Re: 2.6.24-rc2-mm1

mark gross
2007-11-15T19:19:52Z

On Wed, Nov 14, 2007 at 12:40:08PM -0800, Andrew Morton wrote:
> On Wed, 14 Nov 2007 12:29:59 -0800 mark gross <mgross@linux.intel.com> wrote:
>
> > > > [ 102.366932] =======================
> > > > [ 108.552031] printk: 31 messages suppressed.
> > >
> > >
> > > All this BUG / WARNINGS are caused by *-qos* patches. Reverting this 3 patches makes the BUGs go away :
> > >
> > > latencyc-use-qos-infrastructure.patch
> > > pm-qos-infrastructure-and-interface.patch
> > > pm-qos-infrastructure-and-interface-static-initialization-with-blocking-notifiers.patch
> > >
> > >
> > > Gabriel
> > >
> > >
> > This looks like the same issue Rafael saw.
> >
> > Try the patch in the following post:
> >
> > http://marc.info/?l=linux-kernel&m=119265627228498&w=2
> >
>
> Well that's not very good. _I_ can go fishing in my lkml archives for random
> patches but not everyone is set up to do that. And the diff to which you
> refer gets 100% rejects against rc2-mm1 anyway.
>
> Please prepare a tested, changelogged patch against rc2-mm1 asap.

I'm having difficulty coming up with a .config that boots, I'll continue
working on this but the following is what I'm pretty confident will fix
the warnings.

You should hold off until I get a system booting 2.6.24-rc2-mm1 before
taking this.

pm-qos-remove-locks-around-blocking-notifier-registration.patch

Changelog:
Remove spin locking around blocking notifier calls that can sleep.

--mgross

Signed-off-by: mark gross <mgross@linux.intel.com>

Index: linux-2.6.24-rc2-mm1/kernel/pm_qos_params.c
===================================================================
--- linux-2.6.24-rc2-mm1.orig/kernel/pm_qos_params.c 2007-11-15 11:09:27.000000000 -0800
+++ linux-2.6.24-rc2-mm1/kernel/pm_qos_params.c 2007-11-15 11:10:08.000000000 -0800
@@ -319,13 +319,10 @@
*/
int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
{
- unsigned long flags;
int retval;

- spin_lock_irqsave(&pm_qos_lock, flags);
retval = blocking_notifier_chain_register(
pm_qos_array[pm_qos_class]->notifiers, notifier);
- spin_unlock_irqrestore(&pm_qos_lock, flags);

return retval;
}
@@ -341,13 +338,10 @@
*/
int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
{
- unsigned long flags;
int retval;

- spin_lock_irqsave(&pm_qos_lock, flags);
retval = blocking_notifier_chain_unregister(
pm_qos_array[pm_qos_class]->notifiers, notifier);
- spin_unlock_irqrestore(&pm_qos_lock, flags);

return retval;
}