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author | Jay Vosburgh <jay.vosburgh@canonical.com> | 2017-11-07 13:50:07 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-11-08 10:07:10 +0300 |
commit | 055db6957e4735b16cd2fa94a5bbfb754c9b8023 (patch) | |
tree | 78db33199a5d1852a261f48dd0941b35a0028301 /drivers | |
parent | b7e732fa3171318418524b776b841b4024933b2b (diff) | |
download | linux-055db6957e4735b16cd2fa94a5bbfb754c9b8023.tar.xz |
bonding: fix slave stuck in BOND_LINK_FAIL state
The bonding miimon logic has a flaw, in that a failure of the
rtnl_trylock can cause a slave to become permanently stuck in
BOND_LINK_FAIL state.
The sequence of events to cause this is as follows:
1) bond_miimon_inspect finds that a slave's link is down, and so
calls bond_propose_link_state, setting slave->new_link_state to
BOND_LINK_FAIL, then sets slave->new_link to BOND_LINK_DOWN and returns
non-zero.
2) In bond_mii_monitor, the rtnl_trylock fails, and the timer is
rescheduled. No change is committed.
3) bond_miimon_inspect is called again, but this time the slave
from step 1 has recovered. slave->new_link is reset to NOCHANGE, and, as
slave->link was never changed, the switch enters the BOND_LINK_UP case,
and does nothing. The pending BOND_LINK_FAIL state from step 1 remains
pending, as new_link_state is not reset.
4) The state from step 3 persists until another slave changes link
state and causes bond_miimon_inspect to return non-zero. At this point,
the BOND_LINK_FAIL state change on the slave from steps 1-3 is committed,
and the slave will remain stuck in BOND_LINK_FAIL state even though it
is actually link up.
The remedy for this is to initialize new_link_state on each entry
to bond_miimon_inspect, as is already done with new_link.
Fixes: fb9eb899a6dc ("bonding: handle link transition from FAIL to UP correctly")
Reported-by: Alex Sidorenko <alexandre.sidorenko@hpe.com>
Reviewed-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Acked-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/net/bonding/bond_main.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 76e8054bfc4e..b2db581131b2 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2042,6 +2042,7 @@ static int bond_miimon_inspect(struct bonding *bond) bond_for_each_slave_rcu(bond, slave, iter) { slave->new_link = BOND_LINK_NOCHANGE; + slave->link_new_state = slave->link; link_state = bond_check_dev_link(bond, slave->dev, 0); |