From 76e68d950a170fb5cf70165bb442ba9636a19232 Mon Sep 17 00:00:00 2001 From: Roi Dayan Date: Thu, 19 Nov 2020 14:20:44 +0200 Subject: [PATCH] net/mlx5e: CT, Avoid false lock dependency warning To avoid false lock dependency warning set the ct_entries_ht lock class different than the lock class of the ht being used when deleting last flow from a group and then deleting a group, we get into del_sw_flow_group() which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but it's different than the ht->mutex here. ====================================================== WARNING: possible circular locking dependency detected 5.10.0-rc2+ #8 Tainted: G O ------------------------------------------------------ revalidator23/24009 is trying to acquire lock: ffff888128d83828 (&node->lock){++++}-{3:3}, at: mlx5_del_flow_rules+0x83/0x7a0 [mlx5_core] but task is already holding lock: ffff8881081ef518 (&ht->mutex){+.+.}-{3:3}, at: rhashtable_free_and_destroy+0x37/0x720 which lock already depends on the new lock. Signed-off-by: Roi Dayan Reviewed-by: Paul Blakey Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c index f3f6eb0819489..f81da2dc6af12 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c @@ -1539,6 +1539,14 @@ mlx5_tc_ct_free_pre_ct_tables(struct mlx5_ct_ft *ft) mlx5_tc_ct_free_pre_ct(ft, &ft->pre_ct); } +/* To avoid false lock dependency warning set the ct_entries_ht lock + * class different than the lock class of the ht being used when deleting + * last flow from a group and then deleting a group, we get into del_sw_flow_group() + * which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but + * it's different than the ht->mutex here. + */ +static struct lock_class_key ct_entries_ht_lock_key; + static struct mlx5_ct_ft * mlx5_tc_ct_add_ft_cb(struct mlx5_tc_ct_priv *ct_priv, u16 zone, struct nf_flowtable *nf_ft) @@ -1573,6 +1581,8 @@ mlx5_tc_ct_add_ft_cb(struct mlx5_tc_ct_priv *ct_priv, u16 zone, if (err) goto err_init; + lockdep_set_class(&ft->ct_entries_ht.mutex, &ct_entries_ht_lock_key); + err = rhashtable_insert_fast(&ct_priv->zone_ht, &ft->node, zone_params); if (err) -- 2.39.5