Re: mm: slub: invalid memory access in setup_object

David Rientjes
2014-06-30T22:03:26Z

On Wed, 25 Jun 2014, Christoph Lameter wrote:

> On Wed, 25 Jun 2014, Sasha Levin wrote:
>
> > [ 791.669480] ? init_object (mm/slub.c:665)
> > [ 791.669480] setup_object.isra.34 (mm/slub.c:1008 mm/slub.c:1373)
> > [ 791.669480] new_slab (mm/slub.c:278 mm/slub.c:1412)
>
> So we just got a new page from the page allocator but somehow cannot
> write to it. This is the first write access to the page.
>

I'd be inclined to think that this was a result of "slub: reduce duplicate
creation on the first object" from -mm[*] that was added the day before
Sasha reported the problem.

It's not at all clear to me that that patch is correct. Wei?

Sasha, with a revert of that patch, does this reproduce?

[*] http://ozlabs.org/~akpm/mmotm/broken-out/slub-reduce-duplicate-creation-on-the-first-object.patch