On Thu, 31 Jul 2014 10:29:00 +0400
Sergey Popov [off-list ref] wrote:

quoted

I have no patch to fix this issue, but as a workaround, you can use 
ip tunnel change tun_test tos inherit.

Thanks, your workaround works as expected if tos value defined
explicitly. Though, I do not understand why: iproute2 documentation says
that default tos value in 'ip tunnel' command is already 'inherit'.

man ip-tunnel says default tos is 00, and that's true. If you're about *.tex
files under iproute2.git/doc, they are more than 10 years old, I doubt if they
are maintained. Otherwise I don't know where you found it.

This workaround works because setting tos=inherit disables tunnel route cache,
which is buggy in your release (it doesn't cache source address).

Btw, thanks for the report, David has accepted the patch today, commit
95cb574 (ip_tunnel(ipv4): fix tunnels with "local any remote $remote_ip"), so
I think next kernel releases will have it.