Netdev Archive on lore.kernel.org
help / color / mirror / Atom feed
From: David Miller <davem@davemloft.net>
To: jwiesner@suse.com
Cc: netdev@vger.kernel.org, j.vosburgh@gmail.com, vfalico@gmail.com,
	andy@greyhouse.net, kuba@kernel.org, Andreas.Taschner@suse.com,
	mkubecek@suse.cz
Subject: Re: [PATCH net] bonding: fix active-backup failover for current ARP slave
Date: Tue, 18 Aug 2020 15:58:24 -0700 (PDT)	[thread overview]
Message-ID: <20200818.155824.2292310502481809055.davem@davemloft.net> (raw)
In-Reply-To: <20200816185244.GA31426@incl>

From: Jiri Wiesner <jwiesner@suse.com>
Date: Sun, 16 Aug 2020 20:52:44 +0200

> When the ARP monitor is used for link detection, ARP replies are
> validated for all slaves (arp_validate=3) and fail_over_mac is set to
> active, two slaves of an active-backup bond may get stuck in a state
> where both of them are active and pass packets that they receive to
> the bond. This state makes IPv6 duplicate address detection fail. The
> state is reached thus:
> 1. The current active slave goes down because the ARP target
>    is not reachable.
> 2. The current ARP slave is chosen and made active.
> 3. A new slave is enslaved. This new slave becomes the current active
>    slave and can reach the ARP target.
> As a result, the current ARP slave stays active after the enslave
> action has finished and the log is littered with "PROBE BAD" messages:
>> bond0: PROBE: c_arp ens10 && cas ens11 BAD
> The workaround is to remove the slave with "going back" status from
> the bond and re-enslave it. This issue was encountered when DPDK PMD
> interfaces were being enslaved to an active-backup bond.
> 
> I would be possible to fix the issue in bond_enslave() or
> bond_change_active_slave() but the ARP monitor was fixed instead to
> keep most of the actions changing the current ARP slave in the ARP
> monitor code. The current ARP slave is set as inactive and backup
> during the commit phase. A new state, BOND_LINK_FAIL, has been
> introduced for slaves in the context of the ARP monitor. This allows
> administrators to see how slaves are rotated for sending ARP requests
> and attempts are made to find a new active slave.
> 
> Fixes: b2220cad583c9 ("bonding: refactor ARP active-backup monitor")
> Signed-off-by: Jiri Wiesner <jwiesner@suse.com>

Applied and queued up for -stable, thanks Jiri.

      reply	other threads:[~2020-08-18 22:58 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-16 18:52 Jiri Wiesner
2020-08-18 22:58 ` David Miller [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200818.155824.2292310502481809055.davem@davemloft.net \
    --to=davem@davemloft.net \
    --cc=Andreas.Taschner@suse.com \
    --cc=andy@greyhouse.net \
    --cc=j.vosburgh@gmail.com \
    --cc=jwiesner@suse.com \
    --cc=kuba@kernel.org \
    --cc=mkubecek@suse.cz \
    --cc=netdev@vger.kernel.org \
    --cc=vfalico@gmail.com \
    --subject='Re: [PATCH net] bonding: fix active-backup failover for current ARP slave' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).