Re: [ckrm-tech] [PATCH 0/7] Containers (V8): Generic Process Containers

From: Paul Menage
Date: Wed Apr 25 2007 - 01:05:44 EST


On 4/23/07, Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx> 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
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