sk_buff doubt

Hello,

A doubt in sk_buff. I am running the fcc_enet driver provided in the PPC architecture tree for MPC8260 on ADS board. Kernel version is 2.4.1. The driver has been modified to be loaded as a module.
When IFNET provides the sk_buff to transmit I store them up in an array and at transmit complete I release the sk_buff.

When the module is unloaded, I release all the sk_buffs.
When I release the sk_buff I get the following output. Am I doing anything wrong here ?
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# ifconfig eth1 10.1.70.56 netmask 255.255.0.0 up
eth1: config: auto-negotiation on, 10FDX, 10HDX.
# ping 10.1.1.1
Inside fcc_enet_start_xmit... skb: c01e5c60
Inside fcc_enet_start_xmit... skb: c01e5620
Inside fcc_enet_start_xmit... skb: c01e5080
No response from 10.1.1.1
# lsmod
Module                  Size  Used by
enet                   12512   0  (unused)
# rmmod enet
Warning: kfree_skb passed an skb still on a list (from c208360c).
kernel BUG at skbuff.c:277!
Oops: Exception in kernel mode, sig: 4

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Sriram