On 9/5/2013 5:02 AM, Bart Van Assche wrote:
On 07/30/13 14:54, Steve Wise wrote:
On 7/29/2013 6:02 PM, Shawn Bohrer wrote:
On Mon, Jul 15, 2013 at 09:38:19AM -0500, Shawn Bohrer wrote:
On Wed, Jul 03, 2013 at 08:26:11PM +0300, Or Gerlitz wrote:
On 03/07/2013 20:22, Shawn Bohrer wrote:
On Wed, Jul 03, 2013 at 07:33:07AM +0200, Hannes Frederic Sowa
wrote:
On Wed, Jul 03, 2013 at 07:11:52AM +0200, Hannes Frederic Sowa
wrote:
On Tue, Jul 02, 2013 at 01:38:26PM +0000, Cong Wang wrote:
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);
Looks good to me. Shawn, could you test this patch?
ib_unregister_device/ib_unregister_client would need the same
change,
too. I have not checked the other ->add() and ->remove()
functions. Also
cc'ed linux-rdma@vger.kernel.org, Roland Dreier.
Cong's patch is missing the #include <linux/rtnetlink.h> but
otherwise
I've had 34 successful reboots with no deadlocks which is a good
sign.
It sounds like there are more paths that need to be audited and a
proper patch submitted. I can do more testing later if needed.
Thanks,
Shawn
Guys, I was a bit busy today looking into that, but I don't think we
want the IB core layer (core/device.c) to
use rtnl locking which is something that belongs to the network
stack.
Has anymore thought been put into a proper fix for this issue?
I'm no expert in this area but I'm having a hard time seeing a
different solution than the one Cong suggested. Just to be clear the
deadlock I hit was between cxgb3 and the ipoib module, so I've Cc'd
Steve Wise in case he has a better solution from the Chelsio side.
I don't know of another way to resolve this. The rtnl lock is used in
ipoib and mlx4 already. I think we should go forward with the proposed
patch.
(replying to an e-mail of one month ago)
Hello,
It would be appreciated if anyone could report what the current status
of this issue is. I think a deadlock I ran into with kernels 3.10 and
3.11 and PCI pass-through is related to this issue. See also
http://bugzilla.kernel.org/show_bug.cgi?id=60856 for the lockdep report.
Thanks,
Bart.
Roland, what do you think?
As I've said, I think we should go ahead with using the rtnl lock in the
core. Is there a complete patch available for review? looks like the
original was a partial fix.
Steve.
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