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Message-ID: <6599ad830704242204n75e6340cn280999122c54530f@mail.gmail.com>
Date: Tue, 24 Apr 2007 22:04:53 -0700
From: "Paul Menage" <menage@google.com>
To: "Vaidyanathan Srinivasan" <svaidy@linux.vnet.ibm.com>
Subject: Re: [ckrm-tech] [PATCH 0/7] Containers (V8): Generic Process Containers
Cc: vatsa@in.ibm.com, sekharan@us.ibm.com, ckrm-tech@lists.sourceforge.net,
       linux-kernel@vger.kernel.org, xemul@sw.ru, dev@sw.ru,
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On 4/23/07, Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote:
> Hi Paul,
>
> In [patch 3/7] Containers (V8): Add generic multi-subsystem API to
> containers, you have forcefully enabled interrupt in
> container_init_subsys() with spin_unlock_irq() which breaks on PPC64.
>
>
> > +static void container_init_subsys(struct container_subsys *ss) {
> > +     int retval;
> > +     struct list_head *l;
> > +     printk(KERN_ERR "Initializing container subsys %s\n",
> > ss->name);
> > +
> > +     /* Create the top container state for this subsystem */
> > +     ss->root = &rootnode;
> > +     retval = ss->create(ss, dummytop);
> > +     BUG_ON(retval);
> > +     init_container_css(ss, dummytop);
> > +
> > +     /* Update all container groups to contain a subsys
> > +      * pointer to this state - since the subsystem is
> > +      * newly registered, all tasks and hence all container
> > +      * groups are in the subsystem's top container. */
> > +     spin_lock_irq(&container_group_lock);
> > +     l = &init_container_group.list;
> > +     do {
> > +             struct container_group *cg =
> > +                     list_entry(l, struct container_group, list);
> > +             cg->subsys[ss->subsys_id] =
> > dummytop->subsys[ss->subsys_id];
> > +             l = l->next;
> > +     } while (l != &init_container_group.list);
> > +     spin_unlock_irq(&container_group_lock);
>
> Interrupt gets enabled here and on PPC64, the kernel takes a pending
> decrementer and crashes because it is too early to handle them.
>
> Use of irqsave and restore routines would fix the problem.

OK, thanks. I'll add that change.

Paul