From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f178.google.com (mail-ob0-f178.google.com [209.85.214.178]) by kanga.kvack.org (Postfix) with ESMTP id 406986B0038 for ; Mon, 7 Sep 2015 21:47:04 -0400 (EDT) Received: by obqa2 with SMTP id a2so72002517obq.3 for ; Mon, 07 Sep 2015 18:47:04 -0700 (PDT) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com. [119.145.14.66]) by mx.google.com with ESMTPS id y3si1067157oie.0.2015.09.07.18.47.02 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 07 Sep 2015 18:47:03 -0700 (PDT) Message-ID: <55EE3D03.8000502@huawei.com> Date: Tue, 8 Sep 2015 09:42:27 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: [PATCH] kasan: fix last shadow judgement in memory_is_poisoned_16() Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Andrey Ryabinin , adech.fo@gmail.com, rusty@rustcorp.com.au, mmarek@suse.cz Cc: Linux MM , LKML , zhongjiang@huawei.com The shadow which correspond 16 bytes may span 2 or 3 bytes. If shadow only take 2 bytes, we can return in "if (likely(!last_byte)) ...", but it calculates wrong, so fix it. Signed-off-by: Xishi Qiu --- mm/kasan/kasan.c | 3 +-- 1 files changed, 1 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 7b28e9c..8da2114 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -135,12 +135,11 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) if (unlikely(*shadow_addr)) { u16 shadow_first_bytes = *(u16 *)shadow_addr; - s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK; if (unlikely(shadow_first_bytes)) return true; - if (likely(!last_byte)) + if (likely(IS_ALIGNED(addr, 8))) return false; return memory_is_poisoned_1(addr + 15); -- 1.7.1 -- 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