Description of problem:

Linux box is hanging (console & telnet) if try to remove vconfig as listed below.

Linux#vconfig add eth1 86
Added VLAN with VID == 86 to IF -:eth1:-
Linux#ifconfig eth1.86 up
Linux#ifconfig eth1.86 86.0.0.51/8
Linux#ping 86.0.0.51
PING 86.0.0.51 (86.0.0.51) 56(84) bytes of data.
64 bytes from 86.0.0.51: icmp_seq=0 ttl=64 time=0.028 ms
64 bytes from 86.0.0.51: icmp_seq=1 ttl=64 time=0.023 ms

--- 86.0.0.51 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.023/0.025/0.028/0.005 ms, pipe 2

Linux#vconfig add eth1.86 8  <<< Here vlan 8 is assigned to existing vlan 86
Added VLAN with VID == 8 to IF -:eth1.86:-
Linux#vconfig rem eth1.86

Message from syslogd@Linux at Wed Jun 23 05:35:51 2010 ...
Linux kernel: unregister_netdevice: waiting for eth1.86.8 to become free. Usage count = -1

Message from syslogd@Linux at Wed Jun 23 05:36:31 2010 ...
Linux last message repeated 4 times

Message from syslogd@Linux at Wed Jun 23 05:37:32 2010 ...
Linux last message repeated 6 times

Version-Release number of selected component (if applicable):
Linux#uname -a
Linux Linux 2.6.5-1.358smp #1 SMP Sat May 8 09:25:36 EDT 2004 i686 i686 i386 GNU/Linux

Linux#cat /etc/*-release
Fedora Core release 2
LSB_VERSION="1.3"
Fedora Core release 2
Linux#

How reproducible:
Always

Steps to Reproduce:
1. Same as above
2.
3.
  
Actual results:


Expected results:
Should not hang and vlan interface should get Deleted.

Additional info: