[libvirt] Bug:libvirtd boot up blocked in NAT network setup

[Wenchao Xia]

Hello, guys
  I met a strange problem in libvirt+kvm massive deployment case. What
shows is that libvirtd will not respond to any virsh calls, with debug
I found that libvirtd was blocked at the step to setup default nat
network, that is command "iptables -table nat xxxxx".
  In terminal, I found command "iptables -L" will also block, and
"brctl show" shows that about 160 tap devices "vnetXXX" were attached
to virbr0. After I deleted these tap devices, things become normal, But
when I re-create them and attach these tap device to virbr0, it can't
be reproduced. There are too server met this problem in test, so I think
it is not a hardware problem. Does someone have experience this before?

information:
server: RH6.2
libvirt: libvirt-0.9.4
kernel: 2.6.32


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Best Regards

Wenchao Xia