From f06d0ca45827a5790d7508de4759aed976933d4d Mon Sep 17 00:00:00 2001 From: Yamin Friedman Date: Tue, 23 Jul 2019 10:22:47 +0300 Subject: [PATCH] linux/dim: Fix overflow in dim calculation While using net_dim, a dim_sample was used without ever initializing the comps value. Added use of DIV_ROUND_DOWN_ULL() to prevent potential overflow, it should not be a problem to save the final result in an int because after the division by epms the value should not be larger than a few thousand. [ 1040.127124] UBSAN: Undefined behaviour in lib/dim/dim.c:78:23 [ 1040.130118] signed integer overflow: [ 1040.131643] 134718714 * 100 cannot be represented in type 'int' Fixes: 398c2b05bbee ("linux/dim: Add completions count to dim_sample") Signed-off-by: Yamin Friedman Signed-off-by: Leon Romanovsky Acked-by: Saeed Mahameed Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bcmsysport.c | 2 +- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 +- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 2 +- drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 4 ++-- lib/dim/dim.c | 4 ++-- 5 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c index b9c5cea8db16..9483553ce444 100644 --- a/drivers/net/ethernet/broadcom/bcmsysport.c +++ b/drivers/net/ethernet/broadcom/bcmsysport.c @@ -992,7 +992,7 @@ static int bcm_sysport_poll(struct napi_struct *napi, int budget) { struct bcm_sysport_priv *priv = container_of(napi, struct bcm_sysport_priv, napi); - struct dim_sample dim_sample; + struct dim_sample dim_sample = {}; unsigned int work_done = 0; work_done = bcm_sysport_desc_rx(priv, budget); diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 7134d2c3eb1c..7070349915bc 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -2136,7 +2136,7 @@ static int bnxt_poll(struct napi_struct *napi, int budget) } } if (bp->flags & BNXT_FLAG_DIM) { - struct dim_sample dim_sample; + struct dim_sample dim_sample = {}; dim_update_sample(cpr->event_ctr, cpr->rx_packets, diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c index a2b57807453b..d3a0b614dbfa 100644 --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -1895,7 +1895,7 @@ static int bcmgenet_rx_poll(struct napi_struct *napi, int budget) { struct bcmgenet_rx_ring *ring = container_of(napi, struct bcmgenet_rx_ring, napi); - struct dim_sample dim_sample; + struct dim_sample dim_sample = {}; unsigned int work_done; work_done = bcmgenet_desc_rx(ring, budget); diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c index c50b6f0769c8..49b06b256c92 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c @@ -49,7 +49,7 @@ static inline bool mlx5e_channel_no_affinity_change(struct mlx5e_channel *c) static void mlx5e_handle_tx_dim(struct mlx5e_txqsq *sq) { struct mlx5e_sq_stats *stats = sq->stats; - struct dim_sample dim_sample; + struct dim_sample dim_sample = {}; if (unlikely(!test_bit(MLX5E_SQ_STATE_AM, &sq->state))) return; @@ -61,7 +61,7 @@ static void mlx5e_handle_tx_dim(struct mlx5e_txqsq *sq) static void mlx5e_handle_rx_dim(struct mlx5e_rq *rq) { struct mlx5e_rq_stats *stats = rq->stats; - struct dim_sample dim_sample; + struct dim_sample dim_sample = {}; if (unlikely(!test_bit(MLX5E_RQ_STATE_AM, &rq->state))) return; diff --git a/lib/dim/dim.c b/lib/dim/dim.c index 439d641ec796..38045d6d0538 100644 --- a/lib/dim/dim.c +++ b/lib/dim/dim.c @@ -74,8 +74,8 @@ void dim_calc_stats(struct dim_sample *start, struct dim_sample *end, delta_us); curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us); if (curr_stats->epms != 0) - curr_stats->cpe_ratio = - (curr_stats->cpms * 100) / curr_stats->epms; + curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL( + curr_stats->cpms * 100, curr_stats->epms); else curr_stats->cpe_ratio = 0;