linux-kernel - [PATCH] mfd: fix unintentional NULL check in menelaus_set

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Date:	Wed, 28 May 2014 15:33:50 +0200
From:	Emil Goode <emilgoode@...il.com>
To:	Samuel Ortiz <sameo@...ux.intel.com>,
	Lee Jones <lee.jones@...aro.org>,
	Jingoo Han <jg1.han@...sung.com>
Cc:	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
	Emil Goode <emilgoode@...il.com>
Subject: [PATCH] mfd: fix unintentional NULL check in menelaus_set_voltage()

The struct menelaus_vtg pointer vtg cannot be NULL here
so the condition is never true and if it ever was true
it would lead to a NULL pointer dereference when we goto
label set_voltage.

Before the below patch was applied the code was:

if (vtg == 0)

The intention was to check if vtg_val is 0.

commit 59a9f7a32adf6537b4e4db8ca204eeb77d7a634e
("mfd: menelaus: Use NULL instead of 0")

Signed-off-by: Emil Goode <emilgoode@...il.com>
---
Hello,

This is only build tested, it would be good to get a comment
from someone who is familiar with this code.

Found using coccinelle.

Best regards,

Emil Goode

 drivers/mfd/menelaus.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/menelaus.c b/drivers/mfd/menelaus.c
index ad25bfa..4859597 100644
--- a/drivers/mfd/menelaus.c
+++ b/drivers/mfd/menelaus.c
@@ -466,7 +466,7 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
 	struct i2c_client *c = the_menelaus->client;
 
 	mutex_lock(&the_menelaus->lock);
-	if (!vtg)
+	if (vtg_val == 0)
 		goto set_voltage;
 
 	ret = menelaus_read_reg(vtg->vtg_reg);
-- 
1.7.10.4

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