Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] iio/scmi: check if dev is null pointer
To:     Jiasheng Jiang <jiasheng@iscas.ac.cn>, jbhayana@google.com,
        jic23@kernel.org
Cc:     linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1633674573-81211-1-git-send-email-jiasheng@iscas.ac.cn>
From:   Lars-Peter Clausen <lars@metafoo.de>
Message-ID: <d4ccc9c0-c852-1c40-d0a1-70298b6b34c2@metafoo.de>
Date:   Fri, 8 Oct 2021 11:01:42 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <1633674573-81211-1-git-send-email-jiasheng@iscas.ac.cn>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Precedence: bulk

On 10/8/21 8:29 AM, Jiasheng Jiang wrote:
> The parameter 'dev' of scmi_iio_dev_probe() isn't been
> checked before used, including when scmi_iio_dev_probe() is called.
> Therefore, it might be better to check, just in case.
>
> Fixes: 25cbdd4 ("iio/scmi: Port driver to the new scmi_sensor_proto_ops interface")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

Hi,

Thanks for the patch.

Is there anything that makes you think dev could ever be NULL? dev is a 
pointer to a field in `sdev`. So for `dev` to be NULL sdev would have to 
be `-offsetof(struct scmi_device, dev)`.


- Lars

> ---
>   drivers/iio/common/scmi_sensors/scmi_iio.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/iio/common/scmi_sensors/scmi_iio.c b/drivers/iio/common/scmi_sensors/scmi_iio.c
> index 141e8aa..d3ff985 100644
> --- a/drivers/iio/common/scmi_sensors/scmi_iio.c
> +++ b/drivers/iio/common/scmi_sensors/scmi_iio.c
> @@ -592,6 +592,9 @@ static int scmi_iio_dev_probe(struct scmi_device *sdev)
>   
>   	if (!handle)
>   		return -ENODEV;
> +
> +	if (!dev)
> +		return -ENODEV;
>   
>   	sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
>   	if (IS_ERR(sensor_ops)) {