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 d2c3592..8c748b1 100644 (file)
--- 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);