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Subject[PATCH 4.13 25/44] net/mlx5e: Properly deal with encap flows add/del under neigh update
Date
4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Or Gerlitz <ogerlitz@mellanox.com>


[ Upstream commit 3c37745ec614ff048d5dce38f976804b05d307ee ]

Currently, the encap action offload is handled in the actions parse
function and not in mlx5e_tc_add_fdb_flow() where we deal with all
the other aspects of offloading actions (vlan, modify header) and
the rule itself.

When the neigh update code (mlx5e_tc_encap_flows_add()) recreates the
encap entry and offloads the related flows, we wrongly call again into
mlx5e_tc_add_fdb_flow(), this for itself would cause us to handle
again the offloading of vlans and header re-write which puts things
in non consistent state and step on freed memory (e.g the modify
header parse buffer which is already freed).

Since on error, mlx5e_tc_add_fdb_flow() detaches and may release the
encap entry, it causes a corruption at the neigh update code which goes
over the list of flows associated with this encap entry, or double free
when the tc flow is later deleted by user-space.

When neigh update (mlx5e_tc_encap_flows_del()) unoffloads the flows related
to an encap entry which is now invalid, we do a partial repeat of the eswitch
flow removal code which is wrong too.

To fix things up we do the following:

(1) handle the encap action offload in the eswitch flow add function
mlx5e_tc_add_fdb_flow() as done for the other actions and the rule itself.

(2) modify the neigh update code (mlx5e_tc_encap_flows_add/del) to only
deal with the encap entry and rules delete/add and not with any of
the other offloaded actions.

Fixes: 232c001398ae ('net/mlx5e: Add support to neighbour update flow')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 89 ++++++++++++++----------
1 file changed, 54 insertions(+), 35 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -78,9 +78,11 @@ struct mlx5e_tc_flow {
};

struct mlx5e_tc_flow_parse_attr {
+ struct ip_tunnel_info tun_info;
struct mlx5_flow_spec spec;
int num_mod_hdr_actions;
void *mod_hdr_actions;
+ int mirred_ifindex;
};

enum {
@@ -322,6 +324,12 @@ static void mlx5e_tc_del_nic_flow(struct
static void mlx5e_detach_encap(struct mlx5e_priv *priv,
struct mlx5e_tc_flow *flow);

+static int mlx5e_attach_encap(struct mlx5e_priv *priv,
+ struct ip_tunnel_info *tun_info,
+ struct net_device *mirred_dev,
+ struct net_device **encap_dev,
+ struct mlx5e_tc_flow *flow);
+
static struct mlx5_flow_handle *
mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv,
struct mlx5e_tc_flow_parse_attr *parse_attr,
@@ -329,9 +337,27 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv
{
struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
struct mlx5_esw_flow_attr *attr = flow->esw_attr;
- struct mlx5_flow_handle *rule;
+ struct net_device *out_dev, *encap_dev = NULL;
+ struct mlx5_flow_handle *rule = NULL;
+ struct mlx5e_rep_priv *rpriv;
+ struct mlx5e_priv *out_priv;
int err;

+ if (attr->action & MLX5_FLOW_CONTEXT_ACTION_ENCAP) {
+ out_dev = __dev_get_by_index(dev_net(priv->netdev),
+ attr->parse_attr->mirred_ifindex);
+ err = mlx5e_attach_encap(priv, &parse_attr->tun_info,
+ out_dev, &encap_dev, flow);
+ if (err) {
+ rule = ERR_PTR(err);
+ if (err != -EAGAIN)
+ goto err_attach_encap;
+ }
+ out_priv = netdev_priv(encap_dev);
+ rpriv = out_priv->ppriv;
+ attr->out_rep = rpriv->rep;
+ }
+
err = mlx5_eswitch_add_vlan_action(esw, attr);
if (err) {
rule = ERR_PTR(err);
@@ -347,10 +373,14 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv
}
}

- rule = mlx5_eswitch_add_offloaded_rule(esw, &parse_attr->spec, attr);
- if (IS_ERR(rule))
- goto err_add_rule;
-
+ /* we get here if (1) there's no error (rule being null) or when
+ * (2) there's an encap action and we're on -EAGAIN (no valid neigh)
+ */
+ if (rule != ERR_PTR(-EAGAIN)) {
+ rule = mlx5_eswitch_add_offloaded_rule(esw, &parse_attr->spec, attr);
+ if (IS_ERR(rule))
+ goto err_add_rule;
+ }
return rule;

err_add_rule:
@@ -361,6 +391,7 @@ err_mod_hdr:
err_add_vlan:
if (attr->action & MLX5_FLOW_CONTEXT_ACTION_ENCAP)
mlx5e_detach_encap(priv, flow);
+err_attach_encap:
return rule;
}

@@ -389,6 +420,8 @@ static void mlx5e_tc_del_fdb_flow(struct
void mlx5e_tc_encap_flows_add(struct mlx5e_priv *priv,
struct mlx5e_encap_entry *e)
{
+ struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
+ struct mlx5_esw_flow_attr *esw_attr;
struct mlx5e_tc_flow *flow;
int err;

