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| author | Ron Lee <ron@debian.org> | 2009-05-22 04:58:22 +0930 |
|---|---|---|
| committer | Pekka Enberg <penberg@cs.helsinki.fi> | 2009-05-22 11:01:12 +0300 |
| commit | 6746136520cd0827320a83e62d0a023a5a433650 (patch) | |
| tree | 2e57aef24fbb8e8531aad10061245ec4bddda6f9 /mm/slab.c | |
| parent | 45d447406a19cbfd42720f066f156f4eb9d68801 (diff) | |
| download | lwn-6746136520cd0827320a83e62d0a023a5a433650.tar.gz lwn-6746136520cd0827320a83e62d0a023a5a433650.zip | |
slab: fix generic PAGE_POISONING conflict with SLAB_RED_ZONE
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@debian.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/slab.c b/mm/slab.c index 9a90b00d2f91..1a6040d0f41d 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2353,6 +2353,15 @@ kmem_cache_create (const char *name, size_t size, size_t align, /* really off slab. No need for manual alignment */ slab_size = cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab); + +#ifdef CONFIG_PAGE_POISONING + /* If we're going to use the generic kernel_map_pages() + * poisoning, then it's going to smash the contents of + * the redzone and userword anyhow, so switch them off. + */ + if (size % PAGE_SIZE == 0 && flags & SLAB_POISON) + flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); +#endif } cachep->colour_off = cache_line_size(); |