On Wed, Apr 13, 2016 at 08:29:46PM -0400, Valdis Kletnieks wrote:
> I'm seeing my laptop crash/wedge up/something during very early
> boot - before it can write anything to the console. Nothing in pstore,
> need to hold down the power button for 6 seconds and reboot.
>
> git bisect points at:
>
> commit 7a6bacb133752beacb76775797fd550417e9d3a2
> Author: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Date: Thu Apr 7 13:59:39 2016 +1000
>
> mm/slab: factor out kmem_cache_node initialization code
>
> It can be reused on other place, so factor out it. Following patch will
> use it.
>
>
> Not sure what the problem is - the logic *looks* ok at first read. The
> patch *does* remove a spin_lock_irq() - but I find it difficult to
> believe that with it gone, my laptop is able to hit the race condition
> the spinlock protects against *every single boot*.
>
> The only other thing I see is that n->free_limit used to be assigned
> every time, and now it's only assigned at initial creation.
Hello,
My fault. It should be assgined every time. Please test below patch.
I will send it with proper SOB after you confirm the problem disappear.
Thanks for report and analysis!
Thanks.
---------------->8-----------------
diff --git a/mm/slab.c b/mm/slab.c
index 13e74aa..59dd94a 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -856,8 +856,14 @@ static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
* node has not already allocated this
*/
n = get_node(cachep, node);
- if (n)
+ if (n) {
+ spin_lock_irq(&n->list_lock);
+ n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
+ cachep->num;
+ spin_unlock_irq(&n->list_lock);
+
return 0;
+ }
n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
if (!n)
--
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