From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH net-next v12 06/11] vxlan: add ipv6 support
Date: Sat, 31 Aug 2013 10:27:26 -0700
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Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	David Stevens <dlstevens@us.ibm.com>
To: Cong Wang <amwang@redhat.com>
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On Sat, 31 Aug 2013 13:44:33 +0800
Cong Wang <amwang@redhat.com> wrote:

> +#if IS_ENABLED(CONFIG_IPV6)
> +	} else {
> +		ipv6_stub->ipv6_sock_mc_join(sk, ifindex,
> +					     &ip->sin6.sin6_addr);
> +#endif

This isn't safe against IPv6 module getting unloaded. You either
have to figure out a reference count method, or disable IPv6
module unload.

Since it can only be forced unload anyway, I still argue
it should just be disabled (by removing the module exit hook
and code).