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Date:   Sat, 21 Jul 2018 10:26:15 -0700 (PDT)
Message-Id: <20180721.102615.85495078941250538.davem@davemloft.net>
To:     jarod@redhat.com
Cc:     linux-kernel@vger.kernel.org, j.vosburgh@gmail.com,
        vfalico@gmail.com, andy@greyhouse.net, maheshb@google.com,
        netdev@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH net] bonding: set default miimon value for non-arp
 modes if not set
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20180718184936.16037-1-jarod@redhat.com>
References: <20180718184936.16037-1-jarod@redhat.com>
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From: Jarod Wilson <jarod@redhat.com>
Date: Wed, 18 Jul 2018 14:49:36 -0400

> For some time now, if you load the bonding driver and configure bond
> parameters via sysfs using minimal config options, such as specifying
> nothing but the mode, relying on defaults for everything else, modes
> that cannot use arp monitoring (802.3ad, balance-tlb, balance-alb) all
> wind up with both arp_interval=0 (as it should be) and miimon=0, which
> means the miimon monitor thread never actually runs. This is particularly
> problematic for 802.3ad.
 ...
> I believe this became a major issue as of commit 4d2c0cda0744, which for
> 802.3ad bonds, sets slave->link = BOND_LINK_DOWN, with a comment about
> relying on link monitoring via miimon to set it correctly, but since the
> miimon work queue never runs, the link just stays marked down.
> 
> If we simply tweak bond_option_mode_set() slightly, we can check for the
> non-arp modes having no miimon value set, and insert BOND_DEFAULT_MIIMON,
> which gets things back in full working order. This problem exists as far
> back as 4.14, and might be worth fixing in all stable trees since, though
> the work-around is to simply specify an miimon value yourself.
> 
> Reported-by: Bob Ball <ball@umich.edu>
 ...
> Signed-off-by: Jarod Wilson <jarod@redhat.com>

Applied and queued up for -stable, thank you.