Re: [PATCH net] bonding/802.3ad: fix slave link initialization transition states

[David Miller]

From: Jarod Wilson <jarod@xxxxxxxxxx>
Date: Fri, 24 May 2019 09:49:28 -0400

> Once in a while, with just the right timing, 802.3ad slaves will fail to
> properly initialize, winding up in a weird state, with a partner system
> mac address of 00:00:00:00:00:00. This started happening after a fix to
> properly track link_failure_count tracking, where an 802.3ad slave that
> reported itself as link up in the miimon code, but wasn't able to get a
> valid speed/duplex, started getting set to BOND_LINK_FAIL instead of
> BOND_LINK_DOWN. That was the proper thing to do for the general "my link
> went down" case, but has created a link initialization race that can put
> the interface in this odd state.
> 
> The simple fix is to instead set the slave link to BOND_LINK_DOWN again,
> if the link has never been up (last_link_up == 0), so the link state
> doesn't bounce from BOND_LINK_DOWN to BOND_LINK_FAIL -- it hasn't failed
> in this case, it simply hasn't been up yet, and this prevents the
> unnecessary state change from DOWN to FAIL and getting stuck in an init
> failure w/o a partner mac.
> 
> Fixes: ea53abfab960 ("bonding/802.3ad: fix link_failure_count tracking")
> Tested-by: Heesoon Kim <Heesoon.Kim@xxxxxxxxxxx>
> Signed-off-by: Jarod Wilson <jarod@xxxxxxxxxx>

Applied and queued up for -stable.