From 26574401fef6766f6c3ca25b5c13febe662d2a32 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 13 May 2009 17:01:51 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 6 ++++-- drivers/infiniband/ulp/ipoib/ipoib_vlan.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 47d588ba2a7f..4248c3139364 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -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 ipoib_dev_priv *priv = netdev_priv(dev); + if (!rtnl_trylock()) + return restart_syscall(); + /* flush paths if we switch modes so that connections are restarted */ if (IPOIB_CM_SUPPORTED(dev->dev_addr) && !strcmp(buf, "connected\n")) { set_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags); ipoib_warn(priv, "enabling connected mode " "will cause multicast packet drops\n"); - rtnl_lock(); dev->features &= ~(NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO); rtnl_unlock(); 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")) { clear_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags); - rtnl_lock(); if (test_bit(IPOIB_FLAG_CSUM, &priv->flags)) { dev->features |= NETIF_F_IP_CSUM | NETIF_F_SG; 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; } + rtnl_unlock(); return -EINVAL; } diff --git a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c index 4c57f329dd50..e3bf00d8cd25 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c @@ -61,7 +61,8 @@ int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey) ppriv = netdev_priv(pdev); - rtnl_lock(); + if (!rtnl_trylock()) + return restart_syscall(); mutex_lock(&ppriv->vlan_mutex); /* @@ -167,7 +168,8 @@ int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey) ppriv = netdev_priv(pdev); - rtnl_lock(); + if (!rtnl_trylock()) + return restart_syscall(); mutex_lock(&ppriv->vlan_mutex); list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) { if (priv->pkey == pkey) {