From: "zhenzhong.duan" <zhenzhong.duan@oracle.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: zhenzhong.duan@oracle.com, mingo@redhat.com, x86@kernel.org,
tglx@linutronix.de, hpa@zytor.com, Feng Jin <joe.jin@oracle.com>,
ethan.zhao@oracle.com, linux-kernel@vger.kernel.org
Subject: [PATCH v2] Fix an overflow in range_to_mtrr func
Date: Wed, 30 May 2012 12:52:15 +0800 [thread overview]
Message-ID: <4FC5A77F.6060505@oracle.com> (raw)
In-Reply-To: <CAE9FiQV1ckyhy+cWVZC+=rU9s2nrBO6qV0Yt5xkYuv_gS9ZSWQ@mail.gmail.com>
When boot on sun G5+ with 4T mem, see an overflow in mtrr cleanup as below.
*BAD*gran_size: 2G chunk_size: 2G num_reg: 10 lose cover RAM:
-18014398505283592M
This is because 1<<31 sign extended. Use 64bit constant to fix it.
Useful for mem larger than or equal to 4T.
-v2: Use 64bit constant instead of explicit type conversion as suggested
by Yinghai. Description updated too.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
---
arch/x86/kernel/cpu/mtrr/cleanup.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c
b/arch/x86/kernel/cpu/mtrr/cleanup.c
index ac140c7..853a4c6 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -266,7 +266,7 @@ range_to_mtrr(unsigned int reg, unsigned long
range_startk,
if (align > max_align)
align = max_align;
- sizek = 1 << align;
+ sizek = 1UL << align;
if (debug_print) {
char start_factor = 'K', size_factor = 'K';
unsigned long start_base, size_base;
-- 1.7.3
next prev parent reply other threads:[~2012-05-30 4:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-28 12:29 [PATCH] Fix an overflow in range_to_mtrr func Zhenzhong Duan
2012-05-29 17:18 ` Yinghai Lu
2012-05-30 4:52 ` zhenzhong.duan [this message]
2012-05-30 23:22 ` [tip:x86/urgent] x86, mtrr: Fix a type " tip-bot for zhenzhong.duan
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