When ok:
(gdb) bt
#0  0x00000030f2ad7248 in poll () from /lib64/libc.so.6
#1  0x00007ffd47608f4a in virEventPollRunOnce () at util/event_poll.c:594
#2  0x00007ffd47607ba5 in virEventRunDefaultImpl () at util/event.c:247
#3  0x00007ffd47a89f8e in libvirt_virEventRunDefaultImpl (self=<value optimized out>, args=<value optimized out>)
    at libvirt.c:3598
#4  0x00000030feae965b in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#5  0x00000030feaea71d in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#6  0x00000030feaeb04d in PyEval_EvalCodeEx () from /usr/lib64/libpython2.7.so.1.0
#7  0x00000030feaeb162 in PyEval_EvalCode () from /usr/lib64/libpython2.7.so.1.0
#8  0x00000030feb0639c in ?? () from /usr/lib64/libpython2.7.so.1.0
#9  0x00000030feb071d0 in PyRun_FileExFlags () from /usr/lib64/libpython2.7.so.1.0
#10 0x00000030feb07daf in PyRun_SimpleFileExFlags () from /usr/lib64/libpython2.7.so.1.0
#11 0x00000030feb198ce in Py_Main () from /usr/lib64/libpython2.7.so.1.0
#12 0x00000030f2a1ee5d in __libc_start_main () from /lib64/libc.so.6
#13 0x0000000000400649 in _start ()


When unresponsive:
#0  0x00000030f2ad7248 in poll () from /lib64/libc.so.6
#1  0x00007ffd476d259f in virNetClientIOEventLoop (client=0x7ffd47107010, thiscall=0xb5b5d0) at rpc/virnetclient.c:884
#2  0x00007ffd476d3adc in virNetClientIO (client=0x7ffd47107010, msg=<value optimized out>, expectReply=true)
    at rpc/virnetclient.c:1121
#3  virNetClientSend (client=0x7ffd47107010, msg=<value optimized out>, expectReply=true) at rpc/virnetclient.c:1196
#4  0x00007ffd476d4348 in virNetClientProgramCall (prog=0xb27d90, client=0x7ffd47107010, serial=11, proc=212, 
    args_filter=0x7ffd476d1110 <xdr_remote_domain_get_state_args>, args=0x7fff888267a0, 
    ret_filter=0x7ffd476d1180 <xdr_remote_domain_get_state_ret>, ret=0x7fff88826790) at rpc/virnetclientprogram.c:291
#5  0x00007ffd476b5049 in call (priv=0xb8a300, flags=<value optimized out>, proc_nr=212, 
    args_filter=0x7ffd476d1110 <xdr_remote_domain_get_state_args>, args=<value optimized out>, 
    ret_filter=<value optimized out>, ret=0x7fff88826790 "", conn=<value optimized out>) at remote/remote_driver.c:4039
#6  0x00007ffd476bc228 in remoteDomainGetState (domain=0xb139e0, state=0x7fff888268bc, reason=0x7fff888268b8, flags=0)
    at remote/remote_driver.c:1656
#7  0x00007ffd4768b4b7 in virDomainGetState (domain=0xb139e0, state=0x7fff888268bc, reason=0x7fff888268b8, flags=0)
    at libvirt.c:3655
#8  0x00007ffd47a808f5 in libvirt_virDomainGetState (self=<value optimized out>, args=<value optimized out>)
    at libvirt-override.c:1712
#9  0x00000030feae965b in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#10 0x00000030feaea71d in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#11 0x00000030feaea71d in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#12 0x00000030feaeb04d in PyEval_EvalCodeEx () from /usr/lib64/libpython2.7.so.1.0
#13 0x00000030fea71c62 in ?? () from /usr/lib64/libpython2.7.so.1.0
#14 0x00000030fea48fc3 in PyObject_Call () from /usr/lib64/libpython2.7.so.1.0
#15 0x00000030fea5a65f in ?? () from /usr/lib64/libpython2.7.so.1.0
#16 0x00000030fea48fc3 in PyObject_Call () from /usr/lib64/libpython2.7.so.1.0
#17 0x00000030fea490ab in ?? () from /usr/lib64/libpython2.7.so.1.0
#18 0x00000030fea4935b in PyObject_CallMethod () from /usr/lib64/libpython2.7.so.1.0
#19 0x00007ffd47a82082 in libvirt_virConnectDomainEventCallback (conn=<value optimized out>, dom=<value optimized out>, 
    event=2, detail=0, opaque=0x7ffd47ccdb90) at libvirt-override.c:3210
#20 0x00007ffd4764f0c6 in virDomainEventDispatchDefaultFunc (conn=0xb02620, event=0xbbdf90, 
    cb=0x7ffd47a81f30 <libvirt_virConnectDomainEventCallback>, cbopaque=0x7ffd47ccdb90, opaque=<value optimized out>)
    at conf/domain_event.c:1023
#21 0x00007ffd476b48fa in remoteDomainEventDispatchFunc (conn=0xb02620, event=0xbbdf90, 
    cb=0x7ffd47a81f30 <libvirt_virConnectDomainEventCallback>, cbopaque=0x7ffd47ccdb90, opaque=0xb8a300)
    at remote/remote_driver.c:4063
#22 0x00007ffd4764f26f in virDomainEventDispatch (event=0xbbdf90, callbacks=0xa52ac0, dispatch=<value optimized out>, 
    opaque=0xb8a300) at conf/domain_event.c:1136
#23 0x00007ffd4764f30a in virDomainEventQueueDispatch (queue=0x7fff888273e0, callbacks=0xa52ac0, 
    dispatch=0x7ffd476b4870 <remoteDomainEventDispatchFunc>, opaque=0xb8a300) at conf/domain_event.c:1153
#24 0x00007ffd4764f4de in virDomainEventStateFlush (state=0xb5ad00, 
    dispatchFunc=0x7ffd476b4870 <remoteDomainEventDispatchFunc>, opaque=0xb8a300) at conf/domain_event.c:1195
#25 0x00007ffd476b4845 in remoteDomainEventQueueFlush (timer=<value optimized out>, opaque=0xb02620)
    at remote/remote_driver.c:4077
#26 0x00007ffd47609116 in virEventPollDispatchTimeouts () at util/event_poll.c:421
#27 virEventPollRunOnce () at util/event_poll.c:607
#28 0x00007ffd47607ba5 in virEventRunDefaultImpl () at util/event.c:247
#29 0x00007ffd47a89f8e in libvirt_virEventRunDefaultImpl (self=<value optimized out>, args=<value optimized out>)
    at libvirt.c:3598
#30 0x00000030feae965b in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#31 0x00000030feaea71d in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#32 0x00000030feaeb04d in PyEval_EvalCodeEx () from /usr/lib64/libpython2.7.so.1.0
#33 0x00000030feaeb162 in PyEval_EvalCode () from /usr/lib64/libpython2.7.so.1.0
#34 0x00000030feb0639c in ?? () from /usr/lib64/libpython2.7.so.1.0
#35 0x00000030feb071d0 in PyRun_FileExFlags () from /usr/lib64/libpython2.7.so.1.0
#36 0x00000030feb07daf in PyRun_SimpleFileExFlags () from /usr/lib64/libpython2.7.so.1.0
#37 0x00000030feb198ce in Py_Main () from /usr/lib64/libpython2.7.so.1.0
#38 0x00000030f2a1ee5d in __libc_start_main () from /lib64/libc.so.6
#39 0x0000000000400649 in _start ()