Tunneled IPv6 connection over tun device ends with error

What steps will reproduce the problem?
1. First attempt - tunnel6 client from http://tunnel6.4dstabi.com/. Compilation 
on device asus wl500gp with Optware - result ok. Executing t6_client - i 
received IPv6 address but unable to ping ipv6.google.com and others (linux x86 
port compiled on kubuntu by myself tested ok). Killing client leads to syslog 
message:
kernel: unregister_netdevice: waiting for tunnel6 to become free. Usage count = 
1
Client becomes zombie. Messages are filling my syslog file every 10 seconds -> 
manual restart of device to stop them.

2. Second attempt TSP protocol - gogoclient gw6c from 
http://wl500g-repo.googlecode.com/svn/ipkg/openwrt/. Because i use Optware - i 
prepared workaround - chrooting to enable entware system. I have used mount 
--bind /bin /opt/fakeroot/bin and so on for other directories to prepare it. 
Installed entware on other disk and copied files from /opt to 
/opt/fakeroot/opt. Gw6c client worked, i received ipv6 address for tun device 
(anonymous connection) or subnet (ipv6 for tun device, another ipv6 for br0 
generated by radvd). Ping for ipv6.google.com and others worked, router itself 
also replied on ping on one or both ipv6 addresses. But after some time 
(probably self killing or something like that?) same result in syslog:

kernel: unregister_netdevice: waiting for tun to become free. Usage count = 1
 every 10 seconds. Same result if i killed gw6c client manually - it ends as a zombie, same messages.

What is the expected output? What do you see instead?
Working tunneled IPv6 connection to freenet6 over tun device without errors.

What version of the product are you using?
WL500gp-1.9.2.7-rtn-r4502.trx from wpte.kicks-ass.net

Please provide any additional information below.
Connection over cable provider, static private IPv4 address, no native IPv6, in 
configuration of wl500gp I set tunnel 6in4 but i destroy that device six0 by 
start up script (i have set it up just to enable IPv6 in my router).

Original issue reported on code.google.com by y05...@gmail.com on 16 Jul 2012 at 2:43

First of all - stop use of Optware. It has very old uClibc which can cause such 
problems.

We have positive responses on use gw6c gogoclient and it already present in 
Entware repo. Unfortunately, short howto written in russian language only, try 
to read via google translate:

http://translate.google.com/translate?sl=ru&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&la
yout=2&eotf=1&u=http%3A%2F%2Fwl500g.info%2Fshowthread.php%3F24357-IPv6-%25CD%25E
0%25F1%25F2%25F0%25EE%25E9%25EA%25E0-IPv6-%25ED%25E0-Asus-RT-N16%26p%3D245187%26
langid%3D3%23post245187

We haven't any experience with tunnel6 client, so can't help.

Problem, you described, has nothing with firmware itself. Probably uClibc 
issues. Anyway, you mustn't unload/kill tun module before all tunnels closed.

Original comment by lly.dev on 17 Jul 2012 at 6:30

Changed state: Invalid
Added labels: Type-Support
Removed labels: Type-Defect

BackupGGCode / wl500g

Tunneled IPv6 connection over tun device ends with error #336