ping6: failed to get receiving hop limit

[神明達哉]

At Tue, 10 May 2016 10:26:59 +0300,
Dmitry Sivachenko <trtrmitya at gmail.com> wrote:

> Sometimes ping6 command writes the following warning to stderr:
>
> ping6: failed to get receiving hop limit
>
> I can easily reproduce this with
> for n in `jot - 1 1000` ; do /sbin/ping6 -n -c 5 $HOST > /dev/null ; done
>
> It is very likely that even 100 repetitions is enough to catch this.
>
> Other than this warning IPv6 network seems to work properly.
>
> What does it mean?

That should mean the IPV6_RECVHOPLIMIT socket option somehow didn't
work as expected: the kernel didn't provide the information in the
ancillary data chain.  I have no idea about how this could happen -
it's quite likely to be some kind of kernel bug, but I have no
specific idea.

--
JINMEI, Tatuya