@@ -212,8 +212,7 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
enum cfcnfg_phy_preference pref;
enum cfcnfg_phy_type phy_type;
struct cfcnfg *cfg;
- struct caif_device_entry_list *caifdevs =
- caif_device_list(dev_net(dev));
+ struct caif_device_entry_list *caifdevs;
if (dev->type != ARPHRD_CAIF)
return 0;
@@ -222,6 +221,8 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
if (cfg == NULL)
return 0;
+ caifdevs = caif_device_list(dev_net(dev));
+
switch (what) {
case NETDEV_REGISTER:
caifd = caif_device_alloc(dev);
The caif code will register its own pernet_operations, and then register a netdevice_notifier. Each time the netdevice_notifier is triggered, it'll do some stuff... including a lookup of its own pernet stuff with net_generic(). If the net_generic() call ever returns NULL, the caif code will BUG(). That doesn't seem *so* unreasonable, I suppose — it does seem like it should never happen. However, it *does* happen. When we clone a network namespace, setup_net() runs through all the pernet_operations one at a time. It gets to loopback before it gets to caif. And loopback_net_init() registers a netdevice... while caif hasn't been initialised. So the caif netdevice notifier triggers, and immediately goes BUG(). I'm not entirely sure how best to fix this in the general case. Perhaps the netdevice_notifier registration should be pernet too, rather than global? Or perhaps we should suppress the notifier calls during setup_net() and flush them at the end after everything has been initialised? But really, I'm inclined to just take the simple approach. Make caif_device_notify() *not* go looking for its pernet data structures if the device it's being notified about isn't a caif device in the first place. This simple patch is sufficient to avoid the problem, and is probably good enough. Cc: stable@kernel.org Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Sent with MeeGo's ActiveSync support. David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation