PACCH pagings are omitted
During 33c3 I saw a segfault in the PCU that was most probably introduced by da7250ad2c1cd
My fix wasn't really an improvement, because it caused omittance of pagings that should happen in the lower half of sched_select_ctrl_msg(): b78a4a6dfef
The impact is that CS becomes highly unreliable when GPRS is in use, because it sends pagings via the PCU in case of active GPRS -- which are currently dropped.
I'm fairly sure this patch would fix it: https://gerrit.osmocom.org/2420 -- but then again I was just as sure last time and might be wrong again.
More details are available in the comments to the gerrit patch. At this point I'm mostly not sure whether a non-NULL TBF in case of a NULL msg needs some handling.