@@ -404,10 +437,9 @@ void mlx5e_tc_encap_flows_add(struct mlx
mlx5e_rep_queue_neigh_stats_work(priv);

list_for_each_entry(flow, &e->flows, encap) {
- flow->esw_attr->encap_id = e->encap_id;
- flow->rule = mlx5e_tc_add_fdb_flow(priv,
- flow->esw_attr->parse_attr,
- flow);
+ esw_attr = flow->esw_attr;
+ esw_attr->encap_id = e->encap_id;
+ flow->rule = mlx5_eswitch_add_offloaded_rule(esw, &esw_attr->parse_attr->spec, esw_attr);
if (IS_ERR(flow->rule)) {
err = PTR_ERR(flow->rule);
mlx5_core_warn(priv->mdev, "Failed to update cached encapsulation flow, %d\n",
@@ -421,15 +453,13 @@ void mlx5e_tc_encap_flows_add(struct mlx
void mlx5e_tc_encap_flows_del(struct mlx5e_priv *priv,
struct mlx5e_encap_entry *e)
{
+ struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
struct mlx5e_tc_flow *flow;
- struct mlx5_fc *counter;

list_for_each_entry(flow, &e->flows, encap) {
if (flow->flags & MLX5E_TC_FLOW_OFFLOADED) {
flow->flags &= ~MLX5E_TC_FLOW_OFFLOADED;
- counter = mlx5_flow_rule_counter(flow->rule);
- mlx5_del_flow_rules(flow->rule);
- mlx5_fc_destroy(priv->mdev, counter);
+ mlx5_eswitch_del_offloaded_rule(esw, flow->rule, flow->esw_attr);
}
}

@@ -1871,7 +1901,7 @@ static int parse_tc_fdb_actions(struct m

if (is_tcf_mirred_egress_redirect(a)) {
int ifindex = tcf_mirred_ifindex(a);
- struct net_device *out_dev, *encap_dev = NULL;
+ struct net_device *out_dev;
struct mlx5e_priv *out_priv;

out_dev = __dev_get_by_index(dev_net(priv->netdev), ifindex);
@@ -1884,17 +1914,13 @@ static int parse_tc_fdb_actions(struct m
rpriv = out_priv->ppriv;
attr->out_rep = rpriv->rep;
} else if (encap) {
- err = mlx5e_attach_encap(priv, info,
- out_dev, &encap_dev, flow);
- if (err && err != -EAGAIN)
- return err;
+ parse_attr->mirred_ifindex = ifindex;
+ parse_attr->tun_info = *info;
+ attr->parse_attr = parse_attr;
attr->action |= MLX5_FLOW_CONTEXT_ACTION_ENCAP |
MLX5_FLOW_CONTEXT_ACTION_FWD_DEST |
MLX5_FLOW_CONTEXT_ACTION_COUNT;
- out_priv = netdev_priv(encap_dev);
- rpriv = out_priv->ppriv;
- attr->out_rep = rpriv->rep;
- attr->parse_attr = parse_attr;
+ /* attr->out_rep is resolved when we handle encap */
} else {
pr_err("devices %s %s not on same switch HW, can't offload forwarding\n",
priv->netdev->name, out_dev->name);
@@ -1972,7 +1998,7 @@ int mlx5e_configure_flower(struct mlx5e_
if (flow->flags & MLX5E_TC_FLOW_ESWITCH) {
err = parse_tc_fdb_actions(priv, f->exts, parse_attr, flow);
if (err < 0)
- goto err_handle_encap_flow;
+ goto err_free;
flow->rule = mlx5e_tc_add_fdb_flow(priv, parse_attr, flow);
} else {
err = parse_tc_nic_actions(priv, f->exts, parse_attr, flow);
@@ -1983,10 +2009,13 @@ int mlx5e_configure_flower(struct mlx5e_

if (IS_ERR(flow->rule)) {
err = PTR_ERR(flow->rule);
- goto err_free;
+ if (err != -EAGAIN)
+ goto err_free;
}

- flow->flags |= MLX5E_TC_FLOW_OFFLOADED;
+ if (err != -EAGAIN)
+ flow->flags |= MLX5E_TC_FLOW_OFFLOADED;
+
err = rhashtable_insert_fast(&tc->ht, &flow->node,
tc->ht_params);
if (err)
@@ -2000,16 +2029,6 @@ int mlx5e_configure_flower(struct mlx5e_
err_del_rule:
mlx5e_tc_del_flow(priv, flow);

-err_handle_encap_flow:
- if (err == -EAGAIN) {
- err = rhashtable_insert_fast(&tc->ht, &flow->node,
- tc->ht_params);
- if (err)
- mlx5e_tc_del_flow(priv, flow);
- else
- return 0;
- }
-
err_free:
kvfree(parse_attr);
kfree(flow);

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