rate_ctr_group_alloc() may return NULL if a rate counter group name is not up to specifications; make sure all callers handle that.
At least libosmo-mgcp/mgcp_protocol.c has various invocations of rate_ctr_group_alloc() that ignore the possibility that the name might be wrong and the function would return NULL then.
There should be checks for each invocation; if we some day choose to change the names and/or the rules for names, the code should warn about it instead of segfaulting randomly.
grep for rate_ctr_group_alloc() in the code base and make sure each caller can handle a NULL return value in a sane way.
(related: the discussion at https://gerrit.osmocom.org/c/osmo-mgw/+/11521/4/src/libosmo-mgcp/mgcp_protocol.c#1546 )