From: ebiederm@xmission•com (Eric W. Biederman)
To: Amerigo Wang <amwang@redhat•com>
Cc: linux-kernel@vger•kernel.org, Jiri Pirko <jpirko@redhat•com>,
Stephen Hemminger <shemminger@vyatta•com>,
netdev@vger•kernel.org, "David S. Miller" <davem@davemloft•net>,
bonding-devel@lists•sourceforge.net,
Jay Vosburgh <fubar@us•ibm.com>
Subject: Re: [Patch V2] bonding: fix potential deadlock in bond_uninit()
Date: Wed, 31 Mar 2010 23:12:22 -0700 [thread overview]
Message-ID: <m1r5mzsnuh.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20100401061014.4815.7341.sendpatchset@localhost.localdomain> (Amerigo Wang's message of "Thu\, 1 Apr 2010 02\:06\:28 -0400")
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.
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..9f0aaa2 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);
next prev parent reply other threads:[~2010-04-01 6:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-01 6:06 [Patch V2] bonding: fix potential deadlock in bond_uninit() Amerigo Wang
2010-04-01 6:12 ` Eric W. Biederman [this message]
2010-04-01 6:54 ` Cong Wang
2010-04-01 7:30 ` [Patch V3] " Cong Wang
2010-04-02 0:26 ` David Miller
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