| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 186/238] mm, slab: initialize object alignment on cache creation | Date | Fri, 3 Oct 2014 14:31:41 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: David Rientjes <rientjes@google.com>
commit d4a5fca592b9ab52b90bb261a90af3c8f53be011 upstream.
Since commit 4590685546a3 ("mm/sl[aou]b: Common alignment code"), the "ralign" automatic variable in __kmem_cache_create() may be used as uninitialized.
The proper alignment defaults to BYTES_PER_WORD and can be overridden by SLAB_RED_ZONE or the alignment specified by the caller.
This fixes https://bugzilla.kernel.org/show_bug.cgi?id=85031
Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Andrei Elovikov <a.elovikov@gmail.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/slab.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
--- a/mm/slab.c +++ b/mm/slab.c @@ -2189,7 +2189,8 @@ static int __init_refok setup_cpu_cache( int __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) { - size_t left_over, freelist_size, ralign; + size_t left_over, freelist_size; + size_t ralign = BYTES_PER_WORD; gfp_t gfp; int err; size_t size = cachep->size; @@ -2222,14 +2223,6 @@ __kmem_cache_create (struct kmem_cache * size &= ~(BYTES_PER_WORD - 1); } - /* - * Redzoning and user store require word alignment or possibly larger. - * Note this will be overridden by architecture or caller mandated - * alignment if either is greater than BYTES_PER_WORD. - */ - if (flags & SLAB_STORE_USER) - ralign = BYTES_PER_WORD; - if (flags & SLAB_RED_ZONE) { ralign = REDZONE_ALIGN; /* If redzoning, ensure that the second redzone is suitably
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