[systemd-devel] libudev monitor sporadic fail

[John Ernberg]

Hi

I hope this is the correct mailing list in which to ask this, otherwise 
I apologize and please direct me to where I shall ask this question.

I have asked this on the oFono mailing list but it has gone unanswered, 
so I am trying my luck here, hoping that someone might be able to point 
me to what to do next.

I am running an embedded system with systemd 211 (and udev).
This system runs oFono which is started by systemd.
oFono uses libudev and creates an udev monitor from netlink to detect 
modems on for example USB.
The issue I am having is that sometimes the setup of this monitor fails, 
resulting in that oFono will not detect any modem.

The modems were enumerated in the kernel correctly, which means I could 
see them using for example 'lsusb', and could talk AT with them manually.
After some debugging I traced the problem to that the monitor setup 
failed in oFono.
It seems that the glib IOChannel wrap around the udev monitor fd 
receives some sort of error / HUP signal and shuts down.
I have not managed to figure out what's being received due to how 
sporadically this happens, but I would like to fix it.

When checking on google it seems that oFono's implementation of how to 
handle an udev monitor fd is correct, so I wonder what might be going on 
and where the cause is for this failure may reside.
Does anyone have any clue what I should be looking for in order to 
figure out why this happens?

I am not able to boot this system in a VM environment.

Thank you very much in advance and best regards // John Ernberg