From: Shay Drory In case __mlx5e_add_fdb_flow() fails in lower levels, the flow is deleted via mlx5e_tc_del_flow(), and mlx5e_tc_del_flow() is acquiring ESW devcom lock without condition. In addition, in case of peer_flow, __mlx5e_add_fdb_flow() is called while holding ESW devcom comp lock. This results in an AA deadlock. To fix this, introduce a new PEER flag that is set on flows created as peer flows (the duplicate flows on peer devices), and check it in mlx5e_tc_del_flow() before acquiring ESW devcom lock. Lockdep splat: ============================================ WARNING: possible recursive locking detected ============================================ Possible unsafe locking scenario: CPU0 ---- lock(&comp->lock_key#2); lock(&comp->lock_key#2); *** DEADLOCK *** Call Trace: dump_stack_lvl+0x69/0xa0 print_deadlock_bug.cold+0xbd/0xca __lock_acquire+0x1671/0x2ec0 lock_acquire+0x10e/0x2e0 down_read+0x95/0x430 mlx5_devcom_for_each_peer_begin+0x4e/0xe0 [mlx5_core] mlx5e_tc_del_flow+0x11d/0xa70 [mlx5_core] mlx5e_flow_put+0x99/0x100 [mlx5_core] __mlx5e_add_fdb_flow+0x409/0xf00 [mlx5_core] mlx5e_configure_flower+0x2a86/0x4100 [mlx5_core] mlx5e_rep_setup_tc_cls_flower+0x12f/0x1b0 [mlx5_core] mlx5e_rep_setup_tc_cb+0x153/0x750 [mlx5_core] tc_setup_cb_add+0x1dc/0x470 fl_change+0x2f4d/0x626d [cls_flower] tc_new_tfilter+0x79b/0x2310 rtnetlink_rcv_msg+0x778/0xad0 do_syscall_64+0x70/0x960 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: 04de7dda7394 ("net/mlx5e: Infrastructure for duplicated offloading of TC flows") Signed-off-by: Shay Drory Reviewed-by: Cosmin Ratiu Signed-off-by: Tariq Toukan --- drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h | 1 + drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) V2: Remove leftover pharagraph from commit message. V1: https://patchwork.kernel.org/project/netdevbpf/patch/20260717073041.1241894-1-tariqt@nvidia.com/ diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h index 28cab4bf525c..7bfe7cdc5770 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h @@ -30,6 +30,7 @@ enum { MLX5E_TC_FLOW_FLAG_FAILED = MLX5E_TC_FLOW_BASE + 9, MLX5E_TC_FLOW_FLAG_SAMPLE = MLX5E_TC_FLOW_BASE + 10, MLX5E_TC_FLOW_FLAG_USE_ACT_STATS = MLX5E_TC_FLOW_BASE + 11, + MLX5E_TC_FLOW_FLAG_PEER = MLX5E_TC_FLOW_BASE + 12, }; struct mlx5e_tc_flow_parse_attr { diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c index 1bc7b9019124..b290beb4369a 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -2161,7 +2161,8 @@ static void mlx5e_tc_del_flow(struct mlx5e_priv *priv, if (mlx5e_is_eswitch_flow(flow)) { struct mlx5_devcom_comp_dev *devcom = flow->priv->mdev->priv.eswitch->devcom; - if (!mlx5_devcom_for_each_peer_begin(devcom)) { + if (flow_flag_test(flow, PEER) || + !mlx5_devcom_for_each_peer_begin(devcom)) { mlx5e_tc_del_fdb_flow(priv, flow); return; } @@ -4628,6 +4629,7 @@ static int mlx5e_tc_add_fdb_peer_flow(struct flow_cls_offload *f, else in_mdev = priv->mdev; + flow_flags |= BIT(MLX5E_TC_FLOW_FLAG_PEER); parse_attr = flow->attr->parse_attr; peer_flow = __mlx5e_add_fdb_flow(peer_priv, f, flow_flags, parse_attr->filter_dev, base-commit: 97ac08560d236ca17f6606d9e671118e5eae5721 -- 2.44.0