I'm using mysqld_multi to run many instances of mysql on the same machine. Each instance is in a 3 node Galera cluster, so there are three physical boxes running a dozen instances each comprising a dozen clusters.
One instance will always crash given enough time. Sometimes it's less than a day, sometimes it runs for a week, but it always eventually crashes. That instance is no longer in a cluster as I'm trying to troubleshoot it but Galera is still loaded. I've tried not loading the provider as well with the same results.
It is just replicating and not serving any real queries/traffic. I haven't been able to narrow it down to a specific table or query unfortunately. Today was the first time I had another instance crash ever (it's been running for several months). What does stand out though, is that it's always this host that is actually being a slave that crashes. I have not had the other instances of the cluster crash when it was clustered. It's always the one acting as a slave. Someone on #maria IRC mentioned deadlocks with replication and show slave status but I can't confirm anything.
I was encouraged to submit a report and include my core dump traces. The 3rd dump labelled mysql-13 is the new crash I was referring to. The other two are from the same instance that has been repeatedly crashing. When it does crash, I rebuild the data fresh. I have the same data on a host that is running mariadb-server-5.5 (not galera) and has never crashed. It's actually what I use to rebuild/reseed this system from when it crashes.