This fixes an assertion failure in the following backtrace:
__GI___assert_fail
memory_region_transaction_commit
memory_region_add_eventfd
virtio_pci_ioeventfd_assign
virtio_bus_set_host_notifier
virtio_blk_data_plane_start
virtio_bus_start_ioeventfd
virtio_vmstate_change
vm_state_notify
vm_prepare_start
vm_start
dump_cleanup
dump_process
dump_thread
start_thread
clone
vm_start need BQL, acquire it if doing cleaning up from main thread.
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170503072819.14462-1-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
6796b4008b