[libvirt] somtimes libvirtd crashed when fail to start a guest, need help to debug

Dear list, I met a problem when test with the latest libvirt (build from current master branch), i found sometimes libvirtd crashed when guest fail to start. the reproduce way is very easy, but hard to meet: # cat /root/shdo2.sh #！/bin/sh while : do virsh start rhel7.0-rhel done # sh /root/shdo2.sh ... error: Failed to start domain rhel7.0-rhel error: internal error: process exited while connecting to monitor: 2015-12-09T06:58:37.785695Z qemu-kvm: -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu1/rhel7.0-rhel.agent,server,nowait: Failed to bind socket to /var/lib/libvirt/qemu1/rhel7.0-rhel.agent: No such file or directory error: Failed to start domain rhel7.0-rhel error: internal error: process exited while connecting to monitor: 2015-12-09T06:58:42.035103Z qemu-kvm: -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu1/rhel7.0-rhel.agent,server,nowait: Failed to bind socket to /var/lib/libvirt/qemu1/rhel7.0-rhel.agent: No such file or directory error: Disconnected from qemu:///system due to I/O error error: Failed to start domain rhel7.0-rhel error: End of file while reading data: Input/output error error: One or more references were leaked after disconnect from the hypervisor error: failed to connect to the hypervisor error: no valid connection error: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Connection refused and here is the bt full output: http://pastebin.com/sCYHByvP and here is the valgrind output: http://pastebin.com/0VXrYTKT I cannot found what happened, also i am not familiar with virtlogd. could someone please help to debug this ? Thanks, Luyao