From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH] veth: prevent oops caused by netdev destructor Date: Thu, 23 Apr 2009 21:41:20 -0700 Message-ID: <20090423214120.22bcc680@nehalam> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Miller , Pavel Emelyanov Return-path: Received: from mail.vyatta.com ([76.74.103.46]:50360 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753038AbZDXEl0 (ORCPT ); Fri, 24 Apr 2009 00:41:26 -0400 Sender: netdev-owner@vger.kernel.org List-ID: 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 Index: linux-2.6/drivers/net/veth.c =================================================================== --- linux-2.6.orig/drivers/net/veth.c 2009-04-22 14:28:28.074579878 -0700 +++ linux-2.6/drivers/net/veth.c 2009-04-22 14:36:35.947231135 -0700 @@ -210,14 +210,11 @@ 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; @@ -225,16 +222,17 @@ dev_stats->tx_dropped = 0; dev_stats->rx_dropped = 0; - 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; - } + 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; + } return dev_stats; } @@ -261,6 +259,8 @@ netif_carrier_off(dev); netif_carrier_off(priv->peer); + free_percpu(priv->stats); + priv->stats = NULL; return 0; } @@ -291,15 +291,6 @@ 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, @@ -317,7 +308,7 @@ 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; } /*