lkml.org 
[lkml]   [2010]   [Apr]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[Patch V3] bonding: fix potential deadlock in bond_uninit()
Eric W. Biederman wrote:
> Amerigo Wang <amwang@redhat.com> writes:
>
>> bond_uninit() is invoked with rtnl_lock held, when it does destroy_workqueue()
>> which will potentially flush all works in this workqueue, if we hold rtnl_lock
>> again in the work function, it will deadlock.
>>
>> So move destroy_workqueue() to destructor where rtnl_lock is not held any more,
>> suggested by Eric.
>
> The error handling on creating a bond device needs to be updated as well.
>

Done.

V3: fix error handling path of bond_create()

bond_uninit() is invoked with rtnl_lock held, when it does destroy_workqueue()
which will potentially flush all works in this workqueue, if we hold rtnl_lock
again in the work function, it will deadlock.

So move destroy_workqueue() to destructor where rtnl_lock is not held any more,
suggested by Eric.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Jiri Pirko <jpirko@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>

---
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5b92fbf..61f8c63 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4450,6 +4450,14 @@ static const struct net_device_ops bond_netdev_ops = {
.ndo_vlan_rx_kill_vid = bond_vlan_rx_kill_vid,
};

+static void bond_destructor(struct net_device *bond_dev)
+{
+ struct bonding *bond = netdev_priv(bond_dev);
+ if (bond->wq)
+ destroy_workqueue(bond->wq);
+ free_netdev(bond_dev);
+}
+
static void bond_setup(struct net_device *bond_dev)
{
struct bonding *bond = netdev_priv(bond_dev);
@@ -4470,7 +4478,7 @@ static void bond_setup(struct net_device *bond_dev)
bond_dev->ethtool_ops = &bond_ethtool_ops;
bond_set_mode_ops(bond, bond->params.mode);

- bond_dev->destructor = free_netdev;
+ bond_dev->destructor = bond_destructor;

/* Initialize the device options */
bond_dev->tx_queue_len = 0;
@@ -4542,9 +4550,6 @@ static void bond_uninit(struct net_device *bond_dev)

bond_remove_proc_entry(bond);

- if (bond->wq)
- destroy_workqueue(bond->wq);
-
netif_addr_lock_bh(bond_dev);
bond_mc_list_destroy(bond);
netif_addr_unlock_bh(bond_dev);
@@ -4956,8 +4961,8 @@ int bond_create(struct net *net, const char *name)
bond_setup);
if (!bond_dev) {
pr_err("%s: eek! can't alloc netdev!\n", name);
- res = -ENOMEM;
- goto out;
+ rtnl_unlock();
+ return -ENOMEM;
}

dev_net_set(bond_dev, net);
@@ -4966,19 +4971,16 @@ int bond_create(struct net *net, const char *name)
if (!name) {
res = dev_alloc_name(bond_dev, "bond%d");
if (res < 0)
- goto out_netdev;
+ goto out;
}

res = register_netdevice(bond_dev);
- if (res < 0)
- goto out_netdev;

out:
rtnl_unlock();
+ if (res < 0)
+ bond_destructor(bond_dev);
return res;
-out_netdev:
- free_netdev(bond_dev);
- goto out;
}

static int __net_init bond_net_init(struct net *net)
\
 
 \ /
  Last update: 2010-04-01 09:29    [from the cache]
©2003-2011 Jasper Spaans