Subject: [net V2 07/14] net/mlx5e: Fix cleanup null-ptr deref on encap lock

From: Saeed Mahameed <[email-masked]>
Date: Wed, 15 Mar 2023 15:58:40 -0700

From: Paul Blakey <[email-masked]>

During module is unloaded while a peer tc flow is still offloaded,
first the peer uplink rep profile is changed to a nic profile, and so
neigh encap lock is destroyed. Next during unload, the VF reps netdevs
are unregistered which causes the original non-peer tc flow to be deleted,
which deletes the peer flow. The peer flow deletion detaches the encap
entry and try to take the already destroyed encap lock, causing the
below trace.

Fix this by clearing peer flows during tc eswitch cleanup
(mlx5e_tc_esw_cleanup()).

Relevant trace:
[ 4316.837128] BUG: kernel NULL pointer dereference, address: 00000000000001d8
[ 4316.842239] RIP: 0010:__mutex_lock+0xb5/0xc40
[ 4316.851897] Call Trace:
[ 4316.852481]  <TASK>
[ 4316.857214]  mlx5e_rep_neigh_entry_release+0x93/0x790 [mlx5_core]
[ 4316.858258]  mlx5e_rep_encap_entry_detach+0xa7/0xf0 [mlx5_core]
[ 4316.859134]  mlx5e_encap_dealloc+0xa3/0xf0 [mlx5_core]
[ 4316.859867]  clean_encap_dests.part.0+0x5c/0xe0 [mlx5_core]
[ 4316.860605]  mlx5e_tc_del_fdb_flow+0x32a/0x810 [mlx5_core]
[ 4316.862609]  __mlx5e_tc_del_fdb_peer_flow+0x1a2/0x250 [mlx5_core]
[ 4316.863394]  mlx5e_tc_del_flow+0x(/0x630 [mlx5_core]
[ 4316.864090]  mlx5e_flow_put+0x5f/0x100 [mlx5_core]
[ 4316.864771]  mlx5e_delete_flower+0x4de/0xa40 [mlx5_core]
[ 4316.865486]  tc_setup_cb_reoffload+0x20/0x80
[ 4316.865905]  fl_reoffload+0x47c/0x510 [cls_flower]
[ 4316.869181]  tcf_block_playback_offloads+0x91/0x1d0
[ 4316.869649]  tcf_block_unbind+0xe7/0x1b0
[ 4316.870049]  tcf_block_offload_cmd.isra.0+0x1ee/0x270
[ 4316.879266]  tcf_block_offload_unbind+0x61/0xa0
[ 4316.879711]  __tcf_block_put+0xa4/0x310

Fixes: 04de7dda7394 ("net/mlx5e: Infrastructure for duplicated offloading of TC flows")
Fixes: 1418ddd96afd ("net/mlx5e: Duplicate offloaded TC eswitch rules under uplink LAG")
Signed-off-by: Paul Blakey <[email-masked]>
Reviewed-by: Chris Mi <[email-masked]>
Reviewed-by: Roi Dayan <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 90944bf271ce..cc35cbc9934d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -5464,6 +5464,16 @@ int mlx5e_tc_esw_init(struct mlx5_rep_uplink_priv *uplink_priv)
 
 void mlx5e_tc_esw_cleanup(struct mlx5_rep_uplink_priv *uplink_priv)
 {
+	struct mlx5e_rep_priv *rpriv;
+	struct mlx5_eswitch *esw;
+	struct mlx5e_priv *priv;
+
+	rpriv = container_of(uplink_priv, struct mlx5e_rep_priv, uplink_priv);
+	priv = netdev_priv(rpriv->netdev);
+	esw = priv->mdev->priv.eswitch;
+
+	mlx5e_tc_clean_fdb_peer_flows(esw);
+
 	mlx5e_tc_tun_cleanup(uplink_priv->encap);
 
 	mapping_destroy(uplink_priv->tunnel_enc_opts_mapping);
-- 
2.39.2