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.
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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
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Signed-off-by: Jarod Wilson jarod@redhat.com
Applied and queued up for -stable, thank you.