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

[Cong Wang]

Andy Gospodarek wrote:
> 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:
> >
> > http://lkml.org/lkml/2010/4/1/58
> >
> > > You should also configure your kernel with a some of the lock
> > > debugging
> > > enabled.  I've been using the following:
> > > CONFIG_DETECT_HUNG_TASK=y
> > > CONFIG_DEBUG_SPINLOCK=y
> > > CONFIG_DEBUG_MUTEXES=y
> > > CONFIG_DEBUG_LOCK_ALLOC=y
> > > CONFIG_PROVE_LOCKING=y
> > > CONFIG_LOCKDEP=y
> > > CONFIG_LOCK_STAT=y
> > > CONFIG_DEBUG_LOCKDEP=y
> >
> > 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.


Then I should do the right thing.

> > 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?

I use default values on RHEL5:

6 4 1 7

I don't think this is related with loglevel, what I checked
is dmesg, not just the console screen.

Thanks.
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