From: Cong Wang <xiyou.wangc...@gmail.com>
Date: Wed, 21 Jun 2017 14:34:58 -0700
> The per netns loopback_dev->ip6_ptr is unregistered and set to
> NULL when its mtu is set to smaller than IPV6_MIN_MTU, this
> leads to that we could set rt->rt6i_idev NULL after a
> rt6_uncached_list_flush_dev() and then crash after another
> call.
>
> In this case we should just bring its inet6_dev down, rather
> than unregistering it, at least prior to commit 176c39af29bc
> ("netns: fix addrconf_ifdown kernel panic") we always
> override the case for loopback.
>
> Thanks a lot to Andrey for finding a reliable reproducer.
>
> Fixes: 176c39af29bc ("netns: fix addrconf_ifdown kernel panic")
> Reported-by: Andrey Konovalov <andreyk...@google.com>
> Cc: Andrey Konovalov <andreyk...@google.com>
> Cc: Daniel Lezcano <dlezc...@fr.ibm.com>
> Cc: David Ahern <dsah...@gmail.com>
> Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
Applied and queued up for -stable.
