream fix 'dbus: Move roam metrics to the correct
      interface', should reduces the number of events (lp: #1879087)

 -- Sebastien Bacher <email address hidden> Wed, 20 May 2020 19:03:27 +0200

Changed in wpa (Ubuntu):
status: Fix Committed → Fix Released
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