Re: [PATCH net-next] mlx4: fix use-after-free in mlx4_en_fold_software_stats()

[David Miller]

From: Eric Dumazet 
Date: Thu, 01 Dec 2016 05:02:06 -0800

> From: Eric Dumazet 
> 
> My recent commit to get more precise rx/tx counters in ndo_get_stats64()
> can lead to crashes at device dismantle, as Jesper found out.
> 
> We must prevent mlx4_en_fold_software_stats() trying to access
> tx/rx rings if they are deleted.
> 
> Fix this by adding a test against priv->port_up in
> mlx4_en_fold_software_stats()
> 
> Calling mlx4_en_fold_software_stats() from mlx4_en_stop_port()
> allows us to eventually broadcast the latest/current counters to
> rtnetlink monitors.
> 
> Fixes: 40931b85113d ("mlx4: give precise rx/tx bytes/packets counters")
> Signed-off-by: Eric Dumazet 
> Reported-and-bisected-by: Jesper Dangaard Brouer 
> Tested-by: Jesper Dangaard Brouer 

Applied.

Re: [PATCH net-next] mlx4: fix use-after-free in mlx4_en_fold_software_stats()

[Saeed Mahameed]

On Thu, Dec 1, 2016 at 3:02 PM, Eric Dumazet  wrote:
> From: Eric Dumazet 
>
> My recent commit to get more precise rx/tx counters in ndo_get_stats64()
> can lead to crashes at device dismantle, as Jesper found out.
>
> We must prevent mlx4_en_fold_software_stats() trying to access
> tx/rx rings if they are deleted.
>
> Fix this by adding a test against priv->port_up in
> mlx4_en_fold_software_stats()
>
> Calling mlx4_en_fold_software_stats() from mlx4_en_stop_port()
> allows us to eventually broadcast the latest/current counters to
> rtnetlink monitors.
>
> Fixes: 40931b85113d ("mlx4: give precise rx/tx bytes/packets counters")
> Signed-off-by: Eric Dumazet 
> Reported-and-bisected-by: Jesper Dangaard Brouer 
> Tested-by: Jesper Dangaard Brouer 
> Cc: Tariq Toukan 
> Cc: Saeed Mahameed 

Acked-by: Saeed Mahameed 

[PATCH net-next] mlx4: fix use-after-free in mlx4_en_fold_software_stats()

[Eric Dumazet]

From: Eric Dumazet 

My recent commit to get more precise rx/tx counters in ndo_get_stats64()
can lead to crashes at device dismantle, as Jesper found out.

We must prevent mlx4_en_fold_software_stats() trying to access
tx/rx rings if they are deleted.

Fix this by adding a test against priv->port_up in
mlx4_en_fold_software_stats()

Calling mlx4_en_fold_software_stats() from mlx4_en_stop_port()
allows us to eventually broadcast the latest/current counters to
rtnetlink monitors.

Fixes: 40931b85113d ("mlx4: give precise rx/tx bytes/packets counters")
Signed-off-by: Eric Dumazet 
Reported-and-bisected-by: Jesper Dangaard Brouer 
Tested-by: Jesper Dangaard Brouer 
Cc: Tariq Toukan 
Cc: Saeed Mahameed 
---
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c |4 
 drivers/net/ethernet/mellanox/mlx4/en_port.c   |2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c 
b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 
12ea3405f442717478bf0e8882edaf0de77986cb..091b904262bc7932d3edf99cf850affb23b9ce6e
 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -1809,8 +1809,12 @@ void mlx4_en_stop_port(struct net_device *dev, int 
detach)
 
netif_tx_disable(dev);
 
+   spin_lock_bh(>stats_lock);
+   mlx4_en_fold_software_stats(dev);
/* Set port as not active */
priv->port_up = false;
+   spin_unlock_bh(>stats_lock);
+
priv->counter_index = MLX4_SINK_COUNTER_INDEX(mdev->dev);
 
/* Promsicuous mode */
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_port.c 
b/drivers/net/ethernet/mellanox/mlx4/en_port.c
index 
c6c4f1238923e09eced547454b86c68720292859..9166d90e732858610b1407fe85cbf6cbe27f5e0b
 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_port.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_port.c
@@ -154,7 +154,7 @@ void mlx4_en_fold_software_stats(struct net_device *dev)
unsigned long packets, bytes;
int i;
 
-   if (mlx4_is_master(mdev->dev))
+   if (!priv->port_up || mlx4_is_master(mdev->dev))
return;
 
packets = 0;