From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Ahern <dsahern@gmail.com>, David Ahern <dsahern@kernel.org>,
davem@davemloft.net, jakub.kicinski@netronome.com
Cc: netdev@vger.kernel.org, rajendra.dendukuri@broadcom.com
Subject: Re: [PATCH net v2] ipv6: Handle race in addrconf_dad_work
Date: Thu, 3 Oct 2019 09:32:34 -0700 [thread overview]
Message-ID: <43e2c04f-a601-3363-1f98-26fd007be960@gmail.com> (raw)
In-Reply-To: <4c896029-882f-1a4f-c0cc-4553a9429da3@gmail.com>
On 10/3/19 8:50 AM, David Ahern wrote:
> On 10/2/19 3:23 PM, Eric Dumazet wrote:
>>
>> It seems we need to allow the code to do some changes if IF_READY is not set.
>>
>
> That statement was correct. Prior to the patch in question ifp->state is
> bumped to INET6_IFADDR_STATE_DAD in addrconf_dad_work. When
> NETDEV_CHANGE event happens, addrconf_notify calls addrconf_dad_run
> which calls addrconf_dad_kick to restart dad after the dad process
> (applies even if nodad is set -- yes, odd).
>
> With the patch, IF_READY is not set when the bond device is created and
> dad_work skips bumping the state. When the CHANGE event comes through
> the state is not INET6_IFADDR_STATE_DAD (and the restart argument is not
> set), so addrconf_dad_run does not call addrconf_dad_kick.
>
> Bottom line, regardless of IF_READY we need the state change to happen
> in dad_work, we just need to skip the call to addconf_dad_begin.
>
> Can you test the change below on your boxes? It applies on current net.
>
> Rajendra: can you test as well and make sure your problem is still
> resolved?
>
> Thanks,
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index dd3be06d5a06..fce0d0dca7bb 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -4032,12 +4032,6 @@ static void addrconf_dad_work(struct work_struct *w)
>
> rtnl_lock();
>
> - /* check if device was taken down before this delayed work
> - * function could be canceled
> - */
> - if (idev->dead || !(idev->if_flags & IF_READY))
> - goto out;
> -
> spin_lock_bh(&ifp->lock);
> if (ifp->state == INET6_IFADDR_STATE_PREDAD) {
> action = DAD_BEGIN;
> @@ -4068,6 +4062,12 @@ static void addrconf_dad_work(struct work_struct *w)
> }
> spin_unlock_bh(&ifp->lock);
>
> + /* check if device was taken down before this delayed work
> + * function could be canceled
> + */
> + if (idev->dead || !(idev->if_flags & IF_READY))
> + goto out;
> +
> if (action == DAD_BEGIN) {
> addrconf_dad_begin(ifp);
> goto out;
>
Still no luck for me :/
next prev parent reply other threads:[~2019-10-03 16:32 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 3:28 [PATCH net v2] ipv6: Handle race in addrconf_dad_work David Ahern
2019-10-01 18:18 ` Eric Dumazet
2019-10-02 21:08 ` Eric Dumazet
2019-10-02 21:23 ` Eric Dumazet
2019-10-02 22:13 ` David Ahern
2019-10-02 22:21 ` Eric Dumazet
2019-10-02 22:33 ` David Ahern
2019-10-02 22:36 ` Eric Dumazet
2019-10-02 23:11 ` Eric Dumazet
2019-10-02 23:37 ` David Ahern
2019-10-03 0:10 ` David Ahern
2019-10-03 0:36 ` Eric Dumazet
2019-10-03 2:42 ` David Ahern
2019-10-03 15:50 ` David Ahern
2019-10-03 16:32 ` Eric Dumazet [this message]
2019-10-03 17:19 ` Eric Dumazet
2019-10-03 19:29 ` David Ahern
2019-10-02 1:45 ` David Miller
2019-10-06 11:46 ` [ipv6] 58a3c210a3: ltp.ping601.fail kernel test robot
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