ModemManager Process is shutting down

ratnavel nsratnavel at
Fri Oct 16 09:25:27 UTC 2020

Before Logs:

ModemManager[104]: <debug> Signal strength (umts): -79 dBm
ModemManager[104]: <debug> Signal strength: -79 dBm --> 55%
ModemManager[104]: <debug> Modem /org/freedesktop/ModemManager1/Modem/1:
access technology changed (unknown -> umts)
ModemManager[104]: <debug> Modem /org/freedesktop/ModemManager1/Modem/1:
signal quality updated (55)
ModemManager[104]: <debug> Periodic signal quality checks scheduled in 30s
ModemManager[104]: <debug> Running registration checks (CS: 'yes', PS:
'yes', EPS: 'yes')
ModemManager[104]: [/dev/cdc-wdm0] sent message...#012<<<<<< RAW:#012<<<<<<
  length = 13#012<<<<<<   data   = 01:0C:00:00:03:03:00:1B:00:24:00:00:00
 ModemManager[104]: [/dev/cdc-wdm0] sent generic request
(translated)...#012<<<<<< QMUX:#012<<<<<<   length  = 12#012<<<<<<   flags
  = 0x00#012<<<<<<   service = "nas"#012<<<<<<   client  = 3#012<<<<<<
QMI:#012<<<<<<   flags       = "none"#012<<<<<<   transaction =
27#012<<<<<<   tlv_length  = 0#012<<<<<<   message     = "Get Serving
System" (0x0024)
ModemManager[104]: <debug> building consolidated registration state: cs
'idle', ps 'unknown', eps 'unknown' --> 'idle'
ModemManager[104]: <info>  Modem /org/freedesktop/ModemManager1/Modem/0:
3GPP Registration state changed (unknown -> idle)
ModemManager[104]: <debug> building consolidated registration state: cs
'idle', ps 'idle', eps 'unknown' --> 'idle'
ModemManager[104]: <debug> building consolidated registration state: cs
'idle', ps 'idle', eps 'idle' --> 'idle'

dbus[1073]: [system] Rejected send message, 2 matched rules;
type="method_return", sender=":1.140" (uid=0 pid=104
comm="/usr/sbin/ModemManager  ") interface="(unset)" member="(unset)" error
name="(unset)" requested_reply="0" destination=":1.142" (uid=0 pid=240
comm="/usr/bin/ApplnManagerd  ")

After this :
No logs but  the ModemManager restarts, in fact there is a crash and the
core is dumped.
The ModemManager does restart after that and recovers.

Also this happens after the ModemReset in all cases.

On Fri, Oct 16, 2020 at 12:18 PM Aleksander Morgado <
aleksander at> wrote:

>> ModemManager 1.10.8 on Ubuntu 16.04.4 LTS.
>> Sierra Wireless EM74xx modem
>> I had a test where I set the APN as invalid in the modem.
>> After a few hours, the ModemManager daemon restarted owing to the
>> following error.
>> dbus[1001]: [system] Activating via systemd: service
>> name='org.freedesktop.ModemManager1'
>> unit='dbus-org.freedesktop.ModemManager1.service'
>> dbus[1001]: [system] Activation via systemd failed for unit
>> 'dbus-org.freedesktop.ModemManager1.service': Unit
>> dbus-org.freedesktop.ModemManager1.service not found.
>> Though the dbus file is present.
>> Can you let me know on what could possibly be the issue here ?
> Ie that message a real indication of MM restarting?
> Is MM kept stopped? Or is it started at some point?
> I think we need more context, more logs before and after, to try to
> understand that better.
> I think those messages just mean that someone attempted to start MM via
> DBus activation, and IIRC that is not something enabled by default when
> using systemd. I.e. it is systemd itself the one restarting MM if it
> crashed, not the MM users via DBus activation.
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