[PATCH] net/mlx5: fix access to auxiliary flow data

Gregory Etelson getelson at nvidia.com
Wed Jun 25 11:43:39 CEST 2025


The MLX5 PMD keeps non-essential flow data in an auxiliary structure
to reduce flow L1 cache usage.

The auxiliary data location differs in HWS and non-template flows.

The PMD tried to fetch HWS flow table from a non-template flow object
and accessed stale memory address.

The patch separates the `mlx5_flow_hw_aux()` implementation for HWS
and non-template flows

Fixes: 27d171b88031 ("net/mlx5: abstract flow action and enable reconfigure")
Cc: stable at dpdk.org

Signed-off-by: Gregory Etelson <getelson at nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnowski at nvidia.com>
---
 drivers/net/mlx5/mlx5_flow_hw.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_flow_hw.c b/drivers/net/mlx5/mlx5_flow_hw.c
index af2e7a84a5..d65f4cf4e2 100644
--- a/drivers/net/mlx5/mlx5_flow_hw.c
+++ b/drivers/net/mlx5/mlx5_flow_hw.c
@@ -129,12 +129,16 @@ mlx5_flow_hw_aux(uint16_t port_id, struct rte_flow_hw *flow)
 {
 	struct rte_flow_template_table *table = flow->table;
 
-	if (rte_flow_template_table_resizable(port_id, &table->cfg.attr)) {
-		size_t offset = sizeof(struct rte_flow_hw) + mlx5dr_rule_get_handle_size();
+	if (!flow->nt_rule) {
+		if (rte_flow_template_table_resizable(port_id, &table->cfg.attr)) {
+			size_t offset = sizeof(struct rte_flow_hw) + mlx5dr_rule_get_handle_size();
 
-		return RTE_PTR_ADD(flow, offset);
+			return RTE_PTR_ADD(flow, offset);
+		} else {
+			return &table->flow_aux[flow->idx - 1];
+		}
 	} else {
-		return ((flow->nt_rule) ? flow->nt2hws->flow_aux : &table->flow_aux[flow->idx - 1]);
+		return flow->nt2hws->flow_aux;
 	}
 }
 
-- 
2.48.1



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