net: Fix ipoib rtnl_lock sysfs deadlock.

Network device sysfs files that grab the rtnl_lock unconditionally
will deadlock if accessed when the network device is being
unregistered.  So use trylock and syscall_restart to avoid this
deadlock.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2009-05-13 17:01:51 +00:00 committed by David S. Miller
parent af38f29895
commit 26574401fe
2 changed files with 8 additions and 4 deletions

View File

@ -1455,13 +1455,15 @@ static ssize_t set_mode(struct device *d, struct device_attribute *attr,
struct net_device *dev = to_net_dev(d); struct net_device *dev = to_net_dev(d);
struct ipoib_dev_priv *priv = netdev_priv(dev); struct ipoib_dev_priv *priv = netdev_priv(dev);
if (!rtnl_trylock())
return restart_syscall();
/* flush paths if we switch modes so that connections are restarted */ /* flush paths if we switch modes so that connections are restarted */
if (IPOIB_CM_SUPPORTED(dev->dev_addr) && !strcmp(buf, "connected\n")) { if (IPOIB_CM_SUPPORTED(dev->dev_addr) && !strcmp(buf, "connected\n")) {
set_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags); set_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags);
ipoib_warn(priv, "enabling connected mode " ipoib_warn(priv, "enabling connected mode "
"will cause multicast packet drops\n"); "will cause multicast packet drops\n");
rtnl_lock();
dev->features &= ~(NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO); dev->features &= ~(NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO);
rtnl_unlock(); rtnl_unlock();
priv->tx_wr.send_flags &= ~IB_SEND_IP_CSUM; priv->tx_wr.send_flags &= ~IB_SEND_IP_CSUM;
@ -1473,7 +1475,6 @@ static ssize_t set_mode(struct device *d, struct device_attribute *attr,
if (!strcmp(buf, "datagram\n")) { if (!strcmp(buf, "datagram\n")) {
clear_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags); clear_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags);
rtnl_lock();
if (test_bit(IPOIB_FLAG_CSUM, &priv->flags)) { if (test_bit(IPOIB_FLAG_CSUM, &priv->flags)) {
dev->features |= NETIF_F_IP_CSUM | NETIF_F_SG; dev->features |= NETIF_F_IP_CSUM | NETIF_F_SG;
if (priv->hca_caps & IB_DEVICE_UD_TSO) if (priv->hca_caps & IB_DEVICE_UD_TSO)
@ -1485,6 +1486,7 @@ static ssize_t set_mode(struct device *d, struct device_attribute *attr,
return count; return count;
} }
rtnl_unlock();
return -EINVAL; return -EINVAL;
} }

View File

@ -61,7 +61,8 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
ppriv = netdev_priv(pdev); ppriv = netdev_priv(pdev);
rtnl_lock(); if (!rtnl_trylock())
return restart_syscall();
mutex_lock(&ppriv->vlan_mutex); mutex_lock(&ppriv->vlan_mutex);
/* /*
@ -167,7 +168,8 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
ppriv = netdev_priv(pdev); ppriv = netdev_priv(pdev);
rtnl_lock(); if (!rtnl_trylock())
return restart_syscall();
mutex_lock(&ppriv->vlan_mutex); mutex_lock(&ppriv->vlan_mutex);
list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) { list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) {
if (priv->pkey == pkey) { if (priv->pkey == pkey) {