From: David Ahern <dsahern@gmail.com>
To: Guillaume Nault <gnault@redhat.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
davem@davemloft.net, netdev@vger.kernel.org,
yoshfuji@linux-ipv6.org, dsahern@kernel.org, vfedorenko@novek.ru
Subject: Re: [PATCH net] ip6_tunnel: fix GRE6 segmentation
Date: Thu, 24 Jun 2021 08:36:12 -0600 [thread overview]
Message-ID: <18a17215-e4e4-a1ef-b2d0-a934dca2b21c@gmail.com> (raw)
In-Reply-To: <20210624133915.GA4606@pc-32.home>
On 6/24/21 7:39 AM, Guillaume Nault wrote:
> On Wed, Jun 23, 2021 at 12:28:05PM -0600, David Ahern wrote:
>> On 6/23/21 10:14 AM, Jakub Kicinski wrote:
>>> Noob question, why do we need that 2 sec wait with IPv6 sometimes?
>>> I've seen it randomly in my local testing as well I wasn't sure if
>>> it's a bug or expected.
>>
>> It is to let IPv6 DAD to complete otherwise the address will not be
>> selected as a source address. That typically results in test failures.
>> There are sysctl settings that can prevent the race and hence the need
>> for the sleep.
>
> But Jakub's script uses "nodad" in the "ip address add ..." commands.
> Isn't that supposed to disable DAD entirely for the new address?
> Why would it need an additional "sleep 2"?
>
it should yes. I think the selftests have acquired a blend of nodad,
sysctl and sleep. I'm sure it could be cleaned up and made consistent.
next prev parent reply other threads:[~2021-06-24 14:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-22 1:52 [PATCH net] ip6_tunnel: fix GRE6 segmentation Jakub Kicinski
2021-06-22 1:58 ` Vadim Fedorenko
2021-06-22 4:28 ` David Ahern
2021-06-22 22:24 ` Jakub Kicinski
2021-06-23 3:47 ` David Ahern
2021-06-23 16:14 ` Jakub Kicinski
2021-06-23 18:28 ` David Ahern
2021-06-24 13:39 ` Guillaume Nault
2021-06-24 14:36 ` David Ahern [this message]
2021-06-24 16:33 ` Jakub Kicinski
2021-06-22 17:40 ` patchwork-bot+netdevbpf
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