From fefe1ed1398b81e3fadc92d11d91162d343c8836 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Sun, 13 May 2012 20:09:38 +0300
Subject: [PATCH] iommu: Fix off by one in dmar_get_fault_reason()

fault_reason - 0x20 == ARRAY_SIZE(irq_remap_fault_reasons) is
one past the end of the array.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Youquan Song <youquan.song@intel.com>
Cc: walter harms <wharms@bfs.de>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20120513170938.GA4280@elgon.mountain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 drivers/iommu/dmar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 5ef65cf66152..3a74e4410fc0 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1057,8 +1057,8 @@ static const char *irq_remap_fault_reasons[] =
 
 const char *dmar_get_fault_reason(u8 fault_reason, int *fault_type)
 {
-	if (fault_reason >= 0x20 && (fault_reason <= 0x20 +
-				     ARRAY_SIZE(irq_remap_fault_reasons))) {
+	if (fault_reason >= 0x20 && (fault_reason - 0x20 <
+					ARRAY_SIZE(irq_remap_fault_reasons))) {
 		*fault_type = INTR_REMAP;
 		return irq_remap_fault_reasons[fault_reason - 0x20];
 	} else if (fault_reason < ARRAY_SIZE(dma_remap_fault_reasons)) {