Chris,
On Mon, 9 Jul 2012, Thomas Gleixner wrote:
> On Fri, 6 Jul 2012, PRINGLE Chris wrote:
> > It worries me a bit because this could potentially go wrong during
> > runtime if the kernel ever reaps the lookaside cache for memory;
> > this will then crash the entire system.
>
> Found the root cause, working on a fix.
Does the patch below work for you?
Thanks,
tglx
Index: linux-stable-rt/mm/slab.c
===================================================================
--- linux-stable-rt.orig/mm/slab.c
+++ linux-stable-rt/mm/slab.c
@@ -743,8 +743,26 @@ slab_on_each_cpu(void (*func)(void *arg,
{
unsigned int i;
+ get_cpu_light();
for_each_online_cpu(i)
func(arg, i);
+ put_cpu_light();
+}
+
+static void lock_slab_on(unsigned int cpu)
+{
+ if (cpu == smp_processor_id())
+ local_lock_irq(slab_lock);
+ else
+ local_spin_lock_irq(slab_lock, &per_cpu(slab_lock, cpu).lock);
+}
+
+static void unlock_slab_on(unsigned int cpu)
+{
+ if (cpu == smp_processor_id())
+ local_unlock_irq(slab_lock);
+ else
+ local_spin_unlock_irq(slab_lock, &per_cpu(slab_lock, cpu).lock);
}
#endif
@@ -2692,10 +2710,10 @@ static void do_drain(void *arg, int cpu)
{
LIST_HEAD(tmp);
- spin_lock_irq(&per_cpu(slab_lock, cpu).lock);
+ lock_slab_on(cpu);
__do_drain(arg, cpu);
list_splice_init(&per_cpu(slab_free_list, cpu), &tmp);
- spin_unlock_irq(&per_cpu(slab_lock, cpu).lock);
+ unlock_slab_on(cpu);
free_delayed(&tmp);
}
#endif
@@ -4163,9 +4181,9 @@ static void do_ccupdate_local(void *info
#else
static void do_ccupdate_local(void *info, int cpu)
{
- spin_lock_irq(&per_cpu(slab_lock, cpu).lock);
+ lock_slab_on(cpu);
__do_ccupdate_local(info, cpu);
- spin_unlock_irq(&per_cpu(slab_lock, cpu).lock);
+ unlock_slab_on(cpu);
}
#endif
--
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