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Date:   Sun, 14 May 2023 18:38:06 -0700
From:   Bjorn Andersson <andersson@kernel.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Andy Gross <agross@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-arm-msm@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] pinctrl: qcom: sc8180x: gracefully handle missing IO
 memory resource
Message-ID: <20230515013806.ag2rdswrhdhiahis@ripper>
References: <20230513113510.177666-1-krzysztof.kozlowski@linaro.org>
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In-Reply-To: <20230513113510.177666-1-krzysztof.kozlowski@linaro.org>
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On Sat, May 13, 2023 at 01:35:10PM +0200, Krzysztof Kozlowski wrote:
> If device was probed with incorrect DT or ACPI tables, the IO memory
> resource would be missing and driver would derefernce NULL pointer in
> sc8180x_pinctrl_add_tile_resources().  Add simplep check if IO memory
> resource was provided to silence Smatch warning:
> 
>   drivers/pinctrl/qcom/pinctrl-sc8180x.c:1664 sc8180x_pinctrl_add_tile_resources() error: potentially dereferencing uninitialized 'mres'.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Bjorn Andersson <andersson@kernel.org>

> ---
>  drivers/pinctrl/qcom/pinctrl-sc8180x.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-sc8180x.c b/drivers/pinctrl/qcom/pinctrl-sc8180x.c
> index 704a99d2f93c..2fabec096aae 100644
> --- a/drivers/pinctrl/qcom/pinctrl-sc8180x.c
> +++ b/drivers/pinctrl/qcom/pinctrl-sc8180x.c
> @@ -1630,7 +1630,8 @@ static const struct msm_pinctrl_soc_data sc8180x_acpi_pinctrl = {
>  static int sc8180x_pinctrl_add_tile_resources(struct platform_device *pdev)
>  {
>  	int nres_num = pdev->num_resources + ARRAY_SIZE(sc8180x_tiles) - 1;
> -	struct resource *mres, *nres, *res;
> +	struct resource *mres = NULL;
> +	struct resource *nres, *res;
>  	int i, ret;
>  
>  	/*
> @@ -1657,6 +1658,9 @@ static int sc8180x_pinctrl_add_tile_resources(struct platform_device *pdev)
>  			*res++ = *r;
>  	}
>  
> +	if (!mres)
> +		return -EINVAL;
> +
>  	/* Append tile memory resources */
>  	for (i = 0; i < ARRAY_SIZE(sc8180x_tiles); i++, res++) {
>  		const struct tile_info *info = &sc8180x_tile_info[i];
> -- 
> 2.34.1
>