Re: [PATCH] ipv6: Fix for adding multicast route for loopback device automatically.

[David Miller <davem@davemloft.net>]

From: Li Wei <lw@cn.fujitsu.com>
Date: Thu, 08 Dec 2011 08:58:21 +0800

> The problem is that the resulting routing table depends on the sequence
> of interface's initialization and in some situation, that would block all
> muticast packets. Suppose there are two interfaces on my computer
> (lo and eth0), if we initailize 'lo' before 'eth0', the resuting routing
> table(for multicast) would be
> 
> # ip -6 route show | grep ff00::
> unreachable ff00::/8 dev lo metric 256 error -101
> ff00::/8 dev eth0 metric 256
> 
> When sending multicasting packets, routing subsystem will return the first
> route entry which with a error set to -101(ENETUNREACH).
> 
> I know the kernel will set the default ipv6 address for 'lo' when it is up
> and won't set the default multicast route for it, but there is no reason to
> stop 'init' program from setting address for 'lo', and that is exactly what
> systemd did.

Ok, I added this more detailed explanation to the commit message and
applied your patch.

Probably it is a good idea to explain things completely, with all details
and examples, in the commit message from the beginning :-)