[libvirt] [virtio-pci] unbind port from virtio-pci causes kernel crash

I am running kvm based virtual guest. The guest has two virtio-based ports. Now I am trying to unbind ports from their current drivers (by echo "0000:00:06.0" > /sys/bus/pci/drivers/virtio-pci/unbind) and getting kernel crash. Don't know how to move forward. Any suggestions are highly appreciated. [ 110.034006] WARNING: at kernel/irq/manage.c:937 __free_irq+0x205/0x210() [ 110.034006] Hardware name: Standard PC (i440FX + PIIX, 1996) [ 110.034006] Modules linked in: rte_kni igb_uio knpusim(P) knpushm(P) virtio_scsi virtio_blk vmw_pvscsi ata_piix mptsas mptspi mptscsih mptbase ub be2net ixgbevf enic ixgbe mdio e1000e e1000 vmxnet3 virtio_net bnx2 3c59x uhci_hcd ehci_hcd [ 110.034006] Pid: 5578, comm: sh Tainted: P W 2.6.38-staros-v3-ssi-64 #2 [ 110.034006] Call Trace: [ 110.034006] [<ffffffff810a1905>] ? __free_irq+0x205/0x210 [ 110.034006] [<ffffffff810a1905>] ? __free_irq+0x205/0x210 [ 110.034006] [<ffffffff81056710>] ? warn_slowpath_common+0x90/0xc0 [ 110.034006] [<ffffffff8105675a>] ? warn_slowpath_null+0x1a/0x20 [ 110.034006] [<ffffffff810a1905>] ? __free_irq+0x205/0x210 [ 110.034006] [<ffffffff810a1957>] ? free_irq+0x47/0x90 [ 110.034006] [<ffffffff812f96a3>] ? vp_del_vqs+0x73/0xb0 [ 110.034006] [<ffffffffa00192f6>] ? virtnet_del_vqs+0x36/0x50 [virtio_net] [ 110.034006] [<ffffffffa001ab16>] ? remove_vq_common+0x36/0x40 [virtio_net] [ 110.034006] [<ffffffffa001c47f>] ? virtnet_remove+0x3f/0xbc0 [virtio_net] [ 110.034006] [<ffffffff812f8612>] ? virtio_dev_remove+0x22/0x50 [ 110.034006] [<ffffffff8133a176>] ? __device_release_driver+0x66/0xc0 [ 110.034006] [<ffffffff8133a8ed>] ? device_release_driver+0x2d/0x40 [ 110.034006] [<ffffffff81339b8d>] ? bus_remove_device+0x7d/0xe0 [ 110.034006] [<ffffffff81336a98>] ? device_del+0x128/0x1a0 [ 110.034006] [<ffffffff81336b32>] ? device_unregister+0x22/0x60 [ 110.034006] [<ffffffff812f8682>] ? unregister_virtio_device+0x12/0x20 [ 110.034006] [<ffffffff8155fe2d>] ? virtio_pci_remove+0x1d/0x20 [ 110.034006] [<ffffffff812b6ee7>] ? pci_device_remove+0x37/0x70 [ 110.034006] [<ffffffff8133a176>] ? __device_release_driver+0x66/0xc0 [ 110.034006] [<ffffffff8133a8ed>] ? device_release_driver+0x2d/0x40 [ 110.034006] [<ffffffff81339c8b>] ? driver_unbind+0x9b/0xc0 [ 110.034006] [<ffffffff81338bbc>] ? drv_attr_store+0x2c/0x30 [ 110.034006] [<ffffffff8117f0a6>] ? sysfs_write_file+0xe6/0x150 [ 110.034006] [<ffffffff8111fd7e>] ? vfs_write+0xce/0x170 [ 110.034006] [<ffffffff81120485>] ? sys_write+0x55/0x90 [ 110.034006] [<ffffffff8103fc40>] ? sysenter_dispatch+0x7/0x37 [ 110.034006] [<ffffffff81563e49>] ? trace_hardirqs_on_thunk+0x3a/0x3c [ 110.034006] ---[ end trace 4eaa2a86a8e2da24 ]--- [ 110.074389] general protection fault: 0000 [#1] PREEMPT SMP [ 110.075006] last sysfs file: /sys/bus/pci/drivers/virtio-pci/unbind