no sound via mobile network call Last days I have strange behaviour:

No incoming/outgoing sound during calls via mobile network.
After reboot a couple of calls work find and then sound just vanishes.

Viber/skype calls are working just fine.

No external or suspicious applications were installed (actually no new applications were installed for the last months)

dmesg shows nothing related to audio system.

How I can fix the issue? What information I should dig in my phone?

I've Nexus 4 with cyanogenmod (20141205-nightly-mako) [actually before was 20141105-nightly-make and this thing started after almost a month of usage, then I tried to update, but it didn't help].
There seems to be a pretty bad bug that affects Cyanogenmod right now

https://jira.cyanogenmod.org/browse/CYAN-5728

A workaround provided in the thread:

from a root terminal (adb root/adb shell or terminal emulator/su)

pm disable com.google.android.gms/com.google.android.gms.checkin.CheckinService