[bug report] net/mlx5: Change TTC rules to match on undecrypted ESP packets

[Dan Carpenter <error27@gmail.com>]

Hello Jianbo Liu,

Commit 9f24f0c4d4dd ("net/mlx5: Change TTC rules to match on
undecrypted ESP packets") from Sep 18, 2025 (linux-next), leads to
the following Smatch static checker warning:

	drivers/net/ethernet/mellanox/mlx5/core/lib/fs_ttc.c:614 mlx5_create_ttc_table_groups()
	warn: passing zero to 'PTR_ERR'

drivers/net/ethernet/mellanox/mlx5/core/lib/fs_ttc.c
    529 static int mlx5_create_ttc_table_groups(struct mlx5_ttc_table *ttc,
    530                                         bool use_ipv)
    531 {
    532         const struct mlx5_fs_ttc_groups *groups = ttc->groups;
    533         int inlen = MLX5_ST_SZ_BYTES(create_flow_group_in);
    534         int ix = 0;
    535         u32 *in;
    536         int err;
    537         u8 *mc;
    538 
    539         ttc->g = kzalloc_objs(*ttc->g, groups->num_groups);
    540         if (!ttc->g)
    541                 return -ENOMEM;
    542         in = kvzalloc(inlen, GFP_KERNEL);
    543         if (!in) {
    544                 kfree(ttc->g);
    545                 ttc->g = NULL;
    546                 return -ENOMEM;
    547         }
    548 
    549         mc = MLX5_ADDR_OF(create_flow_group_in, in, match_criteria);
    550         if (use_ipv)
    551                 MLX5_SET_TO_ONES(fte_match_param, mc, outer_headers.ip_version);
    552         else
    553                 MLX5_SET_TO_ONES(fte_match_param, mc, outer_headers.ethertype);
    554         MLX5_SET_CFG(in, match_criteria_enable, MLX5_MATCH_OUTER_HEADERS);
    555 
    556         /* TCP UDP group */
    557         if (groups->use_l4_type) {
    558                 MLX5_SET_TO_ONES(fte_match_param, mc, outer_headers.l4_type);
    559                 MLX5_SET_CFG(in, start_flow_index, ix);
    560                 ix += groups->group_size[ttc->num_groups];
    561                 MLX5_SET_CFG(in, end_flow_index, ix - 1);
    562                 ttc->g[ttc->num_groups] = mlx5_create_flow_group(ttc->t, in);
    563                 if (IS_ERR(ttc->g[ttc->num_groups]))
    564                         goto err;
    565                 ttc->num_groups++;
    566 
    567                 MLX5_SET(fte_match_param, mc, outer_headers.l4_type, 0);
    568         }
    569 
    570         /* L4 Group */
    571         MLX5_SET_TO_ONES(fte_match_param, mc, outer_headers.ip_protocol);
    572         MLX5_SET_CFG(in, start_flow_index, ix);
    573         ix += groups->group_size[ttc->num_groups];
    574         MLX5_SET_CFG(in, end_flow_index, ix - 1);
    575         ttc->g[ttc->num_groups] = mlx5_create_flow_group(ttc->t, in);
    576         if (IS_ERR(ttc->g[ttc->num_groups]))
    577                 goto err;
    578         ttc->num_groups++;
    579 
    580         if (mlx5_ttc_has_esp_flow_group(ttc)) {
    581                 err = mlx5_create_ttc_table_ipsec_groups(ttc, use_ipv, in, &ix);
    582                 if (err)
    583                         goto err;


The error code is supposed to stored in ttc->g[ttc->num_groups].
(don't look at me, I didn't invent the rules).

    584 
    585                 MLX5_SET(fte_match_param, mc,
    586                          misc_parameters_2.ipsec_next_header, 0);
    587         }
    588 
    589         /* L3 Group */
    590         MLX5_SET(fte_match_param, mc, outer_headers.ip_protocol, 0);
    591         MLX5_SET_CFG(in, match_criteria_enable, MLX5_MATCH_OUTER_HEADERS);
    592         MLX5_SET_CFG(in, start_flow_index, ix);
    593         ix += groups->group_size[ttc->num_groups];
    594         MLX5_SET_CFG(in, end_flow_index, ix - 1);
    595         ttc->g[ttc->num_groups] = mlx5_create_flow_group(ttc->t, in);
    596         if (IS_ERR(ttc->g[ttc->num_groups]))
    597                 goto err;
    598         ttc->num_groups++;
    599 
    600         /* Any Group */
    601         memset(in, 0, inlen);
    602         MLX5_SET_CFG(in, start_flow_index, ix);
    603         ix += groups->group_size[ttc->num_groups];
    604         MLX5_SET_CFG(in, end_flow_index, ix - 1);
    605         ttc->g[ttc->num_groups] = mlx5_create_flow_group(ttc->t, in);
    606         if (IS_ERR(ttc->g[ttc->num_groups]))
    607                 goto err;
    608         ttc->num_groups++;
    609 
    610         kvfree(in);
    611         return 0;
    612 
    613 err:
--> 614         err = PTR_ERR(ttc->g[ttc->num_groups]);
    615         ttc->g[ttc->num_groups] = NULL;
    616         kvfree(in);
    617 
    618         return err;
    619 }

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regards,
dan carpenter