From: Hangbin Liu When bond_enslave() succeeds up to the XDP setup stage, slave_cnt is already incremented. If XDP setup subsequently fails, the error paths jump directly to err_sysfs_del, bypassing the slave_cnt decrement. This causes slave_cnt to drift upward on each failed enslaving attempt, which would lead to unbalanced traffic distribution with round-robin mode. Fix it by moving the slave_cnt increase after XDP setup. Fixes: 9e2ee5c7e7c3 ("net, bonding: Add XDP support to the bonding driver") Signed-off-by: Hangbin Liu --- Changes in v3: - move the slave_cnt increasement before bond_update_slave_arr() (selftest) - run all bonding selftests on debug kernel to make sure no regression (Jakub) - Link to v2: https://lore.kernel.org/r/20260903-bond_slave_cnt-v2-1-02e27304ca36@kylinos.cn Changes in v2: - move the slave_cnt increasement after XDP setup (Nikolay Aleksandrov) - balance-xor mode is not affected, not mention it (Nikolay Aleksandrov) - Link to v1: https://lore.kernel.org/r/20260902-bond_slave_cnt-v1-1-36e95bf4a6ff@kylinos.cn --- drivers/net/bonding/bond_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index a9bff7663eec..1514a8ba0888 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2284,7 +2284,6 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, } } - WRITE_ONCE(bond->slave_cnt, bond->slave_cnt + 1); netdev_compute_master_upper_features(bond->dev, true); bond_set_carrier(bond); @@ -2332,6 +2331,9 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, bpf_prog_inc(bond->xdp_prog); } + /* Increase the slave count before rebuilding the slave arrays. */ + WRITE_ONCE(bond->slave_cnt, bond->slave_cnt + 1); + /* broadcast mode uses the all_slaves to loop through slaves. */ if (bond_mode_can_use_xmit_hash(bond) || BOND_MODE(bond) == BOND_MODE_BROADCAST) --- base-commit: 38b6be101006d3e7af972999f45d4f1e8250587a change-id: 20260807-bond_slave_cnt-88e78c5f0ab9 Best regards, -- Hangbin Liu