On Wed, Feb 1, 2012 at 10:40 AM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> Hello Javier Martinez Canillas,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 4065d1e7b216: "Input: add Cypress TTSP capacitive
> multi-touch screen support" from Jan 31, 2012, leads to the following
> Smatch complaint:
>
> drivers/input/touchscreen/cyttsp_core.c +526 cyttsp_probe()
> warn: variable dereferenced before check 'dev' (see line 521)
>
> drivers/input/touchscreen/cyttsp_core.c
> 520 {
> 521 const struct cyttsp_platform_data *pdata = dev->platform_data;
> ^^^^^
> dereference.
>
> 522 struct cyttsp *ts;
> 523 struct input_dev *input_dev;
> 524 int error;
> 525
> 526 if (!dev || !bus_ops || !pdata || !pdata->name || irq <= 0) {
> ^^^^
> check.
>
> 527 error = -EINVAL;
> 528 goto err_out;
>
> "dev" is never NULL here so the check can be removed probably.
>
> regards,
> dan carpenter
Hello Dan,
Thank you for running smatch on this driver.
dev is never NULL since both i2c and spi bus drivers pass as an
argument a pointer to a member of an previously allocated structure
(struct i2c_client and struct spi_device respectively).
But you are right that is wrong to check after dereferencing the
pointer. Instead of remove the !dev check I will move the pdata
assignment after the check. I'll send a patch now to fix the issue.
Thank you and best regards,
Javier
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