Re: [S+Q3 20/23] slub: Shared cache to exploit cross cpu cachingabilities.

[Christoph Lameter]

On Tue, 17 Aug 2010, David Rientjes wrote:

> On Tue, 17 Aug 2010, Christoph Lameter wrote:
>
> > > This explodes on the memset() in slab_alloc() because of __GFP_ZERO on my
> > > system:
> >
> > Well that seems to be because __kmalloc_node returned invalid address. Run
> > with full debugging please?
> >
>
> Lots of data, so I trimmed it down to something reasonable by eliminating
> reports that were very similar.  (It also looks like some metadata is
> getting displayed incorrectly such as negative pid's and 10-digit cpu
> numbers.)

Well yes I guess that is the result of large scale corruption that is
reaching into the debug fields of the object.

> [   15.752467]
> [   15.752467] INFO: 0xffff880c7e5f3ec0-0xffff880c7e5f3ec7. First byte 0x30 instead of 0xbb
> [   15.752467] INFO: Allocated in 0xffff88087e4f11e0 age=131909211166235 cpu=2119111312 pid=-30712
> [   15.752467] INFO: Freed in 0xffff88087e4f13f0 age=131909211165707 cpu=2119111840 pid=-30712
> [   15.752467] INFO: Slab 0xffffea002bba4d28 objects=51 new=3 fp=0x0007000000000000 flags=0xa00000000000080
> [   15.752467] INFO: Object 0xffff880c7e5f3eb0 @offset=3760
> [   15.752467]
> [   15.752467] Bytes b4 0xffff880c7e5f3ea0:  18 00 00 00 7e 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ....~...ZZZZZZZZ
> [   15.752467]   Object 0xffff880c7e5f3eb0:  d0 0f 4f 7e 08 88 ff ff 80 10 4f 7e 08 88 ff ff .O~....O~..
> [   15.752467]  Redzone 0xffff880c7e5f3ec0:  30 11 4f 7e 08 88 ff ff                         0.O~..
> [   15.752467]  Padding 0xffff880c7e5f3ef8:  00 16 4f 7e 08 88 ff ff                         ..O~..

16 bytes allocated and a pointer array much larger than that is used.

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