From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 2D5A46B0260 for ; Thu, 28 Jul 2016 11:31:30 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id 33so18967450lfw.1 for ; Thu, 28 Jul 2016 08:31:30 -0700 (PDT) Received: from mail-wm0-x230.google.com (mail-wm0-x230.google.com. [2a00:1450:400c:c09::230]) by mx.google.com with ESMTPS id q197si14173563wmb.145.2016.07.28.08.31.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Jul 2016 08:31:28 -0700 (PDT) Received: by mail-wm0-x230.google.com with SMTP id o80so113731487wme.1 for ; Thu, 28 Jul 2016 08:31:28 -0700 (PDT) From: Alexander Potapenko Subject: [PATCH v8 1/3] mm, kasan: account for object redzone in SLUB's nearest_obj() Date: Thu, 28 Jul 2016 17:31:17 +0200 Message-Id: <1469719879-11761-2-git-send-email-glider@google.com> In-Reply-To: <1469719879-11761-1-git-send-email-glider@google.com> References: <1469719879-11761-1-git-send-email-glider@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: dvyukov@google.com, kcc@google.com, aryabinin@virtuozzo.com, adech.fo@gmail.com, cl@linux.com, akpm@linux-foundation.org, rostedt@goodmis.org, js1304@gmail.com, iamjoonsoo.kim@lge.com, kuthonuzo.luruo@hpe.com Cc: kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org When looking up the nearest SLUB object for a given address, correctly calculate its offset if SLAB_RED_ZONE is enabled for that cache. Previously, when KASAN had detected an error on an object from a cache with SLAB_RED_ZONE set, the actual start address of the object was miscalculated, which led to random stacks having been reported. Fixes: 7ed2f9e663854db ("mm, kasan: SLAB support") Signed-off-by: Alexander Potapenko --- v8: - Updated the patch description --- include/linux/slub_def.h | 10 ++++++---- mm/slub.c | 2 +- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 5624c1f..cf501cf 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -119,15 +119,17 @@ static inline void sysfs_slab_remove(struct kmem_cache *s) void object_err(struct kmem_cache *s, struct page *page, u8 *object, char *reason); +void *fixup_red_left(struct kmem_cache *s, void *p); + static inline void *nearest_obj(struct kmem_cache *cache, struct page *page, void *x) { void *object = x - (x - page_address(page)) % cache->size; void *last_object = page_address(page) + (page->objects - 1) * cache->size; - if (unlikely(object > last_object)) - return last_object; - else - return object; + void *result = (unlikely(object > last_object)) ? last_object : object; + + result = fixup_red_left(cache, result); + return result; } #endif /* _LINUX_SLUB_DEF_H */ diff --git a/mm/slub.c b/mm/slub.c index f9da871..1cdde1a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -124,7 +124,7 @@ static inline int kmem_cache_debug(struct kmem_cache *s) #endif } -static inline void *fixup_red_left(struct kmem_cache *s, void *p) +inline void *fixup_red_left(struct kmem_cache *s, void *p) { if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) p += s->red_left_pad; -- 2.8.0.rc3.226.g39d4020 -- 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