Your message dated Sun, 14 Sep 2025 11:44:36 +0000
with message-id <[email protected]>
and subject line Bug#1109272: fixed in python-dbusmock 0.37.0-1
has caused the Debian Bug report #1109272,
regarding python3-dbusmock: Possible race condition when setting up a private
mock system bus
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
1109272: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1109272
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: python3-dbusmock
Version: 0.34.3-1
Severity: important
Tags: unreproducible
Control: affects -1 + src:mutter
User: [email protected]
Usertags: flaky
After my recent upload of mutter 48.4-2 to unstable, its autopkgtest
failed on ppc64el. At least one of the failures (monitor-unit.test) had
this logged, and the test subsequently timed out:
https://ci.debian.net/packages/m/mutter/testing/ppc64el/62167381/
https://ci.debian.net/data/autopkgtest/testing/ppc64el/m/mutter/62167381/artifacts.tar.gz
> Starting mocked services...
> Traceback (most recent call last):
> File
> "/usr/libexec/installed-tests/mutter-16/mutter-installed-dbus-session.py",
> line 22, in <module>
> result = meta_run(MutterDBusRunner,
> extra_env=extra_env,
> setup_argparse=add_extra_args,
> handle_argparse=handle_extra_args)
> File "/usr/share/mutter-16/tests/mutter_dbusrunner.py", line 325, in
> meta_run
> return run_test_mocked(klass, rest,
> launch=args.launch,
> bind_sockets=True,
> extra_env=extra_env)
> File "/usr/share/mutter-16/tests/mutter_dbusrunner.py", line 271, in
> run_test_mocked
> klass.setUpClass(launch=launch,
> ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
> bind_sockets=bind_sockets)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> File "/usr/share/mutter-16/tests/mutter_dbusrunner.py", line 67, in
> setUpClass
> (klass.mocks_manager, klass.mock_obj) = klass.start_from_local_template(
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
> 'meta-mocks-manager', {'templates-dir': klass.__get_templates_dir()})
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File "/usr/share/mutter-16/tests/mutter_dbusrunner.py", line 119, in
> start_from_local_template
> return klass.start_from_template(template, params, system_bus=system_bus)
> ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> File "/usr/share/mutter-16/tests/mutter_dbusrunner.py", line 108, in
> start_from_template
> klass.spawn_server_template(template,
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
> params,
> ^^^^^^^
> get_subprocess_stdout(),
> ^^^^^^^^^^^^^^^^^^^^^^^^
> system_bus=system_bus)
> ^^^^^^^^^^^^^^^^^^^^^^
> File "/usr/lib/python3/dist-packages/dbusmock/testcase.py", line 438, in
> spawn_server_template
> server = SpawnedMock.spawn_with_template(template, parameters, bustype,
> stdout, stderr=None)
> File "/usr/lib/python3/dist-packages/dbusmock/testcase.py", line 614, in
> spawn_with_template
> server = SpawnedMock.spawn_for_name(module.BUS_NAME, module.MAIN_OBJ,
> interface_name, bustype, stdout, stderr)
> File "/usr/lib/python3/dist-packages/dbusmock/testcase.py", line 557, in
> spawn_for_name
> bus = bustype.get_connection()
> File "/usr/lib/python3/dist-packages/dbusmock/testcase.py", line 58, in
> get_connection
> return dbus.bus.BusConnection(val)
> ~~~~~~~~~~~~~~~~~~~~~~^^^^^
> File "/usr/lib/python3/dist-packages/dbus/bus.py", line 120, in __new__
> bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
> dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoServer: Failed to
> connect to socket /tmp/dbusmock_data_nh20oy7q/system_bus.socket: Connection
> refused
I think this indicates that dbusmock started a dbus-daemon to be the
mock system bus, but then attempted to connect to the socket before the
dbus-daemon was listening on that socket. There is a (very) short window
of time between bind() and listen() during which connection attempts
will fail.
If my theory is correct, this will be difficult to reproduce on-demand:
you would have to be very unlucky with how processes get scheduled.
dbus-daemon provides two mechanisms to avoid this race condition window:
1. If you run it with --print-address=FD and/or --print-pid=FD, and then
read until EOF on the given file descriptor(s) (often 1 for stdout, but
may be any writeable fd), then the read will block until after the
dbus-daemon has called listen(), closing the race condition. This is how
dbus-run-session(1) is implemented.
2. Or, if you run it with --fork, it will "daemonize" and the foreground
process will not exit until the background process has called listen().
This is how dbus-launch(1) is implemented.
I would recommend (1.), blocking on a read() until --print-address or
--print-pid has produced its result (you can ignore the printed address
or pid if you don't need it). For example test/gvfs-test in
gvfs_1.57.2-2 and tests/test-dconf.py in dconf_0.40.0-5 both do this, in
a way that should be compatible with dbusmock's use of subprocess.Popen.
Thanks,
smcv
--- End Message ---
--- Begin Message ---
Source: python-dbusmock
Source-Version: 0.37.0-1
Done: Martin Pitt <[email protected]>
We believe that the bug you reported is fixed in the latest version of
python-dbusmock, which is due to be installed in the Debian FTP archive.
A summary of the changes between this version and the previous one is
attached.
Thank you for reporting the bug, which will now be closed. If you
have further comments please address them to [email protected],
and the maintainer will reopen the bug report if appropriate.
Debian distribution maintenance software
pp.
Martin Pitt <[email protected]> (supplier of updated python-dbusmock package)
(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing [email protected])
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
Format: 1.8
Date: Sun, 14 Sep 2025 11:27:52 +0200
Source: python-dbusmock
Architecture: source
Version: 0.37.0-1
Distribution: unstable
Urgency: medium
Maintainer: Debian Python Team <[email protected]>
Changed-By: Martin Pitt <[email protected]>
Closes: 1109272
Changes:
python-dbusmock (0.37.0-1) unstable; urgency=medium
.
* New upstream release:
- templates: Drop iio-sensors-proxy (See
https://github.com/martinpitt/python-dbusmock/issues/241)
- DBusTestCase: Drop obsolete {start,stop}_dbus() methods
- Fix dbus-daemon startup race condition (Closes: #1109272)
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