From d4a5fca592b9ab52b90bb261a90af3c8f53be011 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 25 Sep 2014 16:05:20 -0700 Subject: [PATCH] mm, slab: initialize object alignment on cache creation 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 Reported-by: Andrei Elovikov Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index a467b308c682..b8b619bc84ad 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2124,7 +2124,8 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 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; @@ -2157,14 +2158,6 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) 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 -- 2.30.2