bonding/802.3ad: fix slave link initialization transition states

BugLink: https://bugs.launchpad.net/bugs/1837518
[ Upstream commit 334031219a84b9994594015aab85ed7754c80176 ]

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")
CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Tested-by: Heesoon Kim <Heesoon.Kim@stratus.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index f89fc6ea60783b115d109d70eecd58ba2228dd69..4eeece3576e1cac11a9f20a5c5408d7afdff792f 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3123,13 +3123,18 @@ static int bond_slave_netdev_event(unsigned long event,
        case NETDEV_CHANGE:
                /* For 802.3ad mode only:
                 * Getting invalid Speed/Duplex values here will put slave
-                * in weird state. So mark it as link-fail for the time
-                * being and let link-monitoring (miimon) set it right when
-                * correct speeds/duplex are available.
+                * in weird state. Mark it as link-fail if the link was
+                * previously up or link-down if it hasn't yet come up, and
+                * let link-monitoring (miimon) set it right when correct
+                * speeds/duplex are available.
                 */
                if (bond_update_speed_duplex(slave) &&
-                   BOND_MODE(bond) == BOND_MODE_8023AD)
-                       slave->link = BOND_LINK_FAIL;
+                   BOND_MODE(bond) == BOND_MODE_8023AD) {
+                       if (slave->last_link_up)
+                               slave->link = BOND_LINK_FAIL;
+                       else
+                               slave->link = BOND_LINK_DOWN;
+               }
 
                if (BOND_MODE(bond) == BOND_MODE_8023AD)
                        bond_3ad_adapter_speed_duplex_changed(slave);