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veth: prevent oops caused by netdev destructor
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From: Stephen Hemminger <shemminger@vyatta.com>

The veth driver will oops if sysfs hooks are open while module is removed.

The net device destructor can not point to code in a module; basically
there are only two possible safe values: NULL - no destructor, or
free_netdev - free on last use

Signed-off-by: David S. Miller <davem@davemloft.net>
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Stephen Hemminger authored and David S. Miller committed Apr 27, 2009
1 parent 6a783c9 commit ae0e8e8
Showing 1 changed file with 16 additions and 25 deletions.
41 changes: 16 additions & 25 deletions drivers/net/veth.c
Original file line number Diff line number Diff line change
Expand Up @@ -210,31 +210,29 @@ static int veth_xmit(struct sk_buff *skb, struct net_device *dev)

static struct net_device_stats *veth_get_stats(struct net_device *dev)
{
struct veth_priv *priv;
struct net_device_stats *dev_stats;
int cpu;
struct veth_priv *priv = netdev_priv(dev);
struct net_device_stats *dev_stats = &dev->stats;
unsigned int cpu;
struct veth_net_stats *stats;

priv = netdev_priv(dev);
dev_stats = &dev->stats;

dev_stats->rx_packets = 0;
dev_stats->tx_packets = 0;
dev_stats->rx_bytes = 0;
dev_stats->tx_bytes = 0;
dev_stats->tx_dropped = 0;
dev_stats->rx_dropped = 0;

for_each_online_cpu(cpu) {
stats = per_cpu_ptr(priv->stats, cpu);
if (priv->stats)
for_each_online_cpu(cpu) {
stats = per_cpu_ptr(priv->stats, cpu);

dev_stats->rx_packets += stats->rx_packets;
dev_stats->tx_packets += stats->tx_packets;
dev_stats->rx_bytes += stats->rx_bytes;
dev_stats->tx_bytes += stats->tx_bytes;
dev_stats->tx_dropped += stats->tx_dropped;
dev_stats->rx_dropped += stats->rx_dropped;
}
dev_stats->rx_packets += stats->rx_packets;
dev_stats->tx_packets += stats->tx_packets;
dev_stats->rx_bytes += stats->rx_bytes;
dev_stats->tx_bytes += stats->tx_bytes;
dev_stats->tx_dropped += stats->tx_dropped;
dev_stats->rx_dropped += stats->rx_dropped;
}

return dev_stats;
}
Expand All @@ -261,6 +259,8 @@ static int veth_close(struct net_device *dev)
netif_carrier_off(dev);
netif_carrier_off(priv->peer);

free_percpu(priv->stats);
priv->stats = NULL;
return 0;
}

Expand Down Expand Up @@ -291,15 +291,6 @@ static int veth_dev_init(struct net_device *dev)
return 0;
}

static void veth_dev_free(struct net_device *dev)
{
struct veth_priv *priv;

priv = netdev_priv(dev);
free_percpu(priv->stats);
free_netdev(dev);
}

static const struct net_device_ops veth_netdev_ops = {
.ndo_init = veth_dev_init,
.ndo_open = veth_open,
Expand All @@ -317,7 +308,7 @@ static void veth_setup(struct net_device *dev)
dev->netdev_ops = &veth_netdev_ops;
dev->ethtool_ops = &veth_ethtool_ops;
dev->features |= NETIF_F_LLTX;
dev->destructor = veth_dev_free;
dev->destructor = free_netdev;
}

/*
Expand Down

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