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IB/ipoib: Do not remove child devices from within the ndo_uninit

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Switching to priv_destructor and needs_free_netdev created a subtle
ordering problem in ipoib_remove_one.

Now that unregister_netdev frees the netdev and priv we must ensure that
the children are unregistered before trying to unregister the parent,
or child unregister will use after free.

The solution is to unregister the children, then parent, in the same batch
all while holding the rtnl_lock. This closes all the races where a new
child could have been added and ensures proper ordering.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
This commit is contained in:
Jason Gunthorpe
2018-07-29 11:34:58 +03:00
parent ee190ab734
commit 25405d98a2
3 changed files with 30 additions and 11 deletions
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28
drivers/infiniband/ulp/ipoib/ipoib_main.c
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@@ -1939,18 +1939,15 @@ static int ipoib_ndo_init(struct net_device *ndev)
static void ipoib_ndo_uninit(struct net_device *dev)
{
struct ipoib_dev_priv *priv = ipoib_priv(dev), *cpriv, *tcpriv;
LIST_HEAD(head);
struct ipoib_dev_priv *priv = ipoib_priv(dev);
ASSERT_RTNL();
/* Delete any child interfaces first */
list_for_each_entry_safe(cpriv, tcpriv, &priv->child_intfs, list) {
/* Stop GC on child */
cancel_delayed_work_sync(&cpriv->neigh_reap_task);
unregister_netdevice_queue(cpriv->dev, &head);
}
unregister_netdevice_many(&head);
/*
* ipoib_remove_one guarantees the children are removed before the
* parent, and that is the only place where a parent can be removed.
*/
WARN_ON(!list_empty(&priv->child_intfs));
ipoib_neigh_hash_uninit(dev);
@@ -2466,16 +2463,25 @@ static void ipoib_add_one(struct ib_device *device)
static void ipoib_remove_one(struct ib_device *device, void *client_data)
{
struct ipoib_dev_priv *priv, *tmp;
struct ipoib_dev_priv *priv, *tmp, *cpriv, *tcpriv;
struct list_head *dev_list = client_data;
if (!dev_list)
return;
list_for_each_entry_safe(priv, tmp, dev_list, list) {
LIST_HEAD(head);
ipoib_parent_unregister_pre(priv->dev);
unregister_netdev(priv->dev);
rtnl_lock();
list_for_each_entry_safe(cpriv, tcpriv, &priv->child_intfs,
list)
unregister_netdevice_queue(cpriv->dev, &head);
unregister_netdevice_queue(priv->dev, &head);
unregister_netdevice_many(&head);
rtnl_unlock();
}
kfree(dev_list);