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author | Martin KaFai Lau <kafai@fb.com> | 2017-04-20 21:40:12 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2017-04-24 12:15:08 -0400 |
commit | 1510d728639e183b60bd1285b09a49c393923ba5 (patch) | |
tree | 142551007497a75149a52a9be931296074aa95b8 /drivers/net/ethernet/mellanox/mlx5/core | |
parent | 94836ecf1e7378b64d37624fbb81fe48fbd4c772 (diff) | |
download | op-kernel-dev-1510d728639e183b60bd1285b09a49c393923ba5.zip op-kernel-dev-1510d728639e183b60bd1285b09a49c393923ba5.tar.gz |
net/mlx5e: Fix race in mlx5e_sw_stats and mlx5e_vport_stats
We have observed a sudden spike in rx/tx_packets and rx/tx_bytes
reported under /proc/net/dev. There is a race in mlx5e_update_stats()
and some of the get-stats functions (the one that we hit is the
mlx5e_get_stats() which is called by ndo_get_stats64()).
In particular, the very first thing mlx5e_update_sw_counters()
does is 'memset(s, 0, sizeof(*s))'. For example, if mlx5e_get_stats()
is unlucky at one point, rx_bytes and rx_packets could be 0. One second
later, a normal (and much bigger than 0) value will be reported.
This patch is to use a 'struct mlx5e_sw_stats temp' to avoid
a direct memset zero on priv->stats.sw.
mlx5e_update_vport_counters() has a similar race. Hence, addressed
together. However, memset zero is removed instead because
it is not needed.
I am lucky enough to catch this 0-reset in rx multicast:
eth0: 41457665 76804 70 0 0 70 0 47085 15586634 87502 3 0 0 0 3 0
eth0: 41459860 76815 70 0 0 70 0 47094 15588376 87516 3 0 0 0 3 0
eth0: 41460577 76822 70 0 0 70 0 0 15589083 87521 3 0 0 0 3 0
eth0: 41463293 76838 70 0 0 70 0 47108 15595872 87538 3 0 0 0 3 0
eth0: 41463379 76839 70 0 0 70 0 47116 15596138 87539 3 0 0 0 3 0
v2: Remove memset zero from mlx5e_update_vport_counters()
v1: Use temp and memcpy
Fixes: 9218b44dcc05 ("net/mlx5e: Statistics handling refactoring")
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/mellanox/mlx5/core')
-rw-r--r-- | drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 66c1337..15cc7b4 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -174,7 +174,7 @@ unlock: static void mlx5e_update_sw_counters(struct mlx5e_priv *priv) { - struct mlx5e_sw_stats *s = &priv->stats.sw; + struct mlx5e_sw_stats temp, *s = &temp; struct mlx5e_rq_stats *rq_stats; struct mlx5e_sq_stats *sq_stats; u64 tx_offload_none = 0; @@ -229,6 +229,7 @@ static void mlx5e_update_sw_counters(struct mlx5e_priv *priv) s->link_down_events_phy = MLX5_GET(ppcnt_reg, priv->stats.pport.phy_counters, counter_set.phys_layer_cntrs.link_down_events); + memcpy(&priv->stats.sw, s, sizeof(*s)); } static void mlx5e_update_vport_counters(struct mlx5e_priv *priv) @@ -243,7 +244,6 @@ static void mlx5e_update_vport_counters(struct mlx5e_priv *priv) MLX5_SET(query_vport_counter_in, in, op_mod, 0); MLX5_SET(query_vport_counter_in, in, other_vport, 0); - memset(out, 0, outlen); mlx5_cmd_exec(mdev, in, sizeof(in), out, outlen); } |