From: Xishi Qiu <qiuxishi@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>, <adech.fo@gmail.com>,
<rusty@rustcorp.com.au>, <mmarek@suse.cz>
Cc: Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>, <zhongjiang@huawei.com>
Subject: [PATCH] kasan: fix last shadow judgement in memory_is_poisoned_16()
Date: Tue, 8 Sep 2015 09:42:27 +0800 [thread overview]
Message-ID: <55EE3D03.8000502@huawei.com> (raw)
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 <qiuxishi@huawei.com>
---
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
next reply other threads:[~2015-09-08 1:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 1:42 Xishi Qiu [this message]
2015-09-08 9:36 ` [PATCH] kasan: fix last shadow judgement in memory_is_poisoned_16() Andrey Ryabinin
2015-09-08 9:49 ` Xishi Qiu
2015-09-08 9:52 ` Xishi Qiu
2015-09-08 10:05 ` Andrey Ryabinin
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