Re: [patch] mfd: vexpress: use after free in vexpress_syscfg_regmap_init()

[Pawel Moll <pawel.moll@arm.com>]

On Wed, 2014-06-11 at 07:07 +0100, Dan Carpenter wrote:
> We should return NULL if regmap_init() fails instead of continuing.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/misc/vexpress-syscfg.c b/drivers/misc/vexpress-syscfg.c
> index 73068e5..2c0ddb2 100644
> --- a/drivers/misc/vexpress-syscfg.c
> +++ b/drivers/misc/vexpress-syscfg.c
> @@ -231,10 +231,12 @@ static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
>  	func->regmap = regmap_init(dev, NULL, func,
>  			&vexpress_syscfg_regmap_config);
>  
> -	if (IS_ERR(func->regmap))
> +	if (IS_ERR(func->regmap)) {
>  		kfree(func);
> -	else
> -		list_add(&func->list, &syscfg->funcs);
> +		return NULL;
> +	}
> +
> +	list_add(&func->list, &syscfg->funcs);
>  
>  	return func->regmap;
>  }

Not really, no. What made you think so?

vexpress_config_bridge_ops.regmap_init should return an ERR_PTR in case
of troubles, not a NULL. See devm_regmap_init_vexpress_config() in
drivers/bus/vexpress-config.c:

        regmap = bridge->ops->regmap_init(dev, bridge->context);
        if (IS_ERR(regmap)) {                                

Pawel