Growing memory consumption with 2.2.17

We have just upgraded from 2.0.2 to 2.2.17 and have spotted an immediate growing memory consumption. On 2.0.2 it was constant, around 400MB (instance running for about two years nonstop):

But as soon as we switched over to 2.2.17, the consumption started rising and seems to be rising until it OOM killer kicks in:

There has been no change in traffic, type of traffic, amount of clients, connections, amount and types of queries etc. We're running readwritesplit service with slave_selection_criteria=LEAST_CURRENT_OPERATIONS router options and galeramon, configuration settings unchanged since 2.0.2.