From: Xiubo Li <Li.Xiubo@freescale.com>
Date: Mon, 18 Aug 2014 09:08:44 +0000 (+0800)
Subject: pwm: Fix possible ZERO_SIZE_PTR pointer dereferencing error.
X-Git-Tag: v3.18-rc2~21^2~7
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=533acc0e8df7d6553f11cf91c177211cb6037968;p=karo-tx-linux.git

pwm: Fix possible ZERO_SIZE_PTR pointer dereferencing error.

Since we cannot make sure the 'chip->npwm' will always be none zero here,
and then if either equal to zero, the kzalloc() will return ZERO_SIZE_PTR,
which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling kzalloc().

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
---

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index d2c35920ff08..8c748b17f416 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -236,7 +236,7 @@ int pwmchip_add(struct pwm_chip *chip)
 	int ret;
 
 	if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
-	    !chip->ops->enable || !chip->ops->disable)
+	    !chip->ops->enable || !chip->ops->disable || !chip->npwm)
 		return -EINVAL;
 
 	mutex_lock(&pwm_lock);