From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f177.google.com (mail-ie0-f177.google.com [209.85.223.177]) by kanga.kvack.org (Postfix) with ESMTP id A6D026B0035 for ; Tue, 23 Sep 2014 17:43:22 -0400 (EDT) Received: by mail-ie0-f177.google.com with SMTP id x19so9950714ier.8 for ; Tue, 23 Sep 2014 14:43:22 -0700 (PDT) Received: from mail-ie0-x236.google.com (mail-ie0-x236.google.com [2607:f8b0:4001:c03::236]) by mx.google.com with ESMTPS id y13si13742857icn.100.2014.09.23.14.43.21 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 23 Sep 2014 14:43:22 -0700 (PDT) Received: by mail-ie0-f182.google.com with SMTP id tp5so5063461ieb.27 for ; Tue, 23 Sep 2014 14:43:21 -0700 (PDT) Date: Tue, 23 Sep 2014 14:43:19 -0700 (PDT) From: David Rientjes Subject: [patch] mm, slab: initialize object alignment on cache creation In-Reply-To: <20140923141940.e2d3840f31d0f8850b925cf6@linux-foundation.org> Message-ID: References: <20140923141940.e2d3840f31d0f8850b925cf6@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Christoph Lameter , Joonsoo Kim , Pekka Enberg , a.elovikov@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Since 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 Reported-by: Andrei Elovikov Signed-off-by: David Rientjes --- a.elovikov: If you respond to this email with your full name, Andrew can give proper credit for reporting this issue. mm/slab.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/mm/slab.c b/mm/slab.c --- a/mm/slab.c +++ b/mm/slab.c @@ -2128,7 +2128,8 @@ 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; @@ -2161,14 +2162,6 @@ __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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org