This is a note to let you know that I've just added the patch titled net/mlx5e: Wait for concurrent flow deletion during neigh/fib events to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-mlx5e-wait-for-concurrent-flow-deletion-during-n.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 00ccb304547b39c0e8631083023e888d99deb6f4 Author: Vlad Buslov <vladbu@xxxxxxxxxx> Date: Thu Oct 21 18:15:10 2021 +0300 net/mlx5e: Wait for concurrent flow deletion during neigh/fib events [ Upstream commit 362980eada85b5ea691e5e0d9257a991aa7ade47 ] Function mlx5e_take_tmp_flow() skips flows with zero reference count. This can cause syndrome 0x179e84 when the called from neigh or route update code and the skipped flow is not removed from the hardware by the time underlying encap/decap resource is deleted. Add new completion 'del_hw_done' that is completed when flow is unoffloaded. This is safe to do because flow with reference count zero needs to be detached from encap/decap entry before its memory is deallocated, which requires taking the encap_tbl_lock mutex that is held by the event handlers code. Fixes: 8914add2c9e5 ("net/mlx5e: Handle FIB events to update tunnel endpoint device") Signed-off-by: Vlad Buslov <vladbu@xxxxxxxxxx> Reviewed-by: Roi Dayan <roid@xxxxxxxxxx> Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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 d1599b7b944bf..c340bf90354a0 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_priv.h @@ -102,6 +102,7 @@ struct mlx5e_tc_flow { refcount_t refcnt; struct rcu_head rcu_head; struct completion init_done; + struct completion del_hw_done; int tunnel_id; /* the mapped tunnel id of this flow */ struct mlx5_flow_attr *attr; }; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c index 1c44c6c345f5d..ec0163d75dd25 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun_encap.c @@ -221,8 +221,14 @@ static void mlx5e_take_tmp_flow(struct mlx5e_tc_flow *flow, struct list_head *flow_list, int index) { - if (IS_ERR(mlx5e_flow_get(flow))) + if (IS_ERR(mlx5e_flow_get(flow))) { + /* Flow is being deleted concurrently. Wait for it to be + * unoffloaded from hardware, otherwise deleting encap will + * fail. + */ + wait_for_completion(&flow->del_hw_done); return; + } wait_for_completion(&flow->init_done); flow->tmp_entry_index = index; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c index 129ff7e0d65cc..d2e7b099b83ab 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -1544,6 +1544,7 @@ static void mlx5e_tc_del_fdb_flow(struct mlx5e_priv *priv, else mlx5e_tc_unoffload_fdb_rules(esw, flow, attr); } + complete_all(&flow->del_hw_done); if (mlx5_flow_has_geneve_opt(flow)) mlx5_geneve_tlv_option_del(priv->mdev->geneve); @@ -4222,6 +4223,7 @@ mlx5e_alloc_flow(struct mlx5e_priv *priv, int attr_size, INIT_LIST_HEAD(&flow->l3_to_l2_reformat); refcount_set(&flow->refcnt, 1); init_completion(&flow->init_done); + init_completion(&flow->del_hw_done); *__flow = flow; *__parse_attr = parse_attr;