Re: [PATCH] pinctrl: imx: make sure that maps are fully initialized

[Leonard Crestez]

On 11/10/18 7:37 PM, Martin Kaiser wrote:
> The commit that added scu based pinctrl support introduced a regression
> for the mmio case. In the for-loop where the maps are initialized, we
> end up creating a partially initialized map in some cases. This causes a
> kernel panic when such a map is used at a later stage.
> 
> Fixes: b96eea718bf6 ("pinctrl: fsl: add scu based pinctrl support")
> Cc: A.s. Dong <aisheng.dong@xxxxxxx>

> diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
> @@ -108,9 +108,6 @@ static int imx_dt_node_to_map(struct pinctrl_dev *pctldev,
>   	new_map++;
>   	for (i = j = 0; i < grp->num_pins; i++) {
>   		pin = &((struct imx_pin *)(grp->data))[i];
> -		new_map[j].type = PIN_MAP_TYPE_CONFIGS_PIN;
> -		new_map[j].data.configs.group_or_pin =
> -					pin_get_name(pctldev, pin->pin);
>   
>   		if (info->flags & IMX_USE_SCU) {
>   			/*
> @@ -126,7 +123,12 @@ static int imx_dt_node_to_map(struct pinctrl_dev *pctldev,
>   			new_map[j].data.configs.num_configs = 1;
>   		}
>   
> -		j++;
> +		if (new_map[j].data.configs.num_configs) {
> +			new_map[j].type = PIN_MAP_TYPE_CONFIGS_PIN;
> +			new_map[j].data.configs.group_or_pin =
> +				pin_get_name(pctldev, pin->pin);
> +			j++;
> +		}

Sorry but I don't think this is correct.

The new_map array is allocated with kmalloc_array so we can't rely on 
new_map[j].data.configs.num_configs being initialized to zero unless 
assigned to.

I was looking at the ssue before I saw your patch and posted an 
different fix. I can't find a give link right now, it takes a while to 
show up in public archives.