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.
I have included the fix along with minor Kconfig correction.
Also your 3/7 patch did not showup on LKML.
--Vaidy
> +
> + need_forkexit_callback |= ss->fork || ss->exit;
Index: linux-2.6.20/kernel/container.c
===================================================================
--- linux-2.6.20.orig/kernel/container.c
+++ linux-2.6.20/kernel/container.c
@@ -1638,6 +1638,7 @@ int container_is_descendant(const struct
static void container_init_subsys(struct container_subsys *ss) {
int retval;
+ unsigned long flags;
struct list_head *l;
printk(KERN_ERR "Initializing container subsys %s\n", ss->name);
@@ -1651,7 +1652,7 @@ static void container_init_subsys(struct
* 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);
+ spin_lock_irqsave(&container_group_lock, flags);
l = &init_container_group.list;
do {
struct container_group *cg =
@@ -1659,7 +1660,7 @@ static void container_init_subsys(struct
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);
+ spin_unlock_irqrestore(&container_group_lock, flags);
need_forkexit_callback |= ss->fork || ss->exit;
Index: linux-2.6.20/init/Kconfig
===================================================================
--- linux-2.6.20.orig/init/Kconfig
+++ linux-2.6.20/init/Kconfig
@@ -239,8 +239,13 @@ config IKCONFIG_PROC
through /proc/config.gz.
config CONTAINERS
- bool
-
+ bool "Container support"
+ help
+ This option will let you create and manage process containers,
+ which can be used to aggregate multiple processes, e.g. for
+ the purposes of resource tracking.
+
+ Say N if unsure
config CPUSETS
bool "Cpuset support"
