High memory usage by ModemManager

[Aleksander Morgado]

>
>>
>> 5. We have updated ModemManager to 1.12.2 and libqmi to 1.24.2
>>
>> The problem we see with ModemManager is that it is slowly using more and more memory while using the QMI interface of our Quectel BG96 modem.
>
>
> I have another report from a company that I work with that shows the same symptoms. I don't have any clear picture yet of what the issue could be, because none of my valgrind tests have shown any relevant memory leak. If you could get a proper valgrind log we could give it a look.
>

I found a reasonably big memory leak (MMPortQmi unref missing)
introduced in 1.12.2 in the QMI bearer connection logic which could
happen when the modem is abruptly reseted or unplugged from the system
while being connected. The fix is here:
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/merge_requests/242/diffs?commit_id=29e64f59af44a23d929107fb4896d10f44b4dfd7
although those lines were then updated to simplify dispose() as
follows: https://gitlab.freedesktop.org/mobile-broadband/ModemManager/merge_requests/242/diffs?commit_id=33b1962615febea5c34f0fbddc24eab8de5a9c7a

I'm not totally sure if the leak happens under some other scenario,
but I can reliably reproduce it just by unplugging a QMI modem while
being connected. Do you think this issue could be the cause of your
high memory usage?

I'm still doing memleak checks, but will probably release a new 1.12.x
update sometime soon, including these fixes.

-- 
Aleksander
https://aleksander.es