[LTP] [PATCH] netns/netns_helper.sh: Fix failure when testing ipv6 in netns

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2017/12/15 22:06, Alexey Kodanev wrote:
> On 12/15/2017 04:13 PM, Xiao Yang wrote:
>> When testing ipv6 in network namespace, we got the following
>> error on some distros(e.g. RHEL7.5Alpha):
>> ----------------------------------------------------------------------------------
>> connect: Cannot assign requested address
>> netns_comm_ns_exec_ipv6_netlink 1 TFAIL: configuration and communication over veth0
>> connect: Cannot assign requested address
>> netns_comm_ns_exec_ipv6_netlink 2 TFAIL: configuration and communication over veth1
>> -----------------------------------------------------------------------------------
>>
>> We could fix this issue by waiting enough time(5s) for address
>> to pass duplicate address detection.
> netns tests disable DAD in setup so this shouldn't happen. It's quite
> likely that the kernel doesn't have the following upstream patch-fix:
>
> 094009531612 ("ipv6: set all.accept_dad to 0 by default")
Hi Alexey,

Thanks for your explanation.  The patch mentioned in your reply can fix 
the error.

Should we fix the error by setting all.accept_dad to 0 manually in netns 
or leave the
error to expose this issue?

Thanks,
Xiao Yang
> Thanks,
> Alexey
>
>
>