3.2.94-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Brian Norris <briannorris@xxxxxxxxxxxx>
commit 8535107aa4ef92520cbb9a4739563b389c5f8e2c upstream.
If we fail to add an interface in mwifiex_add_virtual_intf(), we might
hit a BUG_ON() in the networking code, because we didn't tear things
down properly. Among the problems:
(a) when failing to allocate workqueues, we fail to unregister the
netdev before calling free_netdev()
(b) even if we do try to unregister the netdev, we're still holding the
rtnl lock, so the device never properly unregistered; we'll be at
state NETREG_UNREGISTERING, and then hit free_netdev()'s:
BUG_ON(dev->reg_state != NETREG_UNREGISTERED);
(c) we're allocating some dependent resources (e.g., DFS workqueues)
after we've registered the interface; this may or may not cause
problems, but it's good practice to allocate these before registering
(d) we're not even trying to unwind anything when mwifiex_send_cmd() or
mwifiex_sta_init_cmd() fail
To fix these issues, let's:
* add a stacked set of error handling labels, to keep error handling
consistent and properly ordered (resolving (a) and (d))
* move the workqueue allocations before the registration (to resolve
(c); also resolves (b) by avoiding error cases where we have to
unregister)
[Incidentally, it's pretty easy to interrupt the alloc_workqueue() in,
e.g., the following:
iw phy phy0 interface add mlan0 type station
by sending it SIGTERM.]
This bugfix covers commits like commit 7d652034d1a0 ("mwifiex: channel
switch support for mwifiex"), but parts of this bug exist all the way
back to the introduction of dynamic interface handling in commit
93a1df48d224 ("mwifiex: add cfg80211 handlers add/del_virtual_intf").
Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
[bwh: Backported to 3.2:
- There is no workqueue allocation or cleanup needed here
- Add 'ret' variable
- Keep logging errors with wiphy_err()
- Adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/net/wireless/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/mwifiex/cfg80211.c
@@ -1176,6 +1176,7 @@ struct net_device *mwifiex_add_virtual_i
struct mwifiex_adapter *adapter;
struct net_device *dev;
void *mdev_priv;
+ int ret;
if (!priv)
return ERR_PTR(-EFAULT);
@@ -1216,8 +1217,8 @@ struct net_device *mwifiex_add_virtual_i
ether_setup, 1);
if (!dev) {
wiphy_err(wiphy, "no memory available for netdevice\n");
- priv->bss_mode = NL80211_IFTYPE_UNSPECIFIED;
- return ERR_PTR(-ENOMEM);
+ ret = -ENOMEM;
+ goto err_alloc_netdev;
}
dev_net_set(dev, wiphy_net(wiphy));
@@ -1239,23 +1240,29 @@ struct net_device *mwifiex_add_virtual_i
SET_NETDEV_DEV(dev, adapter->dev);
+ sema_init(&priv->async_sem, 1);
+ priv->scan_pending_on_block = false;
+
/* Register network device */
if (register_netdevice(dev)) {
wiphy_err(wiphy, "cannot register virtual network device\n");
- free_netdev(dev);
- priv->bss_mode = NL80211_IFTYPE_UNSPECIFIED;
- return ERR_PTR(-EFAULT);
+ ret = -EFAULT;
+ goto err_reg_netdev;
}
- sema_init(&priv->async_sem, 1);
- priv->scan_pending_on_block = false;
-
dev_dbg(adapter->dev, "info: %s: Marvell 802.11 Adapter\n", dev->name);
#ifdef CONFIG_DEBUG_FS
mwifiex_dev_debugfs_init(priv);
#endif
return dev;
+
+err_reg_netdev:
+ free_netdev(dev);
+ priv->netdev = NULL;
+err_alloc_netdev:
+ priv->bss_mode = NL80211_IFTYPE_UNSPECIFIED;
+ return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(mwifiex_add_virtual_intf);