Re: [PATCH] pinctrl: berlin: fix 'pctrl->functions' allocation in berlin_pinctrl_build_state

From: Jisheng Zhang
Date: Tue Jul 31 2018 - 22:39:23 EST


Hi,

On Tue, 31 Jul 2018 22:25:01 +0800 YueHaibing wrote:

> fixes following Smatch static check warning:
>
> drivers/pinctrl/berlin/berlin.c:237 berlin_pinctrl_build_state()
> warn: passing devm_ allocated variable to kfree. 'pctrl->functions'
>
> As we will be calling krealloc() on pointer 'pctrl->functions', which means
> kfree() will be called in there, devm_kzalloc() shouldn't be used with
> the allocation in the first place. Fix the warning by calling kcalloc()
> and managing the free procedure in error path on our own.

Good catch. Comments below.

>
> Fixes: 3de68d331c24 ("pinctrl: berlin: add the core pinctrl driver for Marvell Berlin SoCs")
> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
> ---
> drivers/pinctrl/berlin/berlin.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pinctrl/berlin/berlin.c b/drivers/pinctrl/berlin/berlin.c
> index d6d183e..db2afb2 100644
> --- a/drivers/pinctrl/berlin/berlin.c
> +++ b/drivers/pinctrl/berlin/berlin.c
> @@ -216,10 +216,8 @@ static int berlin_pinctrl_build_state(struct platform_device *pdev)
> }
>
> /* we will reallocate later */
> - pctrl->functions = devm_kcalloc(&pdev->dev,
> - max_functions,
> - sizeof(*pctrl->functions),
> - GFP_KERNEL);
> + pctrl->functions = kcalloc(max_functions,
> + sizeof(*pctrl->functions), GFP_KERNEL);
> if (!pctrl->functions)
> return -ENOMEM;
>
> @@ -257,8 +255,10 @@ static int berlin_pinctrl_build_state(struct platform_device *pdev)
> function++;
> }
>
> - if (!found)
> + if (!found) {
> + kfree(function);

is it enough to just free one function? I think we need to free functions.

> return -EINVAL;
> + }
>
> if (!function->groups) {
> function->groups =
> @@ -267,8 +267,10 @@ static int berlin_pinctrl_build_state(struct platform_device *pdev)
> sizeof(char *),
> GFP_KERNEL);
>
> - if (!function->groups)
> + if (!function->groups) {
> + kfree(function);

ditto

> return -ENOMEM;
> + }
> }
>
> groups = function->groups;