On Tue, 02 Jul 2013 at 08:28 GMT, Hannes Frederic Sowa
<han...@stressinduktion.org> wrote:
On Mon, Jul 01, 2013 at 09:54:56AM -0500, Shawn Bohrer wrote:
I've managed to hit a deadlock at boot a couple times while testing
the 3.10 rc kernels. It seems to always happen when my network
devices are initializing. This morning I updated to v3.10 and made a
few config tweaks and so far I've hit it 4 out of 5 reboots. It looks
like most processes are getting stuck on rtnl_lock. Below is a boot
log with the soft lockup prints. Please let know if there is any
other information I can provide:
Could you try a build with CONFIG_LOCKDEP enabled?
The problem is clear: ib_register_device() is called with rtnl_lock,
but itself needs device_mutex, however, ib_register_client() first
acquires device_mutex, then indirectly calls register_netdev() which
takes rtnl_lock. Deadlock!
One possible fix is always taking rtnl_lock before taking
device_mutex, something like below:
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 18c1ece..890870b 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -381,6 +381,7 @@ int ib_register_client(struct ib_client *client)
{
struct ib_device *device;
+ rtnl_lock();
mutex_lock(&device_mutex);
list_add_tail(&client->list, &client_list);
@@ -389,6 +390,7 @@ int ib_register_client(struct ib_client *client)
client->add(device);
mutex_unlock(&device_mutex);
+ rtnl_unlock();
return 0;
}
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c
b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index b6e049a..5a7a048 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1609,7 +1609,7 @@ static struct net_device *ipoib_add_port(const char
*format,
goto event_failed;
}
- result = register_netdev(priv->dev);
+ result = register_netdevice(priv->dev);
if (result) {
printk(KERN_WARNING "%s: couldn't register ipoib port %d; error
%d\n",
hca->name, port, result);