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* [PATCH] mfd: Fix fencepost error in reg cache access check
@ 2010-04-16 12:00 Phil Carmody
  2010-04-16 18:50 ` Mark Brown
  0 siblings, 1 reply; 2+ messages in thread
From: Phil Carmody @ 2010-04-16 12:00 UTC (permalink / raw)
  To: broonie, sameo; +Cc: linux-kernel

From: Phil Carmody <ext-phil.2.carmody@nokia.com>

Accessing num_reg elements in the interval [reg .. reg+num_regs)
is permitted if (reg+numregs <= array size), so barf when that
excluded upper bound is > array size. The prior -1 would give
access to one too many elements.

Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
---
 drivers/mfd/wm8400-core.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/wm8400-core.c b/drivers/mfd/wm8400-core.c
index 865ce01..e08aafa 100644
--- a/drivers/mfd/wm8400-core.c
+++ b/drivers/mfd/wm8400-core.c
@@ -118,7 +118,7 @@ static int wm8400_read(struct wm8400 *wm8400, u8 reg, int num_regs, u16 *dest)
 {
 	int i, ret = 0;
 
-	BUG_ON(reg + num_regs - 1 > ARRAY_SIZE(wm8400->reg_cache));
+	BUG_ON(reg + num_regs > ARRAY_SIZE(wm8400->reg_cache));
 
 	/* If there are any volatile reads then read back the entire block */
 	for (i = reg; i < reg + num_regs; i++)
@@ -144,7 +144,7 @@ static int wm8400_write(struct wm8400 *wm8400, u8 reg, int num_regs,
 {
 	int ret, i;
 
-	BUG_ON(reg + num_regs - 1 > ARRAY_SIZE(wm8400->reg_cache));
+	BUG_ON(reg + num_regs > ARRAY_SIZE(wm8400->reg_cache));
 
 	for (i = 0; i < num_regs; i++) {
 		BUG_ON(!reg_data[reg + i].writable);
-- 
1.6.0.4


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] mfd: Fix fencepost error in reg cache access check
  2010-04-16 12:00 [PATCH] mfd: Fix fencepost error in reg cache access check Phil Carmody
@ 2010-04-16 18:50 ` Mark Brown
  0 siblings, 0 replies; 2+ messages in thread
From: Mark Brown @ 2010-04-16 18:50 UTC (permalink / raw)
  To: Phil Carmody; +Cc: sameo, linux-kernel

On Fri, Apr 16, 2010 at 03:00:09PM +0300, Phil Carmody wrote:
> From: Phil Carmody <ext-phil.2.carmody@nokia.com>
> 
> Accessing num_reg elements in the interval [reg .. reg+num_regs)
> is permitted if (reg+numregs <= array size), so barf when that
> excluded upper bound is > array size. The prior -1 would give
> access to one too many elements.

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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