Re: [Bugme-new] [Bug 33502] New: Caught 64-bit read from uninitialized memory in __alloc_skb

Pekka Enberg
2011-05-09T19:44:20Z

On Wed, 20 Apr 2011, Eric Dumazet wrote:
> [PATCH v4] slub: dont use cmpxchg_double if KMEMCHECK or DEBUG_PAGEALLOC
>
> Christian Casteyde reported a KMEMCHECK splat in slub code.
>
> Problem is now we are lockless and allow IRQ in slab_alloc(), the object
> we manipulate from freelist can be allocated and freed right before we
> try to read object->next.
>
> Same problem can happen with DEBUG_PAGEALLOC
>
> Just dont use cmpxchg_double() if either CONFIG_KMEMCHECK or
> CONFIG_DEBUG_PAGEALLOC is defined.

Christoph, Eric, is this still relevant after commit 1759415 ("slub:
Remove CONFIG_CMPXCHG_LOCAL ifdeffery") in slab/next of slab.git?

Pekka