net/mlx5: fix GCC uninitialized variable warning
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Commit Message
When building with -Db_sanitize=thread, GCC gives a warning:
drivers/net/mlx5/mlx5_flow_meter.c: In function ‘mlx5_flow_meter_create’:
drivers/net/mlx5/mlx5_flow_meter.c:1170:33: warning: ‘legacy_fm’ may be
used uninitialized in this function [-Wmaybe-uninitialized]
This is a false-positive: legacy_fm is initialized and used
if and only if priv->sh->meter_aso_en is false.
Work around this by initializing legacy_fm to NULL.
Add an assertion before legacy_fm use in case the logic changes.
Fixes: 444320186393 ("net/mlx5: support meter creation with policy")
Cc: lizh@nvidia.com
Cc: stable@dpdk.org
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
drivers/net/mlx5/mlx5_flow_meter.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
Comments
Hi,
> -----Original Message-----
> From: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
> Sent: Tuesday, December 28, 2021 11:17 AM
> To: dev@dpdk.org
> Cc: Li Zhang <lizh@nvidia.com>; stable@dpdk.org; Stephen Hemminger
> <stephen@networkplumber.org>; Matan Azrad <matan@nvidia.com>; Slava
> Ovsiienko <viacheslavo@nvidia.com>
> Subject: [PATCH] net/mlx5: fix GCC uninitialized variable warning
>
> When building with -Db_sanitize=thread, GCC gives a warning:
>
> drivers/net/mlx5/mlx5_flow_meter.c: In function
> ‘mlx5_flow_meter_create’:
> drivers/net/mlx5/mlx5_flow_meter.c:1170:33: warning: ‘legacy_fm’ may be
> used uninitialized in this function [-Wmaybe-uninitialized]
>
> This is a false-positive: legacy_fm is initialized and used if and only if priv->sh-
> >meter_aso_en is false.
> Work around this by initializing legacy_fm to NULL.
> Add an assertion before legacy_fm use in case the logic changes.
>
> Fixes: 444320186393 ("net/mlx5: support meter creation with policy")
> Cc: lizh@nvidia.com
> Cc: stable@dpdk.org
>
> Reported-by: Stephen Hemminger <stephen@networkplumber.org>
> Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
Patch applied to next-net-mlx,
Kindest regards,
Raslan Darawsheh
@@ -1167,7 +1167,8 @@ mlx5_flow_meter_create(struct rte_eth_dev *dev, uint32_t meter_id,
struct mlx5_legacy_flow_meters *fms = &priv->flow_meters;
struct mlx5_flow_meter_profile *fmp;
struct mlx5_flow_meter_info *fm;
- struct mlx5_legacy_flow_meter *legacy_fm;
+ /* GCC fails to infer legacy_fm is set when !priv->sh->meter_aso_en. */
+ struct mlx5_legacy_flow_meter *legacy_fm = NULL;
struct mlx5_flow_meter_policy *mtr_policy = NULL;
struct mlx5_indexed_pool_config flow_ipool_cfg = {
.size = 0,
@@ -1273,8 +1274,10 @@ mlx5_flow_meter_create(struct rte_eth_dev *dev, uint32_t meter_id,
if (mlx5_flow_create_mtr_tbls(dev, fm, mtr_idx, domain_bitmap))
goto error;
/* Add to the flow meter list. */
- if (!priv->sh->meter_aso_en)
+ if (!priv->sh->meter_aso_en) {
+ MLX5_ASSERT(legacy_fm != NULL);
TAILQ_INSERT_TAIL(fms, legacy_fm, next);
+ }
/* Add to the flow meter list. */
fm->active_state = 1; /* Config meter starts as active. */
fm->is_enable = 1;