ceph version 0.61.9-12-ga5d0178 (a5d0178088973fdc70df692b0d8740aba40164db)
 1: /usr/bin/ceph-mon() [0x6954af]
 2: (pg_pool_t::remove_unmanaged_snap(snapid_t)+0x52) [0x68f2a2]
 3: (OSDMonitor::prepare_pool_op(MPoolOp*)+0x935) [0x503785]
 4: (OSDMonitor::prepare_update(PaxosServiceMessage*)+0x19b) [0x50d8cb]
 5: (PaxosService::dispatch(PaxosServiceMessage*)+0x946) [0x4e4796]
 6: (Monitor::_ms_dispatch(Message*)+0xb3b) [0x4b156b]
 7: (Monitor::ms_dispatch(Message*)+0x32) [0x4cd022]
 8: (DispatchQueue::entry()+0x3f1) [0x6aa7e1]
 9: (DispatchQueue::DispatchThread::entry()+0xd) [0x6381ed]
 10: (()+0x7e9a) [0x7f745bc7fe9a]
 11: (clone()+0x6d) [0x7f745a38b73d]
 NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.