interface hang after stopping hostapd.

[Zhao Tongyi]

Frist, I used hostapd wired drivers with pae modules to authorize
802.1x on a vlan interface.
the interface created by vconfig add an ethereal .(vconfig add eth0 100).

secondly,I stoped the hostapd and wanted to remove the vlan interface
by(vconfig rem eth0.100)
	
Unexpectedly, the vlan interface was locked,and the kernel
reported:"unregister netdevice:waiting for eth0.100 to become
free,usage count =6"

really appreciated if somebody who are familiar with the issues can help me .

-- 
Best regards,

Tongyi ,Zhao