From: Eric Joyner Date: Thu, 23 Jul 2026 04:13:42 +0000 (-0700) Subject: ethtool: Embed FEC hist ranges as buffer in struct X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97ac08560d236ca17f6606d9e671118e5eae5721;p=thirdparty%2Fkernel%2Fstable.git ethtool: Embed FEC hist ranges as buffer in struct When a driver's .get_fec_stats() handler is called and the driver supports FEC histogram stats, the driver supplies the histogram bin ranges via a pointer. This pointer is assigned while under the netdev ops lock in fec_prepare_data(), but the actual data is only read after the lock is released; so this allows the driver to change the ranges (e.g. from another .get_fec_stats() call) while the current call chain is reading them in fec_fill_reply(). Fix this by adding an ethtool core-owned buffer, ranges_buf, to struct ethtool_fec_hist. Drivers whose ranges are built dynamically (currently just mlx5) fill ranges_buf and then point the existing ranges pointer at it, giving ethtool a consistent copy that stays valid after the netdev ops lock is dropped and later in fec_fill_reply(). Drivers whose ranges are compile-time constants (bnxt, netdevsim) are unaffected by the potential race and keep setting the existing ranges pointer to their constant array, without making copies. Fixes: cc2f08129925 ("ethtool: add FEC bins histogram report") Signed-off-by: Eric Joyner Reviewed-by: Vadim Fedorenko Link: https://patch.msgid.link/20260723041342.39238-1-eric.joyner@amd.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index d507289096c2..6867a5aed42c 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -984,7 +984,6 @@ struct mlx5e_priv { struct mlx5e_mqprio_rl *mqprio_rl; struct dentry *dfs_root; struct mlx5_devcom_comp_dev *devcom; - struct ethtool_fec_hist_range *fec_ranges; }; static inline u16 mlx5e_stats_nch_read(const struct mlx5e_priv *priv) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index c1acb9012d3f..7d47a1da8b6b 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -6415,14 +6415,8 @@ int mlx5e_priv_init(struct mlx5e_priv *priv, if (!priv->channel_stats) goto err_free_tx_rates; - priv->fec_ranges = kzalloc_objs(*priv->fec_ranges, ETHTOOL_FEC_HIST_MAX); - if (!priv->fec_ranges) - goto err_free_channel_stats; - return 0; -err_free_channel_stats: - kfree(priv->channel_stats); err_free_tx_rates: kfree(priv->tx_rates); err_free_txq2sq_stats: @@ -6447,7 +6441,6 @@ void mlx5e_priv_cleanup(struct mlx5e_priv *priv) if (!priv->mdev) return; - kfree(priv->fec_ranges); for (i = 0; i < priv->stats_nch; i++) kvfree(priv->channel_stats[i]); kfree(priv->channel_stats); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c index de38b60806c2..e7e6db7f6bf1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c @@ -1550,7 +1550,7 @@ static bool fec_rs_validate_hist_type(int mode, int hist_type) static u8 fec_rs_histogram_fill_ranges(struct mlx5e_priv *priv, int mode, - const struct ethtool_fec_hist_range **ranges) + struct ethtool_fec_hist_range *ranges) { struct mlx5_core_dev *mdev = priv->mdev; u32 out[MLX5_ST_SZ_DW(pphcr_reg)] = {0}; @@ -1558,8 +1558,6 @@ fec_rs_histogram_fill_ranges(struct mlx5e_priv *priv, int mode, int sz = MLX5_ST_SZ_BYTES(pphcr_reg); u8 hist_type, num_of_bins; - memset(priv->fec_ranges, 0, - ETHTOOL_FEC_HIST_MAX * sizeof(*priv->fec_ranges)); MLX5_SET(pphcr_reg, in, local_port, 1); if (mlx5_core_access_reg(mdev, in, sz, out, sz, MLX5_REG_PPHCR, 0, 0)) return 0; @@ -1575,12 +1573,11 @@ fec_rs_histogram_fill_ranges(struct mlx5e_priv *priv, int mode, for (int i = 0; i < num_of_bins; i++) { void *bin_range = MLX5_ADDR_OF(pphcr_reg, out, bin_range[i]); - priv->fec_ranges[i].high = MLX5_GET(bin_range_layout, bin_range, - high_val); - priv->fec_ranges[i].low = MLX5_GET(bin_range_layout, bin_range, - low_val); + ranges[i].high = MLX5_GET(bin_range_layout, bin_range, + high_val); + ranges[i].low = MLX5_GET(bin_range_layout, bin_range, + low_val); } - *ranges = priv->fec_ranges; return num_of_bins; } @@ -1622,10 +1619,12 @@ static void fec_set_histograms_stats(struct mlx5e_priv *priv, int mode, case MLX5E_FEC_LLRS_272_257_1: case MLX5E_FEC_RS_544_514_INTERLEAVED_QUAD: num_of_bins = - fec_rs_histogram_fill_ranges(priv, mode, &hist->ranges); - if (num_of_bins) + fec_rs_histogram_fill_ranges(priv, mode, hist->ranges_buf); + if (num_of_bins) { + hist->ranges = hist->ranges_buf; return fec_rs_histogram_fill_stats(priv, num_of_bins, hist); + } break; default: return; diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 5d491a98265e..12683b5d125e 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -562,6 +562,7 @@ struct ethtool_fec_hist { u64 per_lane[ETHTOOL_MAX_LANES]; } values[ETHTOOL_FEC_HIST_MAX]; const struct ethtool_fec_hist_range *ranges; + struct ethtool_fec_hist_range ranges_buf[ETHTOOL_FEC_HIST_MAX]; }; /** * struct ethtool_fec_stats - statistics for IEEE 802.3 FEC