| Date | Wed, 09 Nov 2011 13:32:07 -0800 | From | Greg KH <> | Subject | [080/264] caif: Fix BUG() with network namespaces |
| |
3.1-stable review patch. If anyone has any objections, please let me know.
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From: David Woodhouse <dwmw2@infradead.org>
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 â 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>
--- net/caif/caif_dev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/caif/caif_dev.c +++ b/net/caif/caif_dev.c @@ -212,8 +212,7 @@ static int caif_device_notify(struct not 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 not if (cfg == NULL) return 0; + caifdevs = caif_device_list(dev_net(dev)); + switch (what) { case NETDEV_REGISTER: caifd = caif_device_alloc(dev);
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