Re: [PATCH] slab: fix generic PAGE_POISONING conflict withSLAB_RED_ZONE

From: Pekka Enberg
Date: Fri May 22 2009 - 04:03:19 EST


On Fri, 2009-05-22 at 04:58 +0930, Ron wrote:
> A generic page poisoning mechanism was added with commit:
> 6a11f75b6a17b5d9ac5025f8d048382fd1f47377
> which destructively poisons full pages with a bitpattern.
>
> On arches where PAGE_POISONING is used, this conflicts with the slab
> redzone checking enabled by DEBUG_SLAB, scribbling bits all over its
> magic words and making it complain about that quite emphatically.
>
> On x86 (and I presume at present all the other arches which set
> ARCH_SUPPORTS_DEBUG_PAGEALLOC too), the kernel_map_pages() operation
> is non destructive so it can coexist with the other DEBUG_SLAB
> mechanisms just fine.
>
> This patch favours the expensive full page destruction test for
> cases where there is a collision and it is explicitly selected.
>
> Signed-off-by: Ron Lee <ron@xxxxxxxxxx>

Applied, thanks!

Pekka

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