Re: [v2 Patch 3/3] bonding: make bonding support netpoll

From: Andy Gospodarek
Date: Wed Apr 07 2010 - 00:08:39 EST

On Apr 6, 2010, at 10:32 PM, Cong Wang <amwang@xxxxxxxxxx> wrote:

> Andy Gospodarek wrote:
>> On Tue, Apr 06, 2010 at 12:38:16PM +0800, Cong Wang wrote:
>>> Cong Wang wrote:
>>>> Before I try to reproduce it, could you please try to replace
>>>> the 'read_lock()'
>>>> in slaves_support_netpoll() with 'read_lock_bh()'? (read_unlock()
>>>> too) Try if this helps.
>>> Confirmed. Please use the attached patch instead, for your testing.
>>> Thanks!
>> Moving those locks to bh-locks will not resolve this. I tried that
>> yesterday and tried your new patch today without success. That
>> warning
>> is a WARN_ON_ONCE so you need to reboot to see that it is still a
>> problem. Simply unloading and loading the new module is not an
>> accurate
>> test.
>> Also, my system still hangs when removing the bonding module. I do
>> not
>> think you intended to fix this with the patch, but wanted it to be
>> clear
>> to everyone on the list.
> Actually I did reboot and then tested the module. I didn't get any
> warning.
> I just tried again today, and no warnings at all.
> For removing bonding module, you may need another fix of mine,
> which is to fix a potential deadlock of workqueue. Try:
>> You should also configure your kernel with a some of the lock
>> debugging
>> enabled. I've been using the following:
> Sure, I always keep these.
>> Here is the output when I remove a slave from the bond. My
>> xmit_roundrobin patch from earlier (replacing read_lock with
>> read_trylock) was applied. It might be helpful for you when
>> debugging
>> these issues.
> I don't apply your patch, just tested my patch.
>> Dead loop on virtual device bond0, fix it urgently!
> Please provide your bonding configuration and steps to reproduce it.

My first response in this thread provides the commands and
configuration needed to reproduce this.

> What I did is:
> 1. Load bonding module with "mode=0 miimon=100"
> 2. Enslave eth0 and active bond0
> 3. Load netconsole and send messages via bond0
> 4. Remove eth0 from bond0
> 5. Remove bonding module
> 6. Remove netconsole module

Thanks for sending your configuration.

What values are in /proc/sys/kernel/printk?

> And no deadlocks, no warnings.
> Thanks.
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