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| author | Yufeng Mo <moyufeng@huawei.com> | 2021-07-30 05:19:11 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-18 14:40:24 +0300 |
| commit | f710323dcd24ce6209ee767e910ac4a21ffc618c (patch) | |
| tree | 2743ee9b37575189df9afca2fb71fb2193237dde /drivers | |
| parent | 5d008cb7636de3a5962856e6a7eb39d1f7cb9619 (diff) | |
| download | linux-f710323dcd24ce6209ee767e910ac4a21ffc618c.tar.xz | |
bonding: 3ad: fix the concurrency between __bond_release_one() and bond_3ad_state_machine_handler()
[ Upstream commit 220ade77452c15ecb1ab94c3f8aaeb6d033c3582 ]
Some time ago, I reported a calltrace issue
"did not find a suitable aggregator", please see[1].
After a period of analysis and reproduction, I find
that this problem is caused by concurrency.
Before the problem occurs, the bond structure is like follows:
bond0 - slaver0(eth0) - agg0.lag_ports -> port0 - port1
\
port0
\
slaver1(eth1) - agg1.lag_ports -> NULL
\
port1
If we run 'ifenslave bond0 -d eth1', the process is like below:
excuting __bond_release_one()
|
bond_upper_dev_unlink()[step1]
| | |
| | bond_3ad_lacpdu_recv()
| | ->bond_3ad_rx_indication()
| | spin_lock_bh()
| | ->ad_rx_machine()
| | ->__record_pdu()[step2]
| | spin_unlock_bh()
| | |
| bond_3ad_state_machine_handler()
| spin_lock_bh()
| ->ad_port_selection_logic()
| ->try to find free aggregator[step3]
| ->try to find suitable aggregator[step4]
| ->did not find a suitable aggregator[step5]
| spin_unlock_bh()
| |
| |
bond_3ad_unbind_slave() |
spin_lock_bh()
spin_unlock_bh()
step1: already removed slaver1(eth1) from list, but port1 remains
step2: receive a lacpdu and update port0
step3: port0 will be removed from agg0.lag_ports. The struct is
"agg0.lag_ports -> port1" now, and agg0 is not free. At the
same time, slaver1/agg1 has been removed from the list by step1.
So we can't find a free aggregator now.
step4: can't find suitable aggregator because of step2
step5: cause a calltrace since port->aggregator is NULL
To solve this concurrency problem, put bond_upper_dev_unlink()
after bond_3ad_unbind_slave(). In this way, we can invalid the port
first and skip this port in bond_3ad_state_machine_handler(). This
eliminates the situation that the slaver has been removed from the
list but the port is still valid.
[1]https://lore.kernel.org/netdev/10374.1611947473@famine/
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/bonding/bond_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 018af1e38eb9..645c7cabcbe4 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2219,7 +2219,6 @@ static int __bond_release_one(struct net_device *bond_dev, /* recompute stats just before removing the slave */ bond_get_stats(bond->dev, &bond->bond_stats); - bond_upper_dev_unlink(bond, slave); /* unregister rx_handler early so bond_handle_frame wouldn't be called * for this slave anymore. */ @@ -2228,6 +2227,8 @@ static int __bond_release_one(struct net_device *bond_dev, if (BOND_MODE(bond) == BOND_MODE_8023AD) bond_3ad_unbind_slave(slave); + bond_upper_dev_unlink(bond, slave); + if (bond_mode_can_use_xmit_hash(bond)) bond_update_slave_arr(bond, slave); |