On Wed, May 8, 2013 at 2:58 PM, Glauber Costa <glom...@parallels.com> wrote:
> My first guess is that it hit a NULL cache. Being a NULL pointer
> dereference, the thing among all that has the biggest chances of being
> NULL and accessed unconditionally is the cache pointer itself.
>
> Due to the size being too big. But if that were the case, he would have
> hit the WARN_ON recently introduced:
>
> if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
> return NULL;
>
>
> Is this WARN hit ?
I doubt it:
[ 0.000000] r7 : 00000000 r6 : 600001d3 r5 : 00000000 r4 : 00008000
[ 0.000000] r3 : 00000050 r2 : c06ec000 r1 : c06f77c8 r0 : c00eda9c
[ 0.000000] [<c00edab4>] (kmem_cache_alloc_trace+0x50/0x178) from
[<c0086958>] (alloc_desc+0x24/0xb4)
It's the kzalloc_node() in kernel/irq/irqdesc.c::alloc_desc() and
AFAICT based on r4 it's a 32 KB allocation. It's more likely that
KMALLOC_SHIFT_HIGH is less than 25 and because kmalloc_index() doesn't
respect it, we return a pointer to an uninitialized kmalloc cache.
Pekka
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
