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

Pawel Moll
2014-06-11T09:22:31Z

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