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

[Alexey Kodanev]

On 12/18/2017 05:50 AM, Xiao Yang wrote:
> 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?

Ideally, we could check if the kernel is 4.14 and all.accept_dad
not equals 0, then apply workaround and print some warning message...

Anyway, I see that the patch in the queue for stable:
http://patchwork.ozlabs.org/bundle/davem/stable/?state=*

Thanks,
Alexey