caif: Fix BUG() with network namespaces
commit 08613e4626c06ca408fc55071f6aedee36986a87 upstream.
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().
We could imagine a complex and overengineered solution to this generic
class of problems, but this patch takes the simple approach. It just
makes 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.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index 682c0fe..dbdaa95 100644
--- a/net/caif/caif_dev.c
+++ b/net/caif/caif_dev.c
@@ -209,8 +209,7 @@
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;
@@ -219,6 +218,8 @@
if (cfg == NULL)
return 0;
+ caifdevs = caif_device_list(dev_net(dev));
+
switch (what) {
case NETDEV_REGISTER:
caifd = caif_device_alloc(dev);