From the trace it looks like, few threads are in galera_pre_commit, 2-3 in MDL_context::acquire_lock and and 3 in galera::ReplicatorSMM::to_isolation_begin. Since this lasts for more than 600s, it looks like a deadlock among the threads.
From the trace it looks like, few threads are in galera_pre_commit, 2-3 in MDL_context: :acquire_ lock and and 3 in galera: :ReplicatorSMM: :to_isolation_ begin. Since this lasts for more than 600s, it looks like a deadlock among the threads